| 主权项 |
1. A process for the synthesis of chiral 3-substituted tetrahydroquinoline of general formula 2 from 4,5 disubstituted o-nitrohydrocinnamaldehy of general formula 1 with high enantioselectivity (99%) wherein, R and R1 is independently selected from the group consisting of hydrogen, hydroxyl (C1-C6) alkyl, halogen, aryl, alkylaryl, (C1-C6) alkoxy, protecting group such as t-Butyldiphenylsilyl ether (OTBDPS), Methoxymethyl ether (O-MOM), Tosyl, Benzyl, t-Butyl carbamate (Boc) or R and R1 together form —O—CH2—O— linkage; and ‘X’ is selected from —OH or disubstituted hydrazine-1,2-dicarboxylate of formula (—N—CO2R2—NH—CO2R2); wherein ‘R2’ is selected from the group consisting of branched or unbranached (C1-C6) alkyl, preferably ethyl, isopropyl, t-butyl, or substituted or unsubstituted aryl preferably (4-chlorobenzyl) wherein the said process comprising α-functionalizing of aldehyde by stirring 4,5 disubstituted o-nitrohydrocinnamaldehy, a polar aprotic organic solvent, nitrosobenzene or dialkyl azodicarboxylate in presence of D or L proline at temperature ranging between −20 to 30° C. for a period ranging between 10 min to 4 hrs followed by in situ intramolecular reductive cyclization of α-functionalized aldehyde by stirring in presence of 10% PdCH2, (1 atm) and an organic solvent at temperature ranging between 20° to 30° C. for a period ranging between 6 to 12 h to obtain chiral 3-substituted tetrahydroquinoline. |
