Nitric Acid → 1,2-Dimethoxy-4-nitrobenzene

Participants

Reaction Steps

In SCHEME 5 veratrol (12) is selectively nitrated with 70% HNO3 in AcOH to give 4-nitroveratrol (21). Subsequent reaction of (21) with Buli and TMEDA in THF followed by trimethylborate and hydrochloric acid gives boronic acid (22). Boronic acid (22) is reacted under inert conditions with a brominated aromatic or heteroaromatic ester of generell type (15) under Suzuki-type basic conditions (Pd(PPh3)4 and aqueous sodium bicarbonate in dimethoxyethane) to a biaryl of type (23). Biaryl (23) is further hydrolized with aqueous lithium hydroxide in THF and MeOH or MeCN to give the corresponding carboxylic acid (24) which is converted to a building block of type (25) by reaction with oxalyl chloride in anhydrous dichloromethane.

Provenance & Evidence