Treatment of 3-methyl-6-(1-methylhydrazino) uracil (I) with phenacyl bromides in ethanol afforded the corresponding 3-aryl-4, 8-dihydro-1, 6-dimethylpyrimido [4, 5-c]-pyridazine-5, 7 (1H, 6H)-diones (3-aryl-4, 8-dihydro-4-deazatoxoflavins) (II) and 3-aryl-1, 7-dimethyl-6, 8-dioxo-1, 4, 6, 7, 8-pentahydropyrimido [4, 3-c]-as-triazines (III). Oxidation of II with diethyl azodicarboxylate gave the corresponding 3-aryl-4-deazatoxoflavins (IV) in quantitative yields. The reaction of aryl aldehyde N-methyl-N-(3-methyluracil-6-yl)-hydrazones (VII) with triethyl orthoformate in dimethylformamide also gave the corresponding 3-aryl-4-deazatoxoflavins (IV). Compounds IV thus obtained oxidized alcohols under alkaline conditions in the dark to yield the corresponding carbonyl compounds, while they themselves were hydrogenated to compounds II. Under certain conditions, these oxidations were automatically recycled to give the corresponding carbonyl compounds in more than 100% yields.
在
乙醇中将 3-甲基-6-(1-甲基
肼基)尿
嘧啶(I)与苯
乙酰溴处理,可得到相应的 3-芳基-4,8-二氢-1,6-二
甲基嘧啶并[4,5-c]
哒嗪-5、7(1H,6H)-二酮(3-芳基-4,8-二氢-4-脱氮恶黄素)(II)和 3-芳基-1,7-二甲基-6,8-二氧代-1,4,6,7,8-五氢
嘧啶并[4,3-c]-as-三嗪(III)。用
偶氮二甲酸二乙酯对 II 进行氧化,可以定量得到相应的 3-芳基-4-脱氮恶黄素(IV)。芳基醛 N-甲基-N-(3-甲基尿
嘧啶-6-基)-
肼(VII)与
原甲酸三乙酯在二甲基甲酰胺中的反应也得到了相应的 3-芳基-4-脱氮恶黄素(IV)。这样得到的化合物 IV 在黑暗的碱性条件下氧化醇,生成相应的羰基化合物,而它们本身则氢化成化合物 II。在某些条件下,这些氧化反应会自动循环,生成相应的羰基化合物,收率超过 100%。