GB478993A - Process for the manufacture of amides of thioformic acid - Google Patents

Abstract

Thioformylamides are prepared by reacting ammonia or amines with dithioformic acid or a salt thereof. The reaction is effected in a solvent and usually at ordinary temperature. Examples describe the preparation of (1) thioformanilide and thioformyl-anisidine from aniline and p-anisidine respectively; (2) monothioformyl-o-phenylenediamine from o-phenylenediamine; the product changes to benzimidazole on standing; (3) thioformylacetyl - o - phenylenediamine from monoacetyl - o - phenylenediamine; (4) thioformamide from ammonia; (5) N-ethylthioformamide from ethylamine; (6) dithioformylethylenediamine from ethylenediamine hydrate; (7) 1 - phenyl - 2 : 3 - dimethyl - 4 - thioformylamino-5-pyrazolone from the corresponding 4 - amino - pyrazolone; (8) 2-methyl-4-oxy-or amino - 5 - thioformylaminomethyl - pyrimidine from 2-methyl-4-oxy- or amino-5-amino-methyl-pyrimidine hydrochloride respectively; the second reactant in each case is either dithioformic acid or its potassium salt, whilst the solvent is water, alcohol or ether. 2 - Methyl - 4 - oxy - 5 - aminomethyl - pyrimidine is obtained by condensing formylsuccinic acid diethyl ester with acetamidine in the presence of sodium ethylate, converting the resulting 2-methyl-4-oxypyrimidyl-5-acetic acid ethyl ester into its hydrazide by means of hydrazine, treating it in alcohol solution with amyl nitrite in the presence of dry hydrochloric acid, and splitting the urethane of 2-methyl-4-oxy-5-aminomethyl-pyrimidine so formed with concentrated hydrochloric acid under pressure.