Structures of the neuropleptic drugs α- and β-clopenthixol

The tricyclic neuroleptic drug tt-clopenthixol (C22H25C1N2OS) is monoclinic, P21/n, with a = 11.549 (4), b = 15.739 (6), c = 11.627 (5)A, fl = 109.47 (2) °, U = 1992.6 A 3, Z = 4. Its less potent fl isomer is triclinic, Pi, with a = 6.493 (2), b = 7.758(3), c = 21.881 (8)A, ,i = 90.11 (2), /~ = 91.48 (2), y = 92.81 (2) ° , U= 1100.5 A 3, Z = 2, and crystallizes as a dihydrate. The structures have been refined to R = 0.051 for 2503 reflexions (a) and 0.039 for 3170 reflexions (fl). Various structural features of these drugs and those of the closely related t~- and fl-flupenthixol are compared.