β Scribed by Loreto Salazar; Charles J. Sih
No coin nor oath required. For personal study only.
Several prochiral esters of 1,4-dihydropyridines were enantioselectively hydrolyzed by Pseudomonas lipases (AK, P-30, and K-10) and Candida cylindracea lipase (OF-360). The stereochemical preferences of the lipases P-30 and K-10 were found to be always 4-Pro R and that of OF-360 to be 4-Pro S. In contrast, the prochiral preference of the lipase AK varied depending on the substitution on the dihydropyridine ring. The N-methoxymethyl derivatives afforded the 4S isomers (95% ee) whereas the N-unsubstituted compounds yielded the 4R isomers (50-70% ee).
Calcium antagonists of the type 4-aryl-l,4-dihydro-2,6-dimethyl-3,5-pyridine dicarboxylates are important peripheral vasodilators and are commonly used for the treatment of cerebro-circulatory disorders and hypertension.1 In many cases, the enantiomers have been shown to have different pharmacological properties. 2.3 Optically-active 1,4-dihydropyridines have been prepared by conventional chemical resolution of racemates or via chiral column chromatographic separation of the antipodes. 3
π SIMILAR VOLUMES
The fast enanfiosclecfive pm4tease-ca~yzed hydrelyses of 1,4-dihydropysklk~-3,5~\_~ diesters were developed. The monoesters obtained had high optical purity and wege useful chiral tmildiNg MOCKS which could ~ lead to optically active Cablockers.
## Abstract Both enantiomers of the six major kinds of __Ξ³__βlactones were synthesized to >98% e.e. in four steps, starting from succinic anhydride. The key features were the syntheses of the various __rac__β__N__βmethylβ4βhydroxyalkanamides via Grignard reaction and the enantioselective acetylatio