Visible Light‐Catalyzed Decarboxylative Alkynylation of Arenediazonium Salts with Alkynyl Carboxylic Acids: Direct Access to Aryl Alkynes by Organic Photoredox Catalysis
salts have been utilized as the aryl radical source to couple alkynyl carboxylic acids to feature the decarboxylative arylation. A wide range of substrates are amenable to this protocol with broad functional group tolerance, and diversely‐functionalized aryl alkynes could be synthesized undermild, neutral and transition metal‐free reaction conditions using visiblelight irradiation. Alongside synthetic
Studies on Anti-MRSA Parenteral Cephalosporins. III. Synthesis and Antibacterial Activity of 7.BETA.-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2(Z)-alkoxyiminoacetamido]-3-[(E)-2-(1-alkylimidazo[1,2-b]pyridazinium-6-yl)thiovinyl]-3-cephem-4-carboxylates and Related Compounds.
In the course of our exploration for a novel cephalosporin derivative having excellent antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA), we modified the C-3 linked spacers of cephem derivatives bearing a l-methylimidazo[l, 2-b]pyridazinium-6-yl group at the C-3' position and 2-(5-amino-l, 2, 4-thiadiazol-3-yl)-2(Z)-cyclopentyloxyiminoacetyl group at the C-7 position. The optimal spacers were the (E)-2-vinyl and (E)-2-thiovinyl groups seen in 19a and 29aa, respectively. Their anti-MRSA activity was 16 to 32 times as potent as that of cefozopran (CZOP). Focusing on the (E)-2-vinyl and (E)-2-thiovinyl spacers, we further modified the alkoxyimino groups in the C-7 acyl moiety and the 1-alkylimidazo[l, 2-b]pyridazinium moieties at the C-3' position and investigated the structureactivity relationships (SAR) of the derivatives. Consequently, we selected 7β-[2-(5-aminol, 2, 4-thiadiazol-3-yl)-2(Z)-fluoromethoxyiminoacetamido]-3-[(E)-2-(l-methylimidazo[l, 2-b]pyridazinium-6-yl)thiovinyl]-3-cephem-4-carboxylate (29ca) as a new anti-MRSA parenteral cephalosporin candidate for further biological evaluation. The selected 29ca showed anti-MRSA activity comparable to that of vancomycin (VCM) both in vitro and in vivo, high affinity (IC50=2.7 μg/ml) for penicillin binding protein 2' (PBP2') of MRSA and potent activity against Gram-negative bacteria as well.
Disclosed are imidazole and thiazole compounds, as well as pharmaceutical compositions and methods of use thereof. One embodiment is a compound having the structure
and pharmaceutically acceptable salts, prodrugs and N-oxides thereof (and solvates and hydrates thereof), wherein X, A, Z, R1 and R′ are as described herein. In certain embodiments, a compound disclosed herein inhibits TGF-β, and can be used to treat disease by blocking TGF-β signaling.
Disclosed are imidazole and thiazole compounds, as well as pharmaceutical compositions and methods of use thereof. One embodiment is a compound having the structure
and pharmaceutically acceptable salts, prodrugs and N-oxides thereof (and solvates and hydrates thereof), wherein X, A, Z, R1 and R′ are as described herein. In certain embodiments, a compound disclosed herein inhibits TGF-β, and can be used to treat disease by blocking TGF-β signaling.