A concise synthesis of two pyrroles of marine origin
摘要:
2-Ethanolamine and (2R)-2-aminopropanol were converted into their N-pyrrole derivatives, 14 and 15, by reaction with 2,5-dimethoxytetrahydrofuran. The acetoxyacetyl derivatives of 14 and 15 were prepared and submitted to BBr3-promoted rearrangement. Acetylation of the resulting (2-acetoxyacetyl)pyrrol-1-yl-2-ethanol and 2-propanol furnished the corresponding acetates.
The synthesis of chiral 1-(1H-pyrrole) derivatives
摘要:
Enantiomerically pure primary amines possessing an epimerizable center, such as alpha-amino acids and their ester hydrochlorides, undergo condensation with tetrahydro-2,5-dimethoxyfuran 2 in acetic acid or acetic acid containing sodium acetate at 80 degrees C for 30 min. to give the corresponding 1-(1H-pyrrolyl) derivatives with partial racemization (9-18%). By replacing the solvent with a stirred mixture of aqueous acetic acid and 1,2-dichloroethane in the case of the acids and with water-1,2-dichloroethane for the ester hydrochlorides, repetition of the previous experiment gives the corresponding pyrroles in high yield and with complete retention of configuration, beta-Aminoalcohols are also efficiently converted to their 1-(1H-pyrrolyl) derivatives in a stirred, warm mixture of aqueous acetic acid and 1,2-dichloroethane. Copyright (C) 1996 Elsevier Science Ltd