Work

Carbon-13 chemical shifts of alkene carbons in 2-acylidene-3,5-diaryl-2,3-dihydro-1,3,4-thiadiazoles and related benzothiazoles and -selenazoles, and their relationship to other push-pull alkenes

Year: 1996

Type: article

Abstract: Carbon-13 chemical shifts of alkene carbons are observed in the ranges 78–109 ppm (Cα) and 154–164 ppm (Cβ) for a series of 11 2-acylidene-3,5-diaryl-2,3-dihydro-1,3,4-thiadiazoles, 3 2-acylidene-3-alkyl-2,3-dihydrobenzothiazoles, and 2 2-acylidene-3-alkyl-2,3-dihydrobenzoselenazoles of known geometry, indicating appreciable charge polarization in these compounds as in other push–pull olefins. Substitution that promotes more extensive charge delocalization results in the Cα signal shifting to the higher-frequency end of the chemical shift range. The observed shifts are compared with those calculated according to the Pretsch scheme. Key words: carbon-13 NMR, chemical shifts, push–pull olefins, 1,3,4-thiadiazoles, benzothiazoles, benzoselenazoles.

Source: Canadian Journal of Chemistry

DOI: 10.1139/v96-148

Authors: Jennifer L. Mueller, Martin S. Gibson, J. Stephen Hartman

Institution: Brock University

Language: English

Topic: Structural and Chemical Analysis of Organic and Inorganic Compounds

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: bronze

Funder: Natural Sciences and Engineering Research Council of Canada

OpenAlex ID: W2015255406