L. Klemm, J. N. Louris
May 1, 1984
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0
Influential Citations
19
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Journal
Journal of Heterocyclic Chemistry
Abstract
Thieno[3,2-b]pyridine (1) is synthesized in 65% overall yield for two steps which consist of addition of toluene-α-thiol to 2-ethynylpyridine plus vacuum pyrolysis of the addend (7). Cis and trans forms of 7 are described. Compound 1 undergoes (a) electrophilic substitution at C-3 to give chloro, bromo, and iodo derivatives (44–57% yields) and (b) lithiation at C-2 (to give 1a). Intermediate 1a is converted into derivatives of 1 with halo (19–48%), formyl (54%), acetyl, and hydroxymethyl (40%) substituents at C-2. Also described are 2-cyano and 2,3-dibromo derivatives of 1. Structural assignments are based on chemical transformations plus 1H and 13C nmr spectral data. The substitution pattern of 1 is compared with predictions made on the bases of analogous ring systems and molecular orbital calculations.