Process for the preparation of substituted pyridines via
申请人:DSM N.V.
公开号:US05438143A1
公开(公告)日:1995-08-01
Process for the preparation of substituted pyridines by allowing 1-aza-1,3-butadienes to react, in the presence of a catalytic amount of secondary amine and acid, with an aldehyde or ketone, and new 1-aza-1,3-butadienes which are used in this process. Said pyridines can be obtained in high yield in a simple process with a short reaction time. The 1-aza-1,3-butadiene can, if so desired, be prepared in situ from an imine and an aldehyde.
6-alpha/beta-[(C.sub.1 -C.sub.4)Alkoxyaminomethyl and benzyloxyaminomethyl]penicillanic acid 1,1-dioxides, pharmaceutically acceptable salts thereof and conventional esters thereof hydrolyzable under physiological conditions, all of which are useful in medicine as beta-lactamase inhibitors; intermediates and processes therefor; and a process for the conversion of the present compounds to 6-alpha- and 6-beta-(aminomethyl)penicillanic acid 1,1-dioxides and derivatives.
Process for debromination of dibromopenicillanic acid and derivatives
申请人:Pfizer Inc.
公开号:US04468351A1
公开(公告)日:1984-08-28
A process for the debromination of 6-monobromo- and 6,6-dibromopenicillanic acid, and various derivatives thereof, by the action of a bisulfite salt. The debrominated compounds produced find various utilities, as beta-lactamase inhibitors useful in therapy in combination with known beta-lactam antibiotics, or as intermediates in the further synthesis of useful beta-lactam compounds.
The Reactions of Singlet NH Radicals with Methyl and Ethyl Alcohols in the Liquid Phase
作者:Jun Kawai、Shigeru Tsunashima、Shin Sato
DOI:10.1246/bcsj.55.3312
日期:1982.10
The reactions of the singlet NH(a1Δ) radicals with alcohols were studied by the photolyses of hydrogen azide in liquid methyl and ethyl alcohols at the temperature of Dry Ice–methyl alcohol and at 0 °C. The main products were nitrogen, ammonia, and oxime ethers; acetaldehyde oxime O-ethyl ether from ethyl alcohol and formaldehyde oxime O-methyl ether from methylalcohol. The relative yields of the
A simple monoselective C–H oxygenation approach for the synthesis of ursane triterpenoids
作者:Wenyi Mei、Sisi Fan、Yufei Han、Cunjian Shi、Lijie Qiu、Yunheng Shen、Zhenjiang Zhao、Yufang Xu、Honglin Li
DOI:10.1039/d3ob00016h
日期:——
Herein, we presented a simpleapproach for C–H oxidation in the C23 or/and C24 of ursane triterpenoids without any protection of a Δ12,13 double bond. As a result, from commercial ursolic acid (UA), six naturally occurring ursane triterpenoids were synthesized in overall yields of 3.4% to 36.8%, which implied the importance of this approach for the derivation of natural products and their application