2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1&lt;i&gt;H&lt;/i&gt;)-ones as substrates for the synthesis of 2,6,8-triarylquinazolin-4-ones

Mphahlele, Malose J.; Maluleka, Marole M.; Khoza, Tebogo A.

doi:10.4314/bcse.v28i1.10

Cited by 12 publications

(5 citation statements)

References 26 publications

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“…NBS is also employed for ring bromination with the CHCl 3 –CCl 4 binary solvent system. , Substrates such as 2-aminoacetophenone and 2-aminobenzamide undergo dibromination at room temperature with the CHCl 3 –CCl 4 (3:2) solvent system. Pesceet al studied the bromination of phenol with NBS in various solvents .…”

Section: Bromination Reactionsmentioning

confidence: 99%

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

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Section: Bromination Reactionsmentioning

confidence: 99%

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

2016

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“…2-Amino-5-bromobenzamide ( ABB ) [ 19 ], 2-amino-5-iodobenzamide ( AIB ) [ 20 ], 2-amino-3,5-dibromobenzamide ( ABBB ) [ 21 , 22 , 23 ], and 2-amino-5-bromo-3-iodobenzamide ( ABIB ) [ 24 ] were previously prepared from the commercially available 2-aminobenzamide ( AB ) as depicted in Scheme 1 .…”

Section: Resultsmentioning

confidence: 99%

“…Despite the enormous pharmacological [ 11 , 12 , 13 , 15 , 16 , 17 ] and chemical [ 19 , 20 , 21 , 22 , 23 , 24 ] interest in the N -unsubstituted 2-aminobenzamides, to our knowledge, the presence of intramolecular hydrogen bonding in these compounds has been less demonstrated in the literature [ 25 , 26 , 27 , 28 ]. This prompted us to study the structural properties of the known 5-bromo/iodo- and 3,5-dihalogenated 2-aminobezamides by means of spectroscopic (NMR, UV-Vis, IR, Raman) methods and single X-ray crystallography in combination with density functional theory methods.…”

Section: Introductionmentioning

confidence: 99%

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

et al. 2017

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The structures of the mono- and the dihalogenated N-unsubstituted 2-aminobenzamides were characterized by means of the spectroscopic (1H-NMR, UV-Vis, FT-IR, and FT-Raman) and X-ray crystallographic techniques complemented with a density functional theory (DFT) method. The hindered rotation of the C(O)–NH2 single bond resulted in non-equivalence of the amide protons and therefore two distinct resonances of different chemical shift values in the 1H-NMR spectra of these compounds were observed. 2-Amino-5-bromobenzamide (ABB) as a model confirmed the presence of strong intramolecular hydrogen bonds between oxygen and the amine hydrogen. However, intramolecular hydrogen bonding between the carbonyl oxygen and the amine protons was not observed in the solution phase due to a rapid exchange of these two protons with the solvent and fast rotation of the Ar–NH2 single bond. XRD also revealed the ability of the amide unit of these compounds to function as a hydrogen bond donor and acceptor simultaneously to form strong intermolecular hydrogen bonding between oxygen of one molecule and the NH moiety of the amine or amide group of the other molecule and between the amine nitrogen and the amide hydrogen of different molecules. DFT calculations using the B3LYP/6-311++G(d,p) basis set revealed that the conformer (A) with oxygen and 2-amine on the same side predominates possibly due to the formation of a six-membered intramolecular ring, which is assisted by hydrogen bonding as observed in the single crystal XRD structure.

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“…Apart from IBX, various other oxidants (non-metallic) have been applied for oxidative dehydrogenation of C–C and C–N bonds. The synthesis of heteroaromatic compounds such as quinazolinones were facilitated by iodine and DDQ-mediated oxidative dehydrogenation as depicted in Scheme 6 [ 37 – 40 ]. Typically, quinazolinone 25 was refluxed in the polar solvent ethanol with iodine to afford the dihydro derivative 26 ( Scheme 6 ).…”

Section: Reviewmentioning

confidence: 99%

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

Hati¹,

Holzgrabe²,

Sen³

2017

Beilstein J. Org. Chem.

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Nitrogen heteroarenes form an important class of compounds which can be found in natural products, synthetic drugs, building blocks etc. Among the diverse strategies that were developed for the synthesis of nitrogen heterocycles, oxidative dehydrogenation is extremely effective. This review discusses various oxidative dehydrogenation strategies of C–C and C–N bonds to generate nitrogen heteroarenes from their corresponding heterocyclic substrates. The strategies are categorized under stoichiometric and catalytic usage of reagents that facilitate such transformations. The application of these strategies in the synthesis of nitrogen heteroarene natural products and synthetic drug intermediates are also discussed. We hope this review will arouse sufficient interest among the scientific community to further advance the application of oxidative dehydrogenation in the synthesis of nitrogen heteroarenes.

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2-Aryl-6,8-dibromo-2,3-dihydroquinazolin-4(1<i>H</i>)-ones as substrates for the synthesis of 2,6,8-triarylquinazolin-4-ones

Cited by 12 publications

References 26 publications

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Use of Bromine and Bromo-Organic Compounds in Organic Synthesis

Spectroscopic, DFT, and XRD Studies of Hydrogen Bonds in N-Unsubstituted 2-Aminobenzamides

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

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