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In the present investigation, furo[2,3-d]thiazol-5(2H)-one 5 was obtained from reaction of thiosemicarbazone derivative 2 with diethyl acetylene dicarboxylate. A series of newly synthesized 2-(hydrazinyl)thiazol-4(5H)-one 6, 7 &8 and 2-(4-(substituted)-thiazol-2-yl)hydrazono derivatives 9a, b &10 were synthesized from treatment of thiosemicarbazone derivative 2 with appropriate α-halogenated compounds. Also, a one pot synthesis of thiazole derivatives 13 &15 was achieved from three components reaction of hydrazone derivative 11 with phenyl isothiocyanate and α-halogenated compounds catalyzed by DMF/KOH. 4-(4-Morpholino phenyl) thiazol-2-amino 17 was obtained via the reaction of acetophenone derivative 1 with thiourea in presence of iodine. The reactivity of 2-aminothiazole 17 toward some electrophilic reagents was investigated. The structure of the newly compounds was confirmed on the basis of elemental analysis and spectral data. The antibacterial activity towards two Gram negative (Proteus mirabilis &Serratia marcesens) and two Gram positive (Staphylococcus aureus &Bacillus cereus) bacteria was investigated. The anti-inflammatory activity was also investigated and the inhibition of the carrageenin-induced oedema by these compounds was established., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

The key intermediate octahydroquinazoline (1) was obtained in one pot synthesis by a modification of the Biginelli reaction. Compound 1 was allowed to react with phenacyl bromide and bromomalononitrile to furnish thiazolo[2,3-b]quinazoline 3 and 12, respectively. Interaction of compound 12 with formamide, formic acid and phenyl isothiocyanate yielded the corresponding pyrimidino[4',5':4.5]thiazolo[2,3-b] quinazolines 13, 14 and 17, respectively. The structure of the synthesized compounds were elucidated by elemental analyses and spectroscopic analyses. Some of the prepared compounds were tested for their antifungal activity in comparison with tioconazole as a reference fungicide.

The starting materials thiazolo[2,3-b]quinazolines (5a,b) were obtained in one pot synthesis by treating octahydroquinazoline (2) with chloroacetic acid and aromatic aldehydes. Thiazoloquinazoline (5) was reacted with CH2(CN)2/piperidine and CH2(CN)2/NaOH (CH3OH), to furnish pyrano[2',3':4,5]thiazolo[2,3-b]quinazolines (6a,b) and pyrido[2',3':4,5]thiazolo[2,3-b]quinazoline (7), respectively. Refluxing of 5a with NH2CSNH2/KOH and hydrazines in ethanol furnished the corresponding, [1,3]thiazino[4'5':4,5]thiazolo[2,3-b]quinazoline (10) and pyrazolo[3',4':4,5]thiazolo[2,3-b]quinazolines (11a,b), respectively. Antifungal activity was shown for some of the synthesized compounds.