103261-70-7Relevant articles and documents
Generation and Diels-Alder trapping of 4,5-bis(bromomethylene)-4,5-dihydrothiazole
Jouve, Karine,Pautet, Felix,Domard, Monique,Fillion, Houda
, p. 2047 - 2050 (1998)
Treatment of 4,5-bis(dlbromomethyl)thiazole (1a) with sodium iodide in DMF led to 4,5-bis(bromomethylene)-4,5-dihydrothiazole (2a). Trapping the latter in situ with dienophiles afforded directly the aromatized cycloadducts. Starting with 5-hydroxynaphthoquinone or its 2- and 3-bromo derivatives 6 gave a mixture of the tetracyclic quinones 10 + 11 from which the 1,6-regioisomer 10 predominates. Using acrylate dienophiles gave 6-substituted benzothiazoles 13 as the major products. The regiochemistry of the cycloadditions between 2a and naphthoquinones 6 agrees with the predictions of the frontier molecular orbital theory. In contrast, the regioselectivity observed from 2a and acrylate dienophiles 12, similar to that previously obtained with 5-bromomethylene-4-methylene-4,5-dihydrothiazole (2b), is opposite to that predicted and could be better accomodated by a competitive Michael addition followed by a cyclization-elimination step.
ANABASEINE DERIVATIVES USEFUL IN THE TREATMENT OF NEURODEGENERATIVE DISEASES
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Page/Page column 79, (2008/06/13)
The compounds of the present invention are of formula (I): wherein A, R3, R4 is as defined herein, are useful as ligands for nicotinic receptors.