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

The reaction of 2-(2-tosylaminophenyl)-4H-3,1-benzoxazine-4-one with alcohols in pyridine gives tosylanthraniloylanthranilic acid esters. The synthesized compounds luminesce in the crystalline state and in solutions at room temperature. The anomalously high Stokesian shift characteristic for this series of compounds is due to intramolecular hydrogen bonding with the participation of the tosylamino group. Interaction of polar solvents and irradiation with UV light lead to cleavage of the hydrogen bond, and as a consequence, to a decrease in the Stokesian shift.     

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.     

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.     

The chemistry of 4H-3,1-benzoxazin-4-ones

The present review covers the synthesis and reactions of 4H-3,1-Benzoxazin-4-ones. Only those with carbon substituents at the 2-position are included. Literature corverage includes publications primarily from the mid 1960's to May 1998.     

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.     

A Simple Indirect Route for the Synthesis of N-Alkyl-4-imino-1,4-dihydro-2H-3,1-benzoxazin-2-ones

Summary. Novel N-alkyl-4-imino-1,4-dihydro-2H-3,1-benzoxazin-2-ones were synthesized in a single step by Baeyer–Villiger oxidation of N-alkyl-3-imino-2-indolinone derivatives in high yields. The structures of the products were determined by spectral data and by X-ray diffraction. Besides their novel structures, these compounds may have important biological activities and industrial applications.     

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.     

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.     

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.     

Synthesis of NSC-341,964: An unexpected study on the stability of 2-aryl-4H-3,1-benzoxazin-4-ones

Resynthesis of NSC 341,964, which had been assigned structure 1 (1-[[3-(7-chloro-4-oxo-4H-3,1-benzoxazin-2-yl)phenyl]methyl]pyridinium chloride) was approached via 7-chloro-2-(3-methylphenyl)-4H-3,1-benzoxazin-4-one ( 5 ) obtained from 3-methylbenzoyl chloride ( 2 ) and 2-amino-4-chlorobenzoic acid ( 3 ) followed by dehydration in acetic anhydride. Radical bromination provided 6 which with pyridine afforded the bromide analog 7 of 1 . Ion exchange, however, gave ring-opened benzoic acid 8 rather than 1 . The original sample of NSC 341,964 also proved to be ring-opened material. However, 7 upon standing exhibited slow hydrolysis to 8 so that the structure of the original NSC 341,964 remains uncertain. A more direct route to compound 8 is also described.     

6-Iodo-2-isopropyl-4H-3,1-benzoxazin-4-one as building block in heterocyclic synthesis

As a part of ongoing studies in the synthesis of a variety of heterocycles of biological importance, we report here an efficient and convenient method for the synthesis of novel compounds from 6-iodo-2-isopropyl-4H-3,1-benzoxazin-4-one 1 as building block. The reaction of benzoxazinone 1 with various reagents such as diethylmalonate, sodium azide, and phosphorus pentasulfide yielded the compounds 2–5. The behavior of benzothiazin-4-thione 5 toward formamide and hydrazine hydrate was investigated, forming the compounds 6 and 7. The reaction of quinazolinone derivative 8 with β-D-glucose pentaacetate, ethyl 2-methyl-5-((1S,2R,3R)-1,2,3,4-tetrahydroxybutyl)furan-3-carboxylate, epichlorohydrin and benzenesulphonyl chloride afforded quinazolinone derivatives 9, 10, 12, and 13 respectively. The reaction of quinazolinone derivative 10 with acetic anhydride resulted in formation of the acylated compound 11. The behavior of quinazolinylacetohydrazide derivative 14 toward carbon electrophiles^[16 El-Hashash, M. A.; El-Naggar, A. M.; El-Bordany, E. A.; Marzouk, M. I.; Nawar, T. M. S. Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl4H-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity. Synth. Commun. 2016, 46(14), 1230–1241.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]^] has been investigated by its reaction with ethyl benzoylacetate, potassium thiocyanate, and phenyl isothiocyanate, affording the quinazolinone derivatives 15, 16, and 18, respectively. Treatment of compound 16 with sodium hydroxide followed by hydrochloric acid yielded the mercapto-triazole derivative 17. The structures of the newly synthesized compounds were confirmed by elemental analysis, infrared (IR), ¹H NMR, ¹³C NMR, and mass spectra. The antimicrobial activities of some of the synthesized compounds were preliminarily evaluated.     

Reaction of 2-trifluoromethyl-4H-3,1-benzoxazin-4-one derivatives with carboethoxymethylenetriphenylphosphorane

Treatment of a series of 2-trifluoromethyl-4H-3,1-benzoxazin-4-one derivatives 1 with carboethoxymethyl-enetriphenylphosphorane 2 yielded the phosphoranes 3 in boiling toluene solution. Thermolysis of these phosphoranes 3 gave esters 6.     

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.     

Direct oxidative cascade cyclisation of 2-aminobenzoic acid and arylaldehydes to aryl 4H-3,1-benzoxazin-4-ones with oxone

This paper presents a methodology of oxidative cascade cyclisation of 2-aminobenzoic acids and arylaldehyde using I₂ as a catalyst and an environmentally benign oxidant oxone. This method displays facile access to a diverse range of substituted aryl 4H-3,1-benzoxazin-4-ones. This synthetic methodology has many advantages such as: (1) easy availability of starting material, (2) transition metal-free condition (3) use of an environmentally benign oxidant.     

Intramolecular photoinduced proton transfer in 2-(2-aminophenyl)-4H-3,1-benzoxazin-4-ones with different electron-withdrawing N-substituents

Fluorescence spectra of N-substituted 2-(2-aminophenyl)-4H-3,1-benzoxazin-4-ones consist of two bands, the long-wavelength band with anomalous Stokes shift, which corresponds to the emission of the product of intramolecular photoinduced proton transfer, and the short-wavelength band belonging to the form in which proton transfer does not occur. It is assumed that there is equilibrium between two planar rotamers in the ground state: one with the N-H…N hydrogen bond in which the intramolecular photoinduced proton transfer occurs and the other with the N-H…O bond, which does not experience hydrogen transfer. According to ab initio quantum-chemical calculations, the potential energy of proton transfer in the first excited singlet state has a potential barrier of 2.1–26.8 kJ/mol depending on the electron-withdrawing ability of the substituent on the amino group.     

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. 3. Condensation of o-phenylenediamive

3-(2-Benzimidazolyl)-4-hydroxy-2-quinolone was unexpectedly obtained as the principal reaction product on fusion of 2-carbethoxymethyl-4H-3,1-benzoxazin-4-one with o-phenylenediamine. A possible mechanism of its formation is presented.For Communication 2 see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 239–241, February, 1992.