Crystal structures of the Teonanácatl hallucinogens. Part I. Psilocybin C12H17N2O4P

Abstract

The crystal structure of psilocybin, the major hallucinogenic component of Teonanácatl, the sacred mushroom of Mexico, has been determined in crystals of the monomethanolate. Crystals are monoclinic, space group P2₁/c, a= 1264(1), b= 2911(2), c= 884·7(6) pm, β= 107·37(2)°, and contain two molecules of psilocybin and two molecules of methanol of solvation per asymmetric unit. Data were collected on a four-circle diffractometer; the structure was solved by direct methods and refined by block-diagonal least squares to R 0·049 over 4217 significant reflections. The two independent molecules are both zwitterions, have different conformations, and are involved in a complex hydrogen-bonding scheme in which there are very short phosphate–phosphate hydrogen bonds, and in which the methanol of solution also takes part. Significant deviations of the substituents from the indole plane are apparent. Bond lengths have been determined to a precision of 0·5 pm.