Tricyclic or tetracyclic carbapenem compounds, their production and use
申请人:Takeda Chemical Industries, Ltd.
公开号:US05459260A1
公开(公告)日:1995-10-17
A polycyclic carbapenem compound of the formula (Ia'), (Ib') or (Ic') ##STR1## [wherein COOR.sup.2 is a carboxy group which may be esterified; R.sup.a' is --(CH.sub.2).sub.m --K.sup.a --(CH.sub.2).sub.n --U.sup.a' ; J is O or S; R.sup.b' is --(CH.sub.2).sub.m --K.sup.b --(CH.sub.2).sub.n U.sup.b' ; J' is O, S or CH.sub.2 ; R.sup.c' is --(CH.sub.2).sub.m --K.sup.c --(CH.sub.2).sub.n --U.sup.c', --(CH.sub.2).sub.m --K.sup.d --(CH.sub.2).sub.n --U.sup.d or a pair of groups, one of which is a hydroxy group, with the other being a hydroxzy group or an alkylsulfonylamino group, which may be substituted, in the position ortho to the first-mentioned hydroxy group] or a salt thereof are useful as an antibacterial agent.
A visible light-driven, copper-catalyzed aerobic oxidativecleavage of cycloalkanones has been presented. A variety of cycloalkanones with varying ring sizes and various α-substituents reacted well to give the distal keto acids or dicarboxylic acids with moderate to good yields.
We describe a cerium‐catalyzed aerobic oxidative ringexpansion for the expedient construction of synthetically challenging macrolactones under visible‐light conditions. Cyanoanthracene has been employed as co‐catalyst to accelerate the turnover of the cerium cycle leading to a fast conversion within 20 min of irradiation. Taking advantage of the high efficiency and operationally simple conditions
Titanium tetrachloride promoted reaction of trimethylsilylenolethers with ethylene oxide affords homoaldol type products in moderate/good yields. The reaction is believed to proceed via the titanium enolates.
Chemoselective Reduction of Aldehydes in the Presence of Ketones Utilizing Raney Nickel
作者:Alejandro F. Barrero、E. J. Alvarez-Manzaneda、Rachid Chahboun、R. Meneses
DOI:10.1055/s-2000-6498
日期:2000.2
Raney nickel is an effective reagent to achieve the chemoselective reduction of aldehydes in the presence of ketones, which takes place in high yield. Only highly hindered aldehydes do not undergo reduction.