References
- Shapiro , R. H. 1976 . Org. React. , 23 : 405
- Kolonko , K. J. and Shapiro , R. H. 1978 . J. Org. Chem. , 43 : 1404
- Grieco , P. A. and Nishizawa , M. 1977 . J. Org. Chem. , 42 : 1717
- Posner , G. H. 1978 . Angew. Chem. Int. Ed. Engl. , 17 : 487
- The ratio of stereoisomers was measured by 1H NMR on the bases of higher downfield shift of N-H for the hydrogen bonded Z isomer /7, 7–9, 4 ppm for the E isomers and 11, 9–12, 2 ppm for the Z isomers/. No attempts were made to separate the stereoisomers of hydrazones
- Although a straightforward explanation of stereo-selectivity still awaits more detailed studies, inspection of the molecular models suggest, that the preferential formation of the Z isomer of 5d may due to the strong hydrogen bond existing in the molecule, and the predominance of the E isomer of 5c may be the result of the steric hindrance in the corresponding Z isomer
- Bunnel , C. A. and Fuchs , P. L. 1977 . J. Am. Chem. Soc. , 99 : 5184 The corresponding methyl ester had been prepared
- Bamford , W. R. and Stevens , T. S. 1952 . J. Chem. Soc. , : 4735 The yield was not published