Microwave-assisted synthesis of -CF3 functionalized 3,4-dihydropyrimidinone/thione/imine derivatives by using potassium phthalimide (PPI) as a green and reusable organocatalyst and their anti-microbial evaluation

600-617One-pot synthesis of novel -CF3 functional group containing 3,4-dihydropyrimidinone/thione/imine derivatives 8a-l, 9a-l and 10a-l has been successfully performed in high yields through the reaction of aromatic aldehydes, β-dicarbonyl compound, urea/thiourea/guanidine hydrochloride by using potassium phthalimide (PPI) as organocatalyst under solventfree conditions under microwave irradiation at 300 W. PPI has been introduced as an efficient and biodegradable organocatalyst in Biginelli condensation with excellent reusability. The good yield of products, fast reaction time, simple work-up procedure, as well as usage of nontoxic, reusable, and easily recoverable catalyst under magnetic starring have been counted as advantages of the applied process. This organocatalyst can be removed after completion of reaction and reused several times under the same reaction conditions without significant loss of catalyst activity. The anti-microbial activity of all newly synthesised Biginelli products has been investigated against a variety of microorganisms such as E. coli, S. aureus, S. pyogenes, P. aeruginosa, C. albicans, A. niger and A. clavatu

Vasomodulatory effect of novel peroxovanadate compounds on rat aorta: Role of rho kinase and nitric oxide/cGMP pathway

The present study was undertaken to assess the role of reactive oxygen species (ROS) in rat aortic ring vasoreactivity and integrity by using various peroxovanadate (pV) compounds. All the pV compounds (1 nM-300 mu M) used in the present study exerted concentration-dependent contractions on endothelium intact rat aortic rings. All compounds with an exception of DPV-asparagine (DPV-asn) significantly altered vascular integrity as shown by diminished KCl responses. Phenylephrine (PE)-mediated contractions (3 nM-300 mu M) were unaltered in the presence of these compounds. Acetylcholine (Ach)-mediated relaxation in PE (1 mu M) pre-contracted rings was significantly reduced in presence of diperoxovanadate (DPV), poly (sodium styrene sulfonate-co-maleate)-pV (PSS-CoM-pV) and poly (sodium styrene 4-sulfonate)-pV (PSS-pV). However, no significant change in Ach-mediated responses was observed in the presence of poly (acrylate)-pV (PM-pV) and DPV-asn. DPV-asn was thus chosen to further elucidate mechanism involved in peroxide mediated modulation of vasoreactivity. DPV-asn (30 nM-300 mu M) exerted significantly more stable contractions, that was found to be catalase (100 U/ml) resistant in comparison with H(2)O(2) (30 nM-300 mu M) in endothelium intact aortic rings. These contractile responses were found to be dependent on extracellular Ca(2+) and were significantly inhibited in presence of ROS scavenger N-acetylcysteine (100 mu M). Intracellular calcium chelation by BAPTA-AM (10 mu M) had no significant effect on DPV-asn (30 nM-300 mu M) mediated contraction. Pretreatment of aortic rings by rho-kinase inhibitor Y-27632 (10 mu M) significantly inhibited DPV-asn-mediated vasoconstriction indicating role of voltage-dependent Ca(2+) influx and downstream activation of rho-kinase. The small initial relaxant effect obtained on addition of DPV-asn (30 nM-1 mu M) in PE (1 mu M) pre-contracted endothelium intact rings, was prevented in the presence of guanylate cyclase inhibitor, methylene blue (10 mu M) and/or nitric oxide synthase (NOS) inhibitor, L-NAME (100 mu M) suggesting involvement of nitric oxide and cGMP. DPV-asn, like H(2)O(2), exerted a response of vasoconstriction in normal arteries and vasodilation at low concentrations (30 nM-1 mu M) in PE-pre contracted rings with overlapping mechanisms. These findings suggest usefulness of DPV-asn having low toxicity, in exploring the peroxide-mediated effects on various vascular beds. The present study also convincingly demonstrates role of H(2)O(2) in the modulation of vasoreactivity by using stable peroxide DPV-asn and warrants future studies on peroxide mediated signaling from a newer perspective. (C) 2011 Published by Elsevier Ltd