5.6- Disubstituted 3-nitro-2-pyridones

Methyl-5-nitropyrimidin-4(3f/)-one reacts with ketones in the presence of ammonium salts to give 4,5-disubstituted pyrimidines or 5,6-disubstituted 3-nitro-2-pyridones depending on reaction conditions (Eq. 10.83).142... 

The action of hydrazine or hydroxylamine on certain other nitropyrimidine systems leads to 4-nitropyrazoles and 4-nitrooxazoles [549], When 1,5-disubstituted 4-nitro-6-pyridazinone derivatives are heated in an alkaline medium the derivatives of 4-nitropyrazole are formed with high yields. 1-Substituted 4-nitropyrazole-5-carboxyiic acids [550, 551] or 1-substituted 4-nitropyrazoles [552-554] can be obtained, depending on the conditions. Another promising method of synthesis has been opened up for the production of 4-nitropyrazole derivatives. 4-Nitropyrazole is obtained with a high yield in the reaction of 3,5-dinitro-2-pyridone with hydrazine [555] (Scheme 99). 

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See also in sourсe #XX -- [ ]

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