Redox-Neutral [4 + 2] Annulation of <i>N</i>-Methoxybenzamides with Alkynes Enabled by an Osmium(II)/HOAc Catalytic System
作者:Jian Yang、Liexin Wu、Huiying Xu、Hui Gao、Zhi Zhou、Wei Yi
DOI:10.1021/acs.orglett.9b03827
日期:2019.12.20
C-H activation strategy, an efficient osmium(II)-catalyzed redox-neutral [4 + 2] annulation of N-methoxybenzamides with alkynes has been accomplished. Computational and experimental studies revealed that such transformation leading to the synthesis of the isoquinolone core might follow an Os(II)-Os(IV)-Os(II) catalytic pathway, in which an unusual HOAc-assisted oxidative addition of osmium(II) into
Cephalosporin antibiotics represented by the formula ##STR1## wherein R is hydrogen, C.sub.1 -C.sub.4 alkyl or a carboxy substituted alkyl group; R.sub.1 is H or C.sub.1 -C.sub.4 alkyl; n is 0, 1 or 2; and A and A' independently are hydrogen, C.sub.1 -C.sub.4 alkyl or allyl; and pharmaceutically acceptable salts thereof are broad spectrum antibiotics useful in the treatment of gram positive and gram negative infections of mammals.
Atom e[Co]nomical: High chemo- and regioselective C−H and N−H annulation of aryl amide was accomplished throughcobalt-catalyzedC−Hbondactivation with 1,3-diynes using N−OMe as internaloxidant. Broad substrate scope with excellent functional group tolerance was achieved using various amides and diynes.
Synthesis and biological evaluation of a series of parenteral 3'-quaternary ammonium cephalosporins
作者:Raymond F. Brown、Michael D. Kinnick、John M. Morin、Robert T. Vasileff、Fred T. Counter、Edward O. Davidson、Paul W. Ensminger、Judith A. Eudaly、Jeffrey S. Kasher
DOI:10.1021/jm00170a011
日期:1990.8
The preparation and biological evaluation of a series of 7 beta-[2-(2-aminothiazol-4-yl)-2(Z)-methoximinoacetamido]cep halosporins, substituted at the 3'-position with monocyclic or bicyclic nitrogen-containing heterocycles are described. The resulting family of parenteral compounds displays a broad spectrum of antibacterial activity. Some compounds exhibit a similar level of Gram-negative activity to that of the "third-generation" cephalosporins with increased staphylococcal activity. The in vitro and in vivo antimicrobial activity, structure-activity relationships, beta-lactamase stability, and in vitro and in vivo pharmacological evaluations are presented.