Gilbert Revial

Synthesis and Study of Antibacterial and Antifungal Activities of Novel 2-(((Benzoxazole/benzimidazole-2-yl)sulfanyl) acetylamino)thiazoles

Several 2-[[(benzoxazole/benzimidazole-2-yl)sulfanyl]acetylamino]thiazoles derivatives were synthesized by reacting 4-substituted-2-(chloroacetylamino)thiazoles with benzoxazole/benzimidazole-2-thioles in acetone and in the presence of K2CO3. The chemical structures of the compounds were elucidated by IR,1H-NMR, and FAB+-MS spectral data. Their antimicrobial activities againstMicrococcus luteus (NRLL B-4375),Bacillus cereus (NRRL B-3711),Proteus vulgaris (NRRL B-123),Salmonella typhimurium (NRRL B-4420),Staphylococcus aureus (NRRL B-767),Escherichia coli (NRRL B-3704),Candida albicans and Candida globrata (isolates obtained from Osmangazi Uni. Fac.of Medicine) were investigated and in this investigation, a significant level of activity was illustrated.

Enantioselective synthesis of ring-C aromatic steroids by asymmetric Michael-type alkylation of chiral imines.

Abstract Optically active phenanthrones 7 and 12 were prepared, using the asymmetric process involving Michael-type alkylation of chiral imines. Compound 12 was then transformed into the ring-C aromatic steroid 16 .

The asymmetric Michael process involving chiral imines: the diastereofacial differentiation aspect

Abstract A mechanism for the diastereofacial differentiation in the title reaction is proposed on the basis of the variation of the chiral auxiliary amines and of the examination of the crystal structure of enamino-ester 15 .

Enantioselective preparation of key [ABC] intermediates for steroid synthesis through the asymmetric Michael addition process involving chiral imines.

Abstract ( S )-Phenanthrone 7 , prepared from ketone 4 (80 % yield, 93 % ee), was transformed into compounds 8 , 9 , 13 , 15 and 16 , useful intermediates in steroid synthesis.

Diastereoselectivity and enantioselectivity in the addition of chiral imines of 2-methylcyclohexanone to crotonic and methacrylic acid esters

Abstract Additions of the chiral imine (reacting as its secondary enamine tautomer) obtained from ( S )-1-phenylethylamine and 2-methylcyclohexanone were performed with the phenyl ester of crotonic and methacrylic acid as well as with their methyl ester. In each example, the stereochemical relationship of the substituents in the major adduct was shown to be the one predicted in a previous theoretical calculation which established that the reactants complex has a chairlike geometry. In all the examples, the diastereoselectivity is superior to 98%. The enantioselectivity of the reactions is excellent as is usually the case with unsubstituted electrophilic olefins, the example with phenyl methacrylate being particularly remarkable ( de and ee >99%). In each case the favored diastereofacial selectivity is again in accordance with the rule elaborated previously. Relevant facts about the influence of the substituents upon the reactivity, the proportion of regioisomers, the stereoselectivity, and the enantioselectivity of the reaction are given.

Reaction of cyclohexanones imines with substituted nitroolefins. New synthesis of tetrahydroindole derivatives

Abstract The Michael-type addition of cyclohexanones imines, reacting as their secondary enamine tautomers, to β-substituted nitroolefins is followed by a cyclization reaction with elimination of the nitro group to afford substituted tetrahydroindoles. When a 2-methylcyclohexanone imine is reacted, an unexpected inversion of the regioselectivity is observed when compared with β-substituted ethylenic esters. thus allowing to obtain also substituted tetrahydroindoles.

Enantioselective synthesis of (+)-α-vetivone through the Michael reaction of chiral imines

Abstract (+)-α-Vetivone has been synthesised in nine steps. The absolute stereochemistry of the two stereogenic centres is controlled in the same key step involving the stereoselective Michael addition of a chiral imine of 4-isopropylidene-2-methylcyclohexanone to phenyl crotonate.

Asymmetric Michael addition of chiral imines to phenylvinylsulfone : preparation of key chiral building blocks for the synthesis of Aspidosperma and Hunteria alkaloids

Abstract Addition of chiral imine 8 to phenylvinylsulfone 9 led, after hydrolytic work-up to adduct 11 (91 % stereoselectivity). This derivative has been converted into target cyclopentanones 14 and 16 .

Crotonates as dienophiles in high pressure-induced diels-alder cycloadditions: compared intra and intermolecular situations

Abstract The cyclization reactions of trienes 1 and 2 related intermolecular systems (5+6) and (9+10) have been investigated.

Synthesis and Antimicrobial Activity of Some Thiazolyl-Pyrazoline Derivatives

Some 1-(4-aryl-2-thiazolyl)-3-(2-thienyl)-5-aryl-2-pyrazoline derivatives ( TP 1–28 ) were synthesized by reacting substituted 3-(2-thienyl)-5-aryl-1-thiocarbamoyl-2-pyrazolines ( P 1–7 ) with phenacyl bromides in ethanol. Structures of the synthesized compounds were confirmed by elemental analyses and IR, 1 H-NMR and MS-FAB+ spectral data. Their antimicrobial activities against Escherichia coli (NRRL B-3704), Staphylococcus aureus (NRLL B-767), Salmonella typhimurium (NRRL B-4420), Bacillus cereus (NRRL B-3711), Listeria monocytogenes (Ankara University, Faculty of Veterinary, Ankara, Turkey), Aeromonas hydrophila (Ankara University, Faculty of Veterinary, Ankara, Turkey), Candida albicans, and Candida glabrata (isolates obtained from Osmangazi University, Faculty of Medicine, Eskisehir Turkey) were investigated. A significant level of activity was illustrated.