scholarly journals 4H-Benzo[d][1,3]oxazin-4-ones and Dihydro Analogs from Substituted Anthranilic Acids and Orthoesters

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3555 ◽  
Author(s):  
Joel K. Annor-Gyamfi ◽  
Richard A. Bunce

A one-pot route to 2-alkyl and 2-aryl-4H-benzo[d][1,3]oxazin-4-ones (also known as 4H-3,1-benzoxazin-4-ones) has been developed and studied. The method involves the reaction of aryl-substituted anthranilic acids with orthoesters in ethanol catalyzed by acetic acid. Additionally, we have also investigated the reaction under microwave conditions. Not all of the substrates were successful in yielding the target heterocycles as some of the reactions failed to undergo the final elimination. This process led to the isolation of (±)-2-alkyl/aryl-2-ethoxy-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-ones. The formation of the dihydro analogs correlated with the electron density on the aromatic ring: Electron-donating groups favored the 4H- benzo[d][1,3]oxazin-4-ones, while electron-withdrawing groups tended to favor the dihydro product. Substituting a pyridine ring for the benzene ring in the substrate acid suppressed the reaction.

2019 ◽  
Vol 5 (2) ◽  
pp. 34 ◽  
Author(s):  
Cristian Martínez-Hernández ◽  
Samia Benmansour ◽  
Carlos J. Gómez-García

We report the synthesis and the characterization of six new heterometallic chloranilato-based ferrimagnets formulated as (NBu4)[MnCr(C6O4Cl2)3]·nG with n = 1 for G = C6H5Cl (1), C6H5I (3), and C6H5CH3 (4); n = 1.5 for G = C6H5Br (2) and n = 2 for G = C6H5CN (5) and C6H5NO2 (6); (C6O4Cl2)2− = 1,3-dichloro,2,5-dihydroxy-1,4-benzoquinone dianion. The six compounds are isostructural and show hexagonal honeycomb layers of the type [MnCr(C6O4Cl2)3]− alternating with layers containing the NBu4+ cations. The hexagons are formed by alternating Mn(II) and Cr(III) connected by bridging bis-bidentate chloranilato ligands. The benzene derivative solvent molecules are located in the hexagonal channels (formed by the eclipsed packing of the honeycomb layers) showing π-π interactions with the anilato rings. The six compounds behave as ferrimagnets with ordering temperatures in the range 9.8–11.2 K that can be finely tuned by the donor character of the benzene ring and by the number of solvent molecules inserted in the hexagonal channels. The larger the electron density on the aromatic ring and the larger the number of solvent molecules are, the higher Tc is. The only exception is provided by toluene, where the formation of H-bonds might be at the origin of weaker π-π interactions observed in this compound.


ChemInform ◽  
2014 ◽  
Vol 45 (41) ◽  
pp. no-no
Author(s):  
Swarbhanu Sarkar ◽  
Nivedita Chatterjee ◽  
Manas Roy ◽  
Rammyani Pal ◽  
Sabyasachi Sarkar ◽  
...  

2017 ◽  
Vol 67 (3) ◽  
pp. 309-324 ◽  
Author(s):  
Nadjet Rezki ◽  
Mohamed Reda Aouad

AbstractThe present study describes an efficient and ecofriendly, ultrasound, one-pot click cycloaddition approach for the construction of a novel series of 1,4-disubstituted-1,2,3-triazoles tethered with fluorinated 1,2,4-triazole-benzothiazole molecular conjugates. It involved three-component condensation of the appropriate bromoacetamide benzothiazole, sodium azide and 4-alkyl/aryl-5-(2-fluorophenyl)-3-(prop-2-ynylthio)-1,2,4-triazoles4a-ethrough a Cu(I)-catalyzed 1,3-dipolar cycloaddition reaction. This approach involvesin situgeneration of azidoacetamide benzothiazole, followed by condensation with terminal alkynes in the presence of CuSO4/Na-ascorbate in aqueous DMSO under both conventional and ultrasound conditions. Some of the designed 1,2,3-triazole conjugates6a-owere recognized for their antimicrobial activity against some bacterial and fungal pathogenic strains.


ChemInform ◽  
2001 ◽  
Vol 32 (3) ◽  
pp. no-no
Author(s):  
V. S. H. Krishnan ◽  
K. S. Chowdary ◽  
P. K. Dubey
Keyword(s):  
One Pot ◽  

IUCrData ◽  
2017 ◽  
Vol 2 (2) ◽  
Author(s):  
Gao-Ju Wen ◽  
Ming-Xin Wang ◽  
Lian-Shuai Gu

In the title compound, C18H22N4O3, the benzene ring is twisted by 63.29 (15)° with respect to the pyridine ring. In the crystal, molecules are linked by N—H...O hydrogen bonds and C—H...π interactions, forming slabs parallel to theacplane.


2004 ◽  
Vol 69 (9) ◽  
pp. 3236-3239 ◽  
Author(s):  
Jungyeob Ham ◽  
Inho Yang ◽  
Heonjoong Kang

Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 1035-1046 ◽  
Author(s):  
Meng-Yang Chang ◽  
Shin-Mei Chen ◽  
Yu-Ting Hsiao

Trifluoroacetic anhydride mediated one-pot intermolecular formal (4+2) benzannulation of oxygenated arylacetic acids with alkyl aryl ketones provides 4-aryl-2-arylacetoxynaphthalenes in moderate to good yields in the presence of H3PO4 in an open-vessel in a straightforward procedure. A plausible mechanism is proposed and discussed. This protocol provides a highly effective ring-closure via two carbon–carbon (C–C) and one carbon–oxygen (C–O) bond-formation events.


2003 ◽  
Vol 58 (8) ◽  
pp. 787-794 ◽  
Author(s):  
B.Thimme Gowda ◽  
K. L. Jayalakshmi ◽  
K. Jyothi

In an effort to introduce N,N-dichloroarylsulphonamides of different oxidising strengths, four mono- and five di-substituted N,N-dichlorobenzenesulphonamides are prepared, characterised and employed as oxidants for studying the kinetics of oxidation of dimethyl sulphoxide (DMSO) in 50% aqueous acetic acid. The reactions show first order kinetics in [oxidant], fractional to first order in [DMSO] and nearly zero order in [H+]. Increase in ionic strength of the medium slightly increases the rates, while decrease in dielectric constant of the medium decreases the rates. The results along with those of the oxidation of DMSO by N,N-dichlorobenzenesulphonamide and N,N-dichloro-4- methylbenzenesulphonamide have been analysed. Effective oxidising species of the oxidants employed in the present oxidations is Cl+ in different forms, released from the oxidants. Therefore the introduction of different substituent groups into the benzene ring of the oxidant is expected to affect the ability of the reagent to release Cl+ and hence its capacity to oxidise the substrate. Significant changes in the kinetic and thermodynamic data are observed in the present investigations with change of substituent in the benzene ring. The electron releasing groups such as CH3 inhibit the ease with which Cl+ is released from the oxidant, while electron-withdrawing groups such as Cl enhance this ability. The Hammett equation, log kobs = −3.19 + 1.05 σ , is found to be valid for oxidations by all the p-substituted N,N-dichlorobenzenesulphonamides. The substituent effect on the energy of activation, Ea and log A for the oxidations is also analysed. The enthalpies and free energies of activation correlate with an isokinetic temperature of 320 K.


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