Satoko Tanaka

Formation of tetracyclic oxazolidinones from cycloadducts of benzylidene ketones with 4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione (PTAD) by base-promoted backbone participation and rearrangement

Alcoholysis and aminolysis of urazoles 4a–j prepared by the reactions of benzylidene ketones with 4-phenyl-4,5-dihydro-3H-1,2,4-triazole-3,5-dione (PTAD) afforded tricyclic oxazolidinone derivatives 5a��o in moderate yields (16–77%). The structure of compound 5b was confirmed by a single-crystal X-ray analysis. The reaction proceeded via opening of the urazole ring by initial Michael addition of nucleophiles (solvents) to the enone substructure, followed by participation of the carbonyl group and final skeletal rearrangements.

One-pot syntheses of 3-cyanoindoles from 3-acyl- and 3-ethoxycarbonyl-1,2-dihydrocinnoline-1,2-dicarboximides

2-Acyl- and 2-ethoxycarbonyl-3-cyanoindoles were prepared from 3-acyl- and 3-ethoxycarbonyl-1,2-dihydrocinnoline-1,2-dicarboximides and potassium cyanide via Michael addition, skeletal rearrangement and subsequent elimination of isocyanate.

Perkin communications. Ready alcoholysis of the cycloadducts (urazole) of 4-phenyl-1,2,4-triazole-3,5-dione by solvent-assisted backbone participation

A series of urazoles containing αβ-carbonyl groups underwent ready alcoholysis by solvent-assisted backbone participation in the presence of potassium hydroxide to give oxazolinones.

Novel base-promoted addition-elimination reaction of electron-deficient benzylidene derivatives with N-phenyl-1,2,4-triazole-3,5-dione (PTAD)

The reaction of electron-deficient benzylidene derivatives with PTAD afforded the double Diels–Alder product and the Diels–Alder ene product; the latter underwent novel base-induced elimination of phenyl urazole via a stable carbanion.