A case of unusual sterically driven C-tritylation reaction of tricyclic analogues of acyclovir
作者:Joanna Zeidler、Bożenna Golankiewicz
DOI:10.1016/s0040-4020(98)83029-9
日期:1998.3
3,9-Dihydro-3-[(2-hydroxyethoxy)methyl] 6-methyl-9-oxo-5H-imidazo[1,2-a]purine (1) and its silylated derivative (2) when tritylated under conditions suitable for regioselective N-5 alkylation underwent instead C-substitution to give 7-trityl (12, 3) and 7-(4-benzhydrylphenyl) (13, 4) derivatives as major and minor products, respectively. Substrates lacking 6-Me group (5, 6) yielded 5-tritylated (10, 7) and 5,7-ditritylated (11, 8) major products and 7-tritylated (9) minor product. The regioselectivity of the reaction seems to be driven mainly by steric hindrance of the 6-Me substituent. (C) 1998 Elsevier Science Ltd. All rights reserved.