Reactions with Activated Nitriles : A new route for the synthesis of new pyridine and pyrazolopyridine derivatives

It has been found that $\alpha, \beta$-unsaturated nitrile derivatives 1-3 reached with S- methylisothiourea to give the prpone derivatives 4-6 respectively. Cyclisation of 4-6 using ethanolic hydrochloric acid afforded the pyridine derivatives 7-9 in good yields. On the other hand, the reactions of hydrazine hydrate and of phenylhydrazine with each of 7-9 gave the corresponding pyrazolopyridine derivatives 10-15. The structures of the newly synthesised derivatives were assigned on the basis of elemental analyses, IR and $^1H$-NMR spectral data studies.