Ring Expansion and Ring Contraction Observed in Isopropenyldihydrofuran Derivatives

Bulletin of the Chemical Society of Japan

Volumn 70, Issue 11, 1997, Pages 2777-2780

  Yamaguchi, Seiji ^a   Sugioka, Yoshihiko ^a   Kitagawa, Yuzoh ^a   Matsumoto, Yoshinori ^a   Yokoyama, Hajime ^a   Hirai, Yoshiro ^a  

^a UNIVERSITY OF TOYAMA   (Japan)

Author keywords

[No Author keywords available]

Indexed keywords

EID: 1542465172     PISSN: 00092673     EISSN: None     Source Type: Journal    
DOI: 10.1246/bcsj.70.2777     Document Type: Article

References (6)

1. S. Yamaguchi, Y. Sugioka, M. Ishida, H. Yokoyama, and Y. Hirai, J. Heterocycl. Chem., 34, in press (1997).
2. S. Yamaguchi, A. Arisawa, N. Katoh, H. Yokoyama, and Y. Hirai, Bull. Chem. Soc. Jpn., 70, 2215 (1997).
3. 1) aminolysis of diethyl ester 1a with benzylamine gave the corresponding dicarboxamide instead of the corresponding cyclic imide. This might be due to the strain of bicyclo[3.3.0]oct-4(8)-ene ring systems.
4. The precipitates were insoluble in ether, and the structure was supposed to ammonium 2-carbamoyl-4,7-dihydro-6-methyloxepin-3-carboxylate.
5. 1,2 of both stereoisomers of methyl 2-vinylcyclopropane-1-carboxylate, and assigned 8.5 Hz to cis coupling and 4 Hz to the trans coupling. ("Handbook of NMR Parameters," Heyden and Son, Inc., London (1981), Vol. 1, p. 255).
6. These might be due to the properties of 2-carbamoyl-4,7-dihydro-6-methyloxepin-3-carboxylic acid B. Ammonia and benzylamine were enough basic to form the salts with B, and the salt of benzylcarbamoyl acid caused thermal decarboxylation to give 2e and 3a. While, aniline was not so basic, and phenylcarbamoyl acid B was interconvered with N-phenylcarboximidic acid C, and the electron-rich nitrogen in C might attack the carboxyl to afford 2d.