- Preparing method of captopril isomer
-
The invention provides a preparing method of a captopril isomer. The method includes the steps of resolving mixed 3-sulfanyl-2-methyl propionic acid into L-3-sulfanyl-2-methyl propionic acid, making L-3-sulfanyl-2-methyl propionic acid react with thionyl chloride to prepare L-3-sulfanyl-2-methylpropionyl chloride (L-acyl chloride for short), making L-acyl chloride react with L-proline or D-prolineto generate 1-(3-sulfanyl-2-methylpropionyl)-proline (free acid for short), and conducting hydrolysis deprotection on the free acid to prepare the isomer. The preparing method is good in resolving effect, the obtained isomer is high in optical purity, the resolving reaction time and temperature range is large, and control is easy.
- -
-
Paragraph 0020; 0024-0025; 0032; 0036-0037; 0044; 0048; 0049
(2019/04/26)
-
- Organocatalytic enantioselective transient enolate protonation in conjugate addition of thioacetic acid to a-substituted n-acryloyloxazolidinones
-
Organocatalytic conjugate addition of thioacetic acid to a series of a-substituted N-acryloyloxazolidin-2- ones followed by enantioselective protonation has been studied in the presence of thiourea catalysts derived from cinchona alkaloids. Conjugate addition/protonation adducts have been obtained up to 97% ee and high yields. The methodology could serve as an easy and practical route to the syntheses of useful biologically active molecules.
- Unhale, Rajshekhar A.,Rana, Nirmal K.,Singh, Vinod K.
-
supporting information
p. 1911 - 1915
(2013/05/23)
-
- Development of odorless organosulfur reagents and asymmetric reaction using odorless thiols
-
Odorless organosulfur reagents were developed by increasing their molecufar weights to suppress vohtility. 1-Dodecanethiol (4), dodecyl methyl sulfide (5), p-heptylphenylmethanethiol (6), p-dodecylbenzenethiol (7), p-heptylbenzenethiol (8), 2-dodecyl-l,3-propanedithiol (11), p-octyloxyphenylmethanethiol (18b,), and p-octyloxybenzenethiol (19) are typical examples of the odorless thiols and sulfides. 6-Morpholinohexyl thiol (15), methyl 6-morpholinohexyl sulfide (16) and methyl 6-morpholinohexyl sulfoxide (17,) were also developed as separable reagents from reaction products by facile acid-base extraction. In addition, p-tetramethylsilylphenylmethanethiol (18) and p-tetramethylsilylbenzenethiol (14) were synthesized as the odorless synthetic substitutes of benzyl mercaptan and benzenethiol, respectively. In a similar way, silylated diphenyl disulfide (26) and diselenide (21) were prepared as odorless disulfide and diselenide. Moreover, 10-sulfanylisobomeol (1) was found to be an excellent chiral odorless substitute of hydrogen sulfide in Michael addition.
- Node, Manabu,Kajimoto, Tetsuya
-
p. 572 - 583
(2008/02/08)
-
- Asymmetric induction in the conjugate addition of thioacetic acid to methacrylamides with chiral auxiliaries
-
The conjugate addition of thioacetic acid to methacrylamides with chiral C2-symmetric trans-2,5-disubstituted pyrrolidines afforded the addition products in excellent stereoselectivities (>99% de) and good yields (80-90%). The high selectivity was attributed mainly to the steric effect of the chiral auxiliaries. The cyclic nature of the chiral auxiliaries seemed also important for both the stereoselectivity and the reaction rate. Acidic hydrolysis of the adduct containing (2R,5R)-bis(methoxymethyl)pyrrolidine gave (S)-3-mercapto-2-methylpropanoic acid, a key intermediate for captopril, in 98% ee and 96% yield. The chiral auxiliary was recovered in the demethylated form of N-Boc-(2R,3R)-bis(hydroxymethyl)pyrrolidine in 90% yield.
- Kim, Byung Hyun,Lee, Hee Bong,Hwang, Jae Kwang,Kim, Young Gyu
-
p. 1215 - 1220
(2007/10/03)
-
- Effect of the α-methyl substituent on chemoselectivity in esterase-catalyzed hydrolysis of S-acetyl sulfanylalkanoates
-
(Equation Presented) The isomeric compounds 1 and 3, which differ only in the position of a methyl substituent, give opposite chemoselectivities in an esterase-catalyzed hydrolysis reaction. The esterase was chemoselective for the oxoester in 1, but for the thiol ester group in 3. A high enantioselectivity was observed for both 1 and 3.
- Kumar, Ish,Jolly, Ravinder S.
-
p. 207 - 209
(2008/02/11)
-
- Chemical Racemization of Methyl L-β-Acetylthioisobutyrate
-
Methyl L-β-acetylthioisobutyrate was racemized with 1,8-diazabicyclo--undecene-7 as a catalyst.Methyl methacrylate and thioacetic acid were identified as the intermediates of the reaction.Thioacetic acid was relatively unstable and susceptible to decomposition during the racemization process.The addition of excess methyl methacrylate to the reaction mixture prevented a decrease of the racemate.The racemized ester was confirmed to be usable as a substrate for the enzymatic production of D-β-acetylthioisobutyric acid.
- Sakimae, Akihiro,Kobayashi, Yoshimasa,Ohsuga, Naoto,Numazawa, Ryozo,Ohnishi, Hisao
-
-
- Screening of Microorganisms Producing D-β-Acetylthioisobutyric Acid from Methyl DL-β-Acetylthioisobutyrate
-
Microorganisms producing D-β-acetylthioisobutyric acid from methyl DL-β-acetylthioisobutyrate were screened from stock cultures.The D-β-acetylthioisobutyric acid-producing ability was found in 15 strains belonging to the genera Pseudomonas, Agrobacterium, Enterobacter, Cellulomonas, Rhodococcus, Brevibacterium, and Torulopsis.A strain of Pseudomonas fluorescens, IFO 3081, was selected as the best microorganism.The cells having activity (558 units/g of dry cells) could be easily prepared by cultivation at 25 deg C at pH 6.6 for 24 hr in a glucose-containing medium.The D-form of methyl DL-β-acetylthioisobutyrate was selectively hydrolyzed with the cells so that D-β-acetylthioisobutyric acid (97.2percent enantiomeric excess) was produced in a high yield.
- Sakimae, Akihiro,Hosoi, Akihiko,Kobayashi, Etsuko,Ohsuga, Naoto,Numazawa, Ryozo,et al.
-
p. 1252 - 1256
(2007/10/02)
-
- Thiazaspirane derivatives, process for their preparation, and medicaments
-
Novel thiazaspirane derivatives of the general formula STR1 including salts thereof with physiologically acceptable acids and bases, processes for their preparation and medicaments containing them.
- -
-
-