New activating agents, 3,3′-(phenylphosphinylidene)bis[2(3H)-benzoxazolone] (4) and 3,3′-(phenylphosphinylidene)bis[2(3H)-benzothiazolone] (5), were readily prepared by the reaction of phenylphosphonic dichloride (3) with 2(3H)-benzoxazolone (1) and 2(3H)-benzothiazolone (2) respectively in the presence of triethylamine at room temperature. The new activating agents 4 and 5 were found to be useful
A novel process for the amidation or esterification which comprises reacting a compound having a carboxy group with a compound having an amino or imino group which can be acylated or with a compound having a hydroxy group in the presence of a sulfonic acid ester of the formula: R.sub.1 --SO.sub.2 --OR.sub.2 wherein R.sub.1 is an organic group and R.sub.2 O-- is a residue of a strongly acidic N-hydroxy compound as a condensation agent, and a novel sulfonic acid ester useful as such a condensation agent and a process for the preparation thereof.
Synthesis of all the stereoisomers of statine (4-amino-3-hydroxy-6-methylheptanoic acid). Inhibition of pepsin activity by N-carbobenzoxy-L-valyl-L-valyl-statine derived from the four stereoisomers
作者:W. S. Liu、S. C. Smith、G. I. Glover
DOI:10.1021/jm00191a023
日期:1979.5
Synthesis of all fourstereoisomers of the novel amino acid statine, 4-amino-3-hydroxy-6-methylheptanoic acid, found in pepstatin, a potent acid protease inhibitor, has been accomplished. Carbobenzoxy-L-valyl-L-valyl-statine tripeptides derived from all fourstereoisomers have been prepared and their effect on pepsin activity is compared to that of pepstatin.