Synthesis of Hetaryl Pyridinium Salts and Fused 3-Amino-pyrid-2-ones
1-(3-Coumaryl)-pyridinium salts 3 and 1-(3-coumaryl)-tetrahydrothiophenium salts 5 were synthesized from 2-acylphenyl chloro- or bromoacetates 2. 2-Chloro-N1-(3,4-dimethoxyphenyl)-acetamide and substituted 2-chloro-N1-(2-thienyl)-acetamides 8 react with acetyl chloride and pyridine to yield the quinolinyl- and (thieno[2,3-b]pyridin-5-yl)-pyridinium salts 10. Fused thieno[2,3-b]pyridin-ones 19 were formed from N-chloroacetyl-2-aminothiophen-3-carbonitriles 16 with pyridine via Thorpe-Ziegler cyclization and followed by cyclodehydrogenation. In presence of pyridine alkyl 2-chloro-acetylaminobenzoates 21 yield 3-(1-pyridinio)-quinoline-4-olates 23. Zincke-cleavage of 10 and 23 with hydrazinium hydroxide leads to fused 3-amino-pyridine-2-ones 11 and 3-amino-4-hydroxy-quinoline-2-ones 24, respectively. Oxazoloquinolines 25 were synthesized from 24 with acetic anhydride.
Rehwald, Matthias,Bellmann, Peter,Jeschke, Torsten,Gewald, Karl
p. 371 - 378
(2007/10/03)
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