Structure and synthesis of WF 3681, a novel aldose reductase inhibitor

Ni(ii)-Catalyzed vinylic C-H functionalization of 2-acetamido-3-arylacrylates to access isotetronic acids

A ligand-free Ni(ii)-catalyzed cascade annulation reaction for the synthesis of 4-aryl-substituted isotetronic acids from 2-acetamido-3-arylacrylates via vinylic C-H functionalization is reported. The reaction proceeds through heteroatom guided electrophilic insertion of nickel to the vinylic double bond followed by annulation with dibromomethane. This unconventional route features cascade steps, sole product formation, multiple functional group tolerance, low cost of catalysts and reagents, and readily available starting materials. Using this method, various aryl-substituted isotetronic acids have been synthesized which are biologically relevant. The annulation of 2-acetamido-3-arylacrylates has also been assessed with 1,2-dichloroethane, which resulted in the rearranged annulated products of 5-methyl substituted isotetronic acids.

Water enables an asymmetric cross reaction of α-keto acids with α-keto esters for the synthesis of quaternary isotetronic acids

A water promoted asymmetric aldol/lactonization/enolization cascade reaction of α-keto acids and α-keto esters affords chiral quaternary isotetronic acids with excellent enantioselectivity.

p-Terphenyl and diterpenoid metabolites from endophytic Aspergillus sp. YXf3

Six new p-terphenyl derivatives, named 4″-deoxy-3-hydroxyterphenyllin (1), 4″-deoxy-5'-desmethyl-terphenyllin (2), 5'-desmethylterphenyllin (3), 4″-deoxycandidusin A (4), 4,5-dimethoxycandidusin A (5), and terphenolide (6), four new diterpenoids with norcleistanthane (aspergiloid A (12) and aspergiloid B (13)), cleistanthane (aspergiloid C (14)), and isopimarane (aspergiloid D (15)) type skeletons, and five known p-terphenyl compounds (7-11) were isolated from the fermentation broth of the plant endophytic fungus Aspergillus sp. Their structures were elucidated on the basis of detailed spectroscopic analysis and by comparison of their NMR data with those reported in the literature. Compounds 4, 6, 7, and 9 displayed moderate neuraminidase inhibitory activity with IC(50) values ranging from 4.34 to 9.17 μM.