Quinazo lines

The hydrochloride of (3) holds water rather tenaciously, and the infrared spectrum indicates that the water is covalently bound. Mild oxidation of the cation (3) gives 4-hydroxyquinazoline in high yield and ring-chain tautomerism is excluded on the grounds that quinazo-line does not give a positive aldehyde test in acid solution, 2-Methyl-quinazoline also has an anomalous cationic spectrum and a high basic strength (see Table I), but 2,4-dimethylquinazoline is normal in both these respects, which supports the view that abnormal cation formation entails attack on an unsubstituted 4-position. ... 

Heating the mesoionic l-amino-2-thioxo-l,2,4-triazolo[l,5-c]quinazo-lines 59 with aromatic aldehydes and ethanolic hydrochloric acid resulted in the formation of Schiff bases and simultaneous pyrimidine ring cleavage... 

Reduction of 2,3,6,7-tetrahydro-177,5i/-pyrido[3,2,l-//]quinazoline-l,3,7-trione and 7-chloro-6-formyl-2,3-dihydro-177,5i/-pyrido[3,2,1 -(/]quinazo-line-l,3-dione with NaBH4 in THF in the presence of 60% aqueous solution of NaOH gave 7-hydroxy and 7-chloro-6-hydroxymethyl derivatives, respectively (01MI28). 

Lemus, R. L. Lee, C. H. Skibo, E. B. Studies of extended quinone methides. Synthesis and physical studies of purine-like monofunctional and bifunctional imidazo[4,5-g]quinazo-line reductive alkylating agents. J. Org. Chem. 1989, 54, 3611-3618. 

A similar scheme is used to construct a quinazo-line containing halogen at both positions 2 and 4. 

In the present article the primary chemical literature through July of 1997 has been surveyed. Chemical Abstracts Subject and Chemical Substance Indexes through and including Volume 126 have been searched for pyrim-ido[l,2-h]isoquinolines (1), pyrimido[l,2-a]quinolines (3), and pyrimido-[2,l-a]isoquinolines (5), and Volumes 101-126 for pyrido[2,l-6]quinazo-lines (2) and pyrido[l,2-a]quinazolines (4). Throughout this article the... 

Rhodium-catalyzed hydroformylation of 2-amino-/V-(but-3 -enyl)- and -A-(3 -rnethylbut-3 -enyi)benzylamines (381) in the presence of rho-dium(II) acetate dimer and triphenylphosphine in deoxygenated ethyl acetate gave mixtures of 5,5a,6,7,8,9-hexahydro-llH-pyrido[2,l-b]quinazo-line (382), isomeric 6-methyl-5,5a,6,7,8,10-hexahydropyrrolo[2,l-b]quina-zolines (383), and 6-methyl-6,7,8,10-tetrahydropyrrolo[2,l-ft]quinazoline (384), as well as a stereoisomeric mixture of 7-methyl-5,5a,6,7,8,9-hexahy-dro-ll//-pyrido[2,l-b]quinazolines (385) and 15% of 7-methyl-6,7,8,9-tetrahydro-llH-pyrido[2,l-fr)quinazolme (386), (95AJC2023). When the bulky tricyclohexylphosphine was used instead of triphenylphosphine, a 3 7 mixture of compounds 382 and 383 and a 3 1 mixture of isomeric 385 were formed. 

The effect of substituents in the 5-, 6-, 7-, or 8-position of quinazo-line was summed up in the earlier review.38 In general, (—1) substituents promote hydration of the 3,4-bond by lowering the electron density on C-4. Later it was found that a (—1) substituent in the 2-position had the opposite effect. The addition of the negatively charged pole of a water molecule to C-4 is favored by the polarization of the 3,4-bond in this sense —C4 =N—4V But a (—1) group in the 2-position can oppose this polarization. In a study of twenty 2-substituted quinazolines,23 it was found that hydration was helped by (+1) substituents, not greatly affected by (+M), and much diminished by (—I) substituents. The pH rate profile (first-order kinetics) for the hydration of 2-aminoquinazoline, measured from pH 2 to 10, was parabolic,23 typical of molecules that undergo reverse covalent hydration.315... 

Soukri, M., Guillaumet, G., Besson, T., Aziane, D., Aadil, M., Essassi, El M. and Akssira, M., Synthesis of novel 5a,10,14b,15-tetraaza-benzo[fl]indeno[l,2-c] anthracen-5-one and benzimidazo[l,2-c]quinazo line derivatives under microwave irradiation, Tetrahedron Lett., 2000, 41, 5857-5860. 

Data for the unusual pyrido[2,l-/i]benz-2,l-oxazine (27) <86LA69>, various pyrano[2,3-/]quinazo-lines (28) <87JHC603>, pyrano[l,4]benzoxazines (29) <71JCS(C)2079), and Reissert-type phosphonates of 1,7-phenanthroline <86BCJ2362> have been reported. 

Refluxing 5-azidotetrazolo[l,5-a]quinazoline in 6N hydrochloric acid produced quinazo-line-2,4-dione <63ZOB2475) via nucleophilic displacement of the 2 - and 4-azido groups by water followed by keto-enol tautomerism. 

The nitrene adducts 7, obtained by the addition of phthalimidonitrene to 2-methyl-l//-indole and 2-phenyl-1//-indole (cf. Houben-Weyl, Vol. E6b, Part 2, p 1227), afford, on treatment with dimsyl anion. 2-methylquinazoline and 2-phenylquinazoline, respectively. The aziridine 7 obtained by the addition of phthalimidonitrene to l-(phenylsulfonyl)-l//-indole gives quinazo-line on treatment with methanolic potassium hydroxide. 

Quinazoline 1-oxides 1 and quinazoline 3-oxides 3 are reduced to the corresponding quinazo-lines 2 with phosphorus trihalides in chloroform, iron in acetic acid, aqueous... 

Benzenesulfonylquinazolin-4(l//)-ones 1 react smoothly with a series of nucleophilic compounds, namely water, alkoxides, thiols, and organometallic compounds, to afford quinazo-line-2,4(117,3//)-dione and 2-substituted quinazolin-4(l//)-ones (NB tautomerism, cf. PP 13,51). 

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