Shin-ichi Sumida

How 2-anilinovinyl perfluoroalkyl ketones can be mechanistically correlated with their cyclization products 2-(perfluoroalkyl)quinolines

When heated in the presence of phosphoryl chloride, 2-anilinovinyl perfluoroalkyl ketones [e.g., 4-anilino-1,1,1-trifluoro-3-buten-2-one] gave 2-(perfluoroalkyl)quinolines [e.g., 2-(trifluoromethyl)quinoline]. As revealed by cross-over expts., an efficient amine exchange process randomizes the structural component in the final products but not in their aminoenone precursors. 1,3-Diaminoallyl cations (vinylogous formidinium salts) are postulated to act as the turntables. [on SciFinder (R)]

A facile synthesis of C(3)-alkenyl substituted cephems through addition-cyclization of allenecarboxylates derived from penicillin☆

Abstract A short-cut route to cephalosporins bearing alkenyl substituents on the C(3)-position through copper(I) chloride-promoted Michael-type addition of alkenyltributyltins to allenecarboxylates, derived from penicillin, is described.

Synthesis of 3-alkenyl-Δ2-cephems by copper(I) chloride-promoted alkenylation of 3-trifluoromethylsulfonyloxy-Δ3-cephem with alkenyltributyltins

Abstract Synthesis of 3-alkenyl-Δ 2 -cephems 3 was performed in regioselective manner by copper(I) chloride-promoted alkenylation of 3-trifluoromethylsulfonyloxy-Δ 3 -cephem 1 with alkenyltributyltins. Subsequent Diels-Alder reaction of the 3-vinyl-Δ 2 -cephem 3a with acrolein opened a new access to C(2) C(3) fused tricyclic cephalosporin 9 .

Use of aluminium as an electron pool. Reductive coupling of iodobenzenes promoted by electron transfer in an Ni/Pb/A1 multi redox system

Abstract Reductive coupling of iodobenzenes was achieved successfully by use of a stoichiometric amount of aluminium metal as an electron source and catalytic amounts of NiCl2(bpy) (bpy=2,2 - bipyridyl) and lead(II) bromide as electron transfer catalysts in methanol containing potassium iodide.

Construction of cephem framework via sequential reductive 1,2-elimination–hydride addition in a tributyltin hydride–copper(I) chloride–NMP system: synthesis of 3-norcephalosporin

A sequential reductive 1,2-elimination and hydride addition process for 3,4-disubstituted butenoates derived from penicillin is successfully performed with the aid of a combination of tributyltin hydride and copper(I) chloride in N-methyl-2-pyrrolidinone (NMP) to afford 3-norcephalosporin.

Convenient synthesis of cytotoxic (11E)-13-hydroxy-10-oxooctadec-11-enoic acid from undec-10-enoic acid

(11E)-13-Hydroxy-10-oxooctadec-11-enoic acid 1 is conveniently synthesized via a Knoevenagel-type reaction of isopropyl 11-phenylsulfinyl-10-oxoundecanoate 2a (itself easily derived from undec-10-enoic acid) with heptanal to form the γ-hydroxyenone functionality together with carbon chain elongation.

2-Substituted penems, new candidates for cephalosporinase inhibitors

Abstract Upon preliminary bioassay experiments, C(2)-substituted penems 5 exhibit promising activities particularly against E. Cloacae (cephalosporinase).