Quinazolines substituted

Percentage of Anhydrous Cation in the Mixture of Anhydrous AND Hydrated Cations of Substituted Quinazolines... 

The halogen atom in benz-chloro substituted quinazolines is very stable (as in chlorobenzene), whereas the halogen atoms in positions 2 and 4 show the enhanced reactivity observed with halogen atoms on carbon atoms placed a and y to heterocyclic ring nitrogens. The chlorine atom in position 4 is more reactive than in position 2, and this property has been used to introduce two different substituents in the pyrimidine ring. ... 

No doubt the reactivity parallels the hydration pattern observed in benz-substituted quinazolines (see Section II,A,3). 

Reduction of pyrimidine substituted quinazoline 3-oxides, cata-lytically or with phosphorus trichloride, also leads to quinazolines. ... 

Reduction of quinazoline oxides to quinazolines, catalytically (Raney nickel, palladium on charcoal) or with iron and ferrous sulfate in 85% alcohol can be extended to the preparation of benz-substituted quinazolines. ... 

The neutral species of substituted quinazolines are predominantly anhydrous. The ratio of the hydrated to the anhydrous neutral species... 

The key intermediate 2-thioxo-3-phenylquinazohn-4(3H)-one was prepared by adding carbon disulfide and sodium hydroxide solution simultaneously to a vigorously stirred solution of aniline 7 in dimethylsulfoxide over 30 min stirring was then continued for an additional 30 min. Dimethylsulfate was added to the reaction mixture whilst stirring at 5-10°C after which it was stirred for another 2 h and then poured into ice water to obtain a soHd dithiocarbamic acid methylester 6. The compoimd 6 and methylanthranilate 5 when refluxed in ethanol for 18 h yielded the desired 2-thioxo-3-substituted quinazolin-4(3H)-one 4. The product obtained was cycUc and not an open chain thiourea 5a. It was confirmed by its value, high melting point, and its... 

The 2-methylthio-3-substituted quinazolin-4(3H)-one 3 was obtained by dissolving 4 in 2% alcoholic sodium hydroxide solution and methylating with dimethylsulfate whilst stirring at room temperature (yield 88%, m.p 124-126 C). The IR spectrum of 3 showed the disappearance of the amino (NH) and thioxo (CS) stretching signals of the starting materials. It showed a peak for carbonyl (CO) stretching at 1680 cm The NMR spectriun of com-... 

Thermal decomposition of the salt in nitriles produces 2-substituted quinazolines. In trichloroacetonitrile it proceeded explosively. 

Quinazolines 51 have been prepared by the condensation of A-aryl carbamates with hexamine, followed by aromatisation of the dihydro intermediate. A variety of mono- and di-substituted anilides were used, mefa-substituted starting materials giving 7-substituted quinazolines <06T12351>. Benzoquinazolines were also prepared similarly from naphthylamine carbamates <06OL255>. 

El-Hiti reported an in-depth study of the regioselective Iithiation of numerous substituted quinazolines and subsequent trapping of these nucleophiles with an array of electrophiles <00H1839>. As a representative example, Iithiation of dichloroquinazoline 150 gave rise to further substituted quinazolines 151. 

The linearly fused oxadiazoloquinazoline derivative 90 also underwent ring opening with nucleophiles treatment of a toluene solution of this compound with tetrahydropyridine (refluxing conditions for 15 min followed by storage overnight at room temperature) yielded the urea-substituted quinazoline compound 91 in almost quantitative yield <2000S2009>. 

Just as with nondoped red fluorescent dyes, nondoped phosphorescent iridium complexes consisting of two chelating phenyl-substituted quinazoline and one (2-pyridyl) pyrazolate or triazolate have recently been reported by Chen et al. (278-280) (Scheme 3.88) [308]. All of these complexes exhibited bright red phosphorescence with relatively short excited state lifetimes of 0.4-1.05 ps. PHOLEDs fabricated using the compounds A and B with relatively... 

Rastelli, G., Fanelli, F., Menziani, M.C., Cocchi, M. and De Benedetti, P.G. (1991) Conformational analysis, molecular modeling and quantitative structure-activity relationships studies of 2,4-diamino-6,7-dimethoxy-2-substituted quinazoline al-adrenergic antagonists. Journal of Molecular Structure (Theochem), 251, 307—318. 

Blyn, L. B., Wyatt, J. R., Cook, P. D., Ecker, D. J. Structure—activity relationships of novel 2-substituted quinazoline antibacterial agents. J Med Chem 1999, 42, 4705-4713. 

The synthesis of substituted quinazolin-4(. 7/)-ones and quinazolines via directed lithiation has been reviewed <2000H(53)1839>, and the topic has also been briefly discussed in a more general review on the synthesis of quinazolinones and quinazolines <2005T10153>. For example, the lithiation of 4-methoxyquinazoline 312 with LiTMP followed by reaction with acetaldehyde gave only a minor amount of the 2-substituted product 313, with the major product 314 being the result of lithiation at the 8-position in the benzene ring <1997T2871>. 

A phosphine-free procedure has now been developed that avoids the need to prepare the iminophosphoranes altogether. Thus, treatment of benzamidines 831 with aldehydes under microwave conditions results in direct formation of 4-substituted quinazolines 832 and benzoquinazolines <2005T3533>. 

The same microwave procedure has also been used with guanidine derivatives 833 to give 2-amino-4-substituted quinazolines 834 <2005BML2145, 2005T3533>. 

The procedure has also been extended to the synthesis of 2-dialkylamino-4-substituted quinazolines, as shown by the synthesis of 4-cyclohexyl-2-morpholinoquinazoline 868 <2006JA14254>. 

A new synthetic route to quinazolines from N-protected anilines 895 is available using hexamethylenetetramine (HMTA) in trifluoroacetic acid and potassium ferricyanide in aqueous ethanolic KOH. The method affords substituted quinazolines 897 with good selectivity <2006T12351>, and although only moderate yields were initially achieved, good yields have now been obtained under microwave-assisted conditions <2007TL3229>. The method has also been used to prepare benzoquinazolines <20060L255>. 

Substituted quinazolines 970 have been prepared by treatment of dihydrotriazolines 968 with ammonia, in a process which involves initial thermal ring opening to an amidine 969, and cyclocondensation of the ammonia with... 

Substituted quinazoline derivatives can be prepared by thermal ring contraction of 3/7-1,4-benzodiazepines <1999H(51)2407>. Both 5-methoxy 981 and 5-diethylamino-3/7-l,4-benzodiazepines 983 have been converted to the analogous 4-substituted quinazolines 982 and 984. 

Chemical Class Dihydrofolate reductase inhibitor substituted quinazoline Clinical Pharmacology ... 

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