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The first report of monitoring the kinetics of racemization in solution by online vibrational circular dichroism (VCD), chemometrics, and density functional theory (DFT) calculations is presented. The activation energy for the racemization of an imidazoline based on the experimental VCD was determined, and the detailed mechanism of the process utilizing DFT calculations was elucidated. This study demonstrates the utility of VCD for the determination of reaction mechanisms in asymmetric transformations.

A versatile synthesis of pyrazoles from aryl benzophenone hydrazones was demonstrated with a variety of 1,3-bifunctional substrates under acidic conditions. The obtained regioselectivity is consistent with transhydrazonation followed by subsequent cyclization.

Reaction of 4,5-dibromo-1,2,3-triazole with electron-deficient aromatic halides in the presence of potassium carbonate in DMF produces the corresponding 2-aryl-4,5-dibromotriazoles with high regioselectivity. Subsequent debromination of these triazoles by hydrogenation furnishes 2-aryltriazoles in excellent yields. Overall, this two-step process provides an efficient access to 2-aryl-1,2,3-triazoles.

A series of structurally novel, operationally convenient, and efficient chiral 2-phosphino-2,3-dihydrobenzo[d][1,3]oxaphosphole ligands was developed. Applications of ligands 3a and 3b in rhodium-catalyzed asymmetric hydrogenation of alpha-(acylamino)acrylates and beta-(acylamino)acrylates provided excellent enantioselectivities (up to99% ee) and reactivities (up to 10,000 TON).

Pd-catalyzed aminocarbonylation of heteroaryl halides, using monodentate ligand di-tert-butylphosphinoferrocene tetrafluoroborate is reported. Good to high yields were obtained with chiral amines on a variety of substrates including 2-bromo heteroaryls.

Phosphine boranes have been found to hydrophosphinate internal, unactivated alkynes at room temperature under basic conditions without the need for catalysts or radical initiators. The use of air-sensitive secondary phosphines is avoided in this facile process. Broad scope in both the phosphine borane and alkyne partners leads to excellent diversity in the phosphine products. Asymmetric hydrogenation of these species then provides one of the shortest possible routes to chiral monodentate phosphines. Hydrophosphination of allenyl phosphine oxides under similar conditions followed by hydrogenation of the exomethylene moiety yields a wide variety of bis-phosphine derivatives.

The first palladium-catalyzed coupling of vinyl tosylates with arylsulfinate salts is described. A variety of cyclic and acyclic vinyl tosylates were coupled with aryl sulfinate salts using 2.5 mol % Pd 2 (dba) 3 /5.0 mol % XantPhos to give vinyl aryl sulfone products in good yields. The coupling was extended to the preparation of a cyclopropyl vinyl sulfone.

International audience; A recent isolated population of Apis florea has been reported from Aqaba in Jordan at the Red Sea, consisting of numerous colonies within a still limited range which apparently is expanding. This region is about 1500 km apart from its next occurrences in Sudan where it had been introduced and first detected in 1985 and about 2000 km apart from its next natural occurrences in Iran and Oman. These bees apparently have been imported by human transport, most likely by ship. This new location thus represents a major jump in the progression of the species still to fill a wide area of possible locations offering adequate living conditions. Here we attempt to track the possible origin of this new population by morphometric methods. This analysis indicated closest relation to A. florea from Oman, thus being the most likely source of this population.

A fast enantiomeric separation of a chiral aromatic amine was achieved, using ultra high pressure liquid chromatography and highly sulfated beta-cyclodextrin (S-beta-CD) as a chiral additive in the mobile phase. The stationary phase consisted of a core-shell support with a particle size of 2.7mum. Under these conditions the base-line separation was obtained within 2.5min. The influence of the concentration of the additive, along with the thermodynamics of the separation, was studied. Vibrational circular dichroism (VCD) spectroscopy was applied to assess the absolute configuration of the two enantiomeric analytes, as well as the interaction of these enantiomers with the S-beta-CD. The VCD results revealed that S-beta-CD undergoes a temperature-induced conformational change. Further, VCD experiments indicate that the interactions of the two enantiomers with the S-beta-CD occur through an inclusion of the aromatic part of the analyte, as well as through electrostatic interaction between the protonated amine and the sulfate groups located at the narrow part of the S-beta-CD. Molecular mechanics calculations performed according to the VCD results are consistent with experimental data, providing further evidence of these interactions.

Varroa disease is a parasitic disease of adult bees and brood, due to a blood-sucking external parasitic mite, Varroa destructor. This is one of the most dangerous diseases in Algeria. The purpose of this study is to evaluate the effectiveness of two treatments approved based thymol (Thymovar® and Apiguard®) in the fight against varroa in Algerian conditions and to determine the side effects of these treatments on bee colonies local Apis mellifera intermissa. The test was performed on 80 colonies with two different formulations for each treatment. As the results show in our test, a wide variation in the effectiveness between colonies is recorded for both treatments. The average efficiency for the group of colonies ½ Thymovar strap in two applications stood at 84.43%. This efficiency is lower for the group ½ straps in one application (77.23%). For Apiguard, the average efficiency is 81% for formulation 2 x 25g spaced two weeks, against a 79% rate for the formulation of 2X25 spaced one week. During our tests, with a few dead bees and nymphs found on nappies, we never recorded unusually high bee mortality. Further tests are needed to determine the optimal dose and the best time for treatment.

Asymmetric hydrogenation of unsaturated urea esters with the BIPI Ligands has been examined. Optimization of the P−N ligand structure has led to the development of chiral rhodium catalysts capable of producing the targets with >99% ee. The critical phosphine borane SNAr reaction needed for ligand synthesis has been optimized to give the adducts in high yield at ambient temperature with no racemization. An extremely concise, economical, and scalable sequence to these important new ligands for catalysis of asymmetric hydrogenation has been developed.

Bis[3,5-bis(trifluoromethyl)phenyl]-phosphine oxide 3,5-Bis(trifluoromethyl)bromobenzene Diethyl phosphate Bis[3,5-bis(trifluoromethyl)phenyl]phosphine Keywords: electron-deficient; secondary phosphine oxides; secondary phosphines; reduction; arylmagnesium reagent; phosphorus trichloride; trichlorosilane; isobutylaluminum; triisobutylaluminum

A sequential allyl vinyl ether formation-Claisen rearrangement process catalyzed by a palladium(II)-phenanthroline complex is reported. The effects of allylic alcohol structure, type of vinylating agent, and palladium catalysts are discussed. This method provides a convenient approach to gamma,delta-unsaturated aldehydes under mild conditions that avoid the use of toxic Hg(II) catalysts. The new methodology has been successfully demonstrated on the kilogram scale.

Beeswax is composed of fatty acids, odd numbered n-alkanes and wax esters. Focusing on the most stable components of beeswax, namely the n-alkanes, we have found by gas chromatography and gas chromatography-mass spectrometry analyses of combs from twelve colonies from Israel and Jordan that as beeswax ages and darkens its n-alkane composition changes. The amount of even numbered n-alkanes (C22– C32) is significantly higher in darker colored beeswax as compared to light colored beeswax. We attribute this in part to the accumulation of cuticular residues found in the darker colored comb cells. Cuticular residues are known to contain C23–C32 odd and even numbered n-alkanes.

A convergent synthesis of quinolone 2 (key substructure of the protease inhibitor BILN 2061) was developed via palladium-catalyzed carbonylation of 2-iodo-5-methoxyaniline (4) with thiazolylacetylene 5.

Bees fascinate almost everyone not just scientists but school children and the general public as well. This project builds on that fascination and seeks to inform and develop that curiosity into real research as well as reaching out across frontiers.

The detailed development of unique BIPI ligands suitable for asymmetric hydrogenation is described, and the process research leading to their kilogram-scale manufacture is discussed. Full optimization of each ligand region is shown, and the complete design features for these ligands are explained. Application of the best members of this ligand class to asymmetric hydrogenations of ureaesters, BOC- and CBZ-enecarbamates, and a variety of enamides are described. A novel resolution of P-chiral ligand precursors via their zinc complexes is described, and the research leading to the discovery of catalysts capable of carrying out asymmetric hydrogenations in >99% ee at multi-kilogram scale are presented.

The intramolecular photocycloaddition/fragmentation of tertiary vinylogous amides, in which stabilization of the chromophore by intramolecular hydrogen bonding is not possible, and the selective conversion of the derived zwitterionic intermediate to either ketoenamine, aminal or ketoiminium products is described.

Transposition of the chromophore leads to complete reversal of previously observed stereoselectivities in the intramolecular dioxenone photocycloaddition. A proposal to explain this change in stereoselectivity in presented, and the facile transannular reaction of the photoaddition/fragmentation product derived from the transposed photosubstrate 5 is described.

The intramolecular photocycloaddition/fragmentation of tertiary vinylogous amides, in which stabilization of the chromophore by intramolecular hydrogen bonding is not possible, and the selective conversion of the derived zwitterionic intermediate to either ketoenamine, aminal or ketoiminium products is described.