Methylation of 5-isonitroso-1,3-dioxine-4,6-diones (1) with diazomethane afforded 5-methoxyimino-1,3-dioxine-4,6-diones (4) and 5-methylimino-1,3-dioxine-4,6-dione N-oxides (5) together with a cyclic nitrone (7) as a minor product. Compound (5) reacted with two molar equivalents of triphenylphosphine to give phosphonium betaines (8) whereas photoreaction of 5 formed novel spiro compounds (9)via oxaziridine intermediates (G).
Synthesis of Nucleosides and Related Compounds. XXXIV. Synthesis of 5-Isonitroso-1,3-dioxane-4,6-diones and Their Reactions.
Synthesis of 5-isonitroso-1, 3-dioxane-4, 6-dione (2 : isonitroso Meldrum's acid) and related compounds and their reactions were described. Compound (2) reacted with various alcohols to give hydroxyiminoacetic acid esters in moderate yields. Compound 2 was acetylated in the usual manner to give 5-acetoxyimino-1, 3-dioxane-4, 6-dione (9)as a stable crystalline substance, which acted not as a heterodiene but as a heterodienophile and underwent hetero Diels-Alder reaction with various dienes to form [4+2] adducts.