P. Yates, C. Mccall, M. Stevens
Aug 5, 1991
Citations
0
Influential Citations
22
Citations
Journal
Tetrahedron
Abstract
Abstract The benzothiazole derivatives reported here have structural similarities to the 2-phenylindole derivatives that are known to bind to oestrogen receptors. We report the synthesis of 5,6-dimethoxy-2-(4-methoxyphenyl)- benzothiazole together with the determination of its three dimensional crystal structure. Crystals are monoclinic, space group P21/c, a=17.142(1), b=11.165(1), c=7.683(2)A, β=101.34(1)°. 2307 Reflections were refined to R=0.039. The inter-ring twist angle is 21°, greater than in 2-(o-hydroxyphenyl)benzothiazole but similar to that in 2-(4′-bromophenyl)-4,6-dimethoxyindole. Molecular mechanics calculations predict a torsional barrier to inter-ring twist of 6.3 kcal mol−1 for unsubstituted benzothiazole. Molecular orbital calculations show that while hydrogen bonding can confer stability on substituted benzothiazoles, a greater number of non-hydrogen bonding groups as substituents can confer even greater stability.