2-Styryl-4H-1,3-benzoxazin-4-onium salts

A method was developed for the synthesis of 2-styryl-4H-1,3-benzoxazin-4-onium salts by condensation of 2-alkylbenzoxazinonium salts with aromatic aldehydes. It is shown that these same compounds are formed by acid condensation of salicylamides, salicylnitrile, or salicylaldoxime with aromatic aldehydes in acetic anhydride. The hydrolysis and alcoholysis of the synthesized salts were studied.     

Acylation of salicylnitrile and salicylaldoxime as a method for the synthesis of 4H-1,3-benzoxazin-4-onium salts

Methods were developed for the synthesis of 4H-1,3-benzoxazin-4-onium salts by acylation of salicylnitrile and salicylaldoxime with acid anhydrides and chlorides are acids in the presence of perchloric acid or tin perchlorate.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 742–744, June, 1976.     

Reaction of 4H-1, 3-benzoxazine-4-onium salts with C-nucleophilic aromatic compounds

A method is proposed for the synthesis of 2-(4-dialkylaminophenyl)-2,3-dihydro-4H-1,3-benzoxazin-4-ones and diindolylcyaninemethanes by reaction of 4H-1,3-benzoxazin-4-onium salts with N,N-dialkylanilines and indole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 47–50, January, 1977.     

2-Aryl-4H-3,1-benzoxazin-4-ones nitration

2-(3-Nitrophenyl)-4H-3,1-benzoxazin-4-one is formed in the nitration of 2-phenyl-4H-3,1-benzoxazin-4-one, while 2-(2-tosylamino-5-nitrophenyl)-4H-3,1-benzoxazin-4-one is formed in the nitration of 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-one.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 908–909, July, 1974.     

1,1-Dichloro-2,2,2-trihaloethyl Isocyanates and N-(1-Chloro-2,2,2-trihaloethylidene)urethanes in the Synthesis of 4-Trihalomethyl-2H-1,3-benzoxazin-2-ones

4-Trihalomethyl-2H-1,3-benzoxazin-2-ones have been synthesized by the reaction of 1,1-dichloro-2,2,2-trihaloethyl isocyanates or N-(1-chloro-2,2,2-trihaloethylidene)urethanes with 3-dialkylamino(alkoxy)phenols. The character of the products from the addition of nucleophiles has been shown to depend on the nature of the nucleophile and the trihalomethyl group.     

Synthesis and transformation of amides of 4H-3,1-benzoxazin-4-one-2-carboxylic acid

A method for the preparation of amides of 4H-3,1-benzoxazin-4-one-2-carboxylic acid was developed, and N-R-amides of 3-R-4(3H)-quinazolone-2-carboxylic acid were synthesized from them.     

2-Aryl-4H-3,1-benzoxazin-4-ones. Reduction

The reduction of 2-(2-tosylaminophenyl-4H-3,1-benzoxazin-4-one with zinc dust in acetic acid gives N-(o-tosylaminobenzyl)anthranilic acid, the structure of which was proved by mass spectrometry and the ¹³C NMR spectra.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1619–1621, December, 1977.     

4H-3,1-Benzoxazin-4-ones methoxy-substituted 2-(2-arenesulfonylaminophenyl)-4H-3,1-benzoxazin-4-ones

Methoxy-substituted 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-one and 2-phenyl-4H-3,1-benzoxazin-4-one were synthesized. Their UV, IR, and luminescence spectra were studied. The position of the methoxy group affects the strength of the intramolecular hydrogen bond (IHB). The luminescence properties of methoxy-substituted 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-ones are associated with the strength of the IHB. The luminescence maximum is shifted to the short-wave region with strengthening of the IHB, and the luminescence intensity increase simultaneously.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1028–1032, August, 1971.The authors thank Yu. S. Ryabokobylko and A. O. Zisman for measuring the absorption spectra in the IR and UV regions.     

4-Substituted-3,4-dihydro-3-methyl-2H-1,3-benzoxazin-2-ones. III (2,3). Solvolytic-reductive transformation of 4-(2-keto)-benzoxazin-2-ones into oxazin-2-ones

A series of 4-(2-keto-substituted)-3,4-dihydro-3-methyl-2H-1,3-benzoxazin-2-ones 1 (Table I) was synthesized by condensation of 3-alkyl-3,4-dihydro-4-hydroxy-2H-1,3-benzoxazin-2-ones 4 with ketones 5 having active alpha hydrogens. In the presence of alcoholic potassium borohydride, compounds 1 underwent reductive transacylation to give 1,3-oxazin-2-one derivatives 3 (Table III, a,b,c). When the other side of the ketone possessed substituents other than hydrogen, there were always also normal reduction products, i.e., secondary alcohols 2 (Table II) in addition to 3.     

New polyfunctional spiropyran of 1,3-benzoxazin-4-one series with carbonyl-containing substituents in the [2H]-chromene moiety

A polyfunctional spiropyran of 1,3-benzoxazin-4-one series containing one hydroxy and two carbonyl substituents in the [2H]-chromene moiety was synthesized on the basis of a new analogue of 2,4-dihydroxyisophthalic aldehyde, methyl 3,5-diformyl-2,4-dihydroxybenzoate. The structure of resulting 6'-carbomethoxy-3,7-dimethyl-8'-formyl-5'-hydroxy-4-oxo-spiro-(1,3-benzoxazine-2,2'-[2H]-chromene) was unambiguously established by single crystal X-ray diffraction analysis. These data allowed us to reveal the route for the reaction of the new polyfunctional aldehyde with 1,3-benzoxazin-4-onium perchlorate.     

4H-3,1-benzoxazin-4-ones thermal cyclodehydration of N-benzoylanthranilic acid

Water is split out to form 2-phenyl-4H-3,1-benzoxazin-4-one when N-benzoylanthranilic acid is heated. A mass spectrometric study of O¹⁸-labeled N-benzoylanthranilic acid and the product of its thermal cyclodehydration showed that the oxygen atoms of the carboxyl and benzoyl groups participate equally probably in splitting out of water.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 614–615, May, 1977.     

Nitro-substituted 2-phenyl- and 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-one

Nitro-substituted 2-phenyl- and 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-ones were synthesized. The UV, IR, and luminescence spectra were studied. The position of the nitro group affects the strength of the intramolecular hydrogen bond (IHB). The luminescence properties of nitro-substituted 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-ones are associated with the strength of the IHB. The luminescence maximum is shifted to the short-wave region as the IHB becomes stronger.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 616–621, May, 1972.     

Preparation of diastereomeric 5,8-methanobenzoxazino[2,1–6]- and [2,3–6]-1,3-benzoxazin-4-ones by reaction of norbornane/ene-condensed dihydro-1,3-oxazines with salicyl chloride

Norbornane and norbornene-condensed dihydro-1,3-oxazines 1–6 were converted with salicyl chloride to 5,8-methanobenzoxazino[2,1–6]- and -[2,3-b]-1,3-benzoxazin-4-ones 7–12. The addition takes place to the C ? N bond: after acylation, the intermediate is stabilized through cyclization to the aryl-substituted carbon by hydrogen chloride elimination. Diastereomers containing the oxazine rings in isomeric positions could be isolated in two cases. This is the first example of the isolation of diastereomers in such a salicyl chloride reaction. In contrast with earlier findings with reactions of related systems, no addition to the C ? C bond could be observed. The steric structures of the compounds were elucidated by ir, ¹H- and ¹³C-nmr spectroscopy.     

Facile synthesis and herbicidal evaluation of 4H-3,1-benzoxazin-4-ones and 3H-quinazolin-4-ones with 2-phenoxymethyl substituents

Series of 4H-3,1-benzoxazin-4-ones and 3H-quinazolin-4-ones with phenoxy-methyl substituents were rationally designed and easily synthesized via one-pot N-acylation/ring closure reactions of anthranilic acids with 2-phenoxyacetyl chlorides to yield the 4H-3,1-benzoxazin-4-ones, and subsequently substituted with amino derivatives to obtain the 3H-quinazolin-4-ones. The herbicidal evaluation was performed on the model plants barnyard grass (a monocotyledon) and rape (a dicotyledon), and most of the title compounds displayed high levels of phytotoxicity. The active substructure and inhibitory phenotype analysis indicated that these compounds could be attributed to the class of plant hormone inhibitors. A docking study of several representative compounds with the hormone receptor TIR1 revealed an appreciable conformational match in the active site, implicating these compounds are potential lead hits targeting this receptor.     

Synthesis of benzoxazinone derivatives: a new route to 2 (N phthaloylmethyl)-4H-3,1-benzoxazin-4-one

A new method has been designed to prepare the known benzoxazinone derivative 2-(N-phthaloylmethyl)-4H-3,1-benzoxazin-4-one (4). The acyl chloride derivative N-phthaloylglycine reacts with anthranilic acid in chloroform, in the presence of triethylamine, to give an intermediate that is then reacted with cyanuric chloride, used as a cyclization agent, to produce the benzoxazinone derivative.     

4-Hydroxy-2-quinolones. 112. Reaction of 2-ethoxycarbonylmethyl-4H-3,1-benzoxazin-4-one with active methylene compounds

The reaction of 2-ethoxycarbonylmethyl-4H-3,1-benzoxazin-4-one with malononitrile in dry pyridine leads to 1-hydroxy-3,6-dioxo-4,6-dihydro-3H-pyrimido[1,2-a]quinoline-5-carbonitrile. Acetoacetic and cyanoacetic esters under analogous conditions form anilides of 4-hydroxy-2-oxo-1,2-dihydroquinoline-3-carboxylic acid while diethyl malonate gives N,N′-di-2-carboxyanilides of malonic acid. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 75–79, January, 2007.     

2-Carbethoxymethyl-4H-3,1-benzoxazin-4-one. 4. Reaction with anilines

In a solution of DMF, 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one reacts with primarily aromatic amines basically with the formation of the corresponding 2-carbethoxymetlzyl-3-arylquinazolin-4(3H)-ones. Possible mechanisms of these chemical transformations are reported and discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 225–228, February, 1994. Original article submitted June 28, 1993.     

Resin-bound 4H-1,3-oxazine-masked beta-diketones for functionalizing cleavage strategy

Resin-bound 4H-1,3-oxazines are synthesized by the stepwise condensation of an amide resin, an aldehyde, and an alkyne. Upon DDQ activation, oxazines are converted into oxazinium salts. When treated with hydrazines, these resin-bound beta-diketone equivalents yield pyrazoles through a functionalizing release process. This multicomponent capture strategy, tedious to handle in classical synthesis in solution, is well-suited to solid-supported chemistry. It facilitates the handling of sensitive and unstable intermediates, such as N-alpha-methoxyalkylamides and 1,3-oxazinium salts.     

Liquid-crystal 4H-3,1-benzoxazln-4-ones

2,6-Disubstituted 4H-3,1-benzoxazin-4-ones that have mesogenic properties were synthesized by the reaction of 5-substituted anthranilic acid with aroyl chlorides in pyridine. The introduction of a 4H-3,1-benzoxazin-4-one fragment increases the absolute value of the anisotropy of the dielectric permeability. The temperatures and heats of the phase transitions are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1335–1337, October, 1981.     

2-Carbethoxy-4H-3,1-benzoxazin-4-one. 2. Hydrazinolysis

3-Amino-2-carboxymethylquinazolin-4(3H)-one was obtained by hydrazinolysis of 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one. Its transformations into 2-hydroxypyrazolo[5,1-b]quinazolin-9(1H)-oneand3-amino-2-hydrazido-(orbenzylamido)carbonylmethylquinazoline-4(3H)-ones were studied.For Communication 1, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1128–1130, August, 1991.