Partha Pratim Kaishap

Microwave-assisted palladium mediated efficient synthesis of pyrazolo[3,4-b]pyridines, pyrazolo[3,4-b]quinolines, pyrazolo[1,5-a]pyrimidines and pyrazolo[1,5-a]quinazolines

An efficient method was developed for the synthesis of pyrazole fused heterocycles via the palladium-catalyzed solvent free reaction of β-halovinyl/aryl aldehydes and 3-aminopyrazoles/5-aminopyrazoles under microwave irradiation in good yields. This method is applicable for the efficient synthesis of a wide range of substituted pyrazolo[3,4-b]pyridines, pyrazolo[3,4-b]quinolines, pyrazolo[1,5-a]pyrimidines and pyrazolo[1,5-a]quinazolines. Four of the synthesized pyrazole fused compounds showed in vitro cytotoxic activities almost comparable to the drug doxorubicin against the cervical HeLa cancer cell line and prostate DU 205 cancer cell line.

Efficient synthesis of isoquinolines and pyridines via copper(I)-catalyzed multi-component reaction

A wide range of 3-substituted isoquinolines, steroidal pyridines, 5,6-dihydrobenzo[f]isoquinolines and 1,6-naphthyridine were synthesized in good yield via a ligand-free copper-catalyzed three-component reaction of β-halovinyl/aryl aldehyde, aromatic/aliphatic terminal alkyne and tert-butylamine/benzamidine in DMF under microwave irradiation. A catalyst-free reaction of ortho-alkynyl aryl/vinyl aldehydes with benzamidine under microwave irradiation also provided the 3-substituted isoquinoline and substituted pyridine derivatives in excellent yield.

Ru(II)-Catalyzed C–H activation and annulation of salicylaldehydes with monosubstituted and disubstituted alkynes

The Ru(ii)-catalyzed C-H activation and annulation reaction of salicylaldehydes and disubstituted alkynes affords chromones in high yields. This reaction also works with terminal alkynes and tolerates a wide range of sensitive functional groups. The selectivity pattern of this Ru(ii)-catalyzed annulation reaction is different from the known Au(i), Rh(iii)-catalyzed annulation reactions of salicylaldehydes and terminal alkynes.

Palladium-catalyzed multi-component synthesis of steroidal A- and D-ring fused 5,6-disubstituted pyridines under microwave irradiation

The preparation of steroidal A-, D-ring fused 5,6-disubstituted pyridines and nonsteroidal substituted pyridines is described form Pd(OAc)2 catalyzed multi-component reaction of steroidal/nonsteroidal β-halovinyl aldehyde, alkyne and benzylamine in solvent-free condition under microwave irradiation.

Ruthenium(II)‐Catalyzed Synthesis of Spirobenzofuranones by a Decarbonylative Annulation Reaction

The first decarbonylative insertion of an alkyne through C-H/C-C activation of six-membered compounds is reported. The Ru-catalyzed reaction of 3-hydroxy-2-phenyl-chromones with alkynes works most efficiently in the presence of the ligand PPh3 to provide spiro-indenebenzofuranones. Unlike previously reported metal-catalyzed decarbonylative annulation reactions, in the present decarbonylative annulation reaction, the annulation occurs before extrusion of carbon monoxide.

Synthesis of steroidal and nonsteroidal vicinal heterocyclic alcohols, N-(1-cycloalkenyl)heterocycles and their antibacterial studies.

A solvent free steroidal and nonsteroidal epoxide ring opening reaction by nitrogen containing heterocycles under microwave irradiation is described. Some of the epoxide ring opening compounds were converted to their corresponding N-(1-cycloalkenyl)heterocycles via an acid catalyzed dehydration reaction. The antimicrobial activities of the epoxide ring opening compounds and N-(1-cycloalkenyl)heterocyclic compounds were tested by agar diffusion assay. Compounds 6, 9-12, 24 and 27 showed moderate inhibition against the growth of pathogenic bacteria Escherichia coli, Pseudomonas syringae, Bacillus subtilis, Proteus vulgaris and Staphylococcus aureus.

Ruthenium(II)-Catalyzed Dearomatized C−H Activation and Annulation Reaction of Vinylnaphthols with Alkynes: Access to Spiro-Pentacyclic Naphthalenones

The ruthenium(II)-catalyzed annulation of vinylnaphthols and alkynes is described. The reaction proceeds through C-H activation, dearomatization, and alkyne insertion. This reaction affords spiro-pentacyclic naphthalenones that have biological significance in good yields.