Synthesis of perhydro-2(1H)-quinoxalinones and perhydropyrrolo[1,2-a]quinoxalin-4(5H)-one derivatives

The novel trans-bicyclic-perhydro-2(1H)-quinoxalinones 4, 6 and 7 and the tricyclic-perhydropyrrolo[1,2-a]-quinoxalin-4(5H)-one derivatives 8 and 9 are prepared via a ring opening and spontaneous ring closing reaction of the aziridines 2 and 3 with the α-amino acids glycine, L-alanine, L-proline and L-phenylalanine. This methodology was used to prepare 5 and 10 which are novel rigid analogues of the kappa opioid compound 1. Treatment of aziridine 3 with methyl carbamate gave the cyclic urea 11.     

Amine-carbon disulfide promoted synthesis of novel benzo[e][1,3]thiazepin-5(1H)-one derivatives

In this paper, a simple method is introduced for the synthesis of novel 4-substituted-3-thioxo-3,4-dihydrobenzo[e][1,3]thiazepin-5(1H)-one derivatives. The synthesis is based on a two-step reaction of 2-methylbenzoic acid, an amine, and carbon disulfide. In the first step, 2-methylbenzoic acid reacts with sulfuric acid in ethanol, followed by the reaction with N-bromosuccinimide to produce ethyl 2-(bromomethyl)benzoate. Amine and carbon disulfide react in a separate flask in basic medium to give carbamodithioate salt. Carbamodithioate and ethyl 2-(bromomethyl)benzoate react together in dimethylformamide to produce the desired 4-substituted-3-thioxo-3,4-dihydrobenzo[e][1,3]thiazepin-5(1H)-one derivatives. The method is simple and fast and is applicable to a wide variety of substrates and gives the desired products in high isolated yields.     

The synthesis of some derivatives of benzo[f]naphtho[1,8-bc]thiepin-12-one

The preparations of benzo[f]naphtho[1,8-bc]thiepin-12-one, its 6-methyl and 6-methoxy derivatives and their corresponding sulfoxides and sulfones are described. They involve the coupling of suitable halogen naphthyl derivatives with thiophenoxides with the help of copper and the cyclization of the resulting acids with phosphorus pentoxide in benzene. The oxidations to sulfoxides and sulfones were performed with iodo-benzene diacetate and hydrogen peroxide, respectively. The ir and pmr spectra are reported.     

Imidazo[1,5-a]- and Thiazolo[3,4-a]quinoxalines Based on 3-(a-Thiocyanobenzyl)quinoxalin-2(1H)-one

When 3-(a-thiocyanobenzyl-2(1H)-one is heated, competing processes of [a]-annelation of the imidazole or thiazole rings occurs with formation of imidazo[1,5-a]- and thiazolo[3,4-a]quinoxalin-4(5H)-ones.     

Synthesis of benzo[g]quinoline derivatives

The electronic spectra of linear benzo[g]quinoline, its 4-substituted derivatives, and some hydrogenated derivatives are examined and discussed.See [1] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 662–665, May, 1972.     

Synthesis of benzo[g]quinoline derivatives

The synthesis of 4-aminobenzo[g]quinoline has been effected by the following three methods: 1) replacement of the halogen in 4-chlorobenzo[g]quinoline by an amino group; 2) dehydrogenation of the oxime of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline; 3) direct condensation of 1,2,3,4-tetrahydro-4-oxobenzo[g]quinoline with ammonia.     

Synthesis of benzo [g]quinoline derivatives

The IR spectra of linear benzoquinoline derivatives at 700–900, 1400–1700, and 2800–3600 cm^–1 are discussed, and the characteristic frequencies are related to the peculiarities of the structures of the synthesized compounds.See [1] for communication VIIITranslated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 367–372, March, 1972.     

Synthesis of benzo[g]quinoline derivatives

It has been established that the cyclization of -(2-carboxy-3-naphthylamino)propionic acid into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]quinoline takes place with the participation of acetic anhydride and an alkali metal acetate. In the absence of the alkali metal acetate cyclization takes place in a different direction. A mechanism for this reaction has been proposed as taking place through the formation of an internal mixed anhydride, which decomposes under the reaction conditions into N-acetyl-4-oxo-1, 2, 3, 4-tetrahydrobenzo[g]-quinoline and carbon dioxide.For part V, see [1].     

Synthesis of benzo[g]quinoline derivatives

A method for the synthesis of 3-substituted benzo[g]quinolin-4-ones by the condensation of 1,2,3,4-tetrahydrobenzo[g]quinolin-4-one with aromatic aldehydes in an alkaline medium has been developed. It has been found that the first stage of the reaction is the formation of the corresponding benzylidene derivative, which then isomerizes into the more stable benzyl derivative. The structure of the 3-substituted benzo[g]quinolin-4-ones obtained, as existing in the tautomeric oxo form, is confirmed by their IR and UV spectra.For Communication VI, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinii, Vol. 6, No. 6, pp. 798–801, June, 1970.     

Synthesis of benzo[g]quinoline derivatives

4-Amino-substituted benzo[g]quinolines have been synthesized for the first time by the condensation of 4-oxo-1,2,3,4-tetrahydrobenzo[g]-quinoline with amines. This reaction is characterized by the addition of the amine, the splitting out of water, and the complete aromatization of the initial hydrogenated heterocyclic system. The UV spectra of the compounds obtained are similar to those of 4-amino-substituted quinolines, their maxima being displaced somewhat into the long-wave region.For part III, see [2].     

Microwave-assisted synthesis and antibacterial activity of some pyrazol-1-ylquinoxalin- 2(1H)-one derivatives

3-Hydrazinoquinoxalin-2(1H)-one was prepared from quinoxaline-2,3-dione and subsequently used for the synthesis of some potentially biologically active 3-(pyrazol-1-yl)quinoxalin-2(1H)-one derivatives. While 3-(3,5-dimethylpyrazol-1-yl)quinoxalin-2(1H)-one showed a comparative effect with streptomycin, 3-(5-oxo-3-phenyl-4,5-di- hydropyrazol-1-yl)quinoxalin-2(1H)-one was found to be the most active with an MIC value of 7.8 μg/ml.     

Synthesis of benzo[g]quinoline derivatives

In the condensation of 1, 2, 3, 4-tetrahydro-4-oxobenzo[g]quinollne with ammonia, which leads to the formation of 4-aminobenzo[g]quinoline, the by-products are benzo[g]quinoline (V) and 1, 2, 3, 4-tetrahydrobenzo]quinoline (VI), which are also obtained from 1, 2, 3, 4-tetrahydro-4hydroxybenzo[g]quinoline by its dehydration and the subsequent disproportionation of the dihydrobenzo[g]quinoline formed.For communication II, see [1].     

Simple procedure for preparation of quinoxalin-2(1H)-one 3-[Oxo(cyclo)alkyl(idene)] derivatives

A simple preparative procedure was developed for 3-(2-oxoalkylidene)-3,4-dihydroquinoxalin-2(1H)-ones, 4,5-dihydroxy-1-[3-oxo-3,4-dihydroquinoxalin-2(1H)-ylidene]-3,5-octadiene-2,7-dione, and 3-(2,3-dihydroxy-4-methyl-5-oxo-1,3-cyclopentadien-1-yl)quinoxalin-2(1H)-one by reaction of methyl ketones first with diethyl oxalate in the presence of sodium, and then with o-phenylenediamine.     

Substituted 2- and 4-benzylpyridines in the synthesis of benzo[g]quinolines and benzo[g]isoquinolines

Nitrogen-containing heterocyclic analogs of anthracene, viz., benzo[g]isoquinolines and benzo[g]quinolines, were obtained by dehydrocyclization on a K-16 catalyst of mixtures of methyl-substituted 2- and 4-benzylpyridines with methyl groups in various positions of the pyridine and benzyl rings, which are formed by benzylation of -picoline, as well as pyridine, by the Ladenburg method. The spectral characteristics of the synthesized compounds are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 673–676, May, 1980.     

Synthesis of benzo[g]quinoline derivatives. XI. 2,4-Diamino-substituted benzo[g]quinolines

Previously unknown 2,4-diamino-substituted benzo[g]quinolines were synthesized from 2,4-dihydroxybenzo[g]quinoline.     

Recent advances and perspectives on the synthesis and C–H bond functionalization of quinoxalin-2(1H)-one

Abstract

Over the past few decades, quinoxalin-2(1H)-one derivatives are serving as active components in diverse families of drugs such as antimicrobial, anticancer, antithrombotic agents and protein kinase inhibitor. Previously, significant attention has been marked for its synthesis and recent years have also observed an upsurge in the modification of this scaffold as well as its functionalization. This review (2008–2020) focused on selective C–H bond functionalization namely arylation, amination, acylation, amidation, alkylation, benzylation, alkoxycarbonylation, cyanoalkylation and phosphorylation etc. at C-3 position of quinoxalin-2(1H)-one. Additionally, alternative complimentary route (radical cyclization protocol) for its synthesis part is well elaborated herein. We also briefly summarized the mechanistic pathway of the C–H bond functionalization approach.     

An efficient route for synthesis of 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-one

The carbodiimide 2,obtained from the aza-Wittig reactions of iminophosphorane 1 with alkyl isocyanates,reacted with primary amino to give 2-alkylamino benzo[b]thieno[3,2-d]pyrimidin-4(3H)-ones 4 and 5.The formation mechanism of the title compounds has been investigated.     

1H NMR spectra of the 2-trifluoroacetyl derivatives of benzo[b]furan and benzo[b]thiophene

The ¹H NMR spectra of the 2-trifluoroacetyl derivatives of benzo[b]furan and benzo[b]thiophene were recorded at 200MHz in two solvents, chloroform and acetone. A long-range coupling constant, 5J(HF), between the fluorine nuclei of the trifluoroacetyl group and H-3, of a value higher than 1 Hz, was measured. From the comparison of the ¹H chemical shifts of, and the solvent effects on, the trifluoroacetyl compounds and those of the corresponding 2-acetyl derivatives, and on the basis of an empirical interpretation of the ⁵J(HF) coupling constant, a predominant Z conformation was tentatively assigned to these derivatives.     

Synthesis of some 4H,10H[1]benzoxepino[3,4-c]pyrazol-4-one derivatives

1H(or 2H)4H10H[1]Benzoxepino[3,4-c]pyrazol-4-ones were prepared from phenoxymethylpyrazolecarboxylic acids which in turn were synthesized from simple starting materials. Different pathways to allow the predominant formation of the N-1 or N-2 substituted derivatives are described. The isomeric 1 or 2-substituted structures were supported by ¹³C-nmr.