- Bridged Hydroquinolines
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The pyridannulation procedure of condensing vinamidinium salts with ketones having a free α-methylene has been adapted to prepare 3-substituted 5,6,7,8-tetrahydroquinolines; characterization data for the seven systems synthesized are reported.Conditions required are less drastic than those for recently reported alternative approaches to analogous systems.The adaption has considerable generality even though 5,8-methano-bridged 5,6,7,8-tetrahydroquinolines are not accessible through it.Chirality in the starting ketone, not affected by exposure to enolizing conditions, is preserved in the pyridannulated products.
- Balasubrahmanyam, S. N.,Jeyashri, B.
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p. 559 - 562
(2007/10/02)
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- Pyrimidines From Furfural. A Convenient Synthesis of 5-Bromo- and 5-Chloropyrimidine
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A new method for the preparation of 5-bromo- and 5-chloropyrimidine from furfural has been described.
- Kress, Thomas J.,Szymanski, Edward
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p. 1721 - 1722
(2007/10/02)
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- Process for preparing 5-halopyrimidines
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The reaction of formamide at high temperature with a 4-halo-5-hydroxy-2(5H)-furanone provides high yields of 5-chloro or 5-bromopyrimidines.
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- Reactions of Halogenomethanes in the Vapor Phase. Part 4. The Reactions of Imidazoles with Chloroform at 550 deg C, and a Comparison with their Liquid-phase Reactions with Trichloroacetate Ion or Hexachloroacetone and Base
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1-Unsubstituted imidazoles and chloroform at 550 deg C in a flow system give mainly 5-chloropyrimidines, together with 4-chloropyrimidines and chloropyrazines.The effects of methyl substituents on the ratio of products is considered.The liquid-phase reactions of 2-methyl- and 2,4,5-trimethyl-imidazole under conditions in which dichlorocarbene is said to be formed in basic or neutral conditions were studied, and compared with the gas-phase reactions with chloroform.
- Busby, Reginald E.,Khan, Mohammad A.,Khan, Mohammad R.,Parrick, John,Shaw, C. J. Granville,Iqbal, Mohammad
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p. 1427 - 1430
(2007/10/02)
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- Reactions of Halogenomethanes in the Vapour Phase. Part 5. The Reactions of Imidazolines, Anils, and 1-Methylimidazole with Chloroform at 550 deg C, and a Comparison with their Liquid-Phase Reactions with Trichloroacetate Ion or Hexachloroacetone and Base
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The vapor-phase reactions of imidazolines and anils with chloroform at 550 deg C are compared with their liquid-phase reactions in the presence of hexachloroacetone and base or upon thermolysis with trichloroacetate ion.In the vapour-phase reactions imidazolines, unlike imidazoles, gave non-chlorinated pyrimidines, and 1-methyl-imidazole gave 2-cyanopyrrole and the four 3-chlorocyanopyridines.
- Busby, Reginald E.,Khan, Mohammad A.,Khan, Mohammad R.,Parrick, John,Shaw, C. J. Granville
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p. 1431 - 1435
(2007/10/02)
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