title: Facile Preparation of 4-Substituted Quinazoline Derivatives.
abstract: Reported in this paper is a very simple method for direct preparation of 4-substituted quinazoline derivatives from a reaction between substituted 2-aminobenzophenones and thiourea in the presence of dimethyl sulfoxide (DMSO). This is a unique complementary reaction system in which thiourea undergoes thermal decomposition to form carbodiimide and hydrogen sulfide, where the former reacts with 2-aminobenzophenone to form 4-phenylquinazolin-2(1H)-imine intermediate, whilst hydrogen sulfide reacts with DMSO to give methanethiol or other sulfur-containing molecule which then functions as a complementary reducing agent to reduce 4-phenylquinazolin-2(1H)-imine intermediate into 4-phenyl-1,2-dihydroquinazolin-2-amine. Subsequently, the elimination of ammonia from 4-phenyl-1,2-dihydroquinazolin-2-amine affords substituted quinazoline derivative. This reaction usually gives quinazoline derivative as a single product arising from 2-aminobenzophenone as monitored by GC/MS analysis, along with small amount of sulfur-containing molecules such as dimethyl disulfide, dimethyl trisulfide, etc. The reaction usually completes in 4-6 hr at 160 ºC in small scale but may last over 24 hr when carried out in large scale. The reaction product can be easily purified by means of washing off DMSO with water followed by column chromatography or thin layer chromatography.
authors.affiliation: School of Science and Computer Engineering, University of Houston-Clear Lake; Wang@uhcl.edu.
authors.forename: Daniel Z
authors.initials: DZ
authors.lastname: Wang
authors.affiliation: Airgas Specialty Gas, Airgas USA LLC.
authors.forename: Lesong
authors.initials: L
authors.lastname: Yan
authors.affiliation: School of Science and Computer Engineering, University of Houston-Clear Lake.
authors.forename: Lingmei
authors.initials: L
authors.lastname: Ma
mesh_terms: D001577:Benzophenones / Q000138:chemical synthesis*; D060326:Chemistry Techniques, Synthetic / Q000379:methods; D002845:Chromatography / Q000379:methods; D004121:Dimethyl Sulfoxide / Q000138:chemical synthesis / Q000737:chemistry; D004220:Disulfides / Q000138:chemical synthesis; D008872:Microwaves; D011799:Quinazolines / Q000138:chemical synthesis*; D013438:Sulfhydryl Compounds / Q000138:chemical synthesis; D013440:Sulfides / Q000138:chemical synthesis; D014527:Uric Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis
chemical_list: D001577:Benzophenones; D004220:Disulfides; D011799:Quinazolines; D013438:Sulfhydryl Compounds; D013440:Sulfides; D014527:Uric Acid; C005231:methylmercaptan; C054170:dimethyl trisulfide; C021181:dimethyl disulfide; C010352:6-thiouric acid; D004121:Dimethyl Sulfoxide