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Quinazoline 3-oxides, 2-amino- from

Methylation of 4-aminoquinazoline 3-oxide, prepared from 4-methoxy-quinazoline and hydroxylamine, produced a 1 1 mixture of 4-imino-3-methoxy-3,4-dihydroquinazoline (19%) and 3-methoxy-4-methylimino-3,4-dihydroquinazoline (18%). These were reduced with Raney nickel to 4-amino- and 4-methylaminoquinazoline, respectively. [Pg.32]

Synthesis of pyrido[ 1,2-bJquinazolines through formation of the azole ring from properly substituted quinazoline precursors is also known (61AP556). Thus, the cyclodehydrobromination of the 2-(4-bromo-butyl)quinazolin-4-one (445) with alkali was claimed to give only the linearly annulated 1,2,3,4-tetrahydropyrido[ 1,2-6]quinazolin-4-ones (446) (61AP556). Oxidation of the 3-amino-2-(butyn-l-yl)quinazolin-4-ones (447) with lead tetraacetate led to intramolecular addition of the produced /V-nitrene intermediate to the triple bond to give 449 [86JC S(P 1) 1215]. [Pg.77]

From the reaction of 2-chlorobenzoic acid and 2-amino-5-nitropyridine in the presence of potassium carbonate and copper powder or copper(II) oxide, Carboni and Pardi isolated the condensation product 210 (R = H, R -= 5-NO2), which was then cyclized with a strong concentrated acid to the pyrido[2,l-i)]quinazoline 211 (R= H, R = S-NOj). [Pg.382]

Amino-1,4-benzodiazepine 4-oxides 27 are prepared from 2-(chloromethyl)quinazoline 3-... [Pg.476]

Compounds in which other heterocyclic rings (pyrazoles, isoxazoles, imidazoles ) are fused to thiopyrans have been described. The interesting thiazolium salts (56) were prepared by allowing the betaines (55) to react with 4-thioxothiazolidin-2-ones. Application of the Fischer indole synthesis and the Friedlander reaction to tetrahydrothiopyran-3-one led to the exported indolo-and quinolino-derivatives. Ring closure of (57) under acidic conditions afforded the rearranged product (58). Syntheses of benzothiopyrano[4,3,2-flfe]-quinazolines (59) from 1-amino-thioxanthones and of their S- and 7V-oxides have been described. ... [Pg.331]

Same reaction has also been carried out with methyl iodide in place of amine and in the presence of sodium hydride to yield N-methyl-3,4-dihydropyrazino[2,l-b] quinazolin-6-ones. The novel pyrimido[4,5-d]pyrimidine derivatives of biological significance from electron rich 6-[(dimethylamino)methylene]amino uracil undergoes [4+2] cycloaddition reactions with various in situ generated glyoxylate imine and imine oxides, after elimination of dimethylamine from the (1 1) cycloadducts and oxidative aromatization. This method provides a suitable method for the direct synthesis of pyrimido[4,5-d]pyrimidines in excellent yields, when reaction was carried out in the solid state and under microwave irradiations (Prajapati et al., 2006). [Pg.171]


See other pages where Quinazoline 3-oxides, 2-amino- from is mentioned: [Pg.257]    [Pg.317]    [Pg.104]    [Pg.179]    [Pg.75]    [Pg.174]    [Pg.508]    [Pg.612]    [Pg.13]    [Pg.612]    [Pg.64]    [Pg.291]    [Pg.353]    [Pg.352]    [Pg.482]    [Pg.64]    [Pg.612]    [Pg.270]    [Pg.31]    [Pg.32]    [Pg.41]    [Pg.31]    [Pg.32]    [Pg.41]    [Pg.676]    [Pg.264]    [Pg.232]    [Pg.482]    [Pg.180]    [Pg.401]   


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Amino oxidation

Quinazoline 1-oxides

Quinazoline oxidation

Quinazoline, 3-amino

Quinazolines 4-amino

Quinazolines, 4-amino- from

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