Synthesis of some indole based spiro and condensed heterocycles as potential biologically active agents

The reactions of isatin with cyclic ketones, viz camphor (dl, Mp 174–181°C, specific rotation ?1.5° to +1.5°) available from s. d. fine‐ CHEM LTD and menthone (I, Bp 207°–210° C, density 0.893 g/mL) isolated from peppermint oil, in refluxing ethanol in the presence of t‐BuOK afforded the corresponding indolylidene compounds ( 3a ) and ( 3b ) (a mixture of stereochemical isomers E and Z in both the cases) respectively, all obtained as racemates. Cyclocondensation of ( 3a ) and ( 3b ) with thiourea, urea, ethylenediamine and o‐phenylenediamine afforded new spiro ( 4a,b‐7a,b ) and condensed systems ( 4a',b'‐7a',b' ) respectively, whereas with 2‐aminopyridine spiro compounds exclusively were obtained ( 8a,8b ). All the new spiro and condensed systems generated have been isolated as racemates and evaluated for their antimicrobial activity.     

Comparative study of styrene butadiene films in different solvents

We report here a comparative study of K-resin films in different solvents. A comparison of the waveguide parameters (refractive index, propagation losses, birefringence) in different solvents was done. The losses were found to be lower than 2 dB/cm for all solvents. Least losses observed were 0.62 dB/cm in the films dissolved in toluene. The birefringence was found to be in the range of 1 to 3 × 10⁻⁴. K-resin can be used successfully in fabrication of photonic devices.     

Temperature-dependent volumetric and viscometric properties of amino acids in aqueous solutions of an antibiotic drug

Volumetric and viscometric properties of glycine and methionine (amino acids) in a 0.2 vol. % amikacin sulphate (antibiotic drug) aqueous solution with the molality range of 0.025 mol kg^?1–0.25 mol kg^?1 were measured over the temperature range of 20°C–40°C at the interval of 5°C. Different parameters like apparent molar volume (? _V), apparent molar adiabatic compression (? _κ ), isentropic compression (κ _S) along with other acoustical parameters were calculated. Parameters like viscous relaxation time (τ), free volume (V _F), internal pressure (Π _I), and molar cohesive energy (MCE) were calculated from dynamic viscosity measurements. The ? _V values are positive in both cases, but with higher magnitude observed in methionine. These positive values of ? _V are indicative of strong solute-solvent interactions at all temperatures. In case of methionine there is a sharp initial increase in the ? _V values which become almost constant with further additions of the amino acid. Structural differences in the two amino acids studied are clearly reflected in the different nature of the plots of different parameters. In case of an amino acid-drug system, dynamic viscosity increase has been attributed to the increase in the hydrophilic-ionic and hydrophilic-hydrophilic interactions with the increase in the amino acid concentration which in turn may cause more frictional resistance to the flow of the solution. All other parameters are discussed in terms of solute-solvent and solvent-solvent interactions.     

Transesterification of Waste Cooking Oil by an Organic Solvent-Tolerant Alkaline Lipase from Streptomyces sp. CS273

The aim of this present study was to produce a microbial enzyme that can potentially be utilized for the enzymatic transesterification of waste cooking oil. To that end, an extracellular lipase was isolated and purified from the culture broth of Streptomyces sp. CS273. The molecular mass of purified lipase was estimated to be 36.55 kDa by SDS PAGE. The optimum lipolytic activity was obtained at alkaline pH 8.0 to 8.5 and temperature 40 °C, while the enzyme was stable in the pH range 7.0?～?9.0 and at temperature ≤40 °C. The lipase showed highest hydrolytic activity towards p-nitrophenyl myristate (C14). The lipase activity was enhanced by several salts and detergents including NaCl, MnSo₄, and deoxy cholic acid, while phenylmethylsulfonyl fluoride at concentration 10 mM inhibited the activity. The lipase showed tolerance towards different organic solvents including ethanol and methanol which are commonly used in transesterification reactions to displace alcohol from triglycerides (ester) contained in renewable resources to yield fatty acid alkyl esters known as biodiesel. Applicability of the lipase in transesterification of waste cooking oil was confirmed by gas chromatography mass spectrometry analysis.     

Microwave-assisted Vilsmeier-Haack synthesis of Pyrazole-4-carbaldehydes

The synthesis of 4-formylpyrazoles using Vilsmeier-Haack reagent is a common protocol in pyrazole chemistry. An efficient microwave-assisted synthesis of 4-formylpyrazoles by employing Vilsmeier-Haack reagent (OPC-VH) derived from phthaloyl dichloride/dimethylformamide has been described. This method offers the advantages of operational simplicity, avoiding the use of POCl₃ as toxic reagents and reuse of the by-product in the preparation of phthaloyl dichloride.     

Photoinitiated Thiol−Ene Reactions of Various 2,3‐Unsaturated O‐, C‐ S‐ and N‐Glycosides – Scope and Limitations Study

The photoinitiated thiol?ene addition reaction is a highly stereo‐ and regioselective, and environmentally friendly reaction proceeding under mild conditions, hence it is ideally suited for the synthesis of carbohydrate mimetics. A comprehensive study on UV‐light‐induced reactions of 2,3‐unsaturated O‐, C‐, S‐ and N‐glycosides with various thiols was performed. The effect of experimental parameters and structural variations of the alkenes and thiols on the efficacy and regio‐ and stereoselectivity of the reactions was systematically studied and optimized. The type of anomeric heteroatom was found to profoundly affect the reactivity of 2,3‐unsaturated sugars in the thiol?ene couplings. Hydrothiolation of 2,3‐dideoxy O‐glycosyl enosides efficiently produced the axially C2‐S‐substituted addition products with high to complete regioselectivity. Moderate efficacy and varying regio‐ and stereoselectivity were observed with 2,3‐unsaturated N‐glycosides and no addition occurred onto the endocyclic double bond of C‐glycosides. Upon hydrothiolation of 2,3‐unsaturated S‐glycosides, the addition of thiyl radicals was followed by elimination of the thiyl aglycone resulting in 3‐S‐substituted glycals.     

Thiosemicarbazone derivatives of nickel and copper: the unprecedented coordination of furan ring in octahedral nickel(II) and of triphenylphosphine in three-coordinate copper(I) complexes

The influence of substituents at the C(2) carbon of N(1)-substituted thiosemicarbazones, {C(4)H(3)X-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2)} (X = O, S) on the geometry of nickel(ii) complexes has been investigated. The presence of a methyl group at the C(2) position of 2-acetylfuran-N(1)-substituted thiosemicarbazones {(C(4)H(3)O)-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2), R(2) = CH(3), HaftscN-Me; C(2)H(5), HaftscN-Et; C(6)H(5), HaftscN-Ph} induces unusual coordination by the furan ring and yielded high spin octahedral nickel(II) complexes, [Ni(κ(3)-O, N(3), S-aftscN-R(2))(2)], CH(3)1, C(2)H(5)2, and 2[Ni((κ(3)-O, N(3), S-aftscN-Ph)(2)] 3 (μ(eff) = 2.98, 1; 2.96, 2; 2.92, 3). With 2-acetylthiophene-N(1)-substituted thiosemicarbazones, {(C(4)H(3)S)-C(2)(CH(3))=N(3)-N(2)H-C(1)(=S)N(1)HR(2), R(2) = CH(3), HattscN-Me; C(2)H(5), HattscN-Et; C(6)H(5), HattscN-Ph}, N(3), S chelated low spin trans square planar complexes, {[Ni(κ(3)-O, N(3), S-attscN-R(2))(2)], R(2) = CH(3), 4; C(2)H(5), 5; C(6)H(5), 6} with pendant thiophene rings have been obtained. The bigger sized sulfur atoms of the thiophene rings form short intramolecular contacts with the deprotonated hydrazinic nitrogen atoms (SN(2)) inhibiting its lability for possible coordination to nickel(II). Complexes have one independent molecule (1) or two independent molecules (2, 3) in their respective crystal lattices. The simultaneous presence of methyl groups at the C(2) and N(1) atoms of 2-acetylthiophene-N(1)-methylthiosemicarbazone (HattscN-Me) have facilitated the binding of triphenylphosphine in three-coordinate copper(i) halide complexes, [CuX(η(1)-S-HattscN-Me)(Ph(3)P)] (X, Br, 7; Cl, 8), which represent an unusual donor set of ligands, namely, triphenylphosphine, sulfur of a thio-ligand and a halide.