الفهرس | Only 14 pages are availabe for public view |
Abstract Quinazoline and their derivatives have attracted much attention to chemists and pharmacologists because of their broad spectrum biological activities and applications. 2–cyano-3,4-dihydro-4-oxoquinazoline, the first known quinazoline derivative was known as an effective anti-tumor agent. Quinazoline possess a wide variety of biological activities including anti-cancer, anti-inflammation, anti-bacterial, analgesia, anti-virus, anti-cytotoxin, anti-spasm, anti-tuberculosis, anti-oxidation, anti-malarial, anti-hypertension , anti-obesity, anti-psychotic, anti-diabetes, antifungal, etc. Thus the attachement amino acids to quinazoline ring moiety could afford a new interesting series of compounds with modified antitumor activity. The first part of the discussion deals with the synthesis of two quinazoline systems 3-aryl-2-thioxo-2,3-dihydroquinazolin-4(1H)-one 2a-d and 3-arylquinazoline-2,4-(1H,3H)-dione 10a-d as starting materials. Quinazoline derivatives 2a-d was prepared either by the reaction of aryl isothiocyanate with anthranilic acid in glacial acetic acid or could be obtained by the sequential reaction of aniline derivatives with carbon disulfide and potassium hydroxide followed by alkylation with dimethyl sulfate and finally refluxed with methyl anthranilate in ethyl alcohol for 18h to afford the desired quinazoline derivatives 2a-d. Structure modification of the model compound 2a-d could be achieved by the simple chemoselective alkylation reactions with electrophiles. However, the reaction of quinazoline 2a-d with chloroacetic acid in the presence of NaOH gave a mixture of S-substituted carboxylic acid 15a-d contaminated with quinazoline dione 10a-d and benzanilde 16a-d. On the other hand, the reaction of compound 2a-d with methyl chloroacetate in the presence of NEt3 afforded the S-substituted ester 6a-d in an excellent yield. Saponification of ester 6a-d with KOH in methanol |