pounds, presumably oligomers. In glacial acetic acid (CH3C0,H/CH2C12=3 :2, i=40 mA/cm2, T=2OoC, Pt electrode) 17% androstanyl acetate is obtained and 38% androstane is recovered. Remarkable is the selectivity of the oxidation: We found that the 6-(6a), 7-, and 12-acetates are formed in the ratio 35 : 1 : 2 S ; other acetates could not be detected by us. Assignment of the structures was accomplished by hydrolysis, oxidation to the ketone, and comparison of the mass spectra with those given in the literature. The main product was characterized ',C-NMR spectroscopically as 6a-acetoxy-5a-androstane (6a). The electrolysis in methanol (methanol/dichloromethane, 0.1 M NaCIO,, glassy carbon electrode) proceeds even more selectively. At a 53% conversion (47% androstane recovered) 14% 6-methoxyandrostane (7a) and 27% 6-(methoxymethoxy)androstane (Sa) were formed. R Rfi X Y 6 , X = OAc; 7. X = OCHS; a, R = H b, R =

The title compound 1 was prepared by reacting methyl-bis(dimethylamino)difluorophosphorane with butyllithium at -95 °C. The crystalline product is characterized by its NMR and IR spectra. The results of the X-ray crystal and molecular structure analyses are reported.

Resonance fluorescence of recoil-free y-rays from atomic nuclei dcywnd.s on the state of the chemical bonding of the atoms. The latter influences ihr position of' the energy level of the atomic nuclei, so that the energy required f ;~ exciiulion yf' resonance fluorescence is somewhat smaller or greater than the energy ofthe y-quanta r m i t t d by the radiation source. In order to obtain resonance fluorescence, therejorc, the radiation source and absorber have to be kept moving relative to each other. I f the inlensity yf thc rrsonance fluorescence is plotted akgainst this relative velocity, Miissbauer spectra are ohtainrd. The positions of the lines in these spectra make it possible to draw conclusions about the nature of the atom's bonds. The efficiency of this method is demonstrated by illustration with numerous iron compoundr. It was shown, jbr instance, that thc iron atoilis in "insoluble Prussian B k " have well-defined oxidation levels. "Turnbitll's Bhie'' shows ihe identical spectrum. A structure could be ascribed to lri-iron dodccacarhonyl that also cxplains the diama

AbstractThe structures of four compounds containing the P-NH-P unit have been determined by X-ray methods in order to detect prototropism. Ph2P-NH-PPh2 in the solid state is indeed a bis(diphenylphosphino)amin having C2 molecular symmetry. Its bisborane(3) ad­duct possesses the structure Ph2P(BH3)-NH-P(BH3)Ph2 with the BH3 -groups in transoid position. The P-NH-P unit is also observed in (PhO)2P(O)-NH-P(O)(OPh)2 and (PhO)2P(O)-NH-P(O)(C2H5)2. These two compounds show weak intermolecular hydrogen bonding in the solid state to the oxygen atom of a phosphoryl group. The PN bond distances depend on the group X bonded to phosphorus and decrease in the series with X = BH3 > S > O, e.g. with the electron withdrawing ability of X.

Formation, structure, vibrational spectrum and some chemical properties of the title compound are described.