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Studies of substituent effects by carbon‐13 NMR spectroscopy. V —Ethyl ( E )‐(α‐cyano)cinnamates, ( E )‐(α‐cyano)cinnamamides and ethyl (α‐ethoxycarbonyl)cinnamates
Author(s) -
Bottino Francesco A.,
Musumarra Giuseppe,
Rappoport Zvi
Publication year - 1986
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260240108
Subject(s) - cinnamates , chemistry , substituent , chemical shift , medicinal chemistry , carbon 13 nmr , stereochemistry , organic chemistry
13 C NMR shifts for ethyl ( E )‐(α‐cyano)cinnamates, ( E )‐(α‐cyano)cinnamamides and ethyl (α‐ethoxycarbonyl)cinnamates of general formula XC 6 H 4 CHCR 1 R 2 (R 1 CN, R 2 COOEt; R 1 CN, R 2 CONH 2 ; R 1 R 2 COOEt; X p ‐NMe 2 , p ‐OH, p ‐OMe, p ‐Me, H, p ‐Br, p ‐Cl, p ‐NO 2 , m ‐Cl, m ‐NO 2 , o ‐OMe, o ‐CI, o ‐NO 2 ) in DMSO‐ d 6 solution are reported. Substituent chemical shift considerations allow the assignment of the aromatic carbons in the disubstituted rings. The effect of substituents on the aromatic, ethylenic, cyano and carbonyl chemical shifts is discussed in relation to that of other arylethylenes. The J (CCCH) long‐range coupling values provide evidence in favour of the E configuration for both series of cyano derivatives.