Antigoni Kotali

Oxidation of N-Aroylhydrazones of o-hydroxyaryl ketones withlead(IV)acetate: A facile route to aromatic o-diketones

Abstract N-Aroylhydrazones of o-hydroxyaryl ketones are oxidized with lead(IV)acetate to aromatic o-diketones in a synthetically useful reaction.

A novel and facile synthesis of tetraacylbenzenes

Abstract 1,3-Dibenzoyl-2,4-diacyl- and 1,5-Dibenzoyl-2,4-diacylbenzene are prepared in good yields via a further application of a recently reported two step replacement of phenolic hydroxyl by an acyl group.

Synthesis of 6,7-Diacylcoumarins via the Transformation of a Hydroxy into a Carbonyl Group

Abstract The synthesis of 6,7-diacylcoumarins is reported via the oxidation of 6-acetyl-7-hydroxycoumarin N-acylhydrazones with lead tetraacetate. The procedure involves transformation of hydroxy into an acyl group and formation of a new C–C bond.

o-DIACYLBENZENES IN ORGANIC SYNTHESIS. A REVIEW

1 . Condensation Reactions ................................................................................................... 591 2 . Reduction ........................................................................................................................... 592 3 . Photochemical Reactions ................................................................................................. 592 4 . Bmminaiion Reactbns ..................................................................................................... 593 JL REACTIVITY OF 0-DIACYLBENZENES ....................................................................... 591

Synthesis of o-acylarylcarboxylic esters : a new replacement of phenolic hydroxyl by a carbonyl group

Abstract A wide variety of the title esters are prepared in good yields via a new two step replacement of phenolic hydroxyl by an ethaxycarbonyl group.

Synthesis, Characterization and Antileucemic Activity of 7-Hydroxy-8-acetylcoumarin Benzoylhydrazone

As part of a research programme targeting novel molecules derived from nitrogen derivatives of o-hydroxyaryl ketones [1] we synthesised 7-hydroxy-8-acetylcoumarin benzoylhydrazone.[...]

Antioxidant Activity of 3-[N-(Acylhydrazono)ethyl]-4-hydroxy-coumarins

A series of 3-acylhydrazono-4-hydroxycoumarins were synthesized via condensation of 3-acetyl-4-hydroxycoumarin with appropriate hydrazides. The structures of the newly-synthesized compounds were characterized by spectral and elememental analysis or HRMS measurements. Their antioxidant properties were evaluated by using scavenging effects on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical as well as inhibition of lipid peroxidation. Moreover, their ability to inhibit in vitro soybean lipoxygenase has been investigated. They were found to be capable of rapid inactivation of alkylperoxy radicals.

Oxidation of N-acyl hydrazones of ο-aminoaryl ketones: synthesis of 2-acylaminoindazoles

Synthesis of 3-substituted-7-acylaminoindazoles via the lead tetraacetate oxidative cyclization of N-carbonylhydrazones of o-aminoarylketones is reported. A mechanism involving formation of organolead, azoacetate and o-quinonemethide imine intermediates is proposed. The formation of the indazole heterocycle was confirmed by an independent synthesis of 7-benzoylamino-3-phenylindazole

Oxidation of the dioximes of 1,3-diketones with lead tetra-acetate

The oxidation of dioximes of aliphatic and cyclic 1,3-diketones with lead tetra-acetate has been investigated. The formation of pyrazole and pyrazoline 1,2-dioxides in moderate yields has been established. A general reaction scheme is proposed.

N'-[1-(2,4-Dioxo-3,4-dihydro-2H-1-benzopyran-3-yl-idene)eth-yl]thiophene-2-carbo-hydrazide.

The title compound, C16H12N2O4S, was obtained by the condensation of 3-acetyl-4-hydroxycoumarin with thien-2-ylcarbonyl hydrazide. The pyran ring adopts a 2,4-dione tautomeric form. The benzopyran ring system is almost coplanar with the thiophene ring [dihedral angle 0.9 (2)°]. The exocyclic C=C double bond has an E geometry. The molecular conformation is stabilized by an intramolecular N—H⋯O hydrogen bond. In the crystal, intermolecular N—H⋯O hydrogen bonds link the molecules into chains along the a axis.