Phthalide and 2-hydroxymethyl-benzoic acid prepn. - by catalytic phthalaldehydic acid hydrogenation in alkaline soln. and acidification

摘要

Prepn. of phthalide (I) or opt. of 2-hydroxymethyl-benzoic acid, (II), comprises (a) catalytically hydrogenating phthalaldehydic acid in alkaline soln. pref. at pH 8-14; (b) precipitating (II) from reaction prod. soln. by acidification with acid; (c) exposing (II) to further activity of the acid until it is converted to (I), and (d) sepg. and recovering (I). Alternatively, (II) is opt. sepd. and recovered after pptn. When using aq. alkaline soln. hydrogenation of aldehyde gp. of phthalaldehydic acid is arrested at alcohol stage. Phthalide yields are =80%.