Vajja Sambasiva Rao

Progress in the research of artemisinin and its analogues as antimalarials: an update

Malaria is the number one infectious disease in the world today. Worldwide, over two million people die each year from malaria. This shocking reality is largely due to the emergence of drug resistant strains of Plasmodium falciparum. Artemisinin, a sesquiterpene lactone endoperoxide isolated from Artemesia annua has been shown to be a fast acting, safe and effective drug against multidrug-resistant and sensitive strains of P. falciparum. This article reports a survey of the literature dealing with artemisinin related antimalarial issues that have appeared from 1980s to the beginning of 2003. A broad range of medical and pharmaceutical disciplines is covered, including a brief introduction about discovery, phytochemical aspects, antimalarial mechanism of action, pharmacokinetics, and major drawbacks and various structural modifications made to overcome them.

Iodobenzene Diacetate Mediated Solid‐State Synthesis of Heterocyclyl‐1,3,4‐oxadiazoles

Abstract A simple and efficient method has been developed for the oxidation of various heterocyclyl acylhydrazones 3 with iodobenzene diacetate (IBD) to heterocyclyl‐1,3,4‐oxadiazoles 4 in solid state. The reaction took place at room temperature within few minutes. The products were isolated by simple aqueous work-up in good yields.

Facile One‐Step Conversion of Ketones into α‐Azidoketones using [Hydroxy(tosyloxy)iodo]benzene and Sodium Azide in the Presence of a Phase‐Transfer Catalyst under Solvent‐Free Conditions

Abstract We have described a one‐step, solvent‐free synthesis of α‐azidoketones from the corresponding ketones that requires relatively benign [hydroxy(tosyloxy) iodo]‐benzene reagent, sodium azide, and phase‐transfer catalyst at room temperature. Generality of the protocol has been demonstrated by synthesizing various α‐azidoketones high in yield and purity within a short time. The work entitled “A Facile One‐Step Conversion of Ketones into α‐Azidoketones Using [Hydroxy(tosyloxy)iodo]benzene and Sodium Azide in Presence of Phase Transfer Catalyst Under Solvent‐Free Conditions” has not been published elsewhere and that it has not been submitted simultaneously for publication elsewhere.

Design, synthesis, and preliminary in vitro and in vivo pharmacological evaluation of 4-{4-[2-(4-(2-substitutedquinoxalin-3-yl)piperazin-1-yl)ethyl]phenyl}thiazoles as atypical antipsychotic agents

A series of 4-{4-[2-(4-(2-substitutedquinoxalin-3-yl)piperazin-1-yl)ethyl] phenyl} thiazoles were synthesized in an effort to prepare novel atypical antipsychotic agents. The compounds were designed, synthesized, and characterized by spectral data (IR, 1H NMR, and MS) and the purity was ascertained by microanalysis. The D2 and 5-HT2A affinity of the synthesized compounds was screened in vitro by radioligand displacement assays on membrane homogenates isolated from rat striatum and rat cortex, respectively. Furthermore, all the synthesized final compounds (10a–g; 11a–g; 12a–g) were screened for their in vivo pharmacological activity in Swiss albino mice. D2 antagonism studies were performed using climbing mouse assay model and 5-HT2A antagonism studies were performed using quipazine-induced head twitches in mice. It was observed that none of the new chemical entities exhibited catalepsy and 12d, 11f, and 10a were found to be the most active compounds with 5-HT2A/D2 ratio of 1.23077, 1.14286, and 1.12857, respectively, while the standard drug risperidone exhibited 5-HT2A/D2 ratio of 1.0989. Among the twenty one new chemical entities, three compounds (12d, 11f, and 10a) were found to exhibit better atypical antipsychotic activity as they were found to have higher Meltzer index than the standard drug risperidone.