Dynamic effects of solvent on the Brönsted α

In hydroxylic solvents the primary kinetic isotope effect on reactions which transfer hydride between NAD+ analogues is maximized and constant, and the Brönsted α indicates a critical configuration equally resembling reactants and products. However, in certain polar, aprotic solvents, most notably DMSO, the isotope effect is sharply reduced and the Brönsted a indicates a product-like critical configuration. These changes are attributed to a barrier due to solvent

The reactivity of a surfactant-bound micellar phosphotriester

The covalently bound substrate-surfactant-p-nitrophenyldiphenyl phosphate, 2, is more reactive toward iodosocarboxylate and copper metallomicellar catalysts that the parent substrate, 1, in aqueous cetyltrimethylammonium ion micelles

The Reactivity of A Surfactant-bound Micellar Phosphotriester

5The covalently bound substrate-surfactant-p-nitrophenyldiphenyl phosphate, 2, is more reactive toward iodosocarboxylate and copper metallomicellar catalysts that the parent substrate, 1, in aqueous cetyltrimethylammonium ion micelles.nonenoneAnn T. Kotchevar;Robert A. Moss;Paolo Scrimin;Paolo Tecilla;Hongmei ZhangAnn T., Kotchevar; Robert A., Moss; Paolo, Scrimin; Tecilla, Paolo; Hongmei, Zhan

Novel Cytotoxic Oxopyridoindolizines: iso-Propyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC)

A series of eight new alkyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC), analogues of camptothecin (CPT), were prepared in a one-pot reaction of 2,2'-bipyridine-3,3'-dicarboxylic acid (BPA) with a mixture of thionyl chloride/chlorine, followed by addition of the appropriate alcohol. This led to a mixture of OPIC compounds 3a-d, 4a-d and 3,3'-dialkoxycarbonyl-2,2'-bipyridines (BPE, 2a-d). The isopropyl OPIC 3c and its corresponding diastereoisomer 4c showed marked activity against three cancer cell lines compared to other analogs. These same diastereoisomers also displayed high cytotoxic activity against five leukemia cell lines, thus the presence of an isopropyl substituent on the carboxylic ester, as opposed to other alkyl substituents, appears to play a key role in the cytotoxic potency of this new class of compounds

Novel Cytotoxic Oxopyridoindolizines: iso-Propyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC)

A series of eight new alkyl-7,8,9-trichloro-6,7,8,9-tetrahydro-5-oxopyrido[2,3-a]-indolizine-10-carboxylates (OPIC), analogues of camptothecin (CPT), were prepared in a one-pot reaction of 2,2\u27-bipyridine-3,3\u27-dicarboxylic acid (BPA) with a mixture of thionyl chloride/chlorine, followed by addition of the appropriate alcohol. This led to a mixture of OPIC compounds 3a-d, 4a-d and 3,3\u27-dialkoxycarbonyl-2,2\u27-bipyridines (BPE, 2a-d). The isopropyl OPIC 3c and its corresponding diastereoisomer 4c showed marked activity against three cancer cell lines compared to other analogs. These same diastereoisomers also displayed high cytotoxic activity against five leukemia cell lines, thus the presence of an isopropyl substituent on the carboxylic ester, as opposed to other alkyl substituents, appears to play a key role in the cytotoxic potency of this new class of compounds

2,3-Bifunctionalized Quinoxalines: Synthesis, DNA Interactions and Evaluation of Anticancer, Anti-tuberculosis and Antifungal Activity

Abstract A variety of 2,3-bifunctionalized quinoxalines (6-14) have been prepared by the condensation of 1,6-disubstituted-hexan-1,3,4,6-tetraones (1-4) with o-phenylenediamine, (R,R)-1,2-diaminocyclohexane and p-nitro-o-phenylenediamine. It is concluded that strong intramolecular N-H----O bonds in the favoured keto-enamine form may be responsible for the minimal biological activities observed in DNA footprinting, antitubercular, anti-fungal and anticancer tests with these hyper π-conjugated quinoxaline derivatives. However, subtle alteration by addition of a nitro group affecting the charge distribution confers significant improvements in biological effects and binding to DNA