T 1452 (OTTO) 3,4,5-Trimethoxybenzoic acid, 99% Cas 118-41-2 - used as intermediates in medicine and organic synthesis. 3,4,5-Trimethoxybenzoic acid, 99% Cas 118-41-2 - used in making dyes and inks, photographic developers and used as astringents in medically.