GB731397A - Phenylaminopropanediols and their derivatives - Google Patents

Abstract

Aminopropanediols of the formula <FORM:0731397/IV (b)/1> where R1 is hydrogen or nitro and R2 is hydrogen or an aliphatic acyl group of 1-8 carbon atoms (optionally substituted by halogen) are prepared by reducing with sodium borohydride an acid chloride of the formula <FORM:0731397/IV (b)/2> where R3 and R4 are acyl groups as defined for R2, and hydrolysing the product to remove the group R4 and if desired the group R3 also. The reduction step is preferably carried out in an inert organic solvent such as dioxane. Partial hydrolysis may be effected with decinormal caustic soda and acetone at room temperature. For complete hydrolysis 5 per cent hydrochloric acid can be used. The starting materials can be of the erythro or threo form and may be optically active or racemic. They are obtained from the corresponding acids by treatment with thionyl chloride or phosphorus pentachloride. The products (R1=NO2, R2=H) can be converted into chloramphenicol as in Specification 718,580. In the examples: (1) the acid chloride of (-)-threo - N - dichloracetyl - O - acetyl - p - nitrophenylserine is reduced to O-acetyl-chloramphenicol and the latter hydrolysed to chloramphenicol; (2) the acid chloride of racemic erythro - O : N - diacetyl - p - nitrophenylserine is reduced to 1-(p-nitrophenyl)-1-acetoxy - 2 - acetamido - 3 - propanol and the product hydrolysed to dl-erythro-1-(p-nitrophenyl) - 2 - amino - 1 : 3 - propanediol; (3) the acid chloride of (-)-threo-O : N-diacetylphenylserine is reduced to (-)-threo-1-phenyl-1-acetoxy - 2 - acetamido - 3 - propanol which can be either hydrolysed to (-)-threo-1-phenyl-2 - amino - 1 : 3 - propanediol or acylated, nitrated and hydrolysed to give (-)-threo-1-(p - nitrophenyl) - 2 - amino - 1 : 3 - propanediol.