Zur Photodimerisierung von 3‐Phenyl‐2H‐azirinen. Vorläufige Mitteilung

Abstract

the case of 1,3-diaryl-lH-diazirines which are intermediates in the photolysis of 3,4diarylsydnones [loj.Photolysis of 4 yielded 4-phenyl-3-phenyliniino-l-azabicyclo[2,1,0]pentane 1101, whereas 2,4,5-triphenyl-imidazole Summary. Irradiation of 3-phenyl-2H-azirine (2) in benzene solution with a high-pressure inercury lamp yields 4,5-diphenyl-l, 3-diazabicyclo[3,1,0]hex-3-ene (4) and not 3-phenylimino-4phenyl-l-azabicyclo[2,l,0]pentane (11, as had been reported previously by others [ 2 ] . 2-Methyl-3phenyl-2 H-azirine (3) yields on irradiation a 2 :1 mixture of 2-exo, 6-exo-and 2-endo, 6-exo-dimethyl-4,S-diphcnyl-l, 3-diazabicyclo[3,1,0]hex-3-ene (2-exo, 6-exo-and 2-endo, 6-exo-5). Irradiation of 2,3-diphenyl-2 H-azirine (8) leads t o thc formation of 2,4,5-triphenyl-imidazole (9) and tetraphenylpyrazine (10). The suggested reaction path for the generation of 9 and 10 is shown in Scheme 2 .Kurzlich wurde mitgeteilt [ 21, dass bei der Bestrahlung von a-Azidostyrol in benzolischer Losung init einer Quecksilber-Hochdrucklampe neben 3-Phenyl-2H-azirin (2) (vgl. auch 131) in 10% Ausbeute ein weiteres, kristallines Photoprodukt (Snip. 137-140') isoliert werden konnte, dem auf Grund seiner spektralen Daten (NMR .-, 1) 2) 18. Mitteilung uber Photoreaktionen; 17. Mitteilung: siehe [l]. Eine ausfuhrliche Mitteilung sol1 in dieser Zeitschrift erscheinen

Photochemical transformations of small ring heterocyclic compounds. LXV. 1,1-Cycloaddition from a 1,3-dipole

“…The identity of 2 was determined by its straightforward spectral characteristics [ir (neat) 1640 cm-1; NMR (100 MHz) 9.64 (t, 1 H, / = 5.0 Hz), 8.68 (dd, 1 H,7= 8.0 and 5.0 Hz), 8.33 (m, 1 ), 8.13 (s, 3 H), 7.64 (d, 1 H, J = 17.5 Hz), 7.22 (dd, 1 H, J = 17.5 and 8.0 Hz), 2.61-3.10 (m, 5 H)] as well as its facile conversion to 2-methyl-6-phenylpyridine (5) (picrate 131 -132°)9 on heating. When the thermolysis of azabicyclohexene 2 was carried out in toluene in the presence of methyl acrylate, azabicyclo[3.2.1]octene (6); mp 87-88°, was isolated in good yield [NMR (100 MHz) 8.68 (s, 3 H), 7.76 (dd, 1 H,/ = 18.0 and 4.0 Hz), 7.48 (m, 3 H), 6.82 (dd, 1 H, / = 7.0 and 4.0 Hz), 6.36 (s, 3 H), 4.34 (ddd, 1 H, J = 9.5, 4.0, and 2.0 Hz), 4.14 (dt, J = 10.0 and 1.5 Hz), 2.4-2.S (m, 5 H)]. The formation of this adduct is readily interpreted if it is assumed that 2 undergoes an initial 1,3-proton shift to give l-phenyl-3-methyl-2-azabicyclo[3.1.0]hex-3-ene which subsequently undergoes cycloaddition with the added dipolarophile.…”

Studies on the intramolecular addition of vinyl nitrenes to olefins

“…A solution containing 75 mg of (£)or (Z)azirinyl-2-butenoate 1842 in 10 mL of toluene was heated in a sealed tube at 180 °C for 124 h. Removal of the solvent under reduced pressure left a yellow oil which was subjected to thick-layer chromatography. The minor component (37%) isolated from the thick-layer plate was a colorless oil whose structure was assigned as methyl 4-methyl-5-phenylpyrrol-2-ylacetate (20) on the basis of its spectral data: NMR (CDC13, 100 MHz) 7.76 (s, 3 H), 6.34 (s, 2 H), 6.28 (s, 3 ), 4.07 (d, 1 H, J = 1.5 Hz), 2.54-2.90 (m, 5 ), 2.16 (broad s, 1 H, exchanged with D2O); IR (neat) 3300, 2900, 1720, 1600, 1510, 1430, 1242, 1205, 1156, 1012, 792, 767, 697 cm"1; UV (cyclohexane) 350 nm (f 830), 278 (9700). Anal.…”

“…The brown residue obtained after removing the solvent under reduced pressure was subjected to preparative thick-layer chromatography using chloroform as the eluent. The slowest moving band contained 43 mg (14%) of a clear oil whose structure was assigned as 2-methyl-3-phenyl-5vinyl-A2-pyrroli"ie (35) on the basis of its spectroscopic properties: NMR (CC14,100 MHz) 8.12 (s, 3 H), 6.88 (dd, 1 H, J = 17.6,6.0 Hz), 6.56 (dd, 1 H,J= 17.6, 4.5 Hz), 5.24 (dd, 1 H, J = 6.0, 4.5 Hz), 4.72-5.00 (m. 2 ), 4.08 (ddd. 1 H. J = 17.6,11.0,6.0 Hz), 3.50 (broad s, 1 H, exchanged w.th D20), 2.48-2.80 (m, 3 ), When the crude reaction mixture was subjected to preparative vapor-phase chromatography (15% SE-30 column at 170 °C), two additional components were isolated.…”

Photochemical transformations of small ring heterocyclic compounds. 75. Photochemistry of arylazirines in hydroxylic media

“…The above vinyl azide was taken up in 1 1. of toluene and the solution was heated at reflux for 3 h, at which time the nitrogen evolution had ceased. Removal of the solvent under reduced pressure left a yellow oil which was recrystallized from hexane-ether to give 43 g (63%) of a white solid, mp 58-59 °C, whose structure was assigned as 3-phenyl-2//-azirine-2-methanol (15) on the basis of the following data: ir (KBr) 2.98 and 5.76 µ; uv (95% ethanol) 245 nm (e 14 000); NMR (CDC13) r 7.60 (1 H, m), 7.20 (1 H, br s, exchanged with D20), 6.36 (1 H, dd, J = 13.0 and 5.0 Hz), 6.08 (1 H, d, J = 13.0 Hz), 2.60 Anal: Caled for C9H9NO: C, 73.45; , 6.16; N, 9.52. Found: C, 73.43; , 6.20; N, 9.44. Irradiation of 3-Phenyl-2//-azirine-2-methanol.…”