Pratibha Kumari

Facile and Efficient Synthesis of 14‐Alkyl‐ or Aryl‐14‐H‐Dibenzo[a,j]xanthenes using Sulfonyl‐Functionalized Ionic Liquids

Abstract An efficient, simple, and rapid synthesis of 14‐alkyl‐or aryl‐14‐H‐dibenzo[a,j]xanthenes is reported by one‐pot condensation of 2‐naphthol with alkyl or aryl aldehydes in the presence of sulfonyl‐functionalized acidic ionic liquids at 125°C.

Synthesis of Metal‐Free Phthalocyanines in Functionalized Ammonium Ionic Liquids

Abstract A convenient, fast, efficient, and ecofriendly synthesis of metal‐free phthalocyanines from various substituted phthalonitriles in different hydroxyalkylammonium ionic liquids in the presence of 1,8‐diazabicyclo‐[5,4,0]‐undec‐7‐ene (DBU) is reported in moderate yields. The effect of concentration of DBU and temperature on the synthesis of phthalocyanine in N‐(2‐hydroxyethyl)‐N,N‐dimethylbutylammonium bromide ionic liquid has been examined, and the ionic liquid has been recovered and reused conveniently.

Efficient iron(III) porphyrins-catalyzed oxidation of guanidoximes to cyanamides in ionic liquids

AbstractWater soluble iron(III) porphyrins immobilized in imidazolium ionic liquids serve as an effective catalyst for the H2O2 mediated oxidation of guanidoximes to selectively give corresponding cyanamides in good yields. The use of ionic liquid with non-coordinating counter anion PF6 affords the product in high yield by facilitating the formation of anionic iron peroxo intermediate. Graphical AbstractThe selective oxidation of guanidoximes to corresponding cyanamides has been achieved by H2O2 catalyzed by water-soluble iron(III) porphyrins immobilized in imidazolium ionic liquids. The non-coordinating ionic liquid [bmim][PF6] facilitates the formation of anionic iron peroxo intermediate and thereby gives products in highest yield.

Formation of hydridocobalt(III) phthalocyanine by reaction of cobalt(II) phthalocyanines with sodium borohydride and its reactions with antioxidant isoflavones

The reduction of substituted isoflavones with sodium borohydride catalyzed by cobalt(II) phthalocyanines has been achieved efficiently to yield cis- and trans-isoflavan-4-ols under mild conditions via the formation of a hydridocobalt(III) phthalocyanine intermediate. The hydroxy isoflavones react with sodium borohydride to form the corresponding phenolate moiety and thereby prevent the formation of a hydridocobalt(III) phthalocyanine intermediate which inhibits its reduction to corresponding isoflavan-4-ols.

Efficient cobalt(II) phthalocyanine-catalyzed reduction of flavones with sodium borohydride

Efficient and facile reductions of flavones with sodium borohydride (NaBH4) catalyzed by cobalt(II) phthalocyanines afford cis-flavan-4-ols in 89-97% yields.

A highly selective and sensitive chemosensor for L-tryptophan by employing a Schiff based Cu(II) complex

A new Cu(II) complex C40H38N4CuO2 (1) was synthesized and characterized by elemental analysis, mass spectrometry and also authenticated by single crystal X-ray studies. Structural analysis of 1 reveals the distorted square planar geometry around the Cu(II) centre and the presence of C–H⋯O and N–H⋯π hydrogen bonding interactions. The sensing behaviour of 1 towards L-tryptophan (L-Trp) was identified by UV-vis spectroscopic and cyclic voltammetry experiments. In the UV titration of 1 with L-Trp, four distinct isosbestic points were observed. Furthermore, on modifying the surface of the glassy carbon electrode (GCE) by 1 (1-GCE) the oxidation potential of L-Trp at +0.32 V is revealed, which is considerably lower than the values previously reported for other electrodes. Additionally, the 1-GCE can detect L-Trp with a noteworthy detection limit (185 nM), sensitivity (3.156 μA μM−1 cm−2) and with distinguished selectivity in the presence of various other amino acids. The 1-GCE also displays excellent reproducibility, repeatability and long term stability. Finally, electrochemical impedance spectroscopy (EIS) investigations were carried out to gauge the effects of modification with 1 on the characteristics of the GCE. Moreover, the molecular docking study of 1 with various proteins reveals the π–π stacking interaction with L-Trp.

Challenges with Mosquito-borne Viral Diseases: Outbreak of the Monsters

BACKGROUND The viruses responsible for mosquito-borne diseases are on an exploring mode, expanding their horizon, adapting to the situation and comfortably making their presence felt globally, from South Africa to Asia, Europe and United States. The current global scenario and recent documentations indicate towards the real monsters, outbreak of Zika, dengue and chikungunya viruses. Zika, dengue and chikungunya viruses are positive sense single-stranded RNA arbovirus and so their initial symptoms are almost 80% similar and all three are spread by mosquitos which bite during the day. Zika virus may damage brain by targeting the neuron cells in babies, and thereby it is very perilous to pregnant women. Dangerous Type: A less common but highly dangerous type of dengue is one which causes haemorrhagic fever and shock syndrome which are lethal. Chikungunya is not as lethal as Zika and dengue are, but it triggers joints pain which could last for months and even for years. CONCLUSION The vaccines against Zika, dengue and chikungunya viruses are at different stages of development. The challenges associated with the epidemic wave of Zika, dengue and chikungunya viruses have been explained and the current status of drug/ vaccine development against these viruses has been reviewed.

Efficient Reduction of C–N Multiple Bonds Catalyzed by Magnetically Retrievable Magnetite Nanoparticles with Sodium Borohydride

A simple, rapid and efficient methodology has been developed for the reductive transformation of the compounds bearing C–N multiple bonds such as oximes and nitriles to the corresponding amines by sodium borohydride catalyzed by highly active solid Fe3O4 nanoparticles. The catalyst was easily recovered using external magnet and reused five times without losing its catalytic activity.Graphical AbstractA simple, rapid, efficient and reusable heterogeneous catalytic system has been developed for the reductive transformation of oximes and nitriles into corresponding amines by sodium borohydride in presence of Fe3O4 nanoparticles.

Facile One-Pot Friedlander Synthesis of Functional Quinolines using Graphene Oxide Carbocatalyst

BACKGROUND Quinolines represent an important class of bioactive molecules which are present in various synthetic drugs, biologically active natural compounds and pharmaceuticals. Quinolines find their potential applications in various chemical and biomedical fields. Thereby, the demand for more efficient and simple methodologies for the synthesis of quinolines is growing rapidly. OBJECTIVE The green one-pot Friedlander Synthesis of Functionalized Quinolines has been demonstrated by using graphene oxide as a carbocatalyst. METHOD The graphene oxide catalyzed condensation reaction of 2-aminoaryl carbonyl compounds with different cyclic/ acyclic/ aromatic carbonyl compounds in methanol at 70°C affords different quinoline derivatives. RESULTS The reaction has been examined in different protic and aprotic solvents and the best yield of quinoline is observed in methanol at 70°C. CONCLUSION The present method of quinoline synthesis offers various advantages over other reported methods such as short reaction time, high yield of product, recycling of catalyst and simple separation procedure. The graphene oxide carbocatalyst can be easily recovered from the reaction mixture by centrifugation and then can be reused several times without any significant loss in its activity.