O-(2-Oxopyrrolidin-5-yl)trichloroacetimidates as Amidoalkylating Agents − Synthesis of (+)-Lentiginosine

Abstract

Keywords: Amidoalkylation / Trichloroacetimidate / Synthesis / Indolizidines / Glycosidase Inhibitor / Lentiginosine N-α-Hydroxyalkylamides 6a,b, readily available from L-tartrate, with trichloroacetonitrile furnish O-(2-oxopyrrolidin-5-yl)trichloroacetimidates 3a,b. α-Amido-alkylation studies of 3a,b with allyl-trimethylsilane and electron-rich benzene derivatives as C-nucleophiles afforded 5-allyl-and 5-aryl-2-pyrrolidinones 2a,b, 7a,b, and 8−10. The target compound

Total synthesis of (+)-lentiginosine via a key Au catalysis

“…With no surprise, ()-8a-epi-lentiginosine was prepared from epi-7d similarly in a two-step yield of 53%. Both of the structures were confirmed by comparing their NMR spectra and specific rotations with literature data [29]. Scheme 4 Synthesis of lentiginosines.…”

“…The mixture was stirred at room temperature overnight. CF 3 CO 2 H was evaporated under vacuum and the residue was purified through silica gel flash chromatography (eluents:ethyl acetate:methanol:NH 4 OH = 2:1: 0.06) to give desired product in quantitative yield[29]. [] D = 5.0 (c = 0.25, MeOH).…”

Natural Products Containing Medium‐Sized Nitrogen Heterocycles Synthesized by Ring‐Closing Alkene Metathesis

“…Cyclization (catalyst [Ru]-II, toluene, 70 • C) proceeded readily in 85% yield to give the bicyclic skeleton, which upon benzyl deprotection and dihydroxylation of the olefin gave (−)-lentiginosine (209). A different approach leading to ent-lentiginosine (77) was adopted by Schmidt et al [73] who prepared pyrrolidine 214 in three steps from l-tartrate. N-Acyliminium ion-mediated allylation provided 215 in quantitative yield as a diastereomeric mixture (1 : 1), which was separated via column chromatography.…”

Synthesis and Biological Evaluation of Some New Class of Chromenoimidazole Derivatives as Probable Anti Cancer Agents

“…1 Optimization of benzimidazole derivatives based on their structures has resulted in various potent drugs that are now being currently practiced in the market, like albendazole, omeprazole, mebendazole etc. 2,3 Benzimidazole scaffold is known to specifically inhibit human DNA topoisomerase I. 4,5 Bioisosterism of substituted benzimidazole facilitate their interaction to biopolymers such as proteins, enzymes and receptors for better activity with low toxic.…”