Syntheses with nitriles, XCV: Deamination of cytosine derivatives
摘要:
Treatment of 2-formyl-3-dimethylamino-propenenitrile (1a) and 2-ethoxycarbonyl-3-dimethylamino-propenenitrile (1b), resp., with substituted ureas led to the 2-cyano-3-ureidoacrylates 2, which can be cyclized under alkaline conditions to give 5-formyl-5-cyano-, and 5-alkoxycarbonyl-2-oxopyrimidine derivatives 3, 6, and 7. Reaction of 3 with isopentylnitrite gave a mixture of the deaminated and oxidized product 4 and the oxo derivative 5, which was acetalized during the separation step. Similar reaction with the alkoxycarbonyl derivatives 7 led to the formation of 1-alkyl-5-alkoxycarbonyl-pyrimidine-2,6-diones 8a-d.
Synthesis with Nitriles: 92. Synthesis of 5-Formylcytosine Derivatives
摘要:
The reactivity of 3-dimethylamino-2-formylpropenenitrile (1) with various amino compounds is studied. Thus, condensation of 1 with anilines gives the corresponding azomethines (2a-c). Reaction of 1 with thiourea and guanidne resp., leads to 5-formylthiocytosine (3) and 2-amino-5-cyanopyrimidine (4). The 2-formyl-3-ureidopropenenitriles (5a-i) can be obtained by reaction of 1 with urea and substituted ureas. 5a-i can easily be cyclized to 3-substituted 5-formylcytosines (6-e). Condensation of 6 with aniline, benzylamine and phenylhydrazine leads to the azomethines (7a-i). Pyrido [ 2,3-d ] pyrimidine-6-carbonitriles (8a, 8b, Sd and 83) are obtained by reaction of 6 with malononitrile.