Photodecarbonylation of 2-phenyl-4-alkylidene-5(4H)-oxazolones

Tetrahedron Letters

Volumn 37, Issue 23, 1996, Pages 4019-4022

  Jung, Bokyung ^a   Kim, Hongbum ^a   Park, Bong Ser ^a  

^a Dongguk University   (South Korea)

Author keywords

[No Author keywords available]

Indexed keywords

OXAZOLE DERIVATIVE;

ARTICLE; DRUG SYNTHESIS; PHOTOCHEMISTRY;

EID: 0030006940     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/0040-4039(96)00751-4     Document Type: Article

References (19)

1. (a) Rao, Y. S. Synthesis 1975, 749-764, and refs therein.
2. (b) Dixit, V. M.; Bhat, V.; Trozzolo, A. M.; George, M. V. J. Org. Chem. 1919, 44, 4169-4173.
3. (c) Lawrenz, D.; Mohr, S.; Wendrander, B. J. Chem. Soc. Chem. Commun. 1984, 863-865.
4. (d) Walter, R.; Purcell, T. C.; Zimmer, H. J. Heterocycl. Chem. 1966, 235-236.
5. (a) Baumann, N.; Song, M.; Ullman, E. F. J. Am. Chem. Soc. 1968, 90, 4157-4158.
6. (b) Ullman, E. F.; Maumann, N. J. Am. Chem. Soc. 1968, 90, 4158-4160.
7. (c) Ullman, E. F.; Maumann, N. J. Am. Chem. Soc. 1970, 92, 5892-5899.
8. Carter, H. E. Org. React. 1974, 3, 199-239.
9. 3, 200 MHz); δ 8.06 (d, 2H, J = 7.4 Hz), 7.60-7.45 (m, 3H), 6.83 (t, 1H, J = 7.9 Hz), 2.86 (dq, 2H, J = 7.9, 7.7 Hz), 1.18 (t, 3H, J = 7.7 Hz). Other physical properties of 1b were the same as the reported values.(ref 3 and refs therein)
10. Rao, Y. S. J. Org. Chem. 1976, 41, 722-725.
11. Irradiation of one isomer only or the mixture gave the same result.
12. +, 2), 105(100), 77(48). The stereochemistry of the product could not be determined by any methods that we had tried so far. It is possible that this compound exists as stereolabile E, Z isomers that interconvert with a low free energy of activation.(See Guerra, A.; Lunazi, L. J. Org. Chem. 1995, 60, 7959-7965.) We, however, failed to observe such a phenominon by low temperature NMR spectroscopy due to solubility problems.
13. +, 8), 105(100), 77(56).
14. 3, 200 MHz) δ 7.89 (d, 2H, J = 7.4 Hz), 7.55-7.45 (m, 3H), 3.01 (br, 1H), 1.24 (br d, 3H, J = 7.3 Hz).
15. The amounts of products varied from trace to ten percents depending upon the reaction time under this reaction condition. The reaction mixture became complicated at high conversion.
16. 3CN, 200 MHz) δ 8.00 (d, 2H, J = 8.0 Hz), 7.71-7.45 (m, 3H), 4.70 (q, 1H, J = 8.0 Hz), 1.59(d, 3H, J = 8.0 Hz).
17. Johnson, M. R.; Sousa, L. R. J. Org. Chem. 1977, 42, 2439-2443.
18. Fleming, S. A. Tetrahedron 1995, 51, 12479-12520.
19. When 1a was irradiated under our reaction condition, no decarbonylation products were detected. The hydrogen abstraction product that Ullman had reported was observed together with some other unidentifiable products.