Suju C. Joseph

Pd-mediated new synthesis of pyrroles: their evaluation as potential inhibitors of phosphodiesterase 4

A sequential Pd-mediated multi-component reaction followed by Suzuki or Heck or Sonogashira coupling in a single pot has been developed for the synthesis of functionalized pyrroles as potential inhibitors of PDE4.

Iodine catalyzed four-component reaction: a straightforward one-pot synthesis of functionalized pyrroles under metal-free conditions

An iodine-catalyzed four-component reaction of 1,3-dicarbonyl compounds, amines, aldehydes and nitroalkanes afforded polysubstituted pyrroles under a metal free condition. Simplicity, low cost and good yields are the key features of this methodology. The mechanism of this four component process is discussed and structural elaboration of one of the compounds synthesized using Suzuki and Sonogashira coupling is presented.

Yb(OTf)3 mediated MCR: a new and regioselective approach towards polysubstituted pyrroles of pharmacological interest

A regioselective synthesis of 1,2,3,4-tetrasubstituted pyrroles has been achieved via Yb(OTf)3-mediated 3-component reaction of amines, a 1,3-diketone and phenacyl bromide in a single pot. Yb(OTf)3 was identified as a reusable catalyst and a number of pyrrole derivatives were prepared by using this strategy. Single crystal X-ray diffraction study of a representative compound confirmed the substitution pattern on the central pyrrole ring. The crystal structure analysis of the same compound indicated the presence of a sheet-like molecular arrangement along the bc-plane present in the molecule. A possible mechanism for the regioselective formation of 1,2,3,4-tetrasubstituted pyrrole rings is discussed. A number of compounds synthesized showed PDE4 inhibitory properties when tested in vitro and two of them were identified as inhibitors of further interest.

A cascade reaction for the new and direct synthesis of indolofuroquinoxalines

The 7H-indolo[3′,2′:4,5]furo[2,3-b]quinoxaline derivatives are synthesized directly from methyl 2-(2-chloro-1H-indol-3-yl)-2-oxoacetate or its N-alkyl derivatives under neutral or mildly acidic conditions. This new one-pot methodology was found to be general and greener as it avoids the use of environmentally harmful POCl3 and strong alkali required for the previously reported method. It is also amenable for scale-up.

A greener approach towards double heteroarylation of N, O and S nucleophiles: synthesis of bioactive polynuclear fused N-heteroarenes

A catalyst, ligand and solvent free method for double heteroarylation of N, O and S nucleophiles has been developed for the first time leading towards the synthesis of compounds containing an indole ring fused with pyrrolo-, furo- and thieno[2,3-b]quinoxaline moieties. This general and greener approach afforded novel compounds of medicinal importance.

Stereoselective bromohydrin formation from β-hydroxy sulfoxides mediated by the pendant sulfoxide†‡

Regio- and stereo-selective bromohydrin formation promoted by a neighbouring sulfinyl moiety is disclosed.