- Palladium-Catalyzed Decarbonylation of Amino Acid Derivatives via C-C Bond and C-N Bond Dual Activations
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A unique decarbonylation of an amino acid derivative catalytic system has been established via palladium-catalyzed C-C bond and C-N bond dual activations. By employing 8-aminoquinoline as the directing group, this transformation has been found to facilitate the high chemoselectivity to decarbonylation of amino acid derivatives rather than intramolecular deamination or cross-dehydrogenative coupling reactions. This method provides a straightforward avenue for constructing diverse functionalized amide compounds in good to excellent yields. We proposed a possible reaction pathway that may go through the C-C bond and C-N bond dual activations on the basis of the mechanistic studies.
- Deng, Gongtao,Jiang, Yaojia,Jiao, Yongjuan,Li, Yingmei,Wu, Jiamin,Zhang, Jinli,Zhang, Zhengyu
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p. 17462 - 17470
(2021/12/02)
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- Synthesis of new amides based on N-Phthaloyl-α-Amino Acids
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N-phthaloyl derivatives of aliphatic α-amino acids were synthesized using phthalanhydride under standard conditions. The optimization reaction carried out by the thermal method to obtain the amides of these N-phthaloyl amino acids resulted in transimitted rather than amidation. The target amides of N-phthaloyl-α-amino acids were obtained by acylation of the amine with the corresponding acid chloroanhydrides in dichloromethane. These results were compared with the results of a similar acylation in a non-polar solvent (benzene). The dependence of the direction of the reaction on the duration of the acylation and the amount of amine used was established. The conditions for the formation of the corresponding N-phthaloyl-α-amino acid amides and asymmetric phthalic acid diamides were found. It is noteworthy that the formation of diamides is directly proportional to the equivalent amount of amine and the duration of the reaction, which makes it possible to purposefully control the synthesis in one reactor.
- Tukhtaev,Yusupov,Vinogradova
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p. 3049 - 3058
(2021/05/28)
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- General Access to Modified α-Amino Acids by Bioinspired Stereoselective γ-C?H Bond Lactonization
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α-Amino acids represent a valuable class of natural products employed as building blocks in biological and chemical synthesis. Because of the limited number of natural amino acids available, and of their widespread application in proteomics, diagnosis, drug delivery and catalysis, there is an increasing demand for the development of procedures for the preparation of modified analogues. Herein, we show that the use of bioinspired manganese catalysts and H2O2 under mild conditions, provides access to modified α-amino acids via γ-C?H bond lactonization. The system can efficiently target 1°, 2° and 3° γ-C?H bonds of α-substituted and achiral α,α-disubstituted α-amino acids with outstanding site-selectivity, good to excellent diastereoselectivity and (where applicable) enantioselectivity. This methodology may be considered alternative to well-established organometallic procedures.
- Vicens, Laia,Bietti, Massimo,Costas, Miquel
-
supporting information
p. 4740 - 4746
(2020/12/25)
-
- A Novel Class of 7-Membered Heterocyclic Compounds
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The work presented herein describes the synthesis of a formerly inaccessible class of heterocyclic compounds. The reaction relies on α-phthalimido-amides, which are readily prepared from amino acids in 2 simple reactions steps. Under amide activation conditions in which classical keteniminium ions are not formed, the nitrile solvent is incorporated into the new fused 7-membered ring system. Due to the absence of a keteniminium intermediate, the stereogenic information in the α-position is fully retained.
- Bauer, Adriano,Borsos, Eszter,Maulide, Nuno
-
supporting information
p. 3971 - 3974
(2020/05/25)
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- Tetrasubstituted Furans by Nucleophile-Induced Cleavage of Carbonyl Ylide-DMAD Cycloadducts
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Compounds incorporating a 4-aza-8-oxabicyclo[3.2.1]oct-6-en-2-one moiety, which were prepared by a tandem carbenoid carbonyl ylide cyclization/[3+2]-cycloaddition reaction from ethyl 2-diazo-3-oxo-4-phthalimidobutanoates, undergo a nucleophile-induced two-bond ring cleavage when treated with protic heteronucleophiles. In this manner, tetrasubstituted furantricarboxylates, tethered with α-amino acids, esters, thioesters, and amides by a 2-carbonylphenyl moiety, are obtained.
- Dobesch, Matthias,Greiner, Julian,Maas, Gerhard
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p. 2987 - 3000
(2020/08/10)
-
- AMINO ACID DERIVATIVES FOR THE TREATMENT OF INFLAMMATORY DISEASES
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The present disclosure provides certain amino acid derivatives that inhibit NF-kB activation and are therefore useful for the treatment of inflammatory diseases. Also provided are pharmaceutical compositions containing such compounds and processes for preparing such compounds.
- -
-
Page/Page column 33
(2020/08/13)
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- Electrochemical C(sp 3)-H Fluorination
-
A simple and robust method for electrochemical alkyl C-H fluorination is presented. Using a simple nitrate additive, a widely available fluorine source (Selectfluor), and carbon-based electrodes, a wide variety of activated and unactivated C-H bonds are converted into their C-F congeners. The scalability of the reaction is also demonstrated with a 100 gram preparation of fluorovaline.
- Baran, Phil S.,Chen, Longrui,Chen, Miao,Hoshikawa, Tamaki,Kawamata, Yu,Li, Chao,Mykhailiuk, Pavel,Nakamura, Hugh,Peters, Byron K.,Reisberg, Solomon H.,Shibuguchi, Tomoyuki,Takahira, Yusuke
-
supporting information
p. 1178 - 1182
(2019/06/08)
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- Efficient Kinetic Resolution of Sulfur-Stereogenic Sulfoximines by Exploiting CpXRhIII-Catalyzed C?H Functionalization
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Chiral sulfoximines with stereogenic sulfur atoms are promising motifs in drug discovery. We report an efficient method to access chiral sulfoximines through a C?H functionalization based kinetic resolution. A rhodium(III) complex equipped with a chiral Cpx ligand selectively participates in conjunction with phthaloyl phenylalanine in the C?H activation of just one of the two sulfoximine enantiomers. The intermediate reacts with various diazo compounds, providing access to chiral 1,2-benzothiazines with synthetically valuable substitution patterns. Both sulfoximines and 1,2-benzothiazines were obtained in high yields and excellent enantioselectivity, with s-values of up to 200. The utility of the method is illustrated by the synthesis of the key intermediates of two pharmacologically relevant kinase inhibitors.
- Brauns, Marcus,Cramer, Nicolai
-
supporting information
p. 8902 - 8906
(2019/06/04)
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- Amino acid chiral ligand containing bidentate coordination group, chiral catalyst, and corresponding preparation methods and applications thereof
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The present invention relates to an amino acid chiral ligand containing a bidentate coordination group, a chiral catalyst, and corresponding preparation methods and applications thereof. The chiral ligand is prepared from a cheap and easily available amino acid, and the development of the chiral ligand can improve the diversity of the chiral ligand. The chiral Ir (III) catalyst is simply and efficiently prepared from the chiral ligand only through a one-step reaction. The chiral Ir (III) catalyst is characterized in that a bidentate guiding group is introduced to an amino acid framework to change the original coordination mode of the amino acid and Ir in order to enhance the chiral control ability of the amino acid to the Ir(III) catalyst. The chiral Ir(III) catalyst is designed and synthesized for the first time, and the selectivity reaches up to 99% ee when the catalyst is successfully applied to the high-efficiency asymmetric synthesis of chiral gamma-cyclolactam, so the catalyst has superior stereo control ability.
- -
-
Paragraph 0073
(2019/10/02)
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- Oxidative Damage in Aliphatic Amino Acids and Di- and Tripeptides by the Environmental Free Radical Oxidant NO3?: the Role of the Amide Bond Revealed by Kinetic and Computational Studies
-
Kinetic and computational data reveal a complex behavior of the important environmental free radical oxidant NO3? in its reactions with aliphatic amino acids and di- and tripeptides, suggesting that attack at the amide N-H bond in the peptide backbone is a highly viable pathway, which proceeds through a proton-coupled electron transfer (PCET) mechanism with a rate coefficient of about 1 × 106 M-1 s-1 in acetonitrile. Similar rate coefficients were determined for hydrogen abstraction from the α-carbon and from tertiary C-H bonds in the side chain. The obtained rate coefficients for the reaction of NO3? with aliphatic di- and tripeptides suggest that attack occurs at all of these sites in each individual amino acid residue, which makes aliphatic peptide sequences highly vulnerable to NO3?-induced oxidative damage. No evidence for amide neighboring group effects, which have previously been found to facilitate radical-induced side-chain damage in phenylalanine, was found for the reaction of NO3? with side chains in aliphatic peptides.
- Nathanael, Joses G.,Wille, Uta
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p. 3405 - 3418
(2019/03/11)
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- Synthesis and study of modified polyvinyl alcohol containing amino acid moieties as anticancer agent
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A series of new phthalimides compounds[3-7]a-i were synthesized from reaction of Malic anhydride, phthalic anhydride, nitro phthalic anhydride, 2-phenyl-4H-benzo[d][1,3]oxazin-4-one, 2-(4-nitrophenyl)-4H-benzo[d][1,3]oxazin-4-one with different amino acids as glycine, alanine, valine, leucine, isoleucine, serine, threonine, tyrosine and Phenyl alanine [1]a-i under fusion conditions. Compounds [3-7]a-i react with SOCl2 in the presence of benzene to produce compounds [8-12]a-i. Chemical modification of Poly(vinyl alcohol)were obtained by reaction of PVA with compounds [8-12]a-i using the dimethyl formamide to give compounds [13-17]a-i. The structure of the synthesized compounds was characterized by their analytical and spectral data as, IR spectra, 1H, 13C-NMR, Elemental analysis (CHN), UV-Vis Spectroscopy, Scanning electron microscopy (SEM), Antibacterial activity were screened via two kinds of bacteria. Also, anticancer activity were examined for most of the modified polyvinyl alcohol.
- Samir, Ali H.,Saeed, Ruwaidah S.,Matty, Fadhel S.
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p. 286 - 294
(2018/03/21)
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- Synthesis of Quaternary α-Fluorinated α-Amino Acid Derivatives via Coordinating Cu(II) Catalytic α-C(sp3)-H Direct Fluorination
-
A coordinating, copper-catalyzed direct α-C(sp3)-H fluorination method has been developed to prepare vital quaternary α-fluorinated α-amino acid derivatives. A Cu(II) catalytic SET oxidative addition mechanism is proposed, involving a key fluoride-coupled Cu(II) charge transfer complex. The protocol can tolerate a rich variety of α-amino acids, for which the auxiliary group is removed in high yield and substituted for the direct preparation of dipeptide derivatives with detachable, single absolute configurations of the target compounds.
- Wei, Qiang,Ma, Yao,Li, Li,Liu, Qingfei,Liu, Zijie,Liu, Gang
-
supporting information
p. 7100 - 7103
(2018/11/24)
-
- Dehydration of Amides to Nitriles under Conditions of a Catalytic Appel Reaction
-
A highly expedient protocol for a catalytic Appel-type dehydration of amides to nitriles has been developed that employs oxalyl chloride and triethylamine along with triphenylphosphine oxide as a catalyst. The reactions are usually complete in less than 10 min with only a 1 mol % catalyst loading. The reaction scope includes aromatic, heteroaromatic, and aliphatic amides, including derivatives of α-hydroxy and α-amino acids.
- Shipilovskikh, Sergei A.,Vaganov, Vladimir Yu.,Denisova, Elena I.,Rubtsov, Aleksandr E.,Malkov, Andrei V.
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supporting information
p. 728 - 731
(2018/02/09)
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- 3-Amino-1-methyl-1 H-pyridin-2-one-Directed PdII Catalysis: C(sp3)-H Activated Diverse Arylation Reaction
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A new bidentate directing group, 3-amino-1-methyl-1H-pyridin-2-one, is introduced to achieve a powerful PdII metallacycle for selective γ-C(sp3)-H activation and arylation of aromatic and aliphatic carboxylic acid derivatives. The versatility of the directing group is validated for remote arylation of β-C(sp3)-H, β-C(sp2)-H, and γ-C(sp2)-H to achieve therapeutically important 2-pyridone analogues and arylated acid synthons. The traceless removal of the directing group to retrieve the directing element and carboxylic acids makes this method more interesting.
- Pati, Tanmay K.,Debnath, Sudipto,Kundu, Mrinalkanti,Khamrai, Uttam,Maiti, Dilip K.
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supporting information
p. 4062 - 4066
(2018/07/15)
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- Chiral sensors for determining the absolute configurations of α-amino acid derivatives
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A simple strategy for configurational assignments of alpha-amino acids has been developed by comparison of the proton NMR chemical shift values of the alpha hydrogens of N-phthaloyl protected alpha-amino acids in the presence of (R)-CSA 1 and (S)-CSA 1, respectively. Highly resolved NMR spectra can be obtained directly on the mixed solution of the chiral solvating agents with N-phthaloyl protected alpha-amino acids in NMR tubes, giving well distinguishable proton signals without interference which dramatically improve the accuracy of assignment and hasten the assigning procedure. The strategy is widely applicable for varied natural and non-natural amino acids.
- Chen, Zhongxiang,Fan, Hongjun,Yang, Shiwei,Bian, Guangling,Song, Ling
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p. 6933 - 6939
(2018/10/02)
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- Cooperative Effects between Chiral Cpx–Iridium(III) Catalysts and Chiral Carboxylic Acids in Enantioselective C?H Amidations of Phosphine Oxides
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An enantioselective C?H amidation of phosphine oxides by using an iridium(III) catalyst bearing an atropchiral cyclopentadienyl (Cpx) ligand is reported. A very strong cooperative effect between the chiral Cpx ligand and a phthaloyl tert-leucine enabled the transformation. Matched–mismatched cases of the different acid enantiomers are shown. The amidated P-chiral arylphosphine oxides are formed in yields of up to 95 % and with excellent enantioselectivities of up to 99:1 er. Enantiospecific reduction provides access to valuable P-chiral phosphorus(III) compounds.
- Jang, Yun-Suk,Dieckmann, Michael,Cramer, Nicolai
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supporting information
p. 15088 - 15092
(2017/10/11)
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- Chelation-Assisted Palladium-Catalyzed γ-Arylation of Aliphatic Carboxylic Acid Derivatives
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A palladium(II)-catalyzed protocol for the highly regioselective remote γ-C–H arylation of aliphatic carboxylic acid has been disclosed. The 8-aminoquinoline moiety as an intramolecular bidentate chelator was found to be suitable for this γ-C–H arylation. Various aryl iodides successfully produced the regioselectively mono-arylated products with negligible diarylation. Functional group tolerance and easy-to-handle reaction conditions make this method attractive. (Figure presented.).
- Dey, Aniruddha,Pimparkar, Sandeep,Deb, Arghya,Guin, Srimanta,Maiti, Debabrata
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supporting information
p. 1301 - 1307
(2017/04/18)
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- 1,2-Hydride Migration in Dialkyl α-Diazophosphonates Catalyzed by [Cu(MeCN)4]PF6: A Novel Approach to β-Amino (E)-Enylphosphonates
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The regiospecific and stereoselective 1,2-migration reaction of dialkyl α-diazophosphonates for the synthesis of β-amino (E)-enylphosphonates is developed utilizing tetrakis(acetonitrile)copper(I) hexafluorophosphate [Cu(MeCN)4PF6] as the catalyst and N,N-dimethylformamide as an additive. A possible mechanism for the 1,2-migration reaction involving a metal carbene is presented. An investigation on the E/Z isomer selectivity of this process demonstrates that steric factors play an important role on the outcome. This process provides a straightforward access to β-amino (E)-enylphosphonates in moderate to good yields.
- Ge, Haihong,Liu, Shuang,Cai, Yan,Sun, Yuchao,Miao, Zhiwei
-
supporting information
p. 448 - 454
(2016/01/28)
-
- Direct, visible light-sensitized benzylic C[sbnd]H fluorination of peptides using dibenzosuberenone: selectivity for phenylalanine-like residues
-
A visible light-sensitized benzylic sp3C[sbnd]H fluorination protocol using dibenzosuberenone (5?mol?%) and Selectfluoris optimized for the direct functionalization of phenylalanine-like residues in short chain peptides. Amino acids, dipeptides, and tripeptides undergo benzylic fluorination with remarkable regioselectivity in the presence of protected basic, acidic, and nonpolar side chains (including those with tertiary sites). Additionally, protecting group compatibility, a gram scale application, and competition experiments were explored.
- Bume, Desta Doro,Pitts, Cody Ross,Jokhai, Rayyan Trebonias,Lectka, Thomas
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supporting information
p. 6031 - 6036
(2016/09/16)
-
- Chiral Pool-Based Synthesis of Naphtho-Fused Isocoumarins
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A variety of chiral derivatives of benzo[d]naphtho[1,2-b]pyran-6-one were prepared in a single step by Et3N-mediated condensation of homophthalic anhydride with different derivatives of (S)-amino acid chlorides at -5 °C by employing a chiral pool methodology. Chirality 27:951-957, 2015.
- Raza, Abdul Rauf,Saddiqa, Aisha,?akmak, Osman
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p. 951 - 957
(2015/11/16)
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- Trifluoroborane-catalyzed C-H functionalization/S-H insertion reaction: Construction of N,S-acetal quaternary centers
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Abstract The trifluoroborane-catalyzed C-H functionalization/S-H insertion reaction of α-diazophosphonates with thiols has been developed. A plausible reaction mechanism has been proposed to understand the combined reaction. This process provides straightforward access to N,S-acetals containing quaternary centers in moderate to good yields and chemoselectivity.
- Cai, Yan,Ge, Haihong,Sun, Weize,Miao, Zhiwei
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supporting information
p. 1669 - 1677
(2015/06/02)
-
- Prodrugs of neuraminidase inhibitors
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A new class of neuramidase inhibitor prodrugs is provided characterized by a prodrug moiety of a carboxyl group modified to form a carbonyl ethoxy amino acid, a carbonyl ethoxy dipeptide or a carbonyl ethoxy tripeptide, a guanidine group modified to form a carbonyl ethoxy amino acid, a carbonyl ethoxy dipeptide, a carbonyl ethoxy tripeptide; a primary alcohol modified to form an esterified single amino acid, dipeptide or tripeptide of zanavimir of the unaltered therapeutic agent. Exemplary therapeutic agents so modified to form prodrugs include zanavimir, oseltamivir and peramivir. The prodrug has increased oral bioavailability relative to the unaltered neuraminidase inhibitor and is effective in the inhibition of viral infections involving neuraminidase in the viral reproductive cycle.
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Page/Page column 23; 24
(2015/12/01)
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- Chiron based synthesis of isocoumarins: Reactivity of α-substituted carboxylic acids
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The asymmetric synthesis of a novel (S)-isocoumarin has been attempted in a single step by the coupling of homophthalic acid with (S)-N-protected amino acids and α-chloroacids at high temperature by exploiting a chiral pool methodology. The coupling of homophthalic acid with N-protected (S)-amino acids gave exclusion of the carboxyl/alkyl group. However, coupling of homophthalic acid with α-chloroacids afforded asymmetric isocoumarins in high yield.
- Saddiqa, Aisha,Raza, Abdul R.,Black, David Stc.,Kumar, Naresh
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p. 736 - 743
(2014/06/09)
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- Phthaloyl amino acids as anti-inflammatory and immunomodulatory prototypes
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A series of phthalimide analogs were synthesized by derivatization of phthalic anhydride, a highly toxic substance, using a "one pot" condensation reaction to α-amino acids. All phthaloyl amino acid derivatives presented anti-oral inflammatory activity, but compounds 2e and 2g were found to possess the best activities comparable to thalidomide.Most of the compounds effectively suppressed nitric oxide production inmurine cells stimulatedwith lipopolysaccharide. N-phthaloyl amino acids did not exhibit any significant cytotoxicity in vitro when tested against tumor cells as well as a spleen cell culture of BALB/c mice. Compounds 2a, 2g, and 2h were able to inhibit TNF-α and IL-1β production by macrophages. At the same concentration, thalidomide did not exhibit significant inhibitory activity. Springer Science+Business Media 2013.
- Leite, Ana Cristina Lima,Barbosa, Fabio Fernandes,Cardoso, Marcos Verissimo De Oliveira,Moreira, Diogo R. M.,Coelho, Lucas Cunha D.,Da Silva, Elany Barbosa,Filho, Gevanio Bezerra De Oliveira,De Souza, Valdenia Maria Oliveira,Pereira, Valeria Rego A.,Reis, Luiza De C.,Ferreira, Paulo Michel Pinheiro,Pessoa, Claudia,Wanderley, Almir Goncalves,Mota, Fernanda Virginia B.,Da Silva, Teresinha G.
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p. 1701 - 1708
(2014/05/06)
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- Unexpected stereoselective synthesis of (Z)-β-alkenyl substituted β-amino phosphonates through β,γ-dihydrogen shift reaction catalyzed by a copper(I) complex and iodine [Cu(MeCN)4]PF 6/I2
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A series of dialkyl a-diazophosphonates has been prepared from natural amino acids. The diazo decomposition of these diazophosphonate compounds with tetrakis(acetonitrile)copper(I) hexafluorophosphate/iodine, [Cu(MeCN) 4]PF6/I2, as catalyst has been investigated. It was found that the diazo decomposition of dialkyl a-diazophosphonates gave a mixture of β,γ-dihydrogen shift and 1,2-hydride migration products and afforded β-alk- enyl-substituted β-amino phosphonates with the Z configuration. The mechanism of this novel diazo decomposition process was discussed.
- Cai, Yan,Lyu, Hairong,Yu, Chengbin,Miao, Zhiwei
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supporting information
p. 596 - 602
(2014/05/20)
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- Use of a readily removable auxiliary group for the synthesis of pyrrolidones by the palladium-catalyzed intramolecular amination of unactivated γ C(sp3)-H Bonds
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Easy on, easy off: Directing groups found to promote the palladium-catalyzed amination of γ C(sp3)-H and C(sp 2)-H bonds of secondary amides included 5-methoxy-8-aminoquinoline, which can be removed under mild conditions (see scheme; CAN=ceric ammonium nitrate). In conjunction with a β-C-H methylation or γ-C-H arylation step, the γ-C(sp3)-H amination provided access to complex pyrrolidones from readily available precursors. Copyright
- He, Gang,Zhang, Shu-Yu,Nack, William A.,Li, Qiong,Chen, Gong
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supporting information
p. 11124 - 11128
(2013/10/22)
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- Effect of different acids addition on chiral separation of phthalylvaline by quinine carbamate based chiral stationary
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The quinine carbamate type chiral stationary phase used for direct enantiomer separation of amino acid was studied. The influence of mobile phase composition, methanol and different acids were systematically investigated to gain an insight into the overall chiral recognition mechanism.
- Fegas, Rachid,Zerkout, Said,Taberkokt, Meriem,Bettache, Zhor,Righezza, Michel
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p. 6953 - 6956
(2013/07/26)
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- Antioxidant activity of new aramide nanoparticles containing redox-active N-phthaloyl valine moieties in the hepatic cytochrome P450 system in male rats
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We report the synthesis of aramide nanoparticles containing a chiral N-phthaloyl valine moiety and their antioxidant activities on hepatic contents of cytochrome P450, amidopyrene N-demethylase, aniline-4-hyroxylase and induced the hepatic content of cytochrome b5 and nicotinamide adenine dinucleotide phosphate (NADPH) cytochrome C-reductase. Polymers were obtained as well-separated spherical nanoparticles while highly aggregated particles via H-bonding organization of the aramide-containing pyridine led to a thin layer formation. The effects of the nanoparticles and CCl4 on enzyme activities and thiobarbituric acid reactive substances (TBARS) levels of male rat liver were studied. Pretreatments of rats with the polyamides prior to the administration of CCl4 decreased the hepatic content of the tested enzymes. Doses reduced the toxic effects exerted by (CCl3) upon the liver through inhibition of the cytochrome P450 system. Inhibition of such metabolizing enzymes could reduce the carcinogenic effects of chemical carcinogens.
- Hassan, Hammed H.A.M.,El-Banna, Sabah G.,Elhusseiny, Amel F.,Mansour, El-Sayed M.E.
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experimental part
p. 8255 - 8275
(2012/10/18)
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- Acylative kinetic resolution of racemic heterocyclic amines using N-phthaloyl-(S)-amino acyl chlorides with alkyl side chains
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A comparative study of the acylative kinetic resolution of racemic 2-methyl-1,2,3,4 tetrahydroquinoline and 3,4-dihydro-3-methyl-2H-[1,4] benzoxazine using N-phthaloyl-(S)-amino acyl chlorides with alkyl side chains has been carried out. The influence of steric factors on the stereoselectivity of the acylation was demonstrated. The (S)-enantiomers of the heterocyclic amines (ee >99%) were obtained in good yields via a kinetic resolution protocol using N-phthaloyl-(S)-leucyl chloride.
- Gruzdev, Dmitry A.,Levit, Galina L.,Krasnov, Victor P.
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p. 1640 - 1646
(2013/02/23)
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- Hydrogen bonding chains and rings structural motifs in new series of N-phthaloyl aminocarboxylic acid derivatives. Solid state microwave synthesis, structural chemistry, computational calculations and antimicrobial activity
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A series of six N-phthaloyl aminocarboxylic acids were synthesized by using improved microwave irradiation with a multimode reactor. X-ray single crystal diffraction established the molecular structure of three N-protected aminocarboxylic acids derivatives, and spectral data agree with these in solution. The hydrogen bonding characteristics of this class of molecules are discussed on the basis of crystal structural analyses, MP2/DFT quantum calculations and Hirshfeld surfaces analyses. The relative strengths of the structural O-H?O and C-H?O hydrogen bonding chain and ring motifs are compared. Antimicrobial activities of 2-(1,3-dioxoisoindolin-2-yl)propanoic acid, 2-(1,3-dioxoisoindolin-2-yl)-3-phenylpropanoic acid and 2-(4-(1,3-dioxoisoindolin-2-yl)phenyl)acetic acid, were screened against three pathogenic strains; only the first two compounds were found to be quite sensitive against Gram +ve and Gram -ve bacterial strains, respectively. A relative structure-function relationship is observed.
- Al-Farhan, Khalid,Ghazzali, Mohamed,Al-Hazimi, Hassan M.A.,El-Faham, Ayman,Reedijk, Jan
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scheme or table
p. 269 - 275
(2011/08/03)
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- Chiral calcium catalysts for asymmetric hydroamination/cyclisation
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Calcium complexes supported by chiral 1,2-diamines have been shown to be efficient catalysts for the asymmetric hydroamination of amino-olefin substrates; the calcium complexes [Ca(NNR){N(SiMe3) 2}(THF)] (R = tBu, iPr, Ph, 4-C 6H4F) give enantioselectivities of up to 26% which marks a significant increase based upon literature precedence. The structure of [Ca(NNPh){N(SiMe3)2}(py)] has been computed with density functional methods.
- Wixey, James S.,Ward, Benjamin D.
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supporting information; experimental part
p. 5449 - 5451
(2011/06/28)
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- Synthesis of biodegradable chiral poly(ester-imide)s derived from valine-, leucine- and tyrosine-containing monomers
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The present demand for a drastic reduction in environmental pollution is extended to qualitative change in the approach to development of biodegradable polymers. The aim of this article is to focus on the synthesis of biodegradable optically active poly(ester-imide)s (PEI)s, which compose of different amino acids in the main chain as well as in the side chain. These polymers were synthesized by polycondensation of diacid monomers such as 5-(2-phthalimidyl-3- methyl butanoylamino) isophthalic acid (1), 5-(4-methyl-2-phthalimidyl pentanoylamino)isophthalic acid (2) with N,N0-(pyromellitoyl)-bis-L-tyrosine dimethyl ester (3) as a phenolic diol. The direct polycondensation reaction was carried out in a system of tosyl chloride, pyridine and N,N-dimethylformamide as a condensing agent under conventional heating conditions. The optically active PEIs were obtained in good yield and moderate inherent viscosity. The synthesized polymers were characterized by means of FT-IR, 1H-NMR, elemental and thermo gravimetric analysis techniques. In addition, in vitro toxicity and soil burial test were employed for assessing the sensitivity of these compounds to microbial degradation. To this purpose, biodegradability behavior of the monomers and polymers were investigated in culture media and soil condition. The results of this study revealed that synthesized monomers and their derived polymers are biologically active and probably microbiologically biodegradable. Springer-Verlag 2010.
- Mallakpour, Shadpour,Asadi, Parvin,Sabzalian, Mohammad R.
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scheme or table
p. 1215 - 1222
(2012/03/27)
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- Effect of the mobile phase acid additives on enantioselectivity of amino acid derivative using quinine carbamate based chiral stationary phase
-
Quinine carbamate-type chiral stationary phase has been used for the direct liquid chromatographic enantiomer separation of a wide range of chiral acids. In the present work, we demonstrate that this the chiral stationary phase can also be extended to chiral discrimination of amino acid derivative phthalylvalin using methanol containing different organic acids in mobile phases. The influence of mobile phase composition and enantioselectivity was systematically investigated to gain insight into the overall chiral recognition mechanism.
- Fegas,Bensalem,Bettache,Ouahba,Righezza
-
body text
p. 1582 - 1586
(2012/04/10)
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- Catalytic asymmetric protonation of α-amino acid-derived ketene disilyl acetals using P -Spiro diaminodioxaphosphonium barfates as chiral proton
-
Chiral diaminodioxaphosphonium salts have been developed and their unique abilities as a chiral proton have been revealed through the establishment of a highly enantioselective protonation of α-amino acid-derived ketene disilyl acetals.
- Uraguchi, Daisuke,Kinoshita, Natsuko,Ooi, Takashi
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supporting information; experimental part
p. 12240 - 12242
(2010/11/19)
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- AmIno Acid Homologation by the Blaise Reaction: A new entry into nitrogen heterocycles
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(Chemical Equation Presented) A general strategy for the amino acid homologation via Blaise reaction and subsequent reduction is presented. This strategy involves the preparation of protected α-amino nitriles from the corresponding amino acids, followed by the zinc-mediated condensation of tert-butyl bromoacetate, to give the imidazolidones after iminozincate cyclization. Reduction gave the saturated imidazolidinones with cis or trans stereochemistry, depending on the reduction conditions. This strategy was applied to nonfunctionalized amino acids and to functionalized amino acids such as serine and aspartic acid. Additionally, acidic hydrolysis of cis or trans imidazolidinones to the corresponding chiral 4-aminopyrrolidones is described.
- Cam, Thuy Hoang,Bouillere, Francelin,Johannesen, Sine,Zulauf, Anais,Panel, Cecilia,Pouilhes, Annie,Gori, Didier,Alezra, Valerie,Kouklovsky, Cyrille
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scheme or table
p. 4177 - 4187
(2009/09/08)
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- Synthesis, structural, and antibacterial studies of some mixed ligand complexes of Zn(II), Cd(II), and Hg(II) derived from citral thiosemicarbazone and N-phthaloyl amino acids
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A series of new mixed ligand complexes of Zn(II), Cd(II), and Hg(II) with cis-3,7-dimethyl-2,6-octadienthiosemicarbazone (CDOTSC; LH) and N-phthaloyl amino acids (AH) have been synthesized by the reaction of metal dichloride with ligands CDOTSC and N-phthaloyl derivative of DL-glycine (A1H), L-alanine (A2H), or L-valine (A3H) in a 1:1:1 molar ratio in dry refluxing ethanol. All the isolated complexes have the general composition [M(L)(A)]. The plausible structure of these newly synthesized complexes has been proposed on the basis of elemental analyses, molar conductances, molecular weight measurement, and various spectral (IR, 1H NMR, and 13C NMR) studies, and four coordinated geometries have been assigned to these complexes. All the complexes and ligands have been screened for their antibacterial activity. Copyright Taylor & Francis Group, LLC.
- Sharma, Renu,Nagar, Meena
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p. 2863 - 2875
(2007/10/03)
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- Structure-driven design and synthesis of chiral dioxocyclam derivatives
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Based on an analysis of previously reported structures and a potential geometry fit with substrates, a new family of chiral dioxocyclam derivatives have been designed. The synthesis of those ligands was accomplished starting from l-proline and α-d-amino acids (converted to β-amino acids) with a key step of macrocyclization reaction of amino esters. All ligands were converted into neutral copper(II) complexes (amide groups underwent deprotonation of upon treatment of ligands with copper(II) acetate). The complexes exhibit the desired shape of their active surfaces, as proved by X-ray analysis.
- Achmatowicz, Micha?,Szumna, Agnieszka,Zieliński, Tomasz,Jurczak, Janusz
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p. 9031 - 9041
(2007/10/03)
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- The synthesis of N-acyl-2-hydroxymethyl aziridines of biological interest
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A practical synthesis of the title compounds from protected amino acylazides is described. All the compounds might be considered as a novel class of dipeptide isostere precursors; they all induce lymphocyte proliferation and protein production as observed from preliminary biological tests.
- Medjahed,Tabet Zatla,Kajima Mulengi,Baba Ahmed,Merzouk
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p. 1211 - 1213
(2007/10/03)
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- Highly efficient stereoconservative amidation and deamidation of α-amino acids
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(Chemical Equation Presented) An overall stereoconservative protection and deprotection method of amino and carboxyl groups is presented. N-Phthaloyl N-alkyl secondary amides of α-amino acids can be generated from corresponding N-phthaloyl amino acids by coupling reaction of N-alkylamines using mixed anhydride method. These secondary amides can be transformed by thermal rearrangement of intermediate nitrosoamides to O-alkyl esters with retention of configuration and excellent yields.
- Shendage, Deepak M.,Froehlich, Roland,Haufe, Guenter
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p. 3675 - 3678
(2007/10/03)
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- Enantioselection in peptide bond formation
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Selectivity in abiotic condensations of amino acids remains controversial and stereochemically little explored. We find that competitive activated couplings of N-acyl derivatives of glycine, alanine, valine, proline and phenylalanine with binary, ternary and quaternary mixtures of amides and esters of the same group of amino acids show little selectivity among the reactants, except with respect to configuration, where a consistent and significant preference for heterochiral outcomes, mostly >80%, is observed. One possible explanation of this selectivity predicts a predisposition to homochiral coupling under conditions that would require the two carboxyl functions to be co-facial in the activated complex.
- Hill, Roger R.,Birch, David,Jeffs, Graham E.,North, Michael
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p. 965 - 972
(2007/10/03)
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- Methyl 2-((succinimidooxy)carbonyl)benzoate (MSB): a new, efficient reagent for N-phthaloylation of amino acid and peptide derivatives.
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A new, efficient, and readily available reagent, methyl 2-((succinimidooxy)carbonyl)benzoate (MSB), for N-phthaloylation of amino acids and amino acid derivatives is described. The phthaloylation procedure is simple and racemization-free and gives excellent results with alpha-amino acids, alpha-amino alcohols, dipeptides, alpha-amino carboxamides, and alpha-amino esters.
- Casimir, J Richard,Guichard, Gilles,Briand, Jean-Paul
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p. 3764 - 3768
(2007/10/03)
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- Decarboxylative Photocyclization: Synthesis of Benzopyrrolizidines and Macrocyclic Lactones
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The benzopyrrolizidines 2, 6a, and 6b were synthesized from the enantiomerically pure γ-amino acid derivatives 1, 5a, and 5b by decarboxylative photocyclization of the corresponding potassium salts in aqueous acetone. The diastereoselectivity of the radical coupling step was low (dr = 60:40) for the N-phthaloylglutamic acid methyl ester 1, whereas the α-benzyl- and the α-methyl-substituted γ-phthalimido butyric acid derivatives 5a,b cyclized with high cis diastereoselectivity (dr = 91:9 and 97:3, respectively). Acid-catalyzed epimerization of the cis/trans-2 mixture gave exclusively cis-2. The benzopyrrolizidines cis/trans-2 mixture was transformed with high stereoselectivity (dr = 93:7, ee >98%) into the cis methyl ether 3 via the corresponding acyliminium cation and subsequently into the allyl derivative 4 (dr = 86:14) with trimethylallylsilane catalyzed by titanium tetrachloride. The structures of the benzopyrrolizidines rac-3, (+)-3, rac-4, and 6a were determined by X-ray structure analyses. The macrocyclic lactones 8a,b were formed in high yields from the precursors 7a,b. The diastereoselectivity for the valine-derived substrate (in contrast to the reactions of 5a and 5b) was only moderate (dr = 64:36). The structure of the macrolide 9a (from 8a) was determined by X-ray structure analysis.
- Griesbeck, Axel G.,Nerowski, Frank,Lex, Johann
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p. 5213 - 5217
(2007/10/03)
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- Absolute configuration of α-phthalimido carboxylic acid derivatives from circular dichroism spectra
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It is demonstrated that the Cotton effects due to the 220 nm phthalimide π-π* transition observed for a series of derivatives of α- phthalimidocarboxylic acids unequivocally reflect the amino acid absolute configuration. This method is based on the exciton coupling of the allowed transitions of the phthalimide and the carboxylic acid derivative chromophores. (C) 1999 Elsevier Science Ltd.
- Skowronek,Gawronski
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p. 4585 - 4590
(2007/10/03)
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- The influence of α-amido/thioamido functionality in ester reduction with sodium borohydride
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Sodium borohydride in methanol smoothly reduces the esters of α-amino acids having N-acyl (orthioacyl)-N-alkyl (-NRCOR′ or -NRCSR′) substituents, producing amino alcohol derivatives. Esters with α-NHCOR or-CONRR′ functionality however remain unaffected. Electron-withdrawing property of the substituent appears to play a crucial role, anion formation with -NHCOR group perhaps diminishing its effect.
- Roy, Atanu,Bar, Narayan C.,Achari, Basudeb,Mandal, Sukhendu B.
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p. 644 - 650
(2007/10/03)
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- Stereoselective Reactions of Phthalimido-Substituted Radicals Derived from (±)-Threonine: A Comparison with Reactions of N-Phthaloyliminium Ions
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Stereoselective reactions of phthalimido-substituted radicals derived from (±)-threonine with different radical traps are reported (Scheme 3, Table 1). A strong influence of the nature of the radical trap on the stereoselectivity was noticed. Small nucleophilic radical traps gave preferentially the syn products. The observed selectivities are explained with the A1.3 strain model and depend on steric and electronic effects (Fig. 2). Reactions with electrophilic radical traps such as diphenyl diselenide gave the anti diastereoisomers with moderate stereocontrol, presumably due to stereoelectronic effects. The same stereochemical outcome, i.e., preferential formation of the anti products, was observed for the reactions of the related N-phthaloyliminium ion (Scheme 5, Table 2). The stereochemistry of the ionic reaction is rationalized by a Felkin-Anh model (Fig. 3).
- Stojanovic, Aleksandar,Renaud, Philippe,Schenk, Kurt
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p. 268 - 284
(2007/10/03)
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- Restricted rotation about Nsp2-Csp3 bond through π-electronic interactions : A1H NMR study
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The electronic repulsion of a carboxyl group from a phenyl ring has been found to restrict rotation about Nsp2-Csp3 bond. A stable sp3-geometry of a carbon in N-CHR-COOH derivatives of a,β-(9,10-dihydroanthracene-9,10-diyl)succinimide has been demonstrated on the basis of shielding parameters of N′-alkyls. The carboxyl group does not exhibit hydrogen bonding with the carbonyls of the succinimide and remains in anti orientation. Though the anisotropic effect of an olefinic bond is fairly small, the interaction of carboxyl group with the olefinic bond is evident in CPD-MA adduct derivative.
- Singh, Kalpana,Srivastava, Nishi,Verma, Shiva M.
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p. 142 - 145
(2007/10/03)
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- Flash vacuum pyrolysis of stabilised phosphorus ylides. Part 7. Cyclisation of amino acid derived α-phthalimidoacyl ylides to give pyrroloisoindolediones
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A series of 11 amino acid-derived stabilised ylides 12-14 and 16 have been prepared and characterised. In one case, for compound 17, an X-ray structure determination supports formulation of the compounds as phosphonium enolates. Flash vacuum pyrolysis (FVP) of 12 and 13 at 500°C results in loss of R23PO between the ylide function and one carbonyl of the phthalimido group to give products characterised spectroscopically as the pyrroloisoindolediones 18. The identity of these is also supported by the results of 13C and 15N labelling experiments, but owing to their high reactivity complete separation from the phosphine oxide was not generally possible even when Bu3PO rather than Ph3PO was involved. Chromatographic purification of 29, similarly produced by FVP of 14, led to partial hydrolysis, rearrangement and decarboxylation to give 30. FVP of 12 at 750°C gave the 1-unsubstituted pyrroloisoindolediones 19 in two cases.
- Aitken, R. Alan,Cooper, Harris R.,Mehrotra, Amit P.
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p. 475 - 483
(2007/10/03)
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- Synthesis of α-Amino-3-chloro-4,5-dihydro-5-methyl-5-isoxazoleacetic Acid, a Ring-Methylated Analogue of the Antitumor Agent Acivicin (AT-125)
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α-Amino-3-chloro-4,5-dihydro-5-methyl-5-isoxazoleacetic acid (8), a ring-methylated analogue of the potent antitumor agent acivicin (AT-125), is synthesized in a 6-step procedure in 63percent overall yield from (S)-valine.Key step is the 1,3-dipolar addition of bromonitrile oxide to the N,C-protected (S)-isodehydrovaline (6) available from (S)-valine in four steps involving the photoisomerization of N-phthaloylvaline methyl ester (1).The stereochemical course of the 1,3-dipolar cycloaddition is proven by means of a X-ray structure analysis of the major diastereoisomer 7a formed in the chloronitrile oxide cycloaddition.The absolute configuration of the major (u) diastereomer 7a and the bromo derivative 7b is (αS,5R). - Key Words: Acivicin / Photochemistry / 1,3-Dipolar cycloadditions / Nitrile oxides
- Griesbeck, Axel G.,Hirt, Joachim,Peters, Karl,Peters, Eva-Maria,Schnering, Hans-Georg von
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p. 619 - 624
(2007/10/02)
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