The Knoevenagel reaction of cyanoacetylhydrazine with pregnenolone: Synthesis of thiophene, thieno[2,3-d]pyrimidine, 1,2,4-triazole, pyran and pyridine derivatives with anti-inflammatory and anti-ulcer activities.

The reaction of pregnenolone with cyanoacetylhydrazine and ammonium acetate at 120°C gave the Knoevenagel condensation product 3. The latter reacted with different reagents to give thiophene, thieno[2,3-d]pyrimidine, 1,2,4-triazole and pyran derivatives. The anti-inflammatory and anti-ulcer evaluations of the newly synthesized products were evaluated and the results showed that compounds 4, 8c, 10, 11, 13c, 15a, 15c, 17a, 17b, 17e, 18a and 18f possessed higher activity compared to the rest of the compounds. In addition to this, the toxicity of these active compounds was studied against shrimp larvae where compounds 15a, 15c and 18a showed non-toxicity against the tested organisms.