Studies of substituent effects by carbon-13 NMR spectroscopy.V—Ethyl (E)-(α-cyano)cinnamates, (E)-(α-cyano)cinnamamides and ethyl (α-ethoxycarbonyl)cinnamates

✍ Scribed by Francesco A. Bottino; Giuseppe Musumarra; Zvi Rappoport

• Publisher: John Wiley and Sons
• Year: 1986
• Tongue: English
• Weight: 528 KB
• Volume: 24
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.1260240108

✦ Synopsis

13C NMR shifts for ethyl (E)-(a-cyano)cinnamates, (E)-(a-cyano)cinnamamides and ethyl (a-ethoxycarbony1)cinnamates of general formula XC6&CH=CR'RZ (R' = CN, Rz = COOEt; R' = CN, R2 = CONH,; R' = R2 = COOEt; X =p-NMe,, p-OH, p-OMe, p-Me, H, p-Br, p-C1, p-NO,, rn-CI, rn-NO,, o-OMe, 043, o-NO,) in DMSO-I.I, solution are reported. Snbstituent chemical shift considerations allow the assignment of the aromatic carbons in the disubstituted rings. The effect of substituents on the aromatic, ethylenic, cyano and carhonyl 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.