Aza-Wittig Reaction Supported On Poly(Ethylene Glycol) And Synthesis Of Novel Quinazolinones

Quinazolinones have been found to show widespread biological activities such as fungicide, herbicide, pesticide and medicine, and have the applied foreground extensively. Poly (ethylene glycol) (PEG) is used as soluble polymer supports in the field of combinatorial chemistry and organic chemistry since the advantageous features of homogeneous solution chemistry , high reactivity, lack of diffusion phenomena and ease of analysis without following the cleavage-and-check technique. In this paper, we studied the synthesis of 2-dialkylamino-4(3H)-quinazolinones via aza-Wittig reaction on poly (ethylene glycol) (PEG) support, and the synthesis of imidazo[2,1-b]quinazoline-2,5-dione derivatives and 2-amino-4(3H)-quinazolinone derivatives by utilizing aza-Wittig reaction. The structure of these compounds were confirmed by IR, ~1H NMR, MS, elemental analysed and X-ray diffraction. It may be summarized as follows:1. 2-Dialkylamino-4(3H)-quinazolinones have been synthesized by the reaction of PEG-supported carbodiimides with secondary amines. The reaction conditions of 2-azidobenzoyl chloride with PEG were studied.2. Imidazo[2,1-b]quinazoline-2,5-dione derivatives were synthesized by aza-Wittig reaction and the structure of this heterocycles has been verified by X-ray diffraction. The reactions of iminophosphorane with isocyanates were studied and the selectivity of cyclization of subsequent reaction was also investigated.3. The selectivity of carbodiimides withα-amino acid ester hydrochloride was studied. When R≠H,the reaction of carbodiimides withα-amino acid ester hydrochloride produce 2-amino-4(3H)-quinazolinone derivatives in the presence of triethylamine. However, 1-Aryl-1H-imidazo[2,1-b]quinazolin-2,5-diones were easily obtained under the same reaction condition as R=H.