Pyrimidine derivatives and related compounds. Part 41. Reactions of 1,3,6-trimethyl-5-nitrouracil and its 6-bromomethyl analogue with amines and hydrazines. Synthesis of pyrazolo[4,3-d]pyrimidine N-oxides and their ring expansion to pyrimido[5,4-d]pyrimidines

doi:10.1039/P19820000277

Paper

Pyrimidine derivatives and related compounds. Part 41. Reactions of 1,3,6-trimethyl-5-nitrouracil and its 6-bromomethyl analogue with amines and hydrazines. Synthesis of pyrazolo[4,3-d]pyrimidine N-oxides and their ring expansion to pyrimido[5,4-d]pyrimidines

Published 1982 · K. Hirota, Y. Yamada, T. Asao

Journal of The Chemical Society-perkin Transactions 1

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6

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Abstract

Reactions of 1,3,6-trimethyl-5-nitrouracil (1) and 6-bromomethyl-1,3-dimethyl-5-nitrouracil (4) with amines and hydrazines have been studied with the aim of synthesising fused-ring pyrimidines. Treatment of compound (4) with primary amines afforded 2-substituted pyrazolo[4.3-d]pyrimidine 1-oxides (6a–I). Of these, compounds (6h–I) were converted into pyrimido[5,4-d]pyrimidines (11) by treatment with sodium ethoxide. Although treatment of compound (1) with hydrazines caused the known ring transformation giving pyrazolones (2a and b), a new type of denitration reaction was found when compound (4) reacted with hydrazines yielding 6-hydrazonomethyl-1,3-dimethyluracils (15a and b). Treatment of the 6-(substituted methyl)-1,3-dimethyl-5-nitrouracils (13b–d) and (14)[prepared from (4)] with hydrazines also gave (15a and b). Mechanisms for the formation of compounds (6), (11), and (15) are discussed.

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This study demonstrates the synthesis of fused-ring pyrimidines by reacting 1,3,6-trimethyl-5-nitrouracil and its 6-bromomethyl analogue with amines and hydrazines, yielding 6-hydrazonomethyl-1,3-dimethyl-5-

PopulationOlder adults (50-71 years)

Sample size24

MethodsObservational

OutcomesBody Mass Index projections

ResultsSocial networks mitigate obesity in older groups.

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Paper

Pyrimidine derivatives and related compounds. Part 41. Reactions of 1,3,6-trimethyl-5-nitrouracil and its 6-bromomethyl analogue with amines and hydrazines. Synthesis of pyrazolo[4,3-d]pyrimidine N-oxides and their ring expansion to pyrimido[5,4-d]pyrimidines

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References

Citations

An appraisal on synthetic and pharmaceutical perspectives of pyrazolo[4,3-d]pyrimidine scaffold.

Pyrazolo[4,3-d]pyrimidine scaffold has shown potential as an anti-cancer, anti-infectious, and phosphodiesterase inhibitor drug due to its diverse synthetic and pharmacological activities.

Synthesis of fused pyrazoles via intramolecular cyclization of appropriately ortho-substituted nitroarenes and nitroheteroarenes

Intramolecular cyclization of ortho-substituted nitroarenes and nitroheteroarenes is a convenient route for the synthesis of fused pyrazoles, their 1-oxides, and 1-hydroxy derivatives.

An Unexpected Pyrimidine Ring Transformations in the Reaction of 4‐aryl‐5‐nitro‐6‐bromomethylpyrimidin‐2(1H)‐ones with Anilines

The reaction of 4-aryl-6-bromomethyl-5-nitro-3,4-dihydropyrimidin-2(1H)-ones with anilines leads to unexpected pyrimidine ring transformations, including imidazolone formation and 7-aryl-6,7-dihydrois

Bicyclic 5-6 Systems: Other Four Heteroatoms 2:2

This paper explores 59 bicyclic 5-6 systems, including Viagra, and reveals their aromatic nature and reactivity patterns, with potential applications in organic conductors and drug discovery.

Pyrazol-3-ones. Part II: Reactions of the Ring Atoms

Pyrazol-3-ones can react with various compounds, forming weak acids and tautomers depending on the solvent, and can be titrated with strong bases.