- On the reactions of 6-phosphoranylideneaminouracils and related 6-aminouracils with 2,4,6-cyclooctatrienone: Reactions of the intermediates of uracil-annulated 8-azabicyclo[5.3.1]Undecatetraene ring systems
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The reaction of 1,3-dimethyl-6-phosphoranylideneaminouracil (4) with 2,4,6-cyclooctatrienone (7) in AcOH gives an intermediacy of uracil-annulated 8-azabicyclo[5.3.1]undeca-2,4,7,9-tetraene (9), which results in the formation of 9-acetoxy-5a, 10-methano-2
- Nitta, Makoto,Kanda, Hiromi
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p. 491 - 499
(2007/10/03)
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- Carbon transfer reactions of functionalized oxazolidines and their open chain enamine tautomers to enamine nucleophiles. A facile synthesis of substituted pyridines and ring annulated derivatives
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Oxazolidines substituted at C-2 with -CH2-EW(-CO-, etc.) and capable of existing as ring-chain (enamine) tautomers react with cyclic, acyclic and heterocyclic enamine derivatives in a 1:1 stoi-chiometric manner to provide a versatile synthesis of substituted pyridines and their ring annulated derivatives.
- Singh, Kamaljit,Singh, Jasbir,Singh, Harjit
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p. 935 - 942
(2007/10/03)
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- A SIMPLE SYNTHESIS OF 1,3-DIALKYLPYRIDOPYRIMIDINES
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A novel and simplified synthesis of 1,3-dialkylpyridopyrimidine-2,4(1H,3H)-diones from 6-allylamino- and 6-(substituted allyl)aminouracils by PdCl2-CuCl catalyzed oxidative cyclization is described.
- Itoh, Tsuneo,Imini, Toshihiko,Ogura, Haruo,Kawahara, Norio,Nakajima, Takako,et al.
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p. 2177 - 2180
(2007/10/02)
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- Pyrimidines. 20. Novel Reactions of 5-Cyano-1,3-dimethyluracil. A Simple Synthesis of Pyridopyrimidines
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A reaction of 5-cyano-1,3-dimethyluracil (1, R = CN) with acetone in base afforded 1,3,7-trimethylpyridopyrimidine-2,4(1H,3H)-dione (9a) in a moderate yield.From a reaction mixture of 1 (R = CN) with butanone, 1,3,6,7-tetramethyl- and 7-ethyl-1,3-dimethylpyridopyrimidine-2,4(1H,3H)-dione (9b and 9c, respectively) were isolated in low yields.When ethyl cyanoacetate or malononitrile was used in place of the ketone in the above reaction, 7-amino-6-ethoxycarbonyl- and 7-amino-6-cyano-1,3-dimethylpyridopyrimidine-2,4(1H,3H)-dione (14a and 14b, respectively) were obtained in quantitative yields.A plausible mechanism for the formation of bicyclic compounds is discussed.
- Su, Tsann-Long,Watanabe, Kyoichi A.
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p. 1261 - 1262
(2007/10/02)
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- Synthesis of Heterocycles : Part IV - Pyridopyrimidines
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5,7-Disubstituted pyridopyrimidine-2,4-diones (Va-c) have been synthesized by a new route involving Michael addition of 1,3-dimethyl-6-iminouracil (I) to α-enones (IIa-c).Reaction of I and benzalacetone (IId) furnishes 9H-pyrimido-quinoline derivatives (VI, VII).
- Rao, A. Subba,Mitra, R. B.
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p. 159 - 160
(2007/10/02)
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