| Popis: |
DL-Tryptophan in 0,1 N HCl reacts with ninnydrin (triketoindane hydrate) at room temperature to give a brown precipitate; washing the precipitate with cold methanol leaves a yellow compound which is crystallized from boiling methanol (C20H14O4N2, 1 CH3OH). X-ray diffractometry showed that the crystals belong to the monoclinic system, with P21/n as a spatial symmetry group; the unit cell (a = 12.016 A; b = 13.336 A; c = 12.128 A; s = 113.45°) contains four molecules, each one formed by the association of a molecule of methanol with 5-carboxy-14-hydroxy-,(3,14,15,16,17,18,19,20) octadehydro-yohimban-21-one, a hitherto not described compound possessing the same ring skeleton as yohimbine and reserpine, two major indole alkaloids. The structure of a spiro derivative of 2,3,4,5-tetrahydro-s-carboline, previously proposed [16], can thus be eliminated. |
