作者:John L. Wood、Brian M. Stoltz、Hans-Juergen Dietrich
DOI:10.1021/ja00146a039
日期:1995.10
initiates cycloaromatization to form bond D.9 Application of this strategy allows efficient access to both the parent aglycon (3a) and the selectively protected derivative (3c) employed in the totalsynthesis reported herein. Overall, preparation of the enantioenriched furanose 6 and aglycon unit 3c and their conversion to 1 require only 11 synthetic operations with a longest linear sequence of seven steps
Cu(ii)-catalyzed domino reaction of 2H-azirines with diazotetramic and diazotetronic acids. Synthesis of 2-substituted 2H-1,2,3-triazoles
作者:Nikolai V. Rostovskii、Mikhail S. Novikov、Alexander F. Khlebnikov、Sergei M. Korneev、Dmitry S. Yufit
DOI:10.1039/c3ob40708j
日期:——
The Cu(II)-catalyzed addition of two molecules of a 3-aryl-2H-azirine to diazotetramic or diazotetronic acids proceeds as a domino reaction with the formation of 1,2,3-triazole derivatives with ortho-fused (pyrrolo[3,4-b]pyrrol or furo[3,4-b]pyrrol) and spiro-cyclic (1-oxa-4,7-diazaspiro[4.4]nonane or 1,7-dioxa-4-azaspiro[4.4]nonane) substituents at the N2 position. The disclosed reaction is a new type of formation of a 1,2,3-triazole ring from (N–N) and (C–C–N) building blocks.
Radical Scavenging Activity of Ascorbic Acid Analogs Containing a Carbonyl Conjugated Ene-Diol Structure
作者:Masataka Mochizuki、Shogo Nomura、Keiko Inami
DOI:10.3987/com-15-13366
日期:——
Small molecule antioxidants such as ascorbic acid (AscH(2)) prevent the oxidative damage of biological molecules by scavenging reactive oxygen species. A carbonyl-conjugated ene-diol structure is essential for the antioxidant activity of AscH(2). As such, we synthesized novel AscH(2) analogs containing a carbonyl conjugated ene-diol structure and evaluated their radical scavenging activities. When the 1,2-dihydroxyethyl group was removed, radical scavenging activity equal to AscH(2) was observed. Analogs containing an endocyclic nitrogen atom instead of a ring oxygen displayed higher radical scavenging activities than AscH(2). Therefore, the electron donating effect of the carbonyl conjugated ene-diol structure greatly increased the radical scavenging activity of AscH(2) analogs.