Shaik Anwar

Organocatalytic synthesis of multiple substituted bicyclo[4.4.0]decalin system.

An efficient and unprecedented organocatalytic reaction of γ-nitroketones with α,β-unsaturated aldehydes to give polyfunctionalized [4.4.0] bicyclic skeletons was developed. The diphenylprolinol silyl ether mediated nitro-Michael/Aldol reaction afforded the hexa-substituted decalin carboaldehydes with excellent diastereo- and enantioselectivity (up to >99:1 dr and >99% ee) via a formal [4 + 2] carbocyclization process.

Organocatalytic Synthesis of Substituted Spirocyclohexane Carbaldehydes via [4 + 2] Annulation Strategy between 2-Arylideneindane-1,3-diones and Glutaraldehyde

An organocatalytic domino reaction between 2-arylideneindane-1,3-diones and glutaraldehyde has been devised that gives functionalized spirocyclohexane carbaldehydes with an all-carbon quaternary center. The reaction proceeds through a Michael/Aldol sequence in good-to-high chemical yields and with high levels of stereoselectivity (up to >95:5 dr and 99% ee) in the presence of the α,α-L-diphenylprolinol trimethylsilyl ether 3 (20 mol %) and DIPEA (20 mol %) in ether at 0 °C.

Morita–Baylis–Hillman (MBH) Reaction Derived Nitroallylic Alcohols, Acetates and Amines as Synthons in Organocatalysis and Heterocycle Synthesis

The Morita-Baylis-Hillman (MBH) reaction is one of the most useful and efficient protocols for constructing new carbon-carbon bonds between an activated olefin and electrophiles in the presence of a tertiary amine/phosphine. Herein, we present the use of MBH alcohols, which are obtained from the reaction of nitrostyrenes with aldehydes, as well as acetates and amines derived thereof in several organocatalytic transformations. Densely functionalised MBH adducts can also be used to synthesise substituted heteroaromatic compounds, such as furan, pyrrole, pyrazole and imidazole derivatives.

Functionalised dihydroazo pyrimidine derivatives from Morita–Baylis–Hillman acetates: synthesis and studies against acetylcholinesterase as its inhibitors

A wide array of dihydro[1,5]azo[1,2-a]pyrimidine 2-esters have been synthesised at room temperature in moderate to good yields through one-pot reaction between nitrostyrene derived MBH acetates and aminoazole derivatives with γ-α cyclisation. The reaction involves a cascade SN2 reaction followed by intramolecular Michael addition–cyclisation with the generation of two new carbon–nitrogen bonds. The structure was further confirmed by single X-ray crystal analysis. Docking and in vitro studies of dihydrobenzimidazo pyrimidine derivatives against acetylcholinesterase (AChE) have been performed and the compounds 3d and 3e exhibit potent inhibitory activities with an IC50 of 46.8 nM and 42.5 nM respectively.