ELUCIDATION OF THE REACTION-PATH FOR THE NITROSATION OF 2-METHYLPYRIDINE 1-OXIDES AND 4-METHYLPYRIDINE 1-OXIDES WITH ALKYL NITRITE IN LIQUID-AMMONIA

The reaction path for the nitrosation of 2- and 4-methylpyridine 1-oxides with alkyl nitrite in the presence of NaNH2 in liquid NH3 was elucidated experimentally, and theoretically by the use of a semiempirical molecular orbital method (PM3 method). In the case of the nitrosation of 4-methylpyridine 1-oxide at room temperature, only 4-pyridinecarboxamide 1-oxide was obtained, while at -33-degrees-C a thermodynamically unstable aldoxime, (Z)-4-pyridinecarbaldehyde 1-oxide oxime, which was easily transformed into E-form by heating, was obtained. On the other hand, the nitrosation of 2-methylpyridine 1-oxide gave only a thermodynamically stable aldoxime, (E)-2-pyridine-carbaldehyde 1-oxide oxime, both at room temperature and at -33-degrees-C. These results were reasonably explained by PM3 method.