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The 2,3,4trisubstituted 3,4dihydroquinazolines 4were unexpectedly obtained from a sequential Ugi four component condensation 4CCazaWittigcarbodiimidemediated cyclization.

The carbodiimides 2, obtained from reactions of iminophosphorane 1with isocyanates, reacted with hydrazine to give selectively 3amino2arylaminobenzothieno3,2dpyrimidin43Hones 4. Reactions of 4with triphenylphosphine, hexachloroethane, and Et3N produced iminophosphoranes 5. A tandem azaWittig reaction of iminophosphorane 5with isocyanate, acyl chloride generated benzothieno3,2d1,2,4triazolo1,5apyrimidin51Hones 7and 9in satisfactory yields. The effects of the nucleophiles on cyclization have been investigated. J. Heterocyclic Chem., 2009.

The carbodiimides 5, obtained from reactions of iminophosphorane 4with aromatic isocyanates, reacted with amines, phenols or ROH to give 2substituted 5,6,7,8tetrahydropyrido4′,3′:4,5thieno2,3dpyrimidin43Hone 7 in the presence of catalytic amount of sodium alkoxide or solid potassium carbonate in satisfactory yields.

1Aryl32ethoxycarbonylphenylcarbodiimides 2, obtained from azaWittig reactions of iminophosphorane 1with aryl isocyanates, reacted with primary diamines in 1:1 and 2:1 molar ratio under mild conditions to give selectively the regioisomers 3aminoalkyl2arylaminoquinazolin43Hones 3and 3,3′disubstituted bis2arylaminoquinazolin43Hones 4in good yields, respectively. To fully characterize the regioselectivity of azaWittig reactions of 1aryl32ethoxycarbonylphenylcarbodiimides with primary diamines, crystals of 4ewere obtained, and its structure was determined by Xray crystallography.

The thienopyridine derivative 2, obtained from reaction of acetoacetic ester with 1in the presence of tin tetrachloride, was treated with triphenylphosphine in hexachloroethane and Et3N to give iminophosphorane 3. Iminophosphorane 3reacted with phenyl isocyanate to give carbodiimide 4, which was further treated with phenols or ethenol to produce 2substituted 5,8,9trimethyl3phenylthieno3′,2′5,6pyrido4,3dpyrimidin43Hones 5in presence of catalytic amount of K2CO3or EtONa. The structures of compounds 5were confirmed by 1H NMR, IR, MS, and elemental analysis.

A series of new 1Hpyrazolo3,4dpyrimidin45Hone Derivatives 5has been designed and regioselectively synthesized viaa tandem azaWittig reaction. The structures of all compounds prepared have been confirmed by 1H NMR, IR, EIMS spectroscopy and elemental analyses. The results of preliminary bioassay indicate that most compounds 5possess an inhibition effect against Botrytis cinereapersand Pyricularia oryzaeat the concentration of 50 mgL.

Novel 2alkylthio5furylmethylidene4Himidazolin4ones 4 have been synthesized viatandem aza Wittig reaction. The structures were determined by ir, nmr, mass spectroscopy, and elemental analysis. They were screened for fungicidal activities against Fusarium oxysporium, Botryosphaeria berengerianaand Rhizoctonia solani, and growth inhibition of Barnyard grass and Cole root and stalk. A few of them possess significant biological activities.