Oxidative addition of allylic carbonates to palladium(0) complexes: reversibility and isomerization

The oxidative addition of a cyclic allylic carbonate to the palladium(0) complex generated from a [Pd(dba)2]+2 PPh3 mixture affords a cationic pi-allylpalladium(II) complex with the alkyl carbonate as the counter-anion. This reaction is reversible and proceeds with isomerization of the allylic carbonate at the allylic position. The equilibrium constant has been determined in DMF. The influence of the precursor of the palladium(0) is discussed.

Application of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to the structure determination of medium and large macrocycles formed by palladium(0)-catalyzed allylation of arenesulfonamides, sulfamide, and cyanamide.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry allowed the direct determination of the extent of macrocyclic and linear oligomer formation in the palladium(0)-catalyzed allylation of highly acidic and non-nucleophilic arenesulfonamides, sulfamide, and cyanamide. Palladium-containing 15-membered-ring macrocyclic compounds gave unusual [M - H](+) ions besides [M + Na](+) and [M + K](+) adducts. Copyright 1999 John Wiley & Sons, Ltd.

Preparation, antimicrobial evaluation, and mutagenicity of [2-hydroxyaryl]-[1-methyl-5-nitro-1H-2-imidazolyl]methanols , [5-tert-butyl-2-methylaminophenyl]-[1-methyl-5-nitro-1H-2-imidazo lyl]me thanol, and [2-hydroxyaryl]-[1-methyl-5-nitro-1H-2-imidazolyl] ketones.

Efficient preparations of the titled compounds are described, their antimicrobial activity and mutagenic properties being evaluated. Some of the studied compounds are nonmutagenic and present a MIC as low as some of the usual standards in the field.

Synthesis and antimycotic activity of (benzo[b]thienyl)methyl ethers of 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)-ethanol and of (Z)-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanone oxime.

A new series of (benzo[b]thienyl)methyl ethers of 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol and of (Z)-1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanone oxime were synthesis and tested for antifungal activity. Series design, synthesis, preliminary antimycotic data and structure-activity relationships are reported. 7-Chloro-3-[1-(2,4-dichlorophenyl)-2-(1H-imidazol-1- yl)ethoxymethyl]benzo[b] (8i, Sertaconazole, FI-7045, CAS 99592-32-2) and its nitrate were selected for further research.

Synthesis and photochemical reactions of nitroestrogens: possible photoaffinity labels of zero length.

The syntheses of 3,4-dimethoxy-1,3,5(10)-estratrien-17-one and 4-bromo-3-methoxy-2-nitro-1,3,5(10)-estratrein-17-one are described and their photoreactions with amines and hydroxide ion studied. The possible usefulness of these new steroids as photoaffinity labels of zero length is discussed.

How medicinal chemistry triggers fundamental research in heterocyclic chemistry. The chemistry of 4-hydroxy-2-pyrones and a new imidazole antifungal agent.

The results herein described point out that the efforts devoted to the preparation of significant molecules can not be separated from those devoted to the discovery of new synthetic methodologies and to the solution of fundamental chemical problems. The border between basic and applied research vanishes very frequently.

Synthesis of δ-lactonic pheromones ofXylocopa hirsutissima andVespa orientalis and an allomone of some ants of genusCamponotus.

Simple preparations ofcis-3,6-dimethyltetrahydro-2-pyrone, VII,6-n-undecyltetrahydro-2-pyrone, XVIIb, and 6-n-pentyl-5,6-dihydro-2-pyrone, XVIa, have been achieved. Products VII and XVIIb, respectively, are the major constituent of the pheromonal blend of a carpenter bee (Xylocopa hirsutissima) and the pheromone of the queens of the Oriental hornet (Vespa orientalis). The lactone XVIa is a suspected defensive allomone in two species of formicine ants of the genusCamponotus. All three compounds have been prepared from dehydroacetic acid, I, a cheap and industrially available starting material.