Reactions of 3-Chloropropeniminium Salts with Aminopyridines. Synthesis of N-Pyridylpyridinium and Pyrido[1,2-a]pyrimidinium Salts*
نویسندگان
چکیده
N-(Pyridyl)pyridinium salts 7 and 8 as well as 4-phenylpyrido[1,2-a]pyrimidinium salts 4 and 12 have been prepared by reactions of 3-aryl-3-chloropropeniminium salts 5 with aminopyridines (6) using glacial acetic acid as solvent. 2-Phenylpyrido[1,2-a]pyrimidinium salts 2 are formed when ethanol is used as the solvent. The condensation of 2-aminopyridine (6a) with 3-chloro-2,3dehydromorpholino-2-carbiminium salt 13 is described. The HSAB principle of Pearson is discussed to explain the different regioselective ring closure reactions.
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