Ben A. Shoulders

The structure of lumi-4-cholesten-3-one

Abstract UV irradiation of 4-cholesten-3-one has been found to give 1β,5-cyclo-5β,10α-cholestan-2-one, a lumi compound of the dihydrolumisantonin type. A multiplicity of physical data and chemical transformations is described which points to identical stereochemistry in the photoisomerization of this homoannular enone and analogous dienones.

Isolation and characterization of a pentameric amino acid from elastin.

An unknown amino acid was purified from bovine ligament elastin. The compound was shown by proton NMR to have a pyridinium ring structure similar to isodesmosine, yet containing an olefinic double bond on one additional side chain which was not attached to the pyridinium ring. Mass spectral analysis confirmed the NMR data and indicated a parent compound with a mass of 653. A structure is proposed that is derived from the condensation of five lysine residues. The trivial name of pentasine is proposed for this compound.

13C13C coupling constants in a series of η2-alkene complexes of rhodium(I)

Abstract 1 J(CC) has been determined in a series of closely related η 2 -alkenerhodium(I) complexes and found to decrease by about 22 Hz on coordination. It is also observed to be linearly related to the electronegativity of the substituent in coordinated CH 2 CHX) X  C, O or Si).