Geminally activated nitroethenes in reactions with sodium azide. Synthesis of functionalized 1,2,3-triazoles

Primary nitro compounds: progress in the synthesis of isoxazoles by condensation with aldehydes or activated ketones

“…Nitroenones 18 have been prepared from the Schiff bases of aromatic aldehydes with n-butylamine; the addition product with nitroacetone ( 16), in acetic anhydride, affords 18 (Scheme 10, R = aryl, 5 examples, including 2-furyl). 56 Other nitroenones 18 are reported under different experimental conditions: Al 2 O 3 in CH 2 Cl 2 at room temperature, 57 thionyl chloride in ethanol at rt or heating 58,59 and β-alanine and acetic acid in benzene under reflux; [60][61][62][63][64][65] phosphoryl chloride in ethanol at room temperature; 66 acetic anhydride at 120-130 °C, 67 (2S)-2-{diphenyl[(trimethylsilyl)oxy]methyl}pyrrolidine and 4-nitro-benzoic acid in dichloromethane; 68 and 4-methyl-morpholine and titanium tetrachloride at 0 °C. 69 They can be isolated as they do not undergo Michael addition with nitro ketones under the reported conditions.…”

“…Other nitroenones 18 are reported under different experimental conditions: Al 2 O 3 in CH 2 Cl 2 at room temperature, 57 thionyl chloride in ethanol at rt or heating 58,59 and β-alanine and acetic acid in benzene under reflux; 60–65 phosphoryl chloride in ethanol at room temperature; 66 acetic anhydride at 120–130 °C, 67 (2 S )-2-{diphenyl[(trimethylsilyl)oxy]methyl}pyrrolidine and 4-nitro-benzoic acid in dichloromethane; 68 and 4-methyl-morpholine and titanium tetrachloride at 0 °C. 69…”

A Mild Multi-Component Reaction for the Synthesis of 4,5-Disubstituted 1H-1,2,3-Triazoles from Phosphonium Salts, Aldehydes, and Sodium Azide

“…C NMR (75 MHz, CD 3 OD): δ = 160. 6, 145.2, 133.8, 132.2, 131.9, 130.0, 118.2, 112.6, 61.5, 13 1H-1,2,3-triazole-5-carboxylate (3n) 18 Eluent: EtOAc/PE (1:1); yield: 157 mg (31%); white solid; mp 178-180 °C; R f = 0.45 (PE/EtOAc 1:1). 1 H NMR (300 MHz, CD 3 OD): δ = 8.29 (d, J = 9.0 Hz, 2 H arom ), 8.10 (d, J = 9.0 Hz, 2 H arom ), 4.37 (q, J = 7.1 Hz, 2 H, OCH 2 CH 3 ), 1.34 (t, J = 7.1 Hz, 3 H, OCH 2 CH 3 ).…”