Abstract
The reaction of 5-bromo-6-bromomethyl-1, 3-dimethyl- (1a) and 5-bromo-6-bromomethyl-1-(3-bromopropyl)-3-methyl-2, 4(1H, 3H)-pyrimidinedione (4a) with 1.0 and 2.0 eq of the sodium salt of 2-nitropropane yielded a mixture of 6-formyl (2 and 5a) and carbon-carbon bond-cleavage products (3 and 6a). When a large excess of the sodium salt of 2-nitropropane was used, 3 and 6a were obtained as sole products, respectively. The nitrates [(5-bromo-1, 3-dimethyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-6-yl)methyl nitrate (1b) and the dinitrate of 5-bromo-6-hydroxymethyl-1-(3-hydroxypropyl)-3-methyl-2, 4(1H, 3H)-pyrimidinedione (4b)] were exclusively converted to 6-formylpyrimidines (2 and 5b) or 6-unsubstituted pyrimidinediones (3 and 6b) by reaction with 1.0 or 2.0 eq of sodium methoxide, respectively. The dinitrate of 5-bromo-1-(2-hydroxyethyl)-6-hydroxymethyl-3-methyl-2, 4(1H, 3H)-pyrimidinediones (7) was treated with sodium methoxide to yield 2-(5-bromo-6-formyl-3-methyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-1-yl)ethyl nitrate (8), a 3, 4-dihydropyrimido[6, 1-c][1, 4]oxazine derivative (9) and 2-(5-bromo-3-methyl-2, 4-dioxo-1, 2, 3, 4-tetrahydropyrimidin-1-yl)ethyl nitrate (10). A plausible reaction mechanism is presented.
