2-Substituted thiazolidine-4(R)-carboxylic acids as prodrugs of L-cysteine. Protection of mice against acetaminophen hepatotoxicity
作者:Herbert T. Nagasawa、David J. W. Goon、William P. Muldoon、Richard T. Zera
DOI:10.1021/jm00371a006
日期:1984.5
thiazolidine ring must have taken place. Indeed, 1b labeled with 14C in the 2 and methyl positions was rapidly metabolized by the rat to produce 14CO2, 80% of the dose being excreted in this form in the expired air after 24 h. It is suggested that these 2-substituted thiazolidine-4(R)-carboxylic acids are prodrugs of L-cysteine that liberate this sulfhydryl amino acid in vivo by nonenzymatic ringopening, followed
评价了许多2-烷基和2-芳基取代的噻唑烷-4(R)-羧酸对小鼠经LD90剂量对乙酰氨基酚引起的肝毒性死亡的保护作用。2(RS)-甲基-,2(RS)-正丙基-和2(RS)-正戊基噻唑烷-4(R)-羧酸(分别为化合物1b,d,e)在它们上几乎等价根据48小时存活动物的数量以及组织学标准确定保护作用。2(RS)-乙基-,2(RS)-苯基-和2(RS)-(4-吡啶基)噻唑烷-4(R)-羧酸(化合物1c,f,g)的保护性较小。1b的对映异构体,即2(RS)-甲基噻唑烷-4(S)-羧酸(2b),在这方面完全无效。噻唑烷-4(R)-羧酸(1a),但不是其对映异构体2a,是大鼠肝线粒体脯氨酸氧化酶[Km = 1.1 x 10(-4)M; Vmax =5.4μmol·min-1(蛋白质mg)-1]。化合物1b不是脯氨酸氧化酶的底物,但在此系统中与L-半胱氨酸解离。在生理pH和温度下,1b甲基上的氢与溶剂D2O进行氘交换(k1
(+)-Meyeniins A–C, Novel Hexahydroimidazo[1,5-<i>c</i>]thiazole Derivatives from the Tubers of <i>Lepidium meyenii</i>: Complete Structural Elucidation by Biomimetic Synthesis and Racemic Crystallization
作者:Min Zhou、Hang-Ying Ma、Zhi-Hua Liu、Guang-Yu Yang、Gang Du、Yan-Qing Ye、Gan-Peng Li、Qiu-Fen Hu
DOI:10.1021/acs.jafc.6b05805
日期:2017.3.8
(+)-Meyeniins A–C (1–3), a novel class of sulfur-containing hexahydroimidazo[1,5-c]thiazole derivatives, were isolated from the tubers of Lepidium meyenii (maca) cultivated in Lijiang, Yunnan province, China. Guided by their biosynthetic hypothesis, a stereocontrolled biomimeticsynthesis of meyeniins A–C and their individual enantiomers was efficiently accomplished by a combination of a condensation