Pyrano[4,3-d]pyrimidinium salts 4. Transformations of 5,7-diaryl-1,3-dimethyl-2,4-dioxo-1H,3H-pyrano[4,3-d]pyrimidinium bromides under the action of phenylhydrazines and aromatic acid hydrazides |
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Authors: | Kostrub V V Tsupak E B Smol’yakov A F |
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Institution: | (1) Department of Organic Chemistry, V.N. Karazin Kharkov National University, 4 Svobody sq., Kharkov, 61077, Ukraine;(2) STC “Institute for Single Crystals”, 60 Lenin ave., Kharkov, 61001, Ukraine |
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Abstract: | Reactions of 5,7-diaryl-1,3-dimethyl-2,4-dioxo-1H,3H-pyrano4,3-d]pyrimidinium bromides with phenylhydrazines and aromatic acid hydrazides have been studied. The reaction of the salts indicated
with phenylhydrazine at ∼20 °C results in the pyrylium ring opening, whereas elevated temperature leads to recyclization products,
i.e., 1,3-dimethylpyrido4,3-d]pyrimidine-2,4(1H,3H)-diones. The reactions of the starting bromides with m-carboxyphenylhydrazine and aromatic acid hydrazides lead to 6-(R-amino)-1,3-dimethyl-2,4-dioxo-1H,3H-pyrido4,3-d]-pyrimidinium salts. |
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