Crystal and molecular structure of anhydroperforine

A complete x-ray structural investigation has been made of the alkaloid anhydroperforine. The crystals are rhombic: a=17.425(5) Å, b=8.166 Å, c=11.284(5) Å, z=4, space group P2₁2₁2₁ (diffractometer, 1000 reflections, MLS in the anisotropic approximation, R=0.11). The investigation has unambiguously demonstrated the conformation of the anhydroperforine molecule and has confirmed its structure. The lengths of the bonds and the values of the valence angles are the usual ones. The conformations of rings B and C are planar, ring D has a chair, and ring A, a distorted half-chair conformation.     

Crystal and molecular structure of tigogenin

Tigogenin [(25R)-5α-spirostan-3β-o1] was isolated from Digitalis lanata Ehrh., and its crystal and molecular structure was determined by single crystal X-ray diffraction.     

Crystal and molecular structure of isatin

A. A. Zhdanov Irkutsk State University, Institute of Applied Physics, Academy of Sciences of the Moldavian SSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 29, No. 3, pp. 155–158, May–June, 1988.     

Crystal and molecular structure of sarcosine

The crystal structure of sarcosine in pure form has been determined at low temperature (135 K). The crystals are othorhombic, space group P2(1)2(1)2(1) with unit cell dimensions a = 6.687(2) A, b = 7.899(3) A, c = 8.607(3) A. On the basis of 988 reflections with intensities larger than 3 sigma (I) the structure was refined to a conventional R-factor of 0.034 to give e.s.d. in bond lengths of 0.002 A and 0.2 degrees in angles. The molecule is extended and exists in the zwitterionic form. There is a small deviation from planarity in the alpha-amino acid group as well as in the main chain.     

Crystal and molecular structure of hexacarbomethoxycyclopropane

A. N. Nesmeyanov Institute of Heteroorganic Compounds, Academy of Sciences of the USSR. N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR. Translated from Zhurnal Strukturnoi Khimii, Vol. 30, No. 3, pp. 171–173, May–June, 1989.     

Crystal and molecular structure of anhydroperforine

A complete x-ray structural investigation has been made of the alkaloid anhydroperforine. The crystals are rhombic: a=17.425(5) Å, b=8.166 Å, c=11.284(5) Å, z=4, space group P2₁2₁2₁ (diffractometer, 1000 reflections, MLS in the anisotropic approximation, R=0.11). The investigation has unambiguously demonstrated the conformation of the anhydroperforine molecule and has confirmed its structure. The lengths of the bonds and the values of the valence angles are the usual ones. The conformations of rings B and C are planar, ring D has a chair, and ring A, a distorted half-chair conformation.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 805–810, November–December, 1979.