A rapid, sufficiency and economic with no pollution method was adopted to synthesize several 1-aryl-2,5-dione pyrrolidino[3,4-d]-3,6-diphenyl-3,4,5,6-tetrahydro pyridazino [1,2-a]-3,6-diaryl-1,2,3,6-tetrahydro-1,2,4,5-tetrazine compounds (4a-f) and (5af) using a solid phase (solvent-free) microwave irradiation technique. The reaction of dibenzylidine hydrazine (1a) as diaza-heterodiene with N-aryl maleimide compounds (2a-f) as cyclic dienophile yielded the corresponding 1-aryl-2,5dione pyrrolidino[3,4-d]-3,6-diphenyl-3,4,5,6-tetrahydro pyridazine derivatives (3a-f) via Diels-Alder reaction that proceeded through intermolecular 1,4-cycloaddition mechanism and induced by microwave irradiation. Similarly, compounds (3a-f) as cyclic hetero dienophile have been converted directly to the 1,2,3,6-tetrahydro-1,2,4,5-tetrazine derivatives (4a-f) and (5a-f) in presence of diarylidine hydrazines (1b-c) as diaza-heterodiene by means of Diels-Alder reaction induced by microwave irradiation and through intermolecular 1,4-cycloaddition mechanism too. The reaction time has been brought down from hours to few minutes in this technique as compared with the conventional method. This method was, also, efficient, fast economic and environmental friendly. All the prepared compounds were confirmed by the available physical and spectral methods.

A series of new 2,5-disubstituted 1,3,4-oxadiazoles represented by compounds 2-phenyl-1-(2-(5-(5-aryl-1,3,4-oxadiazol-2-yl amino)-4H-1,2,4-triazol-3-yl)phenyl)ethanone (5a-f) have been synthesized from(Z)-3-benzylidene phthalide as useful precursor. 3-Benzylidene phthalide was reacted, firstly with urea under microwave irradiation and dry conditions to afford the corresponding 1-(2-(α-phenylacetyl)benzoyl)urea (1). The later compound underwent cycloaddition reaction with hydrazine hydrate (80%) to give 1-(2-(5-amino-4H-1,2,4-triazol-3yl)phenyl)-2-phenylethanone (2), which upon reaction with ethyl chloroformate provided the corresponding ethyl-5-(2-(α-phenylacetyl)phenyl)-4H-1,2,4-triazol-3-yl carbamate (3). 4-(5-(2-(α-Phenylacetyl)phenyl)-4H-1,2,4-triazol-3-yl) semicarbazide (4) was also prepared from the reaction of compound (3) with hydrazine hydrate (80%) under mild conditions. Finally, 2-phenyl-1-(2-(5-(5-aryl-1,3,4-oxadiazol-2-yl amino)-4H-1,2,4-triazole-3-yl)phenyl) ethanone (5a-f) were obtained via the reaction of compound (4) with various substituted benzoic acid by the action of phosphorous oxychloride. The structure of the prepared compounds were confirmed by the available physical and spectral methods.

2-(α-Phenylacetyl) benzohydrazide (1) was prepared through the reaction of (Z)-3benzylidene phthalide and hydrazine hydrate. Treatment of compound (1) with substituted benzoyl chloride yielded N'-aroyl-2-(α-phenyl acetyl) benzohydrazide (2a-e) which upon reaction with ammonium acetate provided the corresponding 2-phenyl-1-(2-(5-aryl-1,2,4triazole-3-yl)phenyl)ethanones (3a-e). While the reaction of compound (1) with substituted benzaldehyde gave the hydrazones represented by N'-arylidene-2-(α-phenylacetyl) benzohydrazide derivatives (4a-f). Intramolecule cyclization of the latter compounds by means of acetic anhydride yielded 2-(α-phenylacetyl)phenyl-4-acetyl-4,5-dihydro-5-aryl-1,3,4oxadiazoles (5a-f). Compounds 2-(α-phenylacetyl)-N-(3,6-diphenyl-5-aryl-5,6-dihydro-1,2,4-triazine-4yl) benzamide (6a-f) were also obtained from the direct Diel-Alder reaction between dibenzylidine hydrazine as diene and compounds (4a-f) as dienophile enhanced by microwave irradiation. The assigned structure of the prepared compounds were corroborated by available physical and spectral methods.

Solid phase one-pot Multicomponent reaction was used widely to achieved  a board spectrum of heterocyclic compounds due to it’s supreme properties starting from four component mixture of piperonal binzil, p-phenylene diamine and ammonium acetate which was reacted directly through grinding then microwave irradiation at (270 watt) for (8 min) in a cidic media to afford 1-N(p-aminophenyl)-2-(piperonyl-5-yl)-5-hydroxy-4, 5-diphenyl-2H-imidazole (1) which then converted to its N'-aroyl derivatives (2-4) through it’s reaction with substituted benzoyl chloride in basic media terminated by direct reaction with acetic anhydride  to obtained N'-acetyl-N'-aroyl derivative (5-7) followed by inter cyclization reaction with hydrazine hydrate (99%) to achieve 1,2,4-trizole derivatives (8-10) in basic media. The assigned structure of the prepared compounds were corroborated by the available physical and spectral methods.

In this work a mixture of hippuric acid (N-benzoyl glycine) (1) and substituted benzaldehyde undergone Erlenmeyer and Perkin reactions respectively to afford the 4-aryl methylidene-2-phenyl oxazole-5-one (2a-d). This reaction proceeded under acidic media using acetic anhydride and sodium acetate. The azlactones (2a-d) used as starting material to prepare the imidazolone derivatives. New 4-aryl methylidene-5-oxo-2-phenyl-N'-(substituted cyclohexylidene)-4,5-dihydro imidazole-1-carbohydrazide(3a-j) were prepared from reactions the azlactones (2a-d) with Schiff's bases which prepared through condensation reaction of semicarbazide with substituted cyclo hexanone. Finally, the preparation of new 1-(4-acetyl-5-spiro substituted cyclohexyl-1,3,4-oxadiazol-2-yl)-4-aryl methylidene-2phenyl-1H-imidazol-5-one (4a-j) via intracyclization reaction of imidazolones (3a-j) in the presence of acetic anhydride as suitable cyclizing agent. The structure of the synthesized compounds were illustrated by the available physical and spectral analysis (M.