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Reverse anomeric effect of the carbamoyl group of 2,6-disubstituted 6-carbamoyl-5,6-dihydro-2H-pyrans

✍ Scribed by Marek Chmielewski; Janusz Jurczak; Waldemar Priebe; Derek Horton

Publisher
John Wiley and Sons
Year
1987
Tongue
English
Weight
410 KB
Volume
25
Category
Article
ISSN
0749-1581

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✦ Synopsis

The 'H NMR spectra of 2,6-disubstituted 6-carbamoyl-5,6-dihydro-2H-pyrans and their 6-methoxycarbonyl analogs have been recorded. With the use of coupling constants between ring protons, the conformational preference of the carbamoyl group has been evaluated. The 'H6 6Hl conformational equilibria in the above compounds are discussed. It is found that the conformational tendency of the carbamoyl group to the equatorial disposition helps to determine the conformational equilibrium in the seven examples studied.

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