Bhupendra Mishra

Novel porphyrin–psoralen conjugates: synthesis, DNA interaction and cytotoxicity studies

A Cu(i)-catalyzed azide-alkyne cycloaddition reaction (CuAAC) has been utilized to prepare novel triazole-linked cationic porphyrin-psoralen conjugates that exhibited significant photocytotoxicity against A549 cancer cells (IC50 = 84 nM).

Hair growth stimulator property of thienyl substituted pyrazole carboxamide derivatives as a cb1 receptor antagonist with in vivo antiobesity effect

A few thienyl substituted pyrazole derivatives were synthesized to aid in the characterization of the cannabinoid receptor antagonist and also to serve as potentially useful antiobesity agent. Structural requirements for selective CB1 receptor antagonistic activity of 5-thienyl pyrazole derivatives included the structural similarity with potent, specific antagonist rimonabant 1. Compound 3 has been identified as a hair growth stimulator and an antiobesity agent in animal models.

Cationic porphyrin–quinoxaline conjugate as a photochemically triggered novel cytotoxic agent

A novel cationic porphyrin-quinoxaline conjugate 8 was prepared in good yield by the coupling of activated quinoxaline carboxylic acid 5 with an appropriate aminoporphyrin. The UV-vis spectra of conjugate 8 with the addition of ctDNA shows substantial hypochromicity (39%) and a red shift (12 nm) in the Soret band indicating intercalation and self stacking along the surface. The binding constant of conjugate 8 with ctDNA was determined to be 1.26×10(6) M(-1). The porphyrin-quinoxaline conjugate 8 displayed enhanced photocytotoxicity (IC50=0.06 μM) when compared to TMPyP against A549 cancer cells.

Synthesis and fluorescence studies of porphyrin appended 1,3,4-oxadiazoles

A modular synthetic approach for preparing a family of porphyrin appended 1,3,4-oxadiazoles 9 is described. The porphyrin hydrazides are reacted with aryl aldehydes in presence of Yb(OTf)3 as catalyst to give porphyrin hydrazones 8 which are then cyclized to porphyrin appended 1,3,4-oxadiazoles 9 using iodobenzene diacetate. Photophysical studies in CHCl3 solvent shows that the electronic structure of the porphyrin chromophore is not greatly perturbed by the incorporation of the oxadiazole group onto the meso-phenyl ring. Efficient quenching of porphyrin fluorescence was observed in 9g with a pyridinium moiety.

Synthesis of meso-(4′-cyanophenyl) porphyrins: efficient photocytotoxicity against A549 cancer cells and their DNA interactions

We report a facile iodine(III)-mediated synthesis of cyanoporphyrins and their DNA photocleavage activity. Cationic-porphyrin 9a showed intercalative binding towards DNA, whereas Zn(II)-cyanoporphyrinate 9b showed outside electrostatic binding as indicated by their absorption and emission spectra. Porphyrin 9a displayed significant photocytotoxicity against A549 cancer cell line with an IC50 value of 54 nM.

Synthesis and DNA photocleavage studies of novel porphyrin diarylthiazoles

A convenient and regioselective synthesis of porphyrin diarylthiazoles is reported via the reactions of alkynyl(aryl)iodonium tosylates and porphyrin thioamides. Among the synthesized porphyrin diarylthiazoles, compounds 6d and 6f have shown significant interactions with ctDNA and exhibited efficient DNA photocleavage.