Photoredox Catalytic Phosphite‐Mediated Deoxygenation of α‐Diketones Enables Wolff Rearrangement and Staudinger Synthesis of β‐Lactams
作者:Hui Yang、Haijun Li、Guo Wei、Zhiyong Jiang
DOI:10.1002/anie.202107080
日期:2021.9
activation of C=O bonds by exploiting the photoredox chemistry of 1,3,2-dioxaphospholes, readily accessible fromα-diketones and trialkyl phosphites, is reported. This mild and environmentally friendly strategy provides an unprecedented and efficient access to the Wolff rearrangement reaction which traditionally entails α-diazoketones as precursors. The resulting ketenes could be precisely trapped by
A novel method of producing a cephalosporin compound of the formula
wherein R' is a hydrogen atom or an acyl group; R is a hydrogen atom or an ester residue; the dotted line means a double bond in 2- or 3-position of the cephem ring; and R4 is a nucleophilic compound residue, or a salt thereof, directly in one step from a compound of the formula
wherein R', R and the dotted line have the meanings defined above, or a salt thereof, by reacting in the presence of an organic solvent the compound [II] or a salt thereof, a nucleophilic compound or a salt thereof, and (1) a trivalent or pentavalent cyclic phosphorus compound having a partial structure of the formula
wherein W is an oxygen atom, a sulfur atom or NR2; W1 is an oxygen atom, a sulfur atom or NR3; and R and R3 may be the same or different and each means a hydrogen atom or a hydrocarbon group, or a salt thereof, or (2) a reaction product of a compound having a partial structure of the formula
wherein W and W' have the same meanings as defined above, or a salt thereof, with a phosphorus oxyhalide, trihalide or pentahalide.
A compound having the general formula
wherein, R° is a hydrogen atom, a nitrogen-containing heterocyclic group, an acyl group or an amino-protective group; Z is S, S→0,0 or CH2; R4 is a hydrogen atom, a methoxy group, or a formamide group; R" is a hydrogen atom, a methyl group, a hydroxyl group, or a halogen atom; A is a condensed triazolio group which may be substituted, or a pharmaceutically acceptable salt or ester thereof is novel and has an excellent antibacterial activity.
Cephalosporins, process for their preparation and pharmaceutical compositions containing them
申请人:Takeda Chemical Industries, Ltd.
公开号:EP0229369A2
公开(公告)日:1987-07-22
A compound of the general formula:
wherein R° is hydrogen, a nitrogen-containing heterocyclic group, an acyl group or an amino-protective group; Z is S, S→O,O or CH2; R4 is hydrogen, a methoxy or formamido; R" is hydrogen, methyl, hydroxyl or halogen; and A is an optionally substituted condensed cyclic cationic group consisting of the same or different two 5- or 6-membered nitrogen-containing heterocyclic rings sharing a C-N bond with each other, , or a salt or ester thereof.
, and a process for preparing the same and a pharmaceutical composition thereof are disclosed.
Carbon-carbon condensations via oxyphosphoranes from the reaction of hexafluoroacetone with triphenylphosphine and with diphenyl-phosphinite, phenylphosphonite, and phosphite esters. The oxyphosphorane from triphenylphosphine and phenanthrenequinone