The side chain at C-8 (R-8) can be ethyl, n-propyl, isobutyl, or neo-pentyl. The side chain at C-12 (R12) can be methyl or ethyl. The C-8 ethyl group of 3-vinyl-BChlide d is methylated by BchQ, and the C-12 methyl group of 3-vinyl-BChlide d is methylated by BchR (...