Isofuranonaphthoquinones from ventilago maderaspatana: Crystal structure of ventilone-C

From the root bark of Ventilago maderaspatana (Rhamnaceae) five isofuranonaphthoquinones have been isolated. Ventilone-A is 4,9-dihydro-5,8-dihydroxy-6,7-methylenedioxy-1-methylnaphtho[2,3-c] furan-4,9-dione and B is the 5-methyl ether. Ventilone-C has the structure 1,3,4,9-tetrahydro-8-hydroxy-5-methoxy-6, 7-methylenedioxy-1-methylnaphtho[2,3-c]furan-4,9-dione, D is the isomeric 8-methyl ether, and E is the 5,8-dimethyl ether. Structures were determined by spectroscopic methods, and X-ray crystallographic analysis of ventilone-C.     

Isomorphous dichloro‐ and dibromo(2‐methyl‐2‐phenyl­propyl)­phenylstannane,both displaying the same intramolecular π–π interaction at 120 K

The title compounds, di­chloro‐ and di­bromo­neophyl­phenyl­tin, [SnCl₂(C₆H₅)(C₁₀H₁₃)] and [SnBr₂(C₆H₅)(C₁₀H₁₃)], respectively, are remarkable for the `U' shape of the mol­ecules, whereby the two phenyl groups are brought face‐to‐face in an arrangement that permits intermolecular C—H⋯π bonds to connect the mol­ecules into layers parallel to (100). Intermolecular Sn–halide bonds are notably absent from the structures.     

(Aroxymethyl)triphenyltin compounds: Crystal and molecular structure of triphenyl(p-toloxymethyl)tin

Compounds, Ph₃SnCH₂OAr, are available from Ph₃SnCH₂I and NaOAr in EtOH. The crystal and molecular structure of Ph₃SnCH₂OC₆H₄Me-p (II) has been determined by X-ray crystallography. The molecule in the crystal contains a slightly distorted tetrahedral tin atom [C-Sn-C valency angles varying from 106.9(5) to 114.1(6)°] with an intramolecular Sn---O distance of 2.900(11) Å. NMR spectral data for (II) and for Ph₃SnCH₂OC₆H₃Br₂-2,4 are reported.     

Crystal and molecular structure of 3,5-cycloandrostan-6β-ol-17-one

The crystal and molecular structure of 3,5-cycloandrostan-6-ol-17-one has been determined by X-ray analysis,¹³C-NMR,¹H-NMR, IR and elemental analyses. The compound was obtained from dehydroepiandrosterone (DHEA) via the 3-tosyl derivative by refluxing in a butan-2-one/water mixture. The X-ray analysis shows that the planar cyclopropane ring is predominantly orientated and the formation of the C(3)-C(5) bond enables the A ring to adopt a distorted boat conformation. Spectroscopic evidence for the presence of the cyclopropane ring and the 6-hydroxy group are presented.