Solvent-free allylic oxidation of alkenes with O2 mediated by Fe- and Cr-MIL-101

The essential oil extracted by steam distillation from the capitula of Indian Tagetes patula, Asteraceae, was evaluated for its antifungal properties and analyzed by gas chromatography and gas chromatography–mass spectrometry. Thirty compounds were identified, representing 89.1% of the total detected. The main components were piperitone (24.74%), piperitenone (22.93%), terpinolene (7.8%), dihydro tagetone (4.91%), cis-tagetone (4.62%), limonene (4.52%), and allo-ocimene (3.66%). The oil exerted a good antifungal activity against two phytopathogenic fungi, Botrytis cinerea and Penicillium digitatum, providing complete growth inhibition at 10 µl/ml and 1.25 µl/ml, respectively. The contribution of the two main compounds, piperitone and piperitenone, to the antifungal efficacy was also evaluated and ultrastructural modifications in mycelia were observed via electron microscopy, evidencing large alterations in hyphal morphology and a multisite mechanism of action.

Chemical characterization and antifungal activity of essential oil of capitula from wild Indian Tagetes patula L

The intense sweet and coconut-like smelling odorant 1, named ‘wine lactone’, was isolated from different wine varieties. The chemical structure of this compound, which has not yet been detected in wine or a food, was identified by high-resolution mass spectrometry (HR-MS) as 3a,4,5,7a-tetrahydro-3,6-dimethylbenzofuran-2(3H)-one. For the evaluation of the configuration of wine lactone, stereochemically controlled syntheses were developed. All eight isomers were characterized by NMR, MS, IR, and CD measurements. The configuration of ‘wine lactone’ was in agreement with synthesized (3S,3aS,7aR)-enantiomer (1a) on the basis of enantioselective GC. For this isomer, the lowest odor threshold (0.02 pg/1 air) was detected.

Determination of the Configuration of Wine Lactone

Protection for the Hydroxyl Group, Including 1,2‐ and 1,3‐Diols

The peroxovanadium species generated from V(2)O(5) and hydrogen peroxide, which is liberated from peroxy salts such as sodium perborate (SPB) or sodium percarbonate (SPC), transform aldehydes directly into esters in an alcoholic medium. Monoesters of diols have been achieved directly in one pot from aldehydes. High catalytic turnover number combined with inexpensive, easily available reagents and innocuous side products from the reaction make it a suitable alternative for the synthesis of esters from aldehydes.

Peroxovanadium-catalyzed oxidative esterification of aldehydes

Tert-Butyl hydroperoxide-pyridinium dichromate: a convenient reagent system for allylic and benzylic oxidations

A highly selective methodology for the direct conversion of acetals to esters

An efficient and highly selective method for deoximation of ketoximes

Piperidinium tetrathiotungstate has been found to react with a number of 1,n-dihalo compounds to afford the corresponding cyclic disulfides in good yields, under mild reaction conditions. This new methodology has been used as a key step in the synthesis of (+/-)-lipoic acid (35) and asparagusic acid (37).

N. Chidambaram

Papers

Tert-Butyl hydroperoxide-pyridinium dichromate: a convenient reagent system for allylic and benzylic oxidations

A highly selective methodology for the direct conversion of acetals to esters

An efficient and highly selective method for deoximation of ketoximes

Piperidinium tetrathiotungstate as sulfur transfer reagent: synthesis of cyclic disulfides

A general approach to the synthesis of 5,6-dihydro-2(2H)pyranones; simple synthesis of α-pyrone, (±)-argentilactone and (±)-goniothalamin