2- Mercapto-2-methylpropanoic acid

Equilibrium constants Ki reflect the degree of substitution, decreasing from 2.7 for mercaptoacetic acid to 1.31 for 2-mercaptopropanoic acid, and to 0.35 for 2-mercapto-2-methylpropanoic acid (T = 20 °C, / = 1.0 mol 1 ). The trend reflects steric interaction in the five-membered ring. These complexes decompose to yield the corresponding disulphides and iron(m) with a bimolecular rate-determining step. The overall mechanism,... 

A number of papers dealing with the interaction of copper(u) with sulphur-containing substrates have appeared. Complications found in the reaction of copper(n) with penicillamine have been outlined. These can be overcome substantially by using the related substrate 2-mercapto-2-methylpropanoic acid (21). The results indicate that the intensely brown complex (Amax = 485 nm, e = 15001 mol cm ) formed in the reaction with CUCI2 has a stoicheiometry [Cu aCu aC Os] and may be... 

Mercaptoethanol 2-Mercapto-2-methylpropanoic acid 2-Mercapto-A/-2-naphthylacetamide... 

For example, the enantiomer selective hydrolysis of racemic 3-methylthietan-2-one was performed in organic media in PER filled with Pseudomonas cepacia lipase (PcL) immobilized on Celite to produce enantiopure (R)-3-mercapto-2-methylpropanoic acid [86]. The product inhibition was successfully overcome by incorporating an aqueous extraction unit to give the product in 40% yield with 99% ee. 

The use of extracellular lipases of microbial origin to catalyze the stereoselective hydrolysis of 3-acylthio-2-methylpropanoic acid ester in an aqueous system has been demonstrated to produce optically active 3-acylthio-2-methylpropanoic acid [22-24], The synthesis of chiral side chain of captopril by the lipase-catalyzed enantioselective hydrolysis of the thioester bond of racemic 3-acetylthio-2-methylpropanoic acid 4 to yield S-(—)-4 has been demonstrated [25]. Among various lipases evaluated, lipase from Rhizopus oryzae ATCC 24563 (heat-dried cells) and lipase PS-30 in organic solvent system (1,1,2-trichloro-1,2,2-ttifluoroethane or toluene) catalyzed the hydrolysis of thioester bond, an undesired enantiomer of racemic 4, to yield desired S-(—)4, / -(+)-3-mercapto-2-methylpropanoic acid 5 and acetic acid 6 (Fig. 1). The reaction yield of more than 24% (theoretical maximum 50%) and enantiomeric excess (e.e.) of more than 95% were obtained for S -(—)-4 using each lipase in an independent experiment. 

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