1. Crystal and molecular structure of 2 H -thiopyrans
- Author
-
Artur Budzowski, Katarzyna Stadnicka, K. Bogdanowicz-Szwed, and M. Chruszcz
- Subjects
Hydrogen bond ,Organic Chemistry ,Maleic anhydride ,Space group ,Crystal structure ,Analytical Chemistry ,Inorganic Chemistry ,Crystal ,Crystallography ,chemistry.chemical_compound ,chemistry ,Molecule ,Crystal twinning ,Spectroscopy ,Monoclinic crystal system - Abstract
The crystal structures of 2-((dimethylamino)carbonyl)-6-(2-thienyl)-2 H -thiopyran-3-carboxylic acid ( I ) and 2-((dimethylamino)carbonyl)-6-(2-furyl)-2 H -thiopyran-3-carboxylic acid ( II ) have been determined by single-crystal X-ray diffraction. Both the compounds crystallise in monoclinic system, but in different space groups. The crystals data are: ( I ) a =6.5464(1), b =7.5651(2), c=27.6851(7) A , β =96.867(1)°, Z =4, space group P 2 1 ; ( II ) a =10.2683(2), b =10.6690(3), c=12.3477(3) A , β =101.773(1)°, Z =4, space group P 2 1 /c . Substitution of the thienyl- ( I ) by the furyl-group ( II ) in the 2 H -thiopyrans dramatically changes interactions between the molecules in solid state. The packing for these compounds and the hydrogen bond network are different. The crystals of the thienyl-derivative ( I ) have an inclination towards a twinning, which could be explained by some features of the packing. The X-ray analysis indicates that the mechanism for the formation of 2-thienyl and 2-furyl substituted 2 H -thiopyrans in the reaction of enaminothiones (dienes) with maleic anhydride occurs via a rearrangement of the preliminarily formed endo -cycloadducts and five-membered transition state.
- Published
- 2002