P. Manivel

SYNTHESIS OF O-SUBSTITUTED BENZOPHENONES BY GRIGNARD REACTION OF 3-SUBSTITUTED ISOCOUMARINS

ABSTRACT A series of o-substituted benzophenones was prepared by efficient method involving the 3-substituted isocoumarins and phenylmagnesium bromide. The reaction was completed in presence of anhydrous ether under dry ice-solvent bath in few hours with modest to good yields.Key words: Isocoumarins, diketones, aryl, phenyl magnesium bromide, ether, dry ice.e-mail: nawaz_f@yahoo.co.in. INTRODUCTION Synthetic and naturally occurring isocoumarins possess important biological properties. They are useful intermediates in the synthesis of a variety of carbocyclic and heterocyclic compounds 1-6 .In continuous of our interest in carbon-carbon bond formation reaction 7-12 ,the present paper presents an efficient method to synthesize o-substituted benzophenones (2) from 3-substitued isocoumarins (1) and phenyl magnesium bromide in presence of anhydrous ether under dry ice-solvent bath. Benzophenone and its derivatives are important intermediates in dyes, pharmaceutical and other chemical industries

SYNTHESIS OF 3 SUBSTITUTED ISOQUINOLIN-1-YL-2-(CYCLOALK-2-ENYLIDENE) HYDRAZINES AND THEIR ANTIMICROBIAL PROPERTIES

New hydrazine derivatives were synthesized via reaction between 1, 3 cyclic diketones and hydrazinoisoquinoline derivatives. The reaction proceeded smoothly in ethanol under reflux temperature and furnished products in excellent yields (76–87%). The products have been purified and fully characterized by spectroscopy techniques. The compounds 8a-c showed good bacterial inhibition against Bacillus cerus and 8d-f showed good antifungal activity against Candida albicans.

Evaluation of intermolecular interactions in thioisocoumarin derivatives: the role of the sulfur atom in generating packing motifs

Five derivatives of thioisocoumarin bearing aromatic and nonaromatic ring systems have been synthesized and characterized to unravel the importance of interactions due to the presence of a sulfur atom in generating packing motifs in the crystalline state. Apart from the well characterized interactions like C–H⋯S, a CS⋯π interaction is found in one of the case studies. The importance of such interactions in crystal structure packing along with routine C–H⋯π and π⋯π interactions is examined in the context of overall stability in the molecular assembly. The CS⋯π interactions in comparison to CO⋯π interactions have been analyzed using the Cambridge Structural Database (CSD).

3-Butyl-1H-isochromen-1-one

In the title compound, C13H14O2, a derivative of isocoumarin, the packing is stabilized by intermolecular C-H center dot center dot center dot O interactions.

Synthesis of Diversified Thioethers,1-Aroylalkylisoquinolin-1-yl Thioethers, by Electrophilic S-Alkylation of 3-Phenyl Isoquinoline-1(2H)-thione

A mild and efficient method for the synthesis of thioethers has been developed. The 3-phenylisoquinoline-1(2H)-thione underwent S-alkylation to afford structurally diverse sulfides in high yield.

Synthesis of Some New 2,4-Disubstituted Hydrazinothiazoles and 2,5-Disubstituted Thiazolidinones

A series of hydrazinothiazoles has been synthesized by the condensation of thiosemicarbazones and α-bromoketones. Similarly the hydrazinothiazolidiones were prepared by the condensation of thiosemicarbazone and α-bromoesters. The newly synthesized compounds were characterized by NMR and LCMS studies.

3-Phenyl-1-[2-(3-phenyl-isoquinolin-1-yl)-diselan-yl]isoquinoline.

The complete molecule of the title compound, C(30)H(20)N(2)Se(2), is generated by a crystallographic inversion centre at the mid-point of the Se-Se bond. The dihedral angle between the isoquinoline-1-selenol group and the phenyl ring is 14.92 (2)°. The herringbone-like packing of the structure is supported by inter-molecular π-π stacking inter-actions with a shortest perpendicular distance between isoquinoline groups of 3.514 Å; the slippage between these ring systems is 0.972 Å, and the distance between the centroids of the six-membered carbon rings is 3.645 (3) Å.

SYNTHESIS OF 2-(2-(HYDROXYMETHYL)PHENYL)ETHANOL DERIVATIVES AS POTENTIAL ANTIBACTERIAL AGENTS

ABSTRACT Reaction of 3-substituted isocoumarins (1a-h) with excess of sodium borohydride in methanol gave the corresponding 2-(2-(hydroxymethyl)phenyl)ethanol derivatives (2a-h). Antimicrobial activities of synthesized compounds were measured, using Gram-negative (Escherichia coli, Salmonella typhi, Proteus mirabilis) and Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus). Key words: Isocoumarin, sodium borohydride, diol, antimicrobial properties. e-mail: nawaz_f@yahoo.co.in. INTRODUCTION Synthesis of variety of compounds like carbocyclic, heterocyclic compounds and various aromatic compounds can be effected from isocoumarins intermediates. 1 The hydroxyl structural moiety was found in numerous pharmaceutically active compounds and therefore represents an interesting template for combinatorial as well as medicinal chemistry. 2 In particular phenylethanol derivatives have good antifungal properties. 3, 4 An increasing number of new isocoumarins in nature and increasing importance of diol derivatives have stimulated our researcher group a continued interest for synthesis of 2-(2-(hydroxymethyl)phenyl)ethanols from the precursor isocoumarins. Recently, several methods have been reported for the synthesis of diols such as palladium catalyzed reactions, electrophilic aromatic substitution, cyclization of 2-allyl- and alkenyl benzoic acid, etc.

Isocoumarin Thioanalogues as Potential Antibacterial Agents

A series of 3-substituted-1H-isochromene-1-thiones (3) were prepared by the reaction of 3-substituted isocoumarins (2) with Lawessons reagent in the presence of toluene under a nitrogen atmosphere. The antimicrobial activities of the newly synthesized products were measured using Gram-negative (Escherichia coli, Salmonella typhi, and Proteus mirabilis) and Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus). Synthesized thioanalogue of isocoumarins showed good antibacterial activity against Proteus mirabilis.

Organoiodine(III) mediated intramolecular oxidative cyclization of 1-(3-arylisoquinolin-1-yl)-2-(arylmethylene)hydrazines to 5-aryl-3-(aryl)-[1,2,4]triazolo[3,4-a] isoquinolines

A series of 5-aryl-3-(aryl)-[1,2,4]triazolo[3,4-a]isoquinolines, 4 were obtained by oxidative cyclization of 1-(3-arylisoquinolin-1-yl)-2-(arylmethylene)hydrazines, 3, in the presence of a hypervalent iodine oxidant (iodobenzene diacetate, IDB) and dichloromethane at ambient temperature. This methodology involves a proficient metal-free intramolecular C–N bond formation, facilitated by a hypervalent iodine reagent.