Table 3: KOH-alumina (10 mol%) catalyzed solvent-free synthesis of substituted pyridazines under microwave (MW) irradiation.

EntrySubstrate 5 (R4, R5)Substrate 1 R1/R2Product 6Time (min)Yield (%)aM.p. (°C)c

1R4 = CN,R1 = R2 = C6H56a881270–272[19]
R5 = COOC2H5 (5a)
2(5a)R1 = R2 = H6b876b182–184[19]
3(5a)R1 = R2 = CH36c887209–211[19]
4R4 = R5 = COOC2H5 (5b)R1 = R2 = C6H56d882217–219[19]
5R4 = COOC2H5,R1 = R2 = C6H56e88677–79[20]
R5 = COCH3 (5c)
6R4 = R5 = COCH3 (5d)R1 = R2 = C6H56f879132–134[20]

aIsolated yield. bPurified by column chromatography. cLiterature references.