Ethyl mercapto acetate

Thiazolidines (76) undergo facile ring-chain tautomerism, thus affording a latent source of thiol-imine, which can be trapped with ethyl mercapto-acetate at 100°-110° to afford 77 in low yield [Eq. (22)].63 If the corresponding acid is used and water is continuously removed, the yield of 77 approaches 75%. 

Tetrahydro-lf/-l,3-diazepine-2-thiol (73), when heated with ethyl chloro-acetate, gives 74 while the reaction of 73 with chloroacetic acid in aqueous medium affords 3-(<5-aminobutyl)thiazolidine-2,4-dione (75) [Eq. (21)], via initial generation 74, followed by hydrolysis.94 Substituted 2-mercapto-imidiazolines undergo similar ring transformations.95-97... 

A three-component sequence consisting of modified Sonogashira crosscoupling I and cyclocondensation of (hetero)aroyl chlorides 4, terminal alkynes 5, and ethyl 2-mercapto acetate gives rise to 2,4-disubstituted thiophene 5-carboxylates 45 in generally good to excellent yields (Scheme 27) (2012CC(48)2080). 

The enzyme is specific for thiol esters of the type of S-acetyl and S-butyryl glutathione. Besides the three thiol esters already discussed, ethyl thiol-acetate, butyl thiolacetate, acetyl thioglycolic acid, acetyl mercapto propionic acid, S-acetyl-2 mercaptoethanol, acetyl thiomalic, acetyl coenzyme A, and butjryl coenzyme A were inactive with the purified enzyme. Crude extracts of liver attacked butyl thiolacetate and acetyl coenzyme A slowly. 

C4H8O2S mercapto-acetic acid ethyl ester 623-51-8 ... 

Finally,Captopril is produced. Thethioester (0.85g) isdissolved in5.5N methanolicammonia and the solution is kept at room temperature for 2 hours. The solvent is removed in vacuo and the residue Is dissolved in water, applied to an ion exchange column on the H cycle (Dowex 50, analytical grade) and eluted with water. The fractions that give positive thiol reaction are pooled and freeze dried. The residue Is crystallized from ethyl acetate-hexane, yield 0.3 g. The 1 -(3-mercapto-2-D-methylpropanoyl)-L-proline has a melting point of 103°C to 104°C. 

Heating of the acetic acid ethyl ester-substituted mercapto-substituted pyrimidine 214 in acetic acid and sulfuric acid led to cyclodehydration to give the tricyclic system 215 in moderate yield (Equation 57) <2005PS(180)1629>. 

The reaction of 2-mercapto-4-(2, 4 -dichlorophenyl)-5-cyanopyrimidin-6(l//)one 421 (obtained by stirring ethyl cyanoacetate and thiourea with 2,4-dichlorobenzaldehyde in sodium ethylate at room temperature, in 70% yield), with a solution of monochloroacetic acid and />-cholorobenzaldehyde in glacial acetic acid, in the presence of sodium acetate, affords 2-[(/>-chlorophenyl)methylene]-6-cyano-7-(2, 4 -dichlorophenyl)thiazolo[3,2-tf]pyrimidin-3,5-dione 422. Finally, the reaction of compound 422 with hydrazine hydrate converts it into product 423 (Scheme 49) < 1996PS( 116)39>. 

Ochiai, who reported in 1936 the first synthesis of the imidazo[2,l-h]thia-zole system (36CB1650), transformed ethyl 2-mercapto-5-methyl-imidaz-oIe-4-carboxylate with monochloroacetone into 2-(acylalkylthio)-imidazole 36. Refluxing 36 in phosphorus oxychloride yields ethyl 3,5-dimethylim-idazo[2,l-h]thiazole-6-carboxylate. No cyclization could be achieved by heating 36 in acetic anhydride because N-acylation (to 37) inhibited further reaction to the bicyclic system. 

Certain reactions must be catalyzed by aqueous alkali (90MI2 91USP4988812) or by sodium ethoxide, e.g., the condensation of 3-mercapto-AT and ethyl acetoacetate (68UP1), which does not proceed in acetic acid (60JOC361), in contrast with the analogous reaction with acetylacetone (60JCS1829). 

Synthesis of the complex. In a 50-mL Schlenk flask, N,N-bis(2-mercapto-ethyl)2-methylthioethylamine (0.1 g, 0.47 mmole) is dissolved in methanol (10 mL) and subsequently cooled to 5°C in an ice bath. To the cooled solution, a solution of anhydrous nickel acetate (84 mg, 0.47 mmole) in methanol (10 mL) is added dropwise with rapid stirring. The product, a red-black, microcrystalline solid, forms immediately and is collected by filtration, washed several times with small amounts of methanol, and dried in vacuo. Yield = 160 mg (65%). The product obtained from purified ligand is pure by elemental analysis. If crude ligand is used, the complex may be purified by recrystallization from CH2C12 (minimum volume for dissolution) upon addition of petroleum ether or hexane (five times the volume of CH2C12 used). 

Keeping in view the biological and synthetic importance of the (3-lactams and the potential of solvent-free microwave chemistry, Kidwai et al. [148] prepared (3-lactams via an ester-imine based synthesis under solvent-free microwave irradiation. The //Y/n.v-4-aminocyclohexanol (128) was condensed with different aromatic aldehyde to give the respective Schiff base. The Schiff-base was then reacted with ethyl a-mercapto/a-cyano acetate, in the presence of basic alumina, to afford the required 3-mercapto/cyano (3-lactams respectively, outlined in Scheme 41. 

The l-[D-3-(acetylthio)-2-methyl-l-oxopropyl]-cis-4-phenylthio-L-proline (2.0 g, 0.0042 mole) is treated with 3.5 ml of concentrated ammonia in 8.5 ml of water. The base dissolves in about 30 min and the resulting solution (under Argon) is allowed to stand for 2 h at room temperature. This solution is cooled, extracted with 25 ml of ethyl acetate (2 times) and the ethyl acetate extract is discarded. The solution is again layered with 25 ml of ethyl acetate and acidified with 17 ml of 1 1 hydrochloric acid. The mixture is shaken, separated and the aqueous phase extracted with 25 ml of ethyl acetate (3 times). The organic phases are combined, dried (MgS04), filtered and the solvent removed on the rotary evaporator to give to give 1.35 g (100%) of viscous syrupy l-(D-3-mercapto-2-methyl-l-oxopropyl)-cis-4-phenylthio-L-proline. 

A dilution experiment by SHA-0 indicated acetaldehyde, ethyl acetate, dimethylsulfide and dimethyltrisulfide as further potent odorants in Scheurebe and Gewurztraminer wines. AEDA and SHA-0 yielded the same assessment of 4-mercapto-4-methylpentan-2-one and cis-rose oxide, which are responsible for the odor difference of the two varieties, investigated in this study. It should be mentioned that only one sample of each variety was analyzed and for more generality further investigations are necessary. 

To estimate the sensory contribution of the 42 odorants to the overall flavor of the wine samples, their OAV s were calculated (Table II). To take into account the influence of ethanol, the odor threshold values of wine odorants were determined in a mixture of water/ethanol (9+1, w/w) and were used to calculate the OAV s for each compound. According to the results in Table A, 4-mercapto-4-methylpentan-2-one, ethyl octanoate, ethyl hexanoate, 3-methylbutyl acetate, ethyl isobutyrate, (E)-fi-damascenone, linalool, cis rose oxide and wine lactone showed the highest OAV s in the Scheurebe wine. With exception of 4-mercapto-4-methylpentan-2-one the above mentioned odorants also showed the highest OAV s in Gewurztraminer wine. Differences in the OAV s of ethyl octanoate, ethyl hexanoate, 3-methylbutyl acetate and ethyl isobutyrate between the two varieties are probably caused by differences in the maturity of the fruit at harvest and/or by the fermentation process. 

Testosterone. A 4-Chloro 17-acetate (S-114), 4-bromo (S-8), 4-methyl (S-11), 4-chloro 11/3-hydroxy 17-acetate (S-7), 4-fluoro 17-acetate (S-9), 4-hydroxy 17-acetate (S-10), la-methyl 4-chloro 17-acetate (S-79), 4-chloro 17-propionate (S-6), 4-hydroxy 17a-methyl (S-16), 4-chloro Ha-methyl (S-17), 4-mercapto 17a-methyl (S-49), 4-methylthio 17a-methyl (S-50), 4-ethylthio 17a-methyl (S-51), 4-acetylthio 17a-methyl (S-52), and 4-chloro 11/3-hydroxy 17a-methyl (S-102) substitutions all decrease the androgenic property. However, the anabolic potency is only slightly decreased and in a few cases increased, such as S-114, S-11, S-16, S-6. Substitution at the 4-position by bulky substituents i.e., 4-ethyl (S-13) and 4-allyl (S-14), abolishes both activities. 

Testosterone. 7a-Methyl (S-21), 7o -methylthio 17-acetate (S-119), 7o -mercapto 17-acetate (S-121), and la,7a-dimethyl 17-acetate (S-80) compared to la-methyl 17-acetate (S-72) 7a-methyl 17-ketone (S-23) compared to I7-ketone (S-22) 7a-methyl A 17a-methyl (S-138), 7a-mercapto A 17a-methyl (S-57), and 7a-acetylthio A 17a-methyl (S-58) compared to A 17a-methyl (S-15) and 7a-methyl 17a-methyl (S-20) substitutions all increase both potencies, giving rise very often to a favorable anabolic-androgenic ratio. 7a-Acetylthio 17-acetate (S-120), 7a-mercapto 17a-methyl (S-53), 7a-methylthio 17a-methyl (S-54), 7a-ethyl-thio 17a-methyl (S-55), and 7a-acetylthio 17a-methyl (S-56) substitutions cause decrease of both androgenic and anabolic potencies while maintaining a favorable anabolic-androgenic ratio. 

Treatment of diphenylacetonitrile in toluene with sodium amide and 2-chloro-pyrazine gave 2-(C-cyano-C,C-diphenylmethyl)pyrazine (1021), and 2-vinylpyrazine with phenylacetonitrile and sodium heated at 120-130° for 10 minutes gave 2-(3 -cyano-3 -phenylpropyl)pyrazine (731). 2-Amino-5-bromomethyl-3-cyano-pyrazine with sodium hydride and methyl cyanoacetate in tetrahydrofuran formed the dialkylated product (56) (1031). 2-Amino-3-mercapto-5,6-dimethylpyrazine in methanol with potassium hydroxide and chloroacetonitrile gave 2-amino-3-cyanomethyIthio-5,6-dimethylpyrazine (1229), and 2-carboxypyrazine refluxed with chloroacetonitrile and triethylamine in ethyl acetate for 45 minutes gave the cyanomethyl ester (1317). 2-Hydroxy 5-methyl-3-propylpyrazine with cyanogen halides in aqueous sodium hydroxide-dimethylformamide at 0-5° gave l-cyano-5-methyl-2-oxo-3-propyl-l, 2-dihydropyrazine (1123). 

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