- Process for preparing Dess-Martin reagent through solid superacid catalysis
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The invention belongs to the technical field of organic synthesis, and discloses a process for preparing a Dess-Martin reagent through solid superacid catalysis. The process comprises the following steps of: S1, oxidation reaction, specifically, mixing potassium bromate and tap water, adding solid superacid HERD-Cat-1, stirring and heating the materials to 40-90 DEG C; adding o-iodobenzoic acid in batches, reacting for 1-8 hours at the temperature after addition of the o-iodobenzoic acid, performing cooling, and then centrifugally washing a product with water and washing with an organic solvent to obtain an IBX wet product; S2, acetylation reaction, specifically, adding the IBX wet product into an organic solvent, performing dissolving and filtering, recovering solid superacid HERD-Cat-1, adding a catalyst and acetic anhydride, heating to 40-80 DEG C, performing a reaction, performing cooling and crystallizing, and performing centrifugation and drying to obtain the Dess-Martin reagent. After the solid superacid is used for catalysis, generation of a large amount of waste acid is avoided, and meanwhile the purity of IBX is high. The process has the advantages of short reaction steps, high chemical purity, simplicity in operation, low cost, high production safety, environmental friendliness and the like, and is suitable for industrial production.
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Paragraph 0014; 0021; 0023; 0024; 0026; 0027; 0029; ...
(2021/07/31)
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- Changes in the Key Odorants and Aroma Profiles of Hamlin and Valencia Orange Juices Not from Concentrate (NFC) during Chilled Storage
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Application of the aroma extract dilution analysis (AEDA) on the volatiles isolated by extraction/SAFE distillation from NFC (not from concentrate) juice from Hamlin oranges revealed 51 odor-active constituents in the flavor dilution (FD) factor range of 8 to 8192 among which vanillin, wine lactone, and (R)-linalool appeared with the highest FD factors. The AEDA applied on the volatile fraction of the same batch of juice stored at 0 °C for 10 months under aseptic conditions showed clear changes in the aroma profile as well as in the FD factors of key odorants. The reduction in the intensity of the citrus-like, pungent, green odor attributes in the aroma profile correlated with the loss of 1-penten-3-one, acetaldehyde, and (Z)-3-hexenal and a clear decrease in hexanal, octanal, nonanal, decanal, and (E,E)-2,4-decadienal. Quantitation done by stabile isotope dilution assays followed by a calculation of odor activity values (ratio of concentration to odor thresholds in citrate buffer) confirmed that the quick loss of 1-penten-3-one and acetaldehyde already within a few weeks and a significant reduction in nearly all aldehydes over the storage time of 10 months were responsible for the changes in the overall aroma profile of the juice. The same approach applied on Hamlin juice from the next harvest year as well as on chilled stored NFC juice from Valencia oranges confirmed the results for another harvest year and another orange variety.
- Sellami, Ines,Mall, Veronika,Schieberle, Peter
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p. 7428 - 7440
(2018/06/19)
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- Preparation method of DMP (Dess-Martin periodinane)
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The invention discloses a preparation method of a DMP (Dess-Martin periodinane). The target product DMP is obtained through two steps of reactions with 2-iodobenzoic acid, potassium hydrogen persulfate, glacial acetic acid, acetic anhydride and the like as raw materials. The process is convenient and stable, the product is easy to separate and high in yield, the method is environmentally friendly,the comprehensive yield is 82% or above, the raw materials are cheap and easy to obtain, and industrial mass production is facilitated.
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Paragraph 0038; 0039; 0041; 0044; 0054; 0058
(2019/01/13)
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- The crystal structure of the Dess-Martin periodinane
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We report the elusive X-ray structure of the Dess-Martin periodinane (DMP), a hypervalent iodine reagent popular amongst synthetic chemists. In the solid state, the highly crystalline compound forms an intricate coordination polymer held together by intermolecular halogen and hydrogen bonds.
- Schroeckeneder, Albert,Stichnoth, Desiree,Mayer, Peter,Trauner, Dirk
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p. 1523 - 1527,5
(2020/09/14)
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- Tri-peptide Inhibitors of Serine Elastases
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The present invention provides compounds of formula (I): where X is R1—(CR3R4)nOC(O)—; R1—(CR3R4)nC(O)—; R1—C(O)NH(CR3R4)nOC(O)—; R1—C(O)NH(CR3R4)nC(O)—; R1—C(O)(CR3R4)nOC(O)—; or R1—C(O)(CR3R4)nC(O)—; where R1 is optionally substituted C5-10 aryl or heteroaryl; OH or NH2; where R3 and R4 are independently H or methyl; and n is 0 to 6; and Y is —CF3 or one of: where R2 is C1-8 alkyl optionally substituted with halo or —OH; —(CR6R7)p—C5-6 aryl optionally substituted with halo, —OH, C1-8 alkyl, C1-8 haloalkyl, —(CH2)mC(O)NH2 or —(CH2)mOCH3; where R6 and R7 are independently H or methyl; m is 0 to 4, and p is 0 or 1 or a pharmaceutically acceptable salt, ester, metabolite or prodrug thereof
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- TRIAZOLO-PYRIDAZINE COMPOUNDS AND DERIVATIVES THEREOF USEFUL IN THE TREATMENT OF NEUROPATHIC PAIN
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The present invention is directed to a method of use of triazolo-pyridazine compounds in the treatment of neuropathic pain. The present invention is also directed to the use of triazolo-pyridazine compounds in the treatment of psychiatric and mood disorders such as, for example, schizophrenia, anxiety, depression, bipolar disorders, and panic, as well as in the treatment of pain, Parkinson’s disease, cognitive dysfunction, epilepsy, circadian rhythm and sleep disorders - such as shift-work induced sleep disorder and jet-lag, drug addiction, drug abuse, drug withdrawal and other diseases. The present invention is also directed to novel triazolo-pyridazine compounds that selectively bind to α2δ-1 subunit of Ca channels.
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Page/Page column 23; 24; 35; 50
(2010/02/11)
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- Magnesium amide base-mediated enantioselective deprotonation processes
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A novel homochiral magnesium bisamide has been readily prepared and, following careful optimisation, this species has been shown to react efficiently with a series of prochiral 4-substituted cyclohexanones in the presence of TMSCl to give the corresponding silyl enol ethers in enantiomeric ratios of up to 95:5. Additionally, the same chiral base system has been shown to be highly effective in the desymmetrisation of cis-2,6-disubstituted cyclohexanones, providing excellent levels of both conversion and enantioselection (up to >99.5:0.5 er). Furthermore, the magnesium bisamide has also been shown to mediate a kinetic resolution process with the corresponding trans-disubstituted substrates, allowing access to enantioenriched enol ethers and ketones.
- Henderson, Kenneth W,Kerr, William J,Moir, Jennifer H
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p. 4573 - 4587
(2007/10/03)
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- Protease inhibitors
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This invention relates to compounds of formula (I) or a pharmaceutically acceptable salt thereof, which are inhibitors of cysteine proteases, particularly cathepsin K, and are useful in the treatment of diseases in which inhibition of bone loss is a factor.
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- Oxidation of the secondary alcohol present in some common sugar derivatives with Dess-Martin periodinane
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Oxidation of the secondary alcohol present in some common sugar derivatives 3,5,7,9 to the corresponding ketones can be performed conveniently with Dess-Martin periodinane 2, prepared from hydroxyiodinane oxide 1.
- Rao, H. Surya Prakash,Muralidharan, P.,Pria, S.
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p. 816 - 818
(2007/10/03)
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- Phosphorous-containing cysteine and serine protease inhibitors
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The present invention is directed to novel phosphorous-containing inhibitors of cysteine or serine proteases. Methods for the use of the protease inhibitors are also described.
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- Enantioselective total syntheses of [6R,7R] and [6S,7S] tricyclic β-lactams
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The reaction of Ox-glycyl chloride with a chiral imine derived from the combination of D-(R)-glyceraldehyde acetonide and protected D-threonine afforded optically active, highly functionalized cis-substituted β-lactams 11 and 12. These β-lactams provide versatile intermediates for the syntheses of biologically important carbacephalosporins, isooxacephems, and other multicyclic β-lactams. Desilylation and oxidation of 12 with Dess-Martin periodinane followed by intramolecular cyclization produced a novel tricyclic β-lactam 17 and a 1-(hydroxymethyl)-O-2-isocephem 18 with [6R,7R] absolute configuration. Removal of the Ox protecting group and acylation of 17 in a one-pot reaction followed by saponification furnished the target salt 24. Alternatively, reaction of phthaloylglycyl chloride with the chiral imine derived from the combination of L-(S)-glyceraldehyde acetonide and protected D-threonine gave only one enantiomeric azetidinone 27 in high yield. Further manipulation of 27 provided a new tricyclic β-lactam 39 with [6S,7S] absolute configuration which satisfies the stereochemistry typically required for antibacterial activity. This synthetic procedure provides a short, versatile and enantioselective method of preparing polycyclic β-lactams. Biological testing of these tricyclic β-lactams indicated that salt 39 has potential inhibitory activity against four typical strains of bacteria.
- Niu, Chuansheng,Pettersson, Teresia,Miller, Marvin J.
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p. 1014 - 1022
(2007/10/03)
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- A useful 12-i-5 triacetoxyperiodinane (the dess-martin periodinane) for the selective oxidation of primary or secondary alcohols and a variety of related 12-i-5 species1a
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The stable 10-I-4 species 1-hydroxy-1,3-dihydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole 1-oxide ((fluoroalkoxy)iodinane oxide 7) is the ring-closed form of o-iodoxyhexafluorocumyl alcohol. It is prepared by the oxidation of chloroiodinane 6 with potassium bromate in aqueous sulfuric acid. The X-ray crystal structure of the tetrabutylammonium salt of 7 (10-I-4 anion 10) showed the unusual feature of an apical, negatively charged oxide ligand. Iodinane oxides 1 and 7 are readily converted to stable 12-1-5 periodinanes by treatment with carboxylic acid anhydrides or sulfur tetrafluoride. Tris(acyloxy)periodinanes 13 and 14 (derived from the ring-closed form of o-iodoxybenzoic acid), 1-hydroxy-1,2-benziodoxol-3(1H)-one 1-oxide (1), and 17 and 18 (derived from 7) are extraordinarily stable. 1,1,1-Triacetoxy-1,1-dihydro-1,2-benziodoxol-3(1H)-one (13), the "Dess-Martin Periodinane", is an extremely useful reagent for the conversion of primary and secondary alcohols to aldehydes and ketones at 25°C. It does not oxidize aldehydes to carboxylic acids under these conditions. It selectively oxidizes alcohols in the presence of furan rings or sulfides and does not react with vinyl ethers. Geraniol is oxidized to geranial by 13 without isomerization to nerol. Benzylic or allylic alcohols are selectively oxidized in the presence of saturated alkanols. The alcohol oxidation mechanism involves intermediates with alkoxy ligands replacing acetoxy ligands at the 12-I-5 iodine. It also oxidizes N-benzylbenzamide to benzaldehyde. Four other 12-I-5 species, 1,1,1-tris(trifluoroacetoxy)-1,1-dihydro-1,2-benziodoxol-3(1H)-one (14), 1,1,1,-trinuoro-1,1-dihydro-1,2-benziodoxol-3(1H)-one (15), 1,1,1-tris(acetoxy)-1,1,1,3-tetrahydro-3,3-bis(trifluoromethyl)-1,2-benziodoxole (17), and 1,1,1 -tris(trifluoroacetoxy)-1,1,1,3-tetrahydro-3,3-bis(trifluoromethyl)-1,2- benziodoxole (18), also oxidize alcohols to aldehydes and ketones. All of the tris(acyloxy)periodinanes undergo facile ligand exchange with alcohols. The reaction between triacetoxyperiodinane 13 and pinacol gives an isolable, crystalline, spirobicyclic periodinane, 25. The acetoxy group of periodinane 25 undergoes degenerate ligand exchange with acetic acid rapidly on the NMR time scale.
- Dess, Daniel B.,Martin
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p. 7277 - 7287
(2007/10/02)
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- Readily Accessible 12-I-5 Oxidant for the Conversion of Primary and Secondary Alcohols to Aldehydes and Ketones
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Periodinane 2 is a mild, selective reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones.
- Dess, D. B.,Martin, J. C.
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p. 4155 - 4156
(2007/10/02)
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