GB685021A - A new substituted aminopropane diol and processes for its preparation - Google Patents

Abstract

The invention comprises DL-erythro 2-o-carboxybenzamido - 1 - p - nitrophenylpropane - 1 : 3-diol, and the manufacture thereof by condensing p-nitrobenzaldehyde with a -phthalimidoacetaldehyde in the presence of a basic condensing agent to produce a compound having a melting-point between 145 DEG and 185 DEG C., reducing this by known methods for the reduction of an aldehyde group to an alcohol group without affecting a nitro group, and hydrolysing the product under alkaline conditions. The condensation may be effected in an anhydrous organic solvent (e.g. dioxane or pyridine) at 0-25 DEG C. in the presence of a strong organic base (e.g. piperidine, preferably in the form of its acetate, or a strong tertiary amine free from hydroxy groups, such as triethylamine), and the reaction conditions are preferably chosen so that the condensation product (which is probably an addition product of the compound of the formula <FORM:0685021/IV (b)/1> with a -phthalimidoacetaldehyde) has a melting-point between 150 DEG and 170 DEG C. The reduction of this compound to 2-phthalimido-1-p-nitrophenylpropane-1 : 3-diol may be effected by the Meerwein method using an oxidizable aluminium alkoxide (preferably derived from a secondary aliphatic alcohol) or by means of an alkali metal borohydride (advantageously at 10-50 DEG C. in an organic solvent, preferably methanol, dioxane or dimethylacetamide). The hydrolysis is conveniently effected with dilute aqueous caustic soda, after which the reaction mixture may be extracted with ether and the aqueous phase acidified to precipitate the desired product. In examples, the reduction step is effected by means of: (1) and (2) aluminium isopropoxide in isopropanol; (3) sodium borohydride; (4) potassium borohydride.