Rupankar Paira

Amberlite-IRA-402 (OH) ion exchange resin mediated synthesis of indolizines, pyrrolo [1,2-a] quinolines and isoquinolines: Antibacterial and antifungal evaluation of the products

A number of indolizines and pyrrolo[1,2-a]quinolines/isoquinolines were prepared from phenacyl pyridinium, quinolinium and isoquinolinium salts derived from the reaction of the heterocycles with 2-bromo acetophenone with alkynes and alkenes using amberlite-IRA-402 (OH) ion exchange resin as the base. Antibacterial and antifungal studies were carried out against thirteen bacterial and four fungal strains, which revealed that three derivatives (4a, 4b, 7a) out of fifteen are effective against all the thirteen strains and one derivative, 10, showed dual antibactericidal and antifungal efficacy.

Efficient synthesis of 3,3-diheteroaromatic oxindole analogues and their in vitro evaluation for spermicidal potential

Syntheses of 3,3-diheteroaromatic oxindole derivatives has been achieved by coupling indole-2,3-dione (isatin) with differently substituted indoles and pyrrole in presence of I(2) in i-PrOH. The in vitro spermicidal potentials and the mode of spermicidal action of the synthesized analogues were evaluated and the derivative, 3,3-bis (5-methoxy-1H-indol-3-yl) indolin-2-one (3d) exhibited most significant activity.

Regio- and Stereoselective Synthesis of a Library of Bioactive Dispiro-Oxindolo/Acenaphthoquino Andrographolides via 1,3-Dipolar Cycloaddition Reaction Under Microwave Irradiation

Dispiro-pyrrolidino/pyrrolizidino fused oxindoles/acenaphthoquinones have been derived from andrographolide via azomethine ylide cycloaddition to the conjugated double-bond under microwave (MW) irradiation. The reactions are chemo-, stereo-, and regioselective in nature. Change in amino acid from sarcosine/N-benzyl glycine to l-proline changes the regiochemistry. A representative library of 40 compounds along with in vitro anticancer evaluation is reported.

Search for a potent microbicidal spermicide from the isolates of Shorea robusta resin

BACKGROUND An alarming increase in global population is the root cause of poverty, malnutrition, sexually transmitted infections (STIs) and many other social problems. Microbicidal spermicides possessing dual function of contraception and STI protection can effectively combat this problem, and their development is of utmost importance at present. STUDY DESIGN A major metabolite isolated from Shorea robusta resin was spectroscopically characterized as asiatic acid. Spermicidal efficacy of the isolate was evaluated in vitro by a modified Sander-Cramer test. The mode of spermicidal action was assessed by (a) double fluoroprobe staining, (b) hypoosmotic swelling test and (c) scanning electron microscopy. Antimicrobial efficacy was assessed by disc diffusion and broth dilution methods using human isolates of bacteria (Escherichia coli ATCC 25938 and Pseudomonas aeruginosa 71) and fungus (Candida tropicalis). RESULTS The minimum effective concentration of asiatic acid that induced instantaneous immobilization of rat spermatozoa in vitro was 125 mcg/mL. The mechanism of action involved disruption of sperm plasma membrane. The microbicidal efficacy was found to be moderate for vaginal pathogens, with no effect on normal vaginal flora. CONCLUSION Asiatic acid possesses appreciable spermicidal and microbicidal potential and may be explored as an effective microbicidal spermicide.

I2 catalyzed Friedel–Crafts alkylation reaction of substituted anilines with ninhydrin: formation of novel products and their antimicrobial evaluation

Friedel–Crafts reaction of differently substituted anilines with ninhydrin in the presence of molecular iodine at ambient temperature constitutes a facile, cost effective, and regioselective synthesis of a series of 2-mono/2,2-bis-(amino-phenyl)-indane-1,3-dione derivatives. Under identical conditions, use of different substituents in aniline ring led to the formation of different products, emphasizing the pivotal role of the nature and position of the substituents in product formation. In vitro antimicrobial activity evaluation of the synthesized molecules against eight bacterial and four fungal strains revealed that four of them possess duel efficacies (bactericidal as well as fungicidal). The activities are attributed to the disruption of architecture of the microbes as revealed from ultrastructural studies (SEM).Graphical Abstract

Synthesis and Characterization of Furo[3,2-h]Quinoliniums as Potent Non- Detergent Spermicides

7-Aryl substituted furo[3,2-h]quinoliniums have been synthesised in two steps from 5-chloro-8-hydroxy-7- iodo-quinoline through a tandem Sonogashira alkynylation-cyclization pathway using aryl acetylenes followed by quaternisation reaction with alkyl halides under microwave irradiation. The compounds have been characterized spectroscopically and assessed for their sperm-immobilizing efficacy in vitro by modified Sander–Cramer test. Most of the derivatives showed potent spermicidal effect with minimum effective concentration (MEC) ranging from 125�g/ml – 1mg/ml. The results were further confirmed by double fluoroprobe staining with syber14/PI (Propidium Iodide). The mode of spermicidal action was assessed by (a) Hypo-osmotic swelling tests and (b) Scanning electron microscopy. The compounds have been found to be nontoxic to lactobacillus in 36 hours of culture whereas mild to moderately effective on common vaginal pathogens. Taken together it can be inferred that the water-soluble salts prepared from facile technique are potential candidates for spermicides and could further be utilized for the preparation of vaginal contraceptives.

Aqueous phase supramoleculer synthesis of 3,2-and 3,3-dihetero-aromatic oxindoles catalysed by β-cyclodextrin

A high yielding green protocol is described for the synthesis of 3,2 and 3,3-diheteroaromatic oxindole involving the condensation of isatin with indole or pyrrole in an aqueous medium under neutral conditions by supramoleculer catalysis by β-cyclodextrin. The β-cyclodextrin can be easily recovered and reused without any loss of activity.

Amberlite IRA 402(OH)-mediated synthesis and evaluation of fused tricyclic quinolinium salts as potent non-detergent type microbicidal spermicides

Fused tricyclic oxazaquinolinium salts were synthesized using Amberlite IRA 402(OH) in water and assessed for their sperm-immobilizing efficacy in vitro by modified Sander–Cramer test followed by double fluoroprobe staining of rat sperm. Out of 11 derivatives 3 showed potent spermicidal effect. The mode of spermicidal action was assessed by (a) Hypoosmotic swelling tests, (b) Lipid peroxidation studies, and (c) scanning electron microscopy. Antimicrobial efficacies of the potent derivatives, assessed by disc diffusion as well as by agar and broth dilution methods using human isolates of bacteria and fungi, revealed their moderate antimicrobial potential. The compounds, found to be nontoxic to rabbit erythrocytes by haemolytic assay, may be exploited as microbicidal spermicides.

Copper–phenanthroline catalysts for regioselective synthesis of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and of pyrrolo[1,2-a]phenanthrolines under mild conditions

Summary A new series of pyrrolo[3′,4′:3,4]pyrrolo[1,2-a]furoquinolines/phenanthrolines and pyrrolo[1,2-a]phenanthrolines were efficiently built up from an 8-hydroxyquinoline derivative or phenanthroline via 1,3-dipolar cycloaddition reaction involving non-stabilized azomethine ylides, generated in situ from the parent furo[3,2-h]quinoliniums/phenanthroliums, in presence of a copper(II) chloride–phenanthroline catalytic system. The methodology combines general applicability with high yields.

Palladium-Catalyzed 8-Exo Trig Intramolecular Heck Reaction Under Microwave Irradiation in the Presence of Basic Alumina

Abstract The Heck cross-coupling reaction has been employed for efficient conversion of quinolines to benzoxocinoquinoline through a microwave-assisted palladium-catalyzed intramolecular cyclization in the presence of basic alumina. GRAPHICAL ABSTRACT