Synthesis And Characterization Of Some New Quinolin-2(1H)-Ones And Imidazoles Containing 1, 3, 4-Thiadiazoline Ring Derived From Thiosemicarbazone.

A new derivatives of imidazoles and quinolin-2(1H)-ones were synthesized by many reaction steps. Firstly, thiosemicarbazones [1](a,b) were prepared by the condensation of thiosemicarbazide with 4-bromobenzaldehyde or 4-bromoacetophenone then cyclized to get 2,4-diacetamido-1,3,4-thiadiazolines [2](a,b). These compounds were converted to 2-amino-4-acetamido-1,3,4-thiadiazolines [3](a,b) by hydrolysis of amide group (at position -2) to amino group using hydrazine hydrate/water. The reaction of 2-amino-1,3,4-thiadiazolines with different coumarine derivatives and (4-N,N-dimethylbenzaldehyde) in glacial acetic acid led to formation new 1H-quinolin-2-ones [4](a-f) and Schiff bases [5](a,b), respectively. Furthermore, Schiff bases [5](a,b) were reacted with available acid chlorides to get N-acyl compounds [6](a-d) which are converted to thiourea derivatives [7](a-d), followed by cyclization reaction of thiourea derivatives with benzoin to yield new imidazole derivatives [8](a-d). These synthesized compounds were characterized on the basis of IR, H-1-NMR, mass spectra and elemental analysis results.