Patent GB-565501-A (GB)
Title: Manufacture of para-amino-benzene-sulphonamido-pyrimidines
IPC: C07D239/69
Filed: 1943-03-04
Abstract: Para - aminobenzene - sulphonamido pyrimidines are made by treating with a hydrolysing agent a 2-, 6- (identical with 4-) aminopyrimidine N-substituted by two identical benzene sulphonyl residues and containing in para position in the benzene nuclei an amino group or a substituent convertible by hydrolysis or reduction into the amino group.  Alternatively, the 2- or 6-aminopyrimidine may be reacted with the aminopyrimidine from which the aminopyrimidine substituted by two benzene sulphonyl residues used in the reaction is derived. Finally, when necessary, the product is treated with a hydrolysing or reducing agent to form the para amino group.  In the first of the above two alternatives, one of the benzene sulphonyl residues is split off and one molecule of final product is obtained from one mol. of starting material.  In the second alternative process, two mols. of the benzene sulphonamido pyrimidine are obtained from one mol. of starting material.  Starting materials mentioned include bis-N-(p-acylaminobenzenesulphonyl)-such as bis-N-(p-acetylaminobenzenesulphonyl)-, or bis - N - (p - nitrobenzenesulphonyl) - 2 - amino - pyrimidines or 2-amino-alkyl-pyrimidines, such as 2-amino-4-methyl-pyrimidine, or 2-amino-4 : 6-dimethyl-pyrimidines, or 6-amino-alkylpyrimidines, such as 6-amino-2 : 4 - dimethyl - pyrimidines.  In examples: (1) Bis-N-(p-nitrobenzenesulphonyl) - 6 - amino - 2 : 4 - dimethyl - pyrimidine is heated with 6 - amino - 2 : 4 - dimethylpyrimidine in pyridine solution and the product reduced with iron and hydrochloric acid to give 6-(p-aminobenzenesulphonamido)-2 : 4-dimethylpyrimidine. (2) Bis-N-(p-nitrobenzenesulphonyl) - 6 - amino - 2 : 4 - dimethyl - pyrimidine is boiled with aqueous caustic soda and the hydrolysis product acidified with hydrochloric acid to give 6-(p-nitrobenzenesulphonamido)-2 : 4-dimethyl pyrimidine, which may be reduced as in example (1) to give the corresponding para-amino compound.  (3) Bis-N - (p - acetylaminobenzenesulphonyl) - 6 - amino - 2 : 4 - dimethyl pyrimidine is heated with 6-amino - 2 : 4 - dimethylpyrimidine in pyridine solution to give 6-(p-acetylaminobenzenesulphonamido) - 2 : 4 - dimethyl - pyrimidine which may be hydrolysed to the free para-amino compound.  (4) Bis-N-(p-acetylaminobenzenesulphonyl)-6-amino-2 : 4-dimethyl pyrimidine is hydrolysed with aqueous caustic soda and 6 - (p - aminobenzenesulphonamido) - 2 : 4 - dimethyl-pyrimidine precipitated with acid.  (5) Bis-N-(p-nitrobenzenesulphonyl)-2-amino-4 : 6-dimethyl pyrimidine is hydrolysed with caustic soda, the product precipitated with acid and reduced with iron and hydrochloric acid to give 2 - (p - aminobenzenesulphonamido) - 4 : 6 - dimethyl pyrimidine.  Bis - N - (p-nitrobenzenesulphonyl) - 6 - amino-2 : 4-dimethyl pyrimidine is prepared by suspending 6-amino-2 : 4-dimethyl-pyrimidine in dry pyridine and treating it with para-nitrobenzene sulphochloride.  Bis - N - (p - acetylaminobenzenesulphonyl)-6-amino-2 : 4-dimethyl pyrimidine is similarly prepared using para-acetylaminobenzene sulphochloride.  Bis - N - (p-nitrobenzenesulphonyl) - 2 - amino-4 : 6 - dimethyl - pyrimidine is prepared by suspending 2-amino-4 : 6-dimethyl-pyrimidine in dry pyridine and treating it with paranitrobenzene sulphochloride.