GB811846A - Improvements in or relating to the production of chloramphenicol and similar compounds - Google Patents

Abstract

A process for the manufacture of 1-nitro-phenyl - 2 - acylamino - 1 : 3 - diols and their o1 or o3-mono-acyl derivatives comprises reacting nitric esters of the general formula <FORM:0811846/IV (b)/1> wherein R1 and R2 signify a hydrogen atom, a nitro group or an acyl residue with the proviso that either R1 or R2 must be -NO2, and R3 signifies an acyl residue, with a ferrous salt in the presence of water. In examples (1): l-threo-1 - (p - nitrophenyl) 2 - dichloracetylamino - propane-1 : 3-diol (prepared by the nitration of l-threo - 1 - phenyl - 2 - dichloracetylamino-propane-1 : 3-diol with 86 per cent nitric acid at - 20 DEG C.) is treated with an aqueous solution of ferrous sulphate and sulphamic acid to form chloramphenicol; (2) l-threo-1-(p-nitrophenyl) 2 - dichloracetylaminopropane - 1 : 3 - diol-O1 - palmitoyl - O3 - mononitric ester (prepared by the reaction of l - threo - 1 - (p - nitrophenyl) - 2 - dichloroacetylamino - propane-1 : 3 - diol - O3 - mononitric ester with palmitic acid chloride in the presence of pyridine) is treated with a solution of ferrous chloride and sodium formate in methanol to give l-threo-1-(p - nitrophenyl) - 2 - dichloracetylaminopropane - 1 : 3 - diol - O1 - palmitate; (3) l-threo-1 - (p - nitrophenyl) - 2 - dichloracetylamino-propane - 1 : 3 - diol - O3 - palmitoyl - O1-mononitric ester (produced by the nitration of l - threo - 1 - phenyl - 2 - dichloracetylamino-propane - 1 : 3 - diol - O3 - palmitic acid ester) is treated with a solution of ferrous chloride and sodium formate in methanol to give l-threo-1-(p - nitrophenyl) - 2 - dichloracetylamino - propane - 1 : 3 - diol - O3 - palmitic acid ester; (4) in a process similar to that of Example (3) a solution in methanol of ferrous chloride and potassium sulphamate is used to treat the ester; (5) D(-)-threo-1-(p-nitrophenyl)-2-dichloracetylaminopropane - 1 : 3 - diol - dinitric ester is treated with ferrous ammonium sulphate in methanol to give D(-)-threo-1-(p-nitrophenyl)-2-dichloracetylamino-propane-1 : 3-diol.