Carbon‐13 nuclear magnetic resonance spectra of some methyl and phenyl substituted 2H‐azirines

The synthesis of alkyl aryl nitriles from N-(1-arylalkylidene)cyanomethylamines. Part 2. Mechanism

“…After 310 min in refluxing DMF, the conversion was 54% (by GC) and a mixture of E/Z isomers [PhC(᎐ ᎐ NCH᎐ ᎐ CF 2 )Me: 3e (45%) and 3eЈ (3%)] was obtained. Structures were assigned by GC-MS. Mass spectrum (70 eV) m/z (relative intensity): 3e, 181 (M ϩ , 47%), 166 (M ϩ Ϫ Me, 100), 154 (15), 104 (25), 103 (12), 77 (38), 51 (13); 3eЈ, 181 (M ϩ , 37%), 104 (M ϩ Ϫ NCH᎐ ᎐ CF 2 , 10), 103 (100), 77 (25), 51 (11).…”

“…1 H NMR (CDCl 3 ) δ 7.77 (s, 1H, CH᎐ ᎐ ), 7.37-7.32 (m, 4 H, Ph), 4.68 (q, 1H, J = 6.7 Hz), 1.59 (d, 3H, CH 3 , J = 6.7 Hz). Mass spectrum (70 eV) m/z (relative intensity): 249 (M ϩ , <1%), 132 (M ϩ Ϫ CCl 3 , 7), 106 (11), 105 (100), 77 (14), 51 (10).…”

“…After 90 min in refluxing DMF, the conversion was 64% (by GC) and a mixture of E/Z isomers [PhC(᎐ ᎐ NCH᎐ ᎐ CCl 2 )Me 3g (41%) and 3gЈ (20%)] was obtained. Structures were assigned by GC-MS. Mass spectrum (70 eV) m/z (relative intensity): 3g, 215 (M ϩ ϩ 2, 33), 213 (M ϩ , 50%), 202 (11), 200 (66), 199 (11), 198 (M ϩ Ϫ CH 3 , 100), 180 (11), 178 (33), 138 (11), 136 (17), 104 (63), 103 (22), 102 (16), 77 (45), 51 (32); 3gЈ, 213 (M ϩ , <1%), 164 (2), 106 (10), 105 (100), 103 (10), 77 (15).…”

2H-Azirines as ligands: Synthesis and structural characterization of (2H-3-arene-azirine)ReI(CO)3Br complexes

“…The 13 C signals of 4a-d are slightly shifted to lower field in comparison to the signals observed for 3a-d. For example, the CH 2 ring carbon signals are observed at 22.1 ppm (4a) and 21.9 ppm (4b), respectively, compared to 19.5 ppm (3a) and 18.8 ppm (3b). Likewise in the 1 H NMR spectra the tendency of signal shift to lower field, compared to the corresponding signals of the free azirine, is observed [28].…”

Novel base-induced reactions of substituted (1,2-benzisoxazol-3-yl)acetates

“…sulphuric acid was refluxed for 8 h. After evaporation of the solvent, the residue was dissolved in chloroform and the resulting solution was washed with aqueous potassium carbonate, dried, and evaporated to dryness. The residue was subjected to chromatography on silica gel with chloroform-hexane (1 : 1) as eluant to give (4) (5.7 g, 30%) and the chloro ester (3b) (5.6 (5).-Sodium hydride (0.76 g, 19 mmol) was added to a solution of 1,2-benzisoxazol-3-ylacetonitrile 2o (3.0 g, 19 mmol) in D M F (20 ml) was added under ice-cooling, and the mixture was stirred for 20 min. Ethyl chloroformate (2.1 g, 19.4 mmol) was added, the resulting solution was stirred for 10 min at room temperature, and the reaction mixture diluted with water, acidified with hydrochloric acid, and extracted with toluene.…”