Reference

Electrophoretic, chromatographic and mass spectrometric procedures for the identification and isotopic assay of amino acid constituents in etamycin

Electrophoretic, chromatographic and mass spectrometric procedures for the identification and isotopic assay of amino acid constituents in etamycin. Kamal, Fatemah; Katz, Edward; Mauger, Anthony B. (Dep. Microbiol., Georgetown Univ. Sch.Several reagents such as 299-20-7 is used here. Med., Washington, D. C., USA). J. Chromatogr., 151(2), 245-8 (English) 1978. CODEN: JOCRAM. ISSN: 0021-9673. DOCUMENT TYPE: Journal CA Section: 64 (Pharmaceutical Analysis) Section cross-reference(s): 34 Amino acid constituents of etamycin [299-20-7], a peptidolactone antibiotic, were identified by electrophoretic, paper, thin-layer, ion exchange, and gas chromatog.-mass spectrphotometric procedures. Etamycin was hydrolyzed with 6N HCl for 3 h at 121°, 15 psi and the hydrolyzates were analyzed. L-Alanine [56-41-7], sarcosine [107-97-1], D-leucine [328-38-1], L-threonine [72-19-5], allo-hydroxy-D-proline [2584-71-6], N,b-dimethyl-L-leucine [4125-87-5], phenylsarcosine [40643-55-8], and 3-hydroxypicolinic acid [874-24-8] were obtained from the antibiotic hydrolyzates. .

A direct intramolecular asymmetric catalytic aldol cyclodehydration of meso-3,4-disubstituted-1,6-dialdehydes

A direct intramolecular asymmetric catalytic aldol cyclodehydration of meso-3,4-disubstituted-1,6-dialdehydes. Kurteva, Vanya B.; Afonso, Carlos A. M. (Institute of Organic Chemistry, Bulgarian Academy of Sciences, Sofia 1113, Bulg.). Tetrahedron, Volume Date 2005, 61(1), 267-273 (English) 2004 Elsevier B.V. CODEN: TETRAB. ISSN: 0040-4020. DOCUMENT TYPE: Journal CA Section: 21 (General Organic Chemistry) The intramol. asym. catalytic aldol cyclodehydration of 1,6-dialdehydes to the corresponding cyclopentenecarboxaldehydes was accomplished for meso-3,4-disubstituted hexanedials. It was found that the presence of a hydroxyl group in the catalyst mol. seems to be crucial to reach stereocontrol. The chiral center, bearing the carboxylate functionality, in hydroxy amino acids controls the stereochem. of the final product. In the case of amino alcs., where carboxylate functionality does not exist, the configuration of the carbon, connected with the hydroxyl group, seems to be the key one. Addnl., it was obsd. that chiral phosphines and phosphites are effective catalysts for this cyclodehydration but without inducing stereocontrol.Except for chemicals metioned above, 831228-42-3 and 2584-71-6 are also used. .