Nitrated isomers of 2‐(trichloromethyl)quinoline

In the closely related quinoline compounds 8‐nitro‐2‐(trichloromethyl)quinoline, (I), 6‐nitro‐2‐(trichloromethyl)quinoline, (II), and 5‐nitro‐2‐(trichloromethyl)quinoline, (III), all C₁₀H₅Cl₃N₂O₂, which are of both reactivity and pharmacological interest, and for which the biological activity and cytotoxicity appear to be based on the positions of the CCl₃ and nitro substituents, the nitro group is only coplanar with its aromatic substrate in (II). The deviation of the nitro group from coplanarity is concluded to be a function of both its position with respect to the trichloromethyl group and the intermolecular contacts in which it participates. The discrepancies between the crystal structures and the molecular shapes predicted by ab initio calculations are also explained in these terms. The quinoline ring is not rigorously planar in any of the structures, which may be explained by stress produced by the CCl₃ substituent.     

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.     

Modeling the transition state structure to probe a reaction mechanism on the oxidation of quinoline by quinoline 2-oxidoreductase

Background

Quinoline 2-oxidoreductase (Qor) is a member of molybdenum hydroxylase which catalyzes the oxidation of quinoline (2, 3 benzopyridine) to 1-hydro-2-oxoquinoline. Qor has biological and medicinal significances. Qor is known to metabolize drugs produced from quinoline for the treatment of malaria, arthritis, and lupus for many years. However, the mechanistic action by which Qor oxidizes quinoline has not been investigated either experimentally or theoretically.

Purpose of the study

The present study was intended to determine the interaction site of quinoline, predict the transition state structure, and probe a plausible mechanistic route for the oxidative hydroxylation of quinoline in the reductive half-reaction active site of Qor.

Results

Density functional theory calculations have been carried out in order to understand the events taking place during the oxidative hydroxylation of quinoline in the reductive half-reaction active site of Qor. The most electropositivity and the lowest percentage contribution to the HOMO are shown at C₂ of quinoline compared to the other carbon atoms. The transition state structure of quinoline bound to the active site has been confirmed by one imaginary negative frequency of ?104.500/s and ?1.2365899E+06 transition state energies. The Muliken atomic charges, the bond distances, and the bond order profiles were determined to characterize the transition state structure and the reaction mechanism.

Conclusion

The results have shown that C₂ is the preferred locus of interaction of quinoline to interact with the active site of Qor. The transition state structure of quinoline bound to the active site has been confirmed by one imaginary negative frequency. Moreover, the presence of partial negative charges on hydrogen at the transitions state suggested hydride transfer. Similarly, results obtained from total energy, iconicity and molecular orbital analyses supported a concerted reaction mechanism.

     

Reaction of benzoyl and trichloroacetyl isocyanates with quinoline

Conclusions Trichoroacetyl isocyanate under the influence of quinoline forms ditrichloroacetylcarbodiimide, which adds to the C=N bond of quinoline on the type of a 2+4-cycloaddition. Benzoyl isocyanate under the influence of quinoline forms the dimer.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No.2, pp.456–458, February, 1973.     

Thermal behavior of quinoline <Emphasis Type="Italic">N</Emphasis>-oxide hydrates and deuterohydrate

Spectral and thermochemical investigation of physicochemical properties of quinoline N-oxide crystallohydrates with H₂O and D₂O is carried out. Quinoline N-oxide is established to form with H₂O a stable dihydrate where two water molecules are energetically not equal. Complete dehydration of quinoline N-oxide occurs when temperature reaches 150°C. With accounting for the obtained thermochenical data, quinoline N-oxide and its mono- and dihydrates are isolated in the individual state and their IR spectra are registered and considered. It is established that at boiling quinoline N-oxide in D₂O proceeds chemical reaction affording isoindoline-1,3-dione (phthalimide). The product is identified by elemental analysis and ¹H NMR and IR spectroscopy. The band assignment in the IR spectra of quinoline N-oxide, phthalimide and of the complex of the latter with D₂O is based on the quantum-chemical DFT calculations.     

Two optically active iso­quinoline derivatives

In the two title optically active tetra­hydro­iso­quinoline derivatives, namely 3‐hydroxy­methyl‐4‐phenyl‐1,2,3,4‐tetra­hydro­isoquinolin‐2‐ium bromide methanol hemisolvate, C₁₆H₁₈NO⁺·Br^?·0.5CH₃OH, (IIb), and 2‐formyl‐3‐hydroxy­methyl‐4‐phenyl‐1,2,3,4‐tetra­hydro­iso­quinoline, C₁₇H₁₇NO₂, (III), the absolute configurations have been confirmed as 3R,4R by structure refinement using Bijvoet‐pair reflections. The hydroxy­methyl and phenyl groups in (IIb) are oriented in equatorial and pseudo‐equatorial positions, respectively, whereas in (III), the corresponding groups are in axial and pseudo‐axial positions, respectively; the hydroxy­methyl and phenyl groups are trans with respect to one another in both structures. The heterocyclic rings in (IIb) and (III) adopt envelope conformations inverted with respect to each other. In both structures, the mol­ecules are linked through hydrogen bonds.     

Selective direct fluorination of quinoline derivatives

Direct fluorination of various quinoline derivatives in acidic reaction media gives fluorinated quinoline products arising from selective, efficient electrophilic substitution processes.     

Synthesis of some fused quinoline derivatives

Summary Preparations of the novel fused dimethoxyquinoline derivatives of furo[2,3-b]quinoline (5),s-triazolo[4,3-a]quinoline (8) and tetrazolo[1,5-a]quinoline (10) from 6,7-dimethoxy-3-car-boxyquinoline-1-oxide (1) are reported.

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Synthese kondensierter Chinolinderivate

Zusammenfassung Die Synthese der neuen kondensierten Dimethoxy-Chinolinderivate Furo[2,3-b]chinolin (5),s-Triazolo[4,3-a]chinolin (8) und Tetrazolo[1,5-a]chinolin (10) aus 6,7-Dimethoxy-3-carboxychinolin-1-oxid (1) wird beschrieben.

     

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].     

pH‐responsive photoluminescence properties of a water‐soluble copolymer containing quinoline groups in aqueous solution

The synthesis of a water‐soluble copolymer containing quinoline groups, P(DMAM‐co‐SDPQ), through free radical copolymerization of N,N‐dimethylacrylamide, DMAM, with 2,4‐diphenyl‐6‐(4‐vinylphenyl)quinoline, SDPQ, is presented and the optical properties of the final product are investigated in aqueous solution as a function of pH. It is found that the emission peak of SDPQ is red‐shifted from 411 to 484 nm with decreasing pH, due to the protonation of quinoline groups at low pH, suggesting that this copolymer may function as a luminescent pH‐indicator. Moreover, the copolymer exhibits the characteristics of a luminescent pH‐detector within the pH range 2 < pH < 4, as in this pH region the ratio of the emission intensity at 411 nm over that at 484 nm changes linearly in a logarithmic scale with the pH of the solution. Finally, the formation of less polar quinoline clusters in the aqueous P(DMAM‐co‐SDPQ) solution upon increasing pH was detected through Nile red probing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 2078–2083, 2010     

Electrocatalytic reduction of quinoline and its oxy derivatives

Electrocatalytic hydrogenation of quinoline, quinoline N-oxide, 8-oxyquinoline, and 5,7-dibromo-8-oxyquinoline is studied in an aqueous alkali catholyte solution with the additive of organic solvents on skeleton catalysts (Ni, Co, Cu, Fe) used for cathode activation. It is shown that the main product of hydrogenation of quinoline and quinoline N-oxide is 1,2,3,4-tetrahydroquinoline, whereas that of hydrogenation of 8-oxyquinoline, and its dibromo derivative, is 1,2,3,4-tetrahydro-8-oxyquinoline. A conclusion is made on the basis of chromatographic analysis as to the consecutive-parallel processes of deoxidation and hydrogenation of the N-heterocycle under electrocatalytic reduction of quinoline N-oxide.     

Iodine‐Catalyzed Synthesis of Cyclopenta[c]quinoline Derivatives via Imino Diels–Alder Reaction

A mild and efficient method for the synthesis of cyclopenta[c]naphtho[2,3‐f]quinoline and cyclopenta[c]pyrazolo[4,3‐f]quinoline derivatives via an imino Diels–Alder reaction of aromatic aldehyde, anthracen‐2‐amine, or 1H‐indazol‐5‐amine and cyclopentanone catalyzed by iodine is described. This novel procedure has the advantages of mild reaction condition, high yields, and metal‐free catalyst.     

Easily synthesized antimalarial ferrocene triazacyclononane quinoline conjugates

Starting from triazacyclononane, easily accessible ferrocenic quinoline derivatives were synthesized. Their antiplasmodial properties were investigated against chloroquine sensitive (HB3) and chloroquine-resistant (Dd2) Plasmodium falciparum. One of them, 7-chloro-4-[4-(7-chloro-4-quinolyl)-7-ferrocenylmethyl-1,4,7- triazacyclononan-1-yl]quinoline (4) showed potent antimalarial activity in vitro against the chloroquine-resistant strain Dd2 and therefore revealed to be the most promising lead from the present work for new organometallic antimalarial agents.     

Selective Synthesis Dispiro[indoline‐3,2′‐pyrrolidine‐3′,3″‐quinoline] Derivatives and Spiro[imidazole‐4,3′‐quinoline] Derivatives via 1,3‐Dipolar Cycloaddition Reaction

A new class of spiro compounds as dispiro[indoline‐3,2′‐pyrrolidine‐3′,3″‐quinoline] and spiro[imidazole‐4,3′‐quinoline] have been developed from quinolone derivative adopting modern synthetic methodologies.     

Imino Diels–Alder adducts. I. Two furo­[3,2‐c]­quinoline diastereoisomers

The structures of two diastereoisomers of 9‐chloro‐8‐fluoro‐4‐phenyl‐2,3,3a,4,5,9b‐hexa­hydro­furo­[3,2‐c]­quinoline, C₁₇H₁₅ClFNO, are very similar. The orientation of the furan ring, as a result of its fusion to the quinoline nucleus, constitutes the significant difference between the two structures. The dihedral angles between the furan and phenyl rings are 73.4 (1) and 63.8 (1)°.     

Synthesis and characterization of novel quinoline selenium compounds: X-ray structure of 6-methoxy-3H-[1,2]diselenolo[3,4-b]quinoline

A series of novel and synthetically important quinoline selenium compounds have been successfully synthesized using an efficient and simple strategy. The method employed leads to the synthesis of both cyclic as well as open chain quinoline selenium compounds. The prepared selenium compounds have been characterized with the help of various spectroscopic techniques viz., NMR (¹H, ¹³C), FT-IR, mass spectrometry. The structure of 6-methoxy-3H-[1,2]diselenolo[3,4-b]quinoline has been determined by X-ray crystallography.     

Synthesis and structure-activity relationships study of α-aminophosphonate derivatives containing a quinoline moiety

Two series of a-aminophosphonate derivatives containing a quinoline moiety have been designed and synthesized by introducing bioactive quinoline scaffold to a-aminophosphonate. The in vitro cytotoxic activities of target compounds were first investigated against two human cancer cell lines including Eca109 and Huh7 by MTT assay. Results revealed that most of target compounds exhibited moderate to high antitumor activities against the tested cancer cell lines and some demonstrated more potent inhibitory activities compared with Sunitinib. Among them, compounds 4b2 and 4b4 containing methylsubstituted aniline group were found to be more active than Sunitinib against both of two cancer cell lines, with IC50 in the range of 2.26 mmol/L–7.46 mmol/L.     

Studies of imidazo[4, 5-f]quinoline

The UV absorption spectra of imidazo[4, 5-f]quinoline and its quaternary salts were examined. The causes of the development of luminescence in solutions of the quaternary salts of imidazo[4, 5-f]quinoline were elucidated.For part I, see [6].     

Dimeric quinoline alkaloids

The review is denoted to an analysis of the literature on the investigation of dimeric quinoline alkaloids, which are divided into four groups depending on the structures of the terpenoid moiety. The natural sources, structures, stereochemical features, possible biogenetic schemes of formation, and methods of synthesizing the alkaloids of this group are considered.Institute of the Chemistry of Plant Substances, USSR Academy of Sciences, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 4–18, January–February, 1989.     

The 1H NMR spectra of quinoline,quinoline N-oxide,the quinolinium ion and of their monomethyl derivatives

¹H chemical shifts of quinoline, quinoline N-oxide and the quinolinium ion were obtained by complete analysis of their NMR spectra and interpreted critically in an attempt to quantify the possible different effects acting on the shielding constant of protons in these systems. Semi-empirical SCF calculations of electron charge densities and ring current contributions were also performed. It was found that the same effects that act on the shielding of protons directly bonded to the heterocyclic system also act, in an attenuated form, on the proton chemical shift of methyl groups in monomethyl derivatives. Vicinal coupling constants were rationalised in terms of π-electron bond order and electro-negativity of neighbouring atoms.