Disclosed are 2-(syn)-hydroxyimino-acetamide derivatives of the formula: ##STR1## wherein Y is hydrogen, hydroxyl, an acyloxy, carbamoyloxy, a quaternary ammonium or a nitrogen-containing heterocyclic ring-substituted thio group; or pharmaceutically acceptable salts or esters thereof are useful as antibacterial agents. Also disclosed are processes for producing them.
Disclosed is a novel carbapenem derivative having a substituted imidazo[5,1-b]thiazole group at the 2-position on the carbapenem ring have high anti-microbial activities against &bgr;-lactamase producing bacteria, MRSA, resistant-Pseudomonas aeruginosa, PRSP, enterococci, and influenza, and high stabilities to DHP-1. According to the present invention, there is provided a compound represented by the formula (I), or a pharmacologically acceptable salt thereof or an ester at the 3-position on the carbapenem ring thereof:
Regioselective synthesis of 2-O-acyl-3-O-(1-acyloxyalkyl) prodrugs of 5,6-isopropylidene-l-ascorbic acid
作者:John Prybylski、Nikki A. Thiele、Kenneth B. Sloan
DOI:10.1016/j.tetlet.2016.02.112
日期:2016.4
An efficient regioselectivesynthesis of 2-O-acyl-3-O-(1-acyloxyalkyl) prodrugs of vitamin C 5,6-acetonide has been developed which does not involve tedious column chromatographic separation of the desired products from contaminants exhibiting very similar Rf values. Vitamin C 5,6-acetonide is first acylated with one equivalent of acyl halide in the presence of two equivalents of pyridine. The crude
In order to prepare ampicillin prodrugs conveniently for practical use, a new synthetic method for 6β-aminopenicillanic acid (6-APA) esters as key intermediates of various ampicillin prodrugs has been developed. Acylation of 6-APA esters to ampicillin esters was achieved in good yields by using phenylglycyl chloride hydrochloride in dichloromethane in the presence of sodium bicarbonate and amide, or ammonium bicarbonate alone. KBT-1585, bacampicillin, talampicillin and pivampicillin have been obtained in good yields by this procedure.
zol-5- yl)biphenyl-4-yl]methyl]-1H-imidazole-5-carboxylic acid (1), which was superior to EXP3174 in vitro. Since 1 showed only poor activity against angiotensin II-induced pressor response in rats after oral administration, the carboxylic acid function of 1 was converted into prodrug esters (13). Among these, the 1-[(ethoxycarbonyl)oxy]ethyl ester (13a) showed the most potent and longest-lasting activity