Transmission of substituent effects in heterocyclic systems by carbon-13 nuclear magnetic resonance. Benzothiazoles was written by Sawhney, Shanti N.;Boykin, David Withers. And the article was included in Journal of Organic Chemistry in 1979.Application of 68867-17-4 This article mentions the following:
The carbon-13 NMR spectra of 57 benzothiazoles, including 6-substituted 2-aminobenzothiazoles (I), 6-substituted 2-methylbenzothiazoles (II), 6-substituted benzothiazoles (III), 5-substituted 2-methylbenzothiazoles (IV), and 2-substituted benzothiazoles (V) were determined in (CD3)2SO. Single and dual parameter correlations of the chem. shifts with substituent constants were described for C-2 and C-9 of I, II, and III and for C-2 and C-3 of IV. Resonance effects are primarily responsible for the substituent effect on chem. shifts at these carbons. Transmission of substituent effects by the atom is limited, and the primary path of transmission to C-2 is through N. The data from series III and V suggest that transmission of substituent effects from C-2 to C-6 is ∼1/3 less effective than transmission from C-6 to C-2. In the experiment, the researchers used many compounds, for example, Benzothiazole-5-carboxylic acid (cas: 68867-17-4Application of 68867-17-4).
Benzothiazole-5-carboxylic acid (cas: 68867-17-4) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). The nitrogen in thiazole is sp2 hybridized and the lone pair of electrons localized on the nitrogen is less reactive due to increased aromatic character and decreased basicity. It is protonated and alkylated/acylated at nitrogen forming hydrochloride and quaternary thiazolium salt.Application of 68867-17-4
Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica