Ritika Nagpal

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.

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.

Sulfonated graphenes catalyzed synthesis of expanded porphyrins and their supramolecular interactions with pristine graphene

AbstractA newer synthesis of sulfonic acid functionalized graphenes have been developed, which have been characterized, examined as heterogeneous solid acid carbocatalyst in the synthesis of selected expanded porphyrins in different reaction conditions. This environment-friendly catalyst avoids the use of toxic catalysts and enhances the yields of porphyrinoids. The non-covalent interaction of porphyrinoids has also been studied with exfoliated graphene solution in organic solvents by UV-Visible and fluorescence spectroscopy. Graphical AbstractReaction of pyrrole with arylaldehydes catalyzed by newly synthesized sulfonated graphene in ortho-dichlorobenzene gave 5,10,15,20-tetraarylporphyrins and corresponding expanded porphyrins depending upon the reaction conditions. The possible non-covalent interactions with porphyrinoids with prisitine graphene have been examined by UV-visible and fluorescence spectroscopy.

Guanidino-Graphene Catalysed Synthesis of Flavones via Aldol-Michael-Oxidation

Guanidino-graphene has been synthesized by the reaction of bromoamine with reduced graphene oxide and characterized by FT-IR, Raman, TGA, powder XRD, TEM, SEM, and zeta potential. It is a cheap, heterogeneous and environmentally benign solid base catalyst used for cascade Aldol-Michael-oxidation in the synthesis of chalcone, flavonoids.

Triazole linked ruthenium(II)–porphyrin: influence of the connectivity pattern on photophysical and electrochemical properties

Herein a copper catalysed click reaction has been used to covalently link π-conjugated 1,2,3-triazolyl zinc(II) porphyrin and ruthenium(II) bipyridyl with a single change in their connection through the linker. The properties of these compounds have been compared with the porphyrin–ruthenium(II) tris(bipyridine) and ruthenium(II) trisbipyridine complexes. Extensive photophysical and electrochemical studies reveal that changes in the electronic properties of the conjugates are a consequence of the different connectivity patterns with regular and inverse triazolyl–pyridyl moieties.

Efficient synthesis of metallated thioporphyrazines in task specific ionic liquids and their spectroscopic investigation of binding with selected transition metal ions

AbstractTetramerization of substituted maleonitriles in task specific 2-hydroxylethyl based imidazolium ionic liquids at 120∘C gave corresponding electron rich peripheral substituted thioporphyrazines in moderate yield. The 2-hydroxylethyl imidazolium ionic liquids gave better yields of peripheral substituted thioporphyrazines in comparison with non-hydroxyl functionalized ionic liquids. Further, these peripherally functionalized porphyrazines containing sulphur are used to investigate spectroscopically the binding studies with palladium(II) and mercury(II) ions. These metal ions are toxic in nature and deserve serious attention in the area of design of effective separation and efficient micro-sensing techniques. The UV–Vis absorption spectroscopy and fluorescence signalling are mainly used to study peripheral binding of transition metal ions. Graphical AbstractTetramerization of substituted maleonitriles in task specific 2-hydroxylethyl based imidazolium ionic liquids at 120°C gave corresponding thioporphyrazines in moderate yield. The peripherally functionalized porphyrazines containing sulphur are used to investigate spectroscopically the binding studies with palladium(II) and mercury(II) ions. UV–Vis absorption spectroscopy and fluorescence signalling are mainly used as these techniques are highly sensitive and simple to distinguish the chemical and physical changes associated with such metal binding studies.