Amino-acids and peptides. Part 45. The protection of the thiol function of cysteine and the imidazole-N of histidine by the diphenyl-4-pyridylmethyl group
作者:Susan Coyle、Allan Hallett、Michael S. Munns、Geoffrey T. Young
DOI:10.1039/p19810000522
日期:——
group, this protection is stable in acid but it is cleaved readily by zinc–aceticacid, by mercury(II) acetate, by iodine, and by electrolytic reduction. N(lm)-Diphenyl-4-pyridylmethyl-L-histidine derivatives (9)–(13) are also reported; the protecting group is again stable to acid but cleaved by hydrogenolysis, by zinc–aceticacid, and by electrolytic reduction, and it has been used in the synthesis
The use of fluorescent nanoparticles comprising an inorganic core, a passivating layer and specific ligands having a hydrodynamic diameter of the inorganic core with the passivating layer of not more than 15 nm, preferably of not more than 10 nm, particularly preferably of not more than 5 nm, for preparing an in vivo diagnostic aid, the nanoparticles showing an emission of less than 700 nm.
process for the preparation of optically-active cyanomethyl esters
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0109681A2
公开(公告)日:1984-05-30
Stereoisomerically-enriched cyanomethyl esters are prepared by treating a non-symmetrical ketene or an alpha-chiral carboxylic acid halide or reactive derivative thereof with an optically-active alphahydroxynitrile. Certain optically-active optionally substituted S-alphacyano-3-phenoxybenzyl alcohol intermediates are prepared by treating the corresponding aldehyde of ketone with a source of hydrogen cyanide in the presence of a substantially water-immiscible, aprotic solvent and a cyclo(D-phenylalanyl-D-histidine) as a catalyst.
Preparation of optically-active alpha-substituted carboxylic esters and acids
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0116914A1
公开(公告)日:1984-08-29
Optically-active alpha-substituted carboxylic esters are prepared by treating a non-symmetrical ketene with an alcohol in the presence of an optically-active amine catalyst. Hydrolysis of the resulting esters, yields the optically-active acid corresponding to the non-symmetrical ketene.
Process for the preparation of optically-active cyanomethyl esters
申请人:E.I. DU PONT DE NEMOURS AND COMPANY
公开号:EP0291626A2
公开(公告)日:1988-11-23
Stereoisomerically-enriched cyanomethyl esters are prepared by treating a non-symmetrical ketene or an alpha-chiral carboxylic acid halide or reactive derivative thereof with an optically-active alpha-hydroxynitrile. Certain optically-active optionally substituted S-alpha-cyano-3-phenoxybenzyl alcohol intermediates are prepared by treating the corresponding aldehyde or ketone with a source of hydrogen cyanide in the presence of a substantially water-immiscible, aprotic solvent and a cyclo(D-phenylalanyl-D-histidine) as a catalyst.