Studies on Enamines

Abstract

This work has been done to make use of the nucleophilicity of hydrazone CH in developing new approach to pyridazines. Moreover utllity of arylhydrazononitriles as precursors to 1,2,3-triazoles is further explored. Thus when the phenylhydrazonoketone 4 was reacted with aromaticdiazonium chlorides, it afforded the formazanes 7a, b. These may exist in theory in the enol form 8 but according to analytical data, it was concluded that the compounds exist only in the azo-hydrazono form 7.

OH

H CJy N/'r' 3

7 a,Ar' Ph b,Ar' C6 H4 CH3-p

N ...-Ph N

8

When 7a was reacted with ethyl cyanoacetate in micro-wave oven, it afforded readily the pyridazinone

10.

CH3

PhN=N CN

MW '-- N 0 I Ph

7a 10

Also compound 4 reacted with bromine to give the hydrazonyl halide 11 which further reacted with potassium cyanide to give 12. Better yield of 12 could be obtained via coupling 13 with benzenediazonium chloride, then refluxing the formed iminohydrazone 14 in ethanolic HCI for 15 minutes.