The molecular and crystal structure of the Steroidal Alkaloid Aculeamine

Abstract

A new solanocapsine-type alkaloid named aculeamine has been isolated from roots of Solanum aculeatum and its structure has been established by X-ray analysis as 22,26-cpimino-23~-methoxy-16a,23-epoxy-5a,22aH,25~H-cholestane-~~~-ol. The compound crystallizes in the hexagonal space group P6, with the lattice parameters a = b = 16.706, c = 17.056 A, a = ,9 = go", y = 120". The final residual value was R = 0.079. Ein neues Alkaloid vom

A computer program for the determination of the correct positions of misplaced molecules in crystal structures

“…In both cases the data set was poor and some attempts to solve the structure by direct methods failed. On the other hand, the stereochemistry of (Kutschabsky & Adam, 1984), which crystallizes in the space group P212~2~ with one molecule consisting of 32 nonhydrogen atoms in the asymmetric unit, the threedimensional R-value map calculated with 22 atoms and 214 reflections showed seven nearly equivalent minima. Three of them correspond to molecular positions with some too short intermolecular distances and were detected by potentialenergy calculations.…”