1,7-Diazabicyclo 4-hepten-3-ones

A soln. of 2-acetyl-5-methyl-6-phenyl-2,3-dihydro-4H-l,2-diazepin-4-one in methanol exposed 3 hrs. to sunlight in a Pyrex flask -> 2-acetyl-5-methyl-6-phenyl-l,2-diazabicyclo[3.2.0]-6-hepten-4-one. Y 88%. F. e. s. J.-L. Derocque,W. J. Theuer, and J. A. Moore, J. Org. Chem. 33, 4381 (1968). 

Dihydro-1,2-diazabicyclo [3.2.0] -3-hepten-6-ones MI-312 and XII-313 and diazepinones XII-314 are readily interconvertible ring systemsand all three can give l-amino-3-pyridinol salts (see Section IV.3., p. 839) or 3-pyridinols. When heated in methanol, the 2-acetyl- or 2-benzoyl-derivative of MI-313 rearranges to several products including 6-acetamido- or 6-benzamido-3-hydroxy-4-methjd-5-phenylpyridine (XII-317) in 17% and 68% yield, respectively, presumably through intermediates such as XII-315 and... 

A soln. of 3-diazoacetyl-3-methyl-4-phenyl-J -pyrazoline (prepn. s. 18) in glacial acetic acid allowed to stand 15 min. at room temp. 5-methyl-4-phenyl-l,2-diazabicyclo [3.2.0]-2-hepten-6-one (startg. m. f. 548). Y 75% as the picrate. J. A. Moore and R. W. Medeiros, Am. Soc. 81, 6026 (1959). 

Methyl-4-phenyl-l,2-diazabicyclo [3.2.0]-2-hepten-6-one prepn. s. 547) dissolved in methanol, treated with methanolic 10 %-KOH, and allowed to stand 4 hrs. at room temp. 

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