Mettu Ravinder

Synthesis and evaluation of novel 2-pyridone derivatives as inhibitors of phosphodiesterase3 (PDE3): a target for heart failure and platelet aggregation.

Twenty-six 2-pyridone derivatives (8a-8z), which are structurally analogous to amrinone and milrinone two important cardiotonic drugs, are synthesized and characterized. The synthesis of 2-pyridone derivatives involves addition, followed by cyclization between Baylis-Hillman acetates (7a-7k) and enamino esters or nitriles (3a-3e). Thus synthesized pyridones were subjected to PDE3 inhibitory activity, 14 pyridones were found to be hits out of 26 pyridones synthesized and out of 14 hits, there are 5 pyridones found to be lead compounds having excellent PDE3 inhibitory activity. Further we have carried out computational analysis to understand protein/enzyme and 2-pyridone derivative interactions to identify amino acid residues involved in the vicinity of binding and compared with milrinone drug.

Synthesis and biological evaluation of new epalrestat analogues as aldose reductase inhibitors (ARIs).

Baylis-Hillman chemistry derived four series of new epalrestat analogues were synthesized. Three structural changes are introduced in these 39 new epalrestat analogues synthesized. All compounds were evaluated for their in vitro aldose reductase inhibitory (ALR) activity. Biological activity data indicates that compounds 6, 16, 19, 28 and 29 are potent and the activity is in the range of reference drug, epalrestat. Molecular modelling studies were performed to understand the binding interactions of these active molecules with the ALR protein. Molecular docking data indicates the key interactions of epalrestat were retained in some of the active compounds whereas some new interactions were noticed for other molecules. The modifications introduced on epalrestat have impact for developing a new-type of ALR inhibitor.

Synthesis, antitubercular and anticancer activity of new Baylis–Hillman adduct-derived N-cinnamyl-substituted isatin derivatives

Baylis–Hillman adduct-derived N-cinnamyl-substituted isatin derivatives were synthesized and evaluated for their antitubercular activity on Mycobacterium tuberculosis H37Rv strain ATCC 27294 by agar dilution method. Anticancer activity for the same compounds was also screened on four different cell lines: Chinese hamster ovary (CHO cells), Colo 205 (human colon cancer), Sup-T1 (human lymphoma) and C6 glioma (rat glioma) by MTT assay method. The compounds (3j–l) have shown significant activity against Mycobacterium strain and the compound 3l has shown specific cytotoxic activity.

Synthesis, photochemical E (trans)-->Z (cis) isomerization and antimicrobial activity of 2-chloro-5-methylpyridine-3-olefin derivatives.

2-Chloro-5-methylpyridine-3-olefin derivatives (3a-e) have been synthesized from 2-chloro-5-methylnicotinaldehyde (1) and studied their photochemical E (trans)-->Z (cis) isomerization upon direct irradiation and triplet sensitized excitation for the first time. The triplet sensitized excitations of the compounds yielded high Z (4a-e) isomer composition, whereas the direct excitation results in less Z (4a-e) isomer composition, indicating triplet pathway is very efficient in converting the E (trans)-->Z (cis) isomer. Thus synthesized E (3a-c and 3e) and generated Z (4a-c and 4e) isomers were tested for antimicrobial activity. Antifungal activity of these pyridine derivatives are closely comparable to the standard used.

An efficient catalyst-free one-pot synthesis of primary amides from the aldehydes of the Baylis–Hillman reaction

Herein, a facile and efficient method for the preparation of allyl amides from the aldehyde of Baylis–Hillman adducts has been developed using a hydroxylamine/methanol system under a catalyst-free condition. The effects of solvents and temperature on the reaction and substituents on the phenyl ring have been examined. This method is best demonstrated by its advantages such as operational simplicity, moderate to excellent yields, short reaction time, and simple reaction procedure. Most importantly, the reaction proceeds smoothly in the absence of a catalyst and an external oxidant.

Design, synthesis, and biological evaluation of 4- H pyran derivatives as antimicrobial and anticancer agents

A series of pyran derivatives (5–27) were synthesized in good yields by utilizing Baylis–Hillman chemistry and were further investigated for their in vitro anticancer, antibacterial, and antifungal activities. Most of the tested compounds exhibited promising antibacterial activity as compared to the standard towards Gram-positive bacterial strains. The compounds 5–7, 11–13, and 17–19 displayed two-fold higher activity whereas compound 21 showed four-fold higher antibacterial activity against Staphylococcus aureus MTCC 96 as compared to the standard Neomycin. Some of these compounds exhibited moderate antifungal activity against all the tested fungal strains. Two compounds 16 and 23 showed promising anticancer activity against selected four human cancer cell lines such as A549, DU145, HeLa, and MCF7.

Stereoselective Synthesis ofStagonolide G from d-Mannitol

A highly convergent, stereoselective total synthesis of a ten-memberedlactone, stagonolide G, is described. Epoxide ring-opening withvinyl Grignard, Yamaguchi esterification and ring-closing metathesisare the key steps involved in the present approach. D-Mannitolwas used as a chiral pool material for the construction of bothof the key fragments - the olefinic acid and the olefinicalcohol moieties.