Regioselective Reduction of 1H-1,2,3-Triazole Diesters

Regioselective reactions can play pivotal roles in synthetic organic chemistry. The reduction of several 1-substituted 1,2,3-triazole 4,5-diesters by sodium borohydride has been found to be regioselective, with the C(5) ester groups being more reactive towards reduction than the C(4) ester groups. The amount of sodium borohydride and reaction time required for reduction varied greatly depending on the N(1)-substituent. The presence of a beta-hydroxyl group on the N(1)-substituent was seen to have a rate enhancing effect on the reduction of the C(5) ester group. The regioselective reduction was attributed to the lower electron densities of the C(5) and the C(5) ester carbonyl carbon of the 1,2,3-triazole, which were further lowered in cases involving intramolecular hydrogen bonding.

Automated summary

Regioselective reactions are important in synthetic organic chemistry, as seen in the reduction of 1-substituted 1,2,3-triazole 4,5-diesters where the C(5) ester groups are more reactive and the presence of a beta-hydroxyl group on the N(1)-substituent enhances the reduction rate. The regioselectivity is attributed to lower electron densities in the C(5) and C(5) ester carbonyl carbon of the 1,2,3-triazole, especially in cases involving intramolecular hydrogen bonding.