A second polymorphic form of pentazocine hydrochloride at 105 K

Abstract

The crystal structure of pentazocine hydro­chloride [systematic name: 2-hydroxy-5,9-di­methyl-2-(3-methyl­buten-2-yl)-6,7-ben­zomorphanium chloride], C19H28NO+·Cl−, has been determined at 105 K and found to be a second polymorphic form with space group C2/c. The space group and the unit-cell parameters are different from a reported crystal structure at 293 K [Majeste, Poindexter, Jones & Klein (1994). Acta Cryst. C50, 1633–1636]. There are only small differences in the molecular conformation, but the association between the protonated pentazocine mol­ecules and the chloride ion is different.