Neurodegenerative disorders constitute a group of diseases in which there is a progressive and gradual structural and functional deterioration of central or peripheral nervous system. Among them, one of the most common is Alzheimer's disease. Alzheimer's disease (AD) is an irreversible and incurable neurological disorder that impairs memory and cognitive function eventually leading to delirium. Recently, WHO has reported that the affected number has reached 50 million worldwide, and reports 10 million new cases every year. It is caused by the cleavage of Amyloid-beta precursor protein (APP) which results in the accumulation of extracellular amyloid beta (Aβ) and intracellular neurofibrillary tangles because of tau protein hyperphosphorylation, which ultimately results in neuroinflammation and oxidative stress, highlighting free radicals’ involvement in AD. It is also associated with the loss of cholinergic neurons that produce acetylcholine (neurotransmitter) leading to dementia. Acetylcholinesterase, an enzyme, mainly renowned for metabolizing acetylcholine is mainly targeted by four FDA approved drugs which inhibits its activity. Inhibition of enzyme results in increased level of acetylcholine to enhance discernment ability. Recently, organoselenium compounds; ebselen and diphenyl diselenide were tested as promising inhibitors for AChE activity, this has inspired the synthesis of new selenium containing molecules with better activity. In this context, we have synthesized a series of 20 novel organoselenium compounds tailored with substituted oxadiazole-2-thiol moiety which would be tested for Alzheimer disease. All synthesized compounds have been fully characterized spectroscopically via, FTIR, NMR and GCMS, etc.

Amide bond is regarded as key functional group to many natural products, polymers and serve as a backbone in peptides synthesis. Since the advancement in drugs synthesis, a number of methods are available for its formation but these are considered as most expensive and sophisticated because of unfavorable kinetic and thermodynamics of the process, requirement of stoichiometric amounts of promoters or metal mediators, long reaction routes and harsh reaction conditions. In order to circumvent these associated challenges, their direct one-step synthesis from esters/acids and amines had been, and continues to be the focus of significant attention in synthetic chemistry and could be the most crucial revolution in pharmaceutical industry as it is evident in recent surveys where 25% of the registered drugs possess amide functionality. Following the same direction, direct one-step amide bond formation strategies from esters/acids and amines by using green chemistry protocols will be investigated.