Kobalt??katalysiert Cycloadditionen von Alkinen und Nitrilen zu Pyridinen: Ein neuer Zugang zu Pyridoxin (Vitamin B6)

…, M Lalonde, H Stoller, K Schleich

Index: Geiger; Lalonde; Stoller; Schleich Helvetica Chimica Acta, 1984 , vol. 67, # 5 p. 1274 - 1282

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Citation Number: 48

Abstract

Summary A new synthesis of pyridoxine hydrochloride (1) based on a Co-catalyzed cycloaddition of MeCN with substituted di (2-propynyl) ethers (3 and 16) is described. The reaction sequences following cycloaddition and leading to 1 involve as key steps the rearrangement of the pyridine-N-oxide 6 to the 3-hydroxypyridine 7 with Ac, O and a modified Curtius rearrangement of the acid 19 and subsequent diazotation and hydrolysis ...