Summary.
The hetero-Diels-Alder reaction of 3-dimethylamino-1-(2-thienyl)-2-propene-1-thione (diene) with substituted β-nitrostyrenes, as well as maleic and fumaric acids (dienophiles) yielded 3,4-dihydro-2H-thiopyran derivatives. The treatment of some of those cycloadducts with acetic acid caused elimination of dimethylamine, affording stable 2H-thiopyrans. A reaction of the diene with maleic anhydride furnished a cycloadduct which underwent spontaneous rearrangement to form an N,N-dimethylamide derivative. Cycloadditions of the diene to maleimide, N-phenylmaleimide, maleic acid monoanilide, diethyl maleate, fumarate, and butenolide carried out in the presence of acetic anhydride were followed by elimination of dimethylamine under formation of stable 2H-thiopyran derivatives.
Similar content being viewed by others
Author information
Authors and Affiliations
Additional information
Received February 19, 2001. Accepted (revised) March 12, 2001
Rights and permissions
About this article
Cite this article
Bogdanowicz-Szwed, K., Budzowski, A. Efficient Synthesis of Functionalized 2H-Thiopyrans via Hetero-Diels-Alder Reactions of an Enaminothione with Electrophilic Olefins. Monatshefte für Chemie 132, 947–957 (2001). https://doi.org/10.1007/s007060170057
Issue Date:
DOI: https://doi.org/10.1007/s007060170057