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At least 1,171 records · Page 65Linked to original sources
PubMed1995

Vibrational optical activity of oligopeptides.

Vibrational optical activity (VOA) is a relatively new spectroscopic technique, which has two principal manifestations, ir vibrational CD and vibrational Raman optical activity. Progress in the study of oligopeptides using both of these forms of VOA is reviewed from the perspective of theoretical and instrumental techniques, spectral results, and structural interpretations.

Amides↗
PubMed1977

Syntheses and primary pharmacological screening of tandamine and related tetrahydrothiopyranoindoles with potential antidepressant properties.

A series of novel 1,3,4,9-tetrahydro-1-methyl-thiopyrano-[3,4-b]indole-1-ethanamines has been synthesized and examined for effects on reserpine-induced ptosis and reserpine-induced hypothermia in mice. One member of the series, the 9-ethyl-N,N-dimethyl derivative V (tandamine), was selected for further studies in regard to its possible use as an antidepressant agent. Tandamine has been resolved, and the levorotatory enantiomer was found to be more active than the racemic compound. The N-desmethyl derivative XIII, a metabolite of tandamine, has been prepared. The 5-ethyl-1,3,4,5-tetrahydro-N,N,1-trimethylthiopyrano[4,3-b]indole-1-ethanamine XXI, an analog of tandamine with the isomeric ring system, has also been synthesized and evaluated. In the primary pharmacological screening and in the drug-interaction studies with reserpine, tetrabenazine, and tremorine, tandamine was compared to the clinically effective tricyclic antidepressants--desipramine, imipramine, and amitriptyline. Tandamine was more effective than these agents in several screening procedures indicative of potential antidepressant activity.

Alkylation↗
PubMed1989

Optical enrichment of dansyl-rac-amino acids by formation of crystalline inclusion complexes with cyclodextrins.

Optical enrichment from racemic dansyl-leucine, dansyl-norleucine, and dansyl-phenylalanine with both beta- and gamma-cyclodextrins in water is reported. Initial crystallization yielded the dansyl-L-Leucine isomer complexed in excess with beta-cyclodextrin with an optical purity of 62-78% depending on experimental conditions. The optical purities obtained for L-norleucine and L-phenylalanine were 71 and 64%, respectively. The optical purity can be increased with continued recrystallization. The dansyl-D-leucine isomer was obtained in the mother liquor with an optical purity of 54-93% depending on experimental conditions. The optical purities obtained for D-norleucine and D-phenylalanine were 72 and 58%. The optical purity of the isomer depended on the molar ratio of host:guest and the pH value of the solution. Optimum enrichment of both enantiomers was achieved with host:guest ratios of 2:1 and 3:1. Although maximum crystalline yield of the dansyl-leucine/CD inclusion complex was obtained at a pH of 3.5, optical purity of both enantiomers was less than that obtained at other pHs. The influence of the molar ratio of host:guest and the pH value of the solution are discussed. This method is suitable for large-scale enantiomeric separations.

Amino Acids↗