Stereoselective Synthesis of Novel Cyclic γ-Amino Acids and Triazole Derivatives

N-Arylmethylaminoquercitols, a new series of effective antidiabetic agents having α-glucosidase inhibition and antioxidant activity

A new series of N-arylalkylaminoquercitols were synthesized by reductive amination of aminoquercitol bisacetonide 5 and a variety of aryl aldehydes. The targeted N-substituted aminoquercitols having phenolic moiety (7a-7c) displayed significantly enhanced α-glucosidase inhibition, which is 26-32 times more potent than that of the unmodified aminoquercitol 6. In addition, compounds 7a-7c also retained antioxidant activity with relatively more pronounced potency than their original phenolics. This recent finding suggests an approach to develop effective antidiabetic agents by incorporating antioxidative moiety into aminocyclitol core structure.

Intramolecular hydroamination of dithioketene acetals: an easy route to cyclic amino acid derivatives

Catalytic intramolecular hydroamination of dithioketene acetals was developed for the synthesis of cyclic amino acid derivatives. Triggered by the addition of a catalytical amount of n-BuLi, the reaction proceeds to give proline and pipecolic acid derivatives in excellent yields and diastereoselectivity.

Intramolecular anodic olefin coupling reactions: using competition studies to probe the mechanism of oxidative cyclization reactions

A competition experiment was designed so that the relative rates of anodic cyclization reactions under various electrolysis conditions can be determined. Reactions with ketene dithioacetal and enol ether-based substrates that use lithium methoxide as a base were shown to proceed through radical cation intermediates that were trapped by a sulfonamide anion. Results for the oxidative coupling of a vinyl sulfide with a sulfonamide anion using the same conditions were consistent with the reaction proceeding through a nitrogen-radical.

Intramolecular anodic olefin coupling reactions and the synthesis of cyclic amines

Anodic olefin coupling reactions using a tosylamine trapping group have been studied. The cyclizations are favored by the use of a less-polar radical cation and more basic reaction conditions. The most significant factor for obtaining good yields of cyclic product is the use of the more basic reaction conditions. However, a number of factors including the nature of both the solvent and the electrolyte used can influence the yield of the cyclizations. The cyclizations allow for the rapid synthesis of both substituted proline and pipecolic acid type derivatives.