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Compounds with bridgehead nitrogen. 57—NMR spectra and stereochemistry of protonated perhydrooxazolo [3,4-a]pyridines, perhydropyrido[1,2-c] [1,3] oxazine and perhydropyrido[1,2-c] [1,3]oxazepine

✍ Scribed by Trevor A. Crabb; Andrew N. Trethewey

Publisher
John Wiley and Sons
Year
1988
Tongue
English
Weight
544 KB
Volume
26
Category
Article
ISSN
0749-1581

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✦ Synopsis

Protonation of perhydrooxazolo[3,4-a~pyridine, perhydropyrido[1,2-~~[1,3]oxazine and perhydropyridoI 1,2c][ 1,310xazepine by hydrogen chloride gas in diethyl ether gave mixtures of trans-and cis-fused hydrochlorides containing 28, 75 and 79% of the trans-fused salts, respectively, which compare with free base equilibria containing 68, 90 and 74% trans-fused conformers. The cis-fused salts from perhydrooxazolo[3,4-alpyridine existed in solution (CDCl, , 298 K) as an equilibrium containing 55% 0-inside cis-and 17% 0-outside cis-fused conformers. Similar mixtures, but with smaller percentages of cis-fused salts, were formed in D,O-DCl.

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