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The reaction of β‐naphthol with nitrostyrene derived primary MBH acetates in presence of Cs2CO3 as base resulted in the formation of 3‐nitro‐4‐phenyl‐3,4‐dihydro‐2H‐naphthopyran as the major isomer via SN2′ process. Due to the bis‐electrophilic nature of MBH acetates, the minor product 3‐nitro‐2‐phenyl‐3,4‐dihydro‐2H‐naphthopyran was also obtained presumably due to SN2 process with γ ‐attack on MBH acetates. The state of the art density functional theory (DFT) calculations were carried out to account for these competitive pathways towards the formation of major and minor products.

An efficient protocol has been developed for the synthesis of 2‐oxazolines from carboxylic acids and silylated amino alcohols. The advantage of this method was demonstrated by preparing O‐silylated amino alcohols. The reaction proceeds via in situ desilylation of O‐silylated amide followed by cyclization. Studies on silyl deprotection were carried out to explain yield for 2‐oxazolines.

Background: 1,2,4-triazoles scaffolds display significant biological activities due to hydrogen bonding, solubility, dipole character, and rigidity Objective: The core motif of 1,2,4-triazoles plays a vital role in clinical drugs such as Rizatriptan (anti-migraine), Ribavirin (antiviral), anastrozole (anticancer), etizolam (anxiolytic), estazolam (anticonvulsant), alprazolam (anti-hypnotic), letrozole (aromatase inhibitor), loreclezole (anticonvulsant), trazadone (antidepressant) etc Method: Epoxide ring opening of tert-butyl 6-oxa-3-azabicyclo [3.1.0] hexane-3-carboxylate followed by methylation under basic conditions and de-protection gave the corresponding trans 1-(4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole hydrochloride salt as the precursor. This precursor on reaction with substituted benzoyl chlorides and benzyl bromides gave the desired amide and amine products Results: A library of 14 N-substituted pyrrolidine derivatives i.e. trans3-methoxy-4-(1H-1,2,4-triazol-1-yl) pyrrolidin-1-yl) (phenyl)methanone and trans 1-benzyl-4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole were prepared Conclusion: Eight novel amides (6a-h) and six amines (8a-f) derivatives were synthesized using 1-(4-methoxypyrrolidin-3-yl)-1H-1,2,4-triazole 4 salt with substituted benzoyl chlorides and benzyl bromides.

A convenient, efficient method for synthesising indole-3-substituted-2-benzimidazoles and benzothiazoles was carried out using N-arylation followed by condensation-oxidation protocol. N-arylation of 1H-indole-3-carbaldehyde was carried out via CuI/DMED to yield 1-(3-((tert-butylsulfonyl)methyl)phenyl)-1H-indole-3-carbaldehyde. Condensation using various o-phenylenediamines in the presence of CAN/DMF as oxidant furnished the desired 2-(1-(3-((tert-butylsulfonyl)methyl)phenyl)-1H-indol-3-yl)-1H-benzo[d]imidazole. In addition to simple o-phenylenediamines, 1,2-arylenediamines substituted with withdrawing and donating groups, heterocyclic-2,3-phenylene diamines are well tolerated and give good yields of up to 74% yield. As simple reaction between o-phenylenediamines and 1H-substituted indole-3-carboxyaldehyde give indole-3-substituted-2-benzimidazoles with moderate to good yields. These novel indole-derived benzimidazoles and benzothiazoles have shown their efficacy as anti-cancer agents with various cancer K-562, MDA-MB231, colon-205 cell lines.