Thiophene substituted dihydropyridines

The crystal structures of 4-(2-thiophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl) (I)[a = 10.273(5) Angstrom, b = 10.428(5) Angstrom, c = 14.799(9) Angstrom, beta = 98.13(4)degrees, P2(1)/c], 4-(3-thiophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(methoxycarbonyl) (II) [a = 10.636 (9) Angstrom, b = 10.372(8) Angstrom, c = 15.043(15) Angstrom, beta = 98.13(6)degrees, P2(1)/c], and 4-(2-thiophenyl)-2,6-dimethyl-1,4-dihydropyridine-3,5-bis(ethoxycarbonyl) (III) [a = 26.793(16) Angstrom, b = 7.610(6) Angstrom, c = 17.612(10) Angstrom, beta = 97.61(2)degrees, C2/c] reveal patterns of hydrogen bonding pertinent to behavior of these members of the 1,4-dihydropyridine family in receptor site docking. Carbonyl groups substituted at C3 and C5 are seen in ap conformation when hydrogen bonded. Sulphur atoms of the hetero rings do not participate in hydrogen bonding. In these structures the position of the herero atom is seen to be disordered over two equivalent sites. Thus, there is no demonstrated preference for conformation of the hetero ring.