Trifluoromethanesulfonyloxy-group-directed regioselective (3 + 2) cycloadditions of benzynes for the synthesis of functionalized benzo-fused heterocycles
3-Aryl-5-vinyl-2-isoxazolines and 3-Aryl-5-vinylisoxazoles from Aryl Nitrile Oxides and Methyl Vinyl Ketone Lithium Enolate: Reaction Limits and Synthetic Utility Exploitation
were synthesized by reacting aryl nitrile oxides with the lithiumenolate of methyl vinyl ketone (MVK) at –78 °C. Fair to good yields are obtained in the case of aryl nitrile oxides bearing electron-withdrawing groups on the aryl moiety or less bulky groups. Conversely, lower yields or no reaction was observed in the presence of hindered aryl nitrile oxides. Such a behavior was confirmed by ab initio
compounds were elucidated by both elemental and spectral (IR, NMR, and MS) analysis. Compound 9 shows activity against some bacterial species. No antibacterial activities were observed for compounds 10a–c. The antioxidantactivity of the new compounds has been screened. Compound 9 showed higher antioxidantactivity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2’-azino–bis(3-ethylbenzoline-6-sulfonic
Dedicated to Professor Emeritus Miha Tišler on the occasion of his 75th birthday
在其75岁生日之际献给名誉教授MihaTišler
Cycloaddition of 1,3-dipoles to bullvalene
作者:A.Gamba Invernizzi、R. Gandolfi、M. Strigazzi
DOI:10.1016/s0040-4020(01)90657-x
日期:1974.1
and other 1,3-dipoles (diphenylnitrilimine, 3,4-dihydroisoquinoline-N-oxide and diazoethane) has been studied. The 3 + 2 → 5 cycloaddition is perispecific. Valence tautomerism of the cycloadducts is evaluated and the influence of the substituents in the isoxazoline ring is briefly discussed.
Strong correlation was found between 13C NMR chemicalshifts of dipolarophilic CHCH carbons and regioselectivity in 1,3‐dipolar cycloadditions of new acridin‐9‐yl dipolarophiles with stable benzonitrile oxides (BNO). Accordingly, two starting dipolarophiles, (acridin‐9‐yl)‐CHCH‐R (R = COOCH3 or Ph), reacted with three BNOs (2,4,6‐trimethoxy, 2,4,6‐trimethyl, and 2,6‐dichloro) to give a mixture of