- Hydroamination and Hydrophosphination of Isocyanates/Isothiocyanates under Catalyst-Free Conditions
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Symmetrical and unsymmetrical N,N’-disubstituted as well as trisubstituted ureas/thioureas by the hydroamination of isocyanates/isothiocyanates, and various phosphathioureas by the hydrophosphination of isothiocyanates have been synthesized in good to excellent yields under catalyst-free and mild conditions. This protocol is also applicable for the efficient synthesis of chiral ureas and thioureas and common herbicides, such as fenuron and monuron.
- Zhu, Xiancui,Xu, Mengchen,Sun, Jinrong,Guo, Dianjun,Zhang, Yiwei,Zhou, Shuangliu,Wang, Shaowu
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p. 5213 - 5218
(2021/10/19)
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- Facile synthesis of phthalidyl fused spiro thiohydantoins through silica sulfuric acid induced oxidative rearrangement of ninhydrin adducts of thioureas
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A one-pot three-component sequential synthetic protocol produces structurally and biologically important phthalidyl fused spiro N,N′-disubstituted thiohydantoins from readily available aromatic isothiocyanates, primary amines and ninhydrin. In this three-step synthesis while the initial two steps are catalyst-free, in the final step silica sulfuric acid (SSA) induces an oxidative rearrangement in [3.3.0]-bicyclic 1,2-diol adducts of ninhydrin and thioureas under solvent-free condition to generate the final products spiro-fused thiohydantoins. The adequate acidity of SSA in cooperation with moderate oxidizing property promotes a facile oxidative rearrangement in 1,2-diol intermediates to produce the spiro-fused thiohydantoins with diverse functionalities. Easy recyclability of SSA, good to excellent yield of the products, wider substrate scope, shorter reaction time, solvent-free two steps out of three and high atom economy make this method attractive and practicable.
- Mandal, Subhro,Pramanik, Animesh
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- Hydrogen-Bond Catalysis of Imine Exchange in Dynamic Covalent Systems
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The reversibility of imine bonds has been exploited to great effect in the field of dynamic covalent chemistry, with applications such as preparation of functional systems, dynamic materials, molecular machines, and covalent organic frameworks. However, acid catalysis is commonly needed for efficient equilibration of imine mixtures. Herein, it is demonstrated that hydrogen bond donors such as thioureas and squaramides can catalyze the equilibration of dynamic imine systems under unprecedentedly mild conditions. Catalysis occurs in a range of solvents and in the presence of many sensitive additives, showing moderate to good rate accelerations for both imine metathesis and transimination with amines, hydrazines, and hydroxylamines. Furthermore, the catalyst proved simple to immobilize, introducing both reusability and extended control of the equilibration process.
- Schaufelberger, Fredrik,Seigel, Karolina,Ramstr?m, Olof
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supporting information
p. 15581 - 15588
(2020/10/02)
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- Micelle-Enabled One-Pot Guanidine Synthesis in Water Directly from Isothiocyanate using Hypervalent Iodine(III) Reagents under Mild Conditions
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In this work, we developed a one-pot synthesis of guanidine directly from isothiocyanate using DIB (diacetoxyiodobenzene) as a desulfurizing agent under micellar conditions in water. Our optimization study revealed that the use of 1 % TPGS-750-M as a surfactant with NaOH as an additive base at room temperature can convert a variety of isothiocyanates and amines into corresponding guanidines in excellent yields (69–95 %). This synthetic process in water can be applied to prepare guanidine at gram-scale quantity. Our aqueous micellar medium also demonstrated high reusability as the reaction can be performed for several cycles without losing its efficiency. The reaction is metal-free, utilizes water as solvent and practical (room temperature and open flask).
- Srisa, Jakkrit,Tankam, Theeranon,Sukwattanasinitt, Mongkol,Wacharasindhu, Sumrit
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p. 3335 - 3343
(2019/09/12)
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- Nickle Catalysis Enables Access to Thiazolidines from Thioureas via Oxidative Double Isocyanide Insertion Reactions
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An efficient synthesis of thiazolidine-2,4,5-triimine derivatives was developed via Ni-catalyzed oxidative double isocyanide insertion to thioureas under air conditions, in which thioureas play three roles as a substrate, a ligand, and overcoming isocyanide polymerization. The reaction is featured by employing a low-cost and low loading Ni(acac)2 catalyst, without any additives, and high atom economy. This is the first example to directly apply a Ni(II) catalyst in oxidative double isocyanide insertion reactions.
- Yuan, Wen-Kui,Liu, Yan Fang,Lan, Zhenggang,Wen, Li-Rong,Li, Ming
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supporting information
p. 7158 - 7162
(2018/11/25)
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- Antileishmanial thioureas: Synthesis, biological activity and in Silico evaluations of new promising derivatives
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Leishmaniasis is a neglected tropical disease caused by protozoan parasites belonging to the genus Leishmania. Currently, the drugs available for treatment of this disease present high toxicity, along with development of parasite resistance. In order to overcome these problems, efforts have been made to search for new and more effective leishmanicidal drugs. The aim of this study was to synthesize and investigate the leishmanicidal effect of N,N′-disubstituted thioureas against Leishmania amazonensis, with evaluation of their in silico pharmacokinetics and toxicity profiles. Our results showed that different thioureas could be obtained in high to moderate yields using simple reaction conditions. Nine thiourea derivatives (3e, 3i, 3k, 3l, 3p, 3q, 3v, 3x and 3z) were active against parasite promastigotes (IC50 21.48–189.10μM), with low cytotoxicity on mice peritoneal macrophages (CC50>200μM), except for thiourea 3e (CC50=49.22μM). After that, the most promising thioureas (3k, 3l, 3p, 3q and 3v) showed IC50 ranging from 70 to 150μM against L. amazonensis amastigotes in infected macrophages. Except for thiourea 3p, the leishmanicidal activity of the derivatives were independent of nitric oxide (NO) production. Thioureas 3q and 3v affected promastigotes cell cycle without disturbing the mitochondrial membrane potential. Furthermore, our derivatives showed satisfactory theoretical absorption, distribution, metabolism, excretion, toxicity (ADMET) properties. These data indicate that thiourea derivatives are good candidates as leading compounds for the development of new leishmanicidal drugs.
- Viana, Gil Mendes,Do Amaral, Lilian Henriques,Meireles, Paloma Wetler,Nunes, Raquel Pinto,Da Silva, Luiz Cláudio Rodrigues Pereira,De Sousa, Valeria Pereira,Sathler, Plínio Cunha,Cabral, Lucio Mendes,Soares, Deivid Costa,Saraiva, Elvira Maria,Santana, Marcos Vinicius,Castro, Helena Carla,De Sequeira Aguiar, Lúcia Cruz,Rodrigues, Carlos Rangel,Abreu, Paula Alvarez
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p. 911 - 919
(2018/10/31)
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- Ph3P/I2-mediated synthesis of N,N′,N″-substituted guanidines and 2-iminoimidazolin-4-ones from aryl isothiocyanates
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A convenient one-pot procedure for the synthesis of acyclic and cyclic guanidines mediated by the Ph3P/I2 system is described. Sequential condensation of aryl isothiocyanates with amines followed by dehydrosulfurization and guanylation could lead to both symmetric and unsymmetric N,N′,N″-substituted derivatives. Through a tandem guanylation-cyclization, a series of 2-iminoimidazolin-4-ones could also be prepared in good yields from the reaction of aryl isothiocyanates with amino acid methyl esters.
- Wangngae, Sirilak,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 10331 - 10340
(2018/05/31)
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- Thiocarbonyl Surrogate via Combination of Sulfur and Chloroform for Thiocarbamide and Oxazolidinethione Construction
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An efficient and practical thiocarbonyl surrogate via combination of sulfur and chloroform has been developed. A variety of thiocarbamides and oxazolidinethiones have been established, including chiral thiourea catalysts and chiral oxazolidinethione auxiliaries with high selectivity. Meanwhile, pesticides Diafenthiuron (an acaricide), ANTU (a rodenticide), and Chloromethiuron (an insecticide) were practically synthesized through this method in gram scale. Dicholorocarbene, as the key intermediate, was further confirmed via a carbene-trapping control experiment.
- Tan, Wei,Wei, Jianpeng,Jiang, Xuefeng
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supporting information
p. 2166 - 2169
(2017/04/27)
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- One-Pot Synthesis of C2 Symmetric and Asymmetric N,N′,N″-Substituted Guanidines from Aryl Isothiocyanates and Amines
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Highly substituted guanidines were conveniently prepared through a one-pot reaction between aryl isothiocyanates and amines mediated by the Ph3P-I2/Et3N system. The C 2-symmetric N,N′,N″-substituted guanidines were readily accessed using a 1:2 molar ratio of an aryl isothiocyanate and an amine; while sequential addition of two different amines in equimolar ratios gave rise to asymmetric derivatives. Both primary and secondary amines were found to react preferentially with electron-deficient aryl isothiocyanates, rapidly providing guanidines in good yields under mild conditions.
- Wangngae, Sirilak,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 1121 - 1127
(2016/05/19)
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- Convenient synthesis of unsymmetrical N,N′-disubstituted thioureas in water
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A simple and convenient two-step method has been developed and used to synthesise 25 (4 of which are novel) unsymmetrical N,N′-disubstituted thioureas in water. Alkylamines or variously substituted arylamines reacted smoothly with phenyl chlorothionoformate at room temperature to form thiocarbamates, which were then reacted with another alkyl- or arylamine in water at reflux to afford the unsymmetrical N,N′-disubstituted thioureas in good to excellent yields. Mild conditions, simple work-up, high yields as well as using water as solvent are the major advantages of the method.
- Li, Zhengyi,Chen, Yuan,Yin, Yue,Wang, Zhiming,Sun, Xiaoqiang
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p. 670 - 673
(2016/11/18)
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- Synthesis and antiplatelet activity of antithrombotic thiourea compounds: Biological and structure-activity relationship studies
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The incidence of hematological disorders has increased steadily in Western countries despite the advances in drug development. The high expression of the multi-resistance protein 4 in patients with transitory aspirin resistance, points to the importance of finding new molecules, including those that are not affected by these proteins. In this work, we describe the synthesis and biological evaluation of a series of N,N′-disubstituted thioureas derivatives using in vitro and in silico approaches. New designed compounds inhibit the arachidonic acid pathway in human platelets. The most active thioureas (compounds 3d, 3i, 3m and 3p) displayed IC50 values ranging from 29 to 84 μM with direct influence over in vitro PGE2 and TXA2 formation. In silico evaluation of these compounds suggests that direct blockage of the tyrosyl-radical at the COX-1 active site is achieved by strong hydrophobic contacts as well as electrostatic interactions. A low toxicity profile of this series was observed through hemolytic, genotoxic and mutagenic assays. The most active thioureas were able to reduce both PGE2 and TXB2 production in human platelets, suggesting a direct inhibition of COX-1. These results reinforce their promising profile as lead antiplatelet agents for further in vivo experimental investigations.
- Louren?o, André Luiz,Saito, Max Seidy,Dorneles, Luís Eduardo Gomes,Viana, Gil Mendes,Sathler, Plínio Cunha,De Aguiar, Lúcia Cruz Sequeira,De Pádula, Marcelo,Domingos, Thaisa Francielle Souza,Fraga, Aline Guerra Manssour,Rodrigues, Carlos Rangel,DeSousa, Valeria Pereira,Castro, Helena Carla,Cabral, Lucio Mendes
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p. 7174 - 7200
(2015/05/06)
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- Synthesis of thiazolidines via regioselective addition of unsymmetric thioureas to maleic acid derivatives
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A wide range of unsymmetric thioureas has been studied in reaction with N-arylmaleimides and maleic anhydride. The regioselectivity of the addition depends not only on steric factors but on both solvent polarity and type of maleic acid derivative (imide o
- Pankova, Alena S.,Samartsev, Mikhail A.,Shulgin, Igor A.,Golubev, Pavel R.,Avdontceva, Margarita S.,Kuznetsov, Mikhail A.
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p. 51780 - 51786
(2014/12/10)
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- Cerium ammonium nitrate-catalyzed aerobic oxidative coupling of dithiocarbamates: Facile synthesis of thioureas and bis(aminothiocarbonyl)disulfides
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Diverse disubstituted and trisubstituted thioureas were synthesized by the condensation of dithiocarbamate TEA (or DABCO) salts and amines using cerium ammonium nitrate (CAN) as a catalyst in high yields at room temperature. It is a one-pot method and it is unnecessary to isolate isothiocyanates. This reaction probably took place through nucleophilic addition of amines to isothiocyanates, which were generated by oxidative coupling of dithiocarbamates and the following decomposition of bis(aminothiocarbonyl)disulfides. When secondary amines and CS2served as the reactants, bis(aminothiocarbonyl)disulfides were obtained via tandem nucleophilic addition/oxidative coupling reactions in moderate to excellent yields. In all the coupling reactions, the oxidant was air and CAN possibly acted as an SET catalyst.
- Li, Tian-Tian,Song, Xiang-Hai,Wang, Mei-Shuang,Ma, Ning
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p. 40054 - 40060
(2014/12/10)
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- Tandem regioselective synthesis of tetrazoles and related heterocycles using iodine
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A one-pot, tandem process has been developed for the synthesis of a library of tetrazoles from aryl isothiocyanates. Condensation of aryl isothiocyanates with ammonia, and aryl amines (R-NH2) provided mono, 1,3-disubstituted symmetrical and unsymmetrical thioureas, which on desulfurization with molecular iodine (I2) led to formation of the corresponding heterocumulene (cyanamides or carbodiimides). The in situ generated heterocumulene on subsequent treatment with sodium azide at room temperature gave corresponding tetrazoles. The product regioselectivity for unsymmetrical 1,3-disubstituted thioureas was found to be correlated with the basicities (pKa's) of the parent amines attached to the thiourea. Aryl-sec-alkyl unsymmetrical thioureas gave thioamido guanidino products rather than the 5-aminotetrazoles produced by HgCl2 mediation of the reaction. Bis-thioureas derived from aryl isothiocyanates and hydrazine gave thiadiazoles exclusively.
- Yella, Ramesh,Khatun, Nilufa,Rout, Saroj Kumar,Patel, Bhisma K.
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supporting information; experimental part
p. 3235 - 3245
(2011/06/20)
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- Structural requirement of phenylthiourea analogs for their inhibitory activity of melanogenesis and tyrosinase
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Effect of a series of 1-phenylthioureas 1a-k and 1,3-disubstituted thioureas 2a-k were evaluated against melanin formation in melanoma B16 cell line and mushroom tyrosinase. Inhibitory activity of tyrosinase of 1-phenylthioureas 1a-k is parallel to their melanogenic inhibition. Thus, the melanogenic inhibition in melanoma B16 cells of 1-phenylthioureas could be the result of inhibition of tyrosinase. However, 1,3-diaryl or 1-phenyl-3- alkylthioureas, 2a-k, appears as melanogenic inhibitor without inhibition of tyrosinase. The molecular docking study of 1e and 2b to binding pocket of tyrosinase provided convincing explanation regarding the necessity of direct connection of planar phenyl to thiourea unit without N′-substitution of phenylthioureas 1 as tyrosinase inhibitor and 2 as non-tyrosinase inhibitor.
- Thanigaimalai, Pillaiyar,Lee, Ki-Cheul,Sharma, Vinay K.,Joo, Cheonik,Cho, Won-Jea,Roh, Eunmiri,Kim, Youngsoo,Jung, Sang-Hun
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experimental part
p. 6824 - 6828
(2011/12/22)
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- Antimicrobial activity and structural study of disubstituted Thiourea Derivatives
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The antimicrobial activity of six N-phenyl- and fourteen N-benzoylthiourea derivatives were evaluated from their Minimal Inhibitory Concentration (MIC) values using the microdilution procedure against ten microorganisms. Most of the compounds exhibited selective activity against fungi and Gram-positive bacteria, which were very effectively inhibited by some of the tested thioureas. Additionally, SAR considerations and four novel X-ray diffraction structures of N-benzoylthioureas are included. Springer-Verlag 2007.
- Cunha, Silvio,MacEdo Jr., Fernando C.,Costa, Giselle A. N.,Rodrigues Jr., Manoel T.,Verde, Rosival B. V.,De Souza Neta, Lourdes C.,Vencato, Ivo,Lariucci, Carlito,Sa, Fernando P.
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p. 511 - 516
(2008/02/03)
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- Ultrasound-promoted scavenging: A rapid parallel purification for solution phase combinatorial synthesis
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Ultrasound irradiation enhances the mass transfer and reaction rate in scavenging, avoiding the trouble of time-consuming purification procedure in solution-phase parallel synthesis. An application of this technique is demonstrated in the scavenging of excess isothiocyanates from reaction mixtures.
- Peng, Yanqing,Song, Gonghua,Xu, Xiaoyong
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p. 261 - 263
(2007/10/03)
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- 1-(Methyldithiocarbonyl)imidazole: A useful thiocarbonyl transfer reagent for synthesis of substituted thioureas
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1-(Methyldithiocarbonyl)imidazole 1 and its N-methyl quaternary salt 2 have been shown to be efficient methyldithiocarbonyl and thiocarbonyl transfer reagents for the synthesis of dithiocarbamates, symmetrical and unsymmetrical mono-, di- and tri-substituted thioureas in high yields under mild and simple non-hazardous reaction conditions. (C) 2000 Elsevier Science Ltd.
- Mohanta, Pramod K.,Dhar, Sanchita,Samal,Ila,Junjappa
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p. 629 - 637
(2007/10/03)
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- A convenient route to cyanoguanidines
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A facile and versatile method for the preparation of cyanoguanidines 7 from amines 3 and isothiocyanates 4 via a methylation, cyanamide-treatment sequence is described.
- Novak, Lajos,Hanania, Michel,Kovacs, Peter,Kovacs, Csilla Erika,Kolonits, Pal,Szantay, Csaba
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p. 1757 - 1766
(2007/10/03)
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- The HgCl2-promoted guanylation reaction: The scope and limitations
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The HgCl2-promoted guanylation reaction was studied with various substituted thiourea starting materials and the scope and limitations are presented. The process was found to be effective with thioureas containing at least one N-conjugated subs
- Levallet, Catherine,Lerpiniere, Joanne,Ko, Soo Y.
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p. 5291 - 5304
(2007/10/03)
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- A facile conversion of symmetrical to unsymmetrical thioureas
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A convenient route for quantitative conversion of symmetrical thioureas into unsymmetrical thioureas is described. The method circumvents the use of toxic isothiocyanates and a case study is reported using 1,3-diphenylthiourea.
- Ramadas,Srinivasan,Janarthanan
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p. 6447 - 6450
(2007/10/02)
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- Influence of Substituents on the Synthesis of Thiazolidinones
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The influence of substituents (subunits) in the synthesis of thiazolidinones by the reaction of unsymmetrical thioureas with monochloroacetic acid in ethanol has been rationalised by the characterisation of the hydrolysis products of the resulting thiazolidinones.The formation of thiol from thiourea, which is the key intermediate in thiazolidinone synthesis, invariably involves the -NH- group adjacent to more electron withdrawing subunits.
- Sabu, M.,Garnaik, B. K.,Behera, Rajani K.
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p. 779 - 781
(2007/10/02)
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- DI-2-PYRIDYL THIONOCARBONATE. A NEW REAGENT FOR THE PREPARATION OF ISOTHIOCYANATES AND CARBODIIMIDES.
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Reaction of amines with di-2-pyridyl thionocarbonate affords the corresponding isothiocyanates at room temperature, while reaction of N,N'-disubstituted thioureas with di-2-pyridyl thionocarbonate in the presence of 4-dimethylaminopyridine as a catalyst affords the corresponding carbodiimides in high yields.
- Kim, Sunggak,Yi, Kyu Yang
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p. 1661 - 1664
(2007/10/02)
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- Studies on the Development of the Tritylsulfenyl Group as a Nitrogen Protecting Group and Application in a Synthesis of δ-Coniceine
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The (triphenylmethyl)sulfenyl (tritylsulfenyl, TRS) group was found to posses properties which should make it useful as a nitrogen protecting group.The almost instantaneous reaction of TrSCl (6) with amines produced the corresponding triphenylmethanesulfenamides.The TRS group was found to render the nitrogen atom nonbasic and relatively nonnucleophilic, was stable to aqueous acid, aqueous base, and various reducing agents, and was moderately stable to Moffat oxidation conditions.The TRS group could be cleaved under mild conditions, generating the amine with either CuCl2/EtOH-THF, HI/THF-H2O, or trimethylsilyl iodide (Me3SiI)/CH2Cl2.A synthesis of δ-coniceine (16) illustrates carbon-carbon bond formation with tritylsulfenimine methodology and the utility of the tritylsulfenyl group as a nitrogen protecting group.
- Branchaud, Bruce P.
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p. 3538 - 3544
(2007/10/02)
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