659. isoOxazolones. Part III. Some reactions of arylaminomethyleneisooxazolidones with bases

Conjugate Addition of 3-Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

“…2-Methylaniline (0.107 mL, 1.0 mmol) and 3-butyn-2-one (0.0782 mL, 1.0 mmol) were stirred in EtOH (4 mL) (completion indicated after 20 min) to give compound 3b as an off-white solid (0.160 g, 93%) after purification by Kugelrohr distillation under vacuum (120−130 °C): mp = 34−36 °C; 1 H NMR (600 MHz, CDCl 3 ) δ 2.18 (s, 3H), 2.36 (s, 3H), 5.35 (d, J = 7.6 Hz, 1H), 6.98 (t, J = 7. 4 27 (3Z)-4-[(3,5-Dimethylphenyl)amino]but-3-en-2-one, 3d. 3,5-Dimethylaniline (0.125 mL, 1.0 mmol) and 3-butyn-2-one (0.0782 mL, 1.0 mmol) were stirred in EtOH (4 mL) (completion indicated after 40 min) to give compound 3d as a clear light yellow oil (0.178 g, 94%) after purification by Kugelrohr distillation under vacuum (120− 140 °C): 1 H NMR (700 MHz, CDCl 3 ) δ 2.14 (s, 3H), 2.29 (s, 6H), 5.26 (d, J = 7.7 Hz, 1H), 6.65 (s, 2H), 6.69 (s, 1H), 7.21 (dd, J = 12.4, 7.7 Hz, 1H), 11.50 (br d, J = 10.4 Hz, 1H); 13 C NMR (176 MHz, CDCl 3 ) δ 21.5, 29.7, 97.2, 114.…”

The conversion of isothiazoles into pyrazoles using hydrazine

“…Furthermore the transformations of isoxazolium salts, 36 isoxazolidin-2-yl, 37 isoxazolidin-5-ones, 38 isoxazol-4-one oximes 39,40 and isoxazole-4,5-diones 41 into pyrazoles have been reported. While there are several reports on the analogous conversion of isothiazolium salts into pyrazoles, [42][43][44][45] there is only one report on the transformation of isothiazoles into pyrazoles using arylhydrazines.…”