Reaction of aroyl-substituted heterocyclic ketene aminals with nitrile imines: An efficient synthesis of fully substituted pyrazoles and evidence of nucleophilic addition of enamines to 1,3-dipoles

Tetrahedron Letters

Volumn 40, Issue 41, 1999, Pages 7399-7402

  Liu, Bo ^a   Wang, Mei Xiang ^a   Huang, Zhi Tang ^a  

^a INSTITUTE OF CHEMISTRY   (China)

Author keywords

Heterocyclic ketene aminal; Hydrazone; Nitrile imine; Pyrazole

Indexed keywords

AMINE; HYDRAZONE DERIVATIVE; IMINE; PYRAZOLE DERIVATIVE;

ARTICLE; MOLECULAR INTERACTION; REACTION ANALYSIS; SYNTHESIS;

EID: 0033536657     PISSN: 00404039     EISSN: None     Source Type: Journal    
DOI: 10.1016/S0040-4039(99)01528-2     Document Type: Article

References (11)

1. 1. Carruthers, W. Cycloaddition Reactions in Organic Synthesis; Oxford: Pergamon Press, 1990; pp. 269-331.
2. 2. (a) Cook, A. G. Cycloaddition of Enamines. In Enamines: Synthesis, Structures, and Reactions; Cook, A. G., Ed.; Marcel Dekker: New York, 1988; pp. 347-440;
3. (b) Chinchilla, R.; Backvall, J.-E. In The Chemistry of Enamines; Rappoport, Z., Ed. Cycloadditions to enamines. John Wiley: Chichester, 1994; pp. 993-1048.
4. 3. For a summary of 1,3-dipolar cycloaddition reactions of enediamines, see: Huang, Z. T.; Wang, M. X. In The Chemistry of Enamines; Rappoport, Z., Ed. 1,1-Enediamines. John Wiley: Chichester, 1994; pp. 1303-1363.
5. 4. For a recent review of heterocyclic ketene aminals, see: Huang, Z. T.; Wang, M. X. Heterocycles 1994, 37, 1233.
6. 5. Huang, Z. T.; Wang, M. X. J. Org. Chem. 1992, 57, 184.
7. 6. Huang, Z. T.; Wang, M. X. Synth. Commun. 1991, 27, 1909.
8. 7. For a recent review of enamine-imine and enediamine-amidine tautomerism, see: Huang, Z. T.; Wang, M. X. In The Chemistry of Enamines; Rappoport, Z., Ed. Rearrangements and tautomerization of enamines. John Wiley: Chichester, 1994, pp. 889-922.
9. 8. General procedure for the reaction of heterocyclic ketene aminals with nitrile imines: To a suspension of 1 (1 mmol) in chloroform (15 ml) was added five drops of triethylamine and 2 (1.1 mmol). After stirring at room temperature for a period of time (Tables 1 and 2), the mixture was washed three times with saline. The organic layer was dried and concentrated, and products were obtained after chromatography.
10. 4O requires: C, 76.44; H, 5.92; N, 13.72. Found: C, 75.95; H, 5.99; N, 13.53.
11. 5 requires: C, 61.72; H, 4.56; N, 17.28. Found: C, 61.49; H, 4.62; N, 17.56.