Manoj Manickam

The present work describes the development of sustainable bio‐benzoxazines for oil water separation and its composites for applications where a low dielectric constant is required. In addition, cardanol benzoxazine monomers (C‐ida and C‐pyta) with low curing temperature were designed with inbuilt catalytic core using two different heterocyclic amines, namely tetra aryl imidazole diamine (ida) and pyridine core triamine (pyta). Cotton fabric coated with poly(C‐ida) and poly(C‐pyta) show water contact angle values of 160° and 164°, respectively. The oil‐water separation efficiency of the polybenzoxazines coated cotton fabrics was 95%. Further, the poly(C‐ida) and poly(C‐pyta) matrices were reinforced with varying weight percentages (1, 3, 5, 7, and 10 wt%) of glycidylpropoxytrimethylsilane‐functionalized biosilica. The benzoxazine matrices and composites obtained were characterized using different analytical techniques in order to assess their molecular structure, cure behavior, thermal stability, morphology, surface, and dielectric behavior. Data obtained from different studies suggest that these matrices and composites can be used as coatings for oil‐water separation and high‐performance micro‐electronics insulation applications under adverse environmental conditions.

A novel series of Schiff base dimers have been designed and synthesized from phthalaldehydes and various amines including aliphatic, aromatic and heterocycles by grinding at room temperature. This solvent free green protocol approach is superior to the classical approach which uses ethanol as solvent. The advantage of this new method is that wide substrates can be incorporated, very simple to carry out the reaction, easy workup with high product yield. Compounds obtained have been screened for anti-bacterial activity against nine different strains (six Gram-negative and three Gram-positive) which include E.coli, Proteus mirabilis, Klebsiella pneumonia, Proteus vulgaris, Morganella morgana, Salmonella typhi, Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus, Enterococci faecalis. Among them, the heterocyclic groups in the side chain of the Schiff base showed better activity than the aromatic and aliphatic groups. Particularly the thiophene substituted 1,4-isomer of the Schiff base dimer showed good antibacterial activity against seven strains. Interestingly, the 1,3 isomer of the Schiff base dimer with thiophene substituent exhibited a potent antibacterial activity. An effective Structure-Activity Relationship have also been established for the Schiff base dimers to find novel and potent anti-bacterial agents.

Dimerization of proteins/receptors plays a critical role in various cellular processes, including cell proliferation and differentiation. Therefore, targeting such dimeric proteins/receptors by dimeric small molecules could be a potential therapeutic approach to treating various diseases, including inflammation‐associated diseases like cancer. A novel series of bis‐imidazoles (13–18) and bis‐imidazo[1,2‐a]pyridines (19–28) were designed and synthesized from Schiff base dimers (1–12) for their anticancer activities. All the synthesized compounds were screened for anticancer activities against three cancer cell lines, including cervical (HeLa), breast (MDA‐MB‐231), and renal cancer (ACHN). From structure–activity relationship studies, imidazo[1,2‐a]pyridines (19–28) showed remarkable cytotoxic activities, with compounds 19 and 24 showing the best inhibitory activities against all three cell lines. Especially, both 19 and 24 were very effective against the breast cancer cell line (19, GI₅₀ = 0.43 µM; 24, GI₅₀ = 0.3 µM), exceeding the activity of the control adriamycin (GI₅₀ = 0.51 µM). The in vivo anticancer activity results of compounds 19 and 24 were comparable with those of the animals treated with the standard drug tamoxifen. Therefore, the dimeric imidazo[1,2‐a]pyridine scaffold could serve as a potential lead for the development of novel anticancer agents.

An efficient procedure has been proposed for the synthesis of linear and angular phenyl-substituted dibenzonaphthyridines from anilinoquinolines and benzoic acid in up to 85% yield using Eaton’s...