Recyclization reactions of 1-alkylpyrimidinium salts

The reaction of 4-amino-2-benzyl-1-methyl-5-ethoxycarbonylpyrimidinium iodide ( 3 ) with alcoholic methylamine resulted in the formation of the methylimine of 2-amino-4- hydroxy-6-methylamino-5-phenylpyridine-3-carbaldehyde ( 5 ). Heating of the same pyrimidinium salt in benzylamine gave a mixture of products of two C - C recyclizations: 2-benzyl-4-benzylamino-5- carbamoylpyrimidine ( 7 ) and the benzylimine of 4-amino-2-benzyl-6- benzylaminopyrimidine- 5-carbaldehyde ( 8 ). The reaction of 2-amino-1,4-dimethyl-5- ethoxycarbonylpyrimidinium iodide ( 10 ) with KOH ethanolic solution gave a single product of C - C-recyclization: 2-amino- 5-acetyl-4-hydroxypyrimidine ( 11 ).