Reflux In Benzene Research Articles

Photodegradation of Methylene Blue by Nano-Titania developed from Novel Heteroleptic Titanium(IV) Complexes

Three new heteroleptic mononuclear derivatives of titanium(IV) have been synthesised and characterized by physico-chemical techniques. The newly synthesised titanium complexes [C26H21Br2NO5Ti] 1, [C26H21Cl2NO5Ti] 2 and [C26H21F2NO5Ti] 3 were obtained by treating [Ti(OPri)4] with 8-hydroxyquinoline, acetylacetone and corresponding phenol derivatives in 1:1:1:2 stoichiometry while refluxing in benzene as a reaction solvent under anhydrous stringent conditions. The newly synthesised titanium(IV) complexes were established by NMR (1H and 13C), FTIR and HRMS. Derivative 1 was employed as a precursor for the synthesis of nano titania by sol-gel method. The morphology of TiO2 was confirmed by several analytical tools such as FTIR, powder XRD, UV-Vis, RAMAN, SEM and TEM analyses. Further, the nano-structured titanium oxide developed herein was exploited to evaluate the catalytic photodegradation of methylene blue dye in aqueous solution on illumination of UV light that resulted in the extent of decolourization up to 68%, 81% and 94% by taking 20, 30 and 40 mg of catalyst in account respectively.

A new route to the synthesis of 4-amino-substituted pyrido[2,3-d]pyrimidin-5-one derivatives

The reaction of 6-(R-amino)-5-acetyl-4-methylsulfonyl-2-phenylpyrimidines with amines was studied. 6-Arylamino derivatives react with alkylamines to form 6-alkylamino-4-arylamino-5-acetyl-2-phenylpyrimidines, which upon refluxing in benzene with dimethylformamide dimethylacetal are converted to 4-alkylamino-8-aryl-2-phenylpyrido[2,3-d]pyrimidin-5(8H)-ones. The cyclization proceeds selectively with participation of the arylamino group only, the alkylamino group being not involved. At the same time, refluxing of 5-acetyl-4,6-dibenzylamino-2-phenylpyrimidine with dimethylformamide dimethylacetal in toluene affords the product of condensation on the acetyl group, which upon refluxing in o-xylene transforms to 4-benzylamino-8-benzyl-2-phenylpyrido[2,3-d]pyrimidin-5(8H)-one.

3-Nitro-2-phenyl-2-(trifluoromethyl)-2H-chromenes in reaction with N-methylazomethine ylide: stereoselective synthesis of 3a,4,4-trisubstituted chromeno[3,4-c]pyrrolidines

1,3-Dipolar cycloaddition of unstabilized azomethine ylide obtained in situ from sarcosine and paraform occurred stereoselectively at the double bond of 3-nitro-2-phenyl-2-(trifluoromethyl)-2H-chromenes activated by the presence of nitro group. The synthetic procedure required refluxing in benzene for 2 h and gave chromeno[3,4-c]pyrrolidines with trans configuration of trifluoromethyl group and nitro group as the major products. The structure of the obtained products was confirmed by X-ray structural analysis.

ChemInform Abstract: Synthesis of 4‐Aryl‐6‐methyl‐7a‐(trifluoromethyl)‐2,4a,5,6,7,7a‐hexahydropyrano [2,3‐c]pyrrol‐2‐ones from 4‐Aryl‐6‐(trifluoromethyl)‐2‐pyrones, Sarcosine, and Formaldehyde.

4-Aryl-6-(trifluoromethyl)-2-pyrones reacted with the nonstabilized azomethine ylide obtained from sarcosine and formaldehyde under reflux in benzene for 6 h, resulting in [3+2] cycloaddition that gave 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano-[2,3-c]pyrrol-2-ones in 42–56% yields. In the case of 4-aryl-3-carbethoxy-6-(trifluoromethyl)-2-pyrones, besides the respective pyrano-[2,3-c]pyrrolidines (66–71% yields) also 4-aryl-1-methyl-2-(trifluoromethyl)pyrroles were isolated as minor products.

SYNTHESIS OF 4-ARYL-6-METHYL-7a-(TRIFLUOROMETHYL)-2,4a,5,6,7,7a-HEXAHYDROPYRANO[2,3- c ]PYRROL-2-ONES FROM 4-ARYL-6-(TRIFLUOROMETHYL)-2-PYRONES, SARCOSINE, AND FORMALDEHYDE

4-Aryl-6-(trifluoromethyl)-2-pyrones reacted with the nonstabilized azomethine ylide obtained from sarcosine and formaldehyde under reflux in benzene for 6 h, resulting in [3+2] cycloaddition that gave 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano[2,3- c ]pyrrol-2-ones in 42–56% yields. In the case of 4-aryl-3-carbethoxy-6-(trifluoromethyl)-2-pyrones, besides the respective pyrano-[2,3-c]pyrrolidines (66–71% yields) also 4-aryl-1-methyl-2-(trifluoromethyl)pyrroles were isolated as minor products. How to Cite Usachev, S. A.; Popova, N. V.; Moshkin, V. S.; Sosnovskikh, V. Ya. Chem. Heterocycl. Compd. 201 5 , 51 , 913. [ Khim. Geterotsikl. Soedin. 2015 , 51 , 913.] For this article in the English edition see DOI 10.1007/s10593-015-1795-1

Synthesis of 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano[2,3-c]pyrrol-2-ones from 4-aryl-6-(trifluoromethyl)-2-pyrones, sarcosine, and formaldehyde

4-Aryl-6-(trifluoromethyl)-2-pyrones reacted with the nonstabilized azomethine ylide obtained from sarcosine and formaldehyde under reflux in benzene for 6 h, resulting in [3+2] cycloaddition that gave 4-aryl-6-methyl-7a-(trifluoromethyl)-2,4a,5,6,7,7a-hexahydropyrano-[2,3-c]pyrrol-2-ones in 42–56% yields. In the case of 4-aryl-3-carbethoxy-6-(trifluoromethyl)-2-pyrones, besides the respective pyrano-[2,3-c]pyrrolidines (66–71% yields) also 4-aryl-1-methyl-2-(trifluoromethyl)pyrroles were isolated as minor products.

Trans,trans,trans-[ReO2I2(PPh3)2], a rare rhenium(VI) complex — Synthesis and DFT study

The heating of cis-[ReO2I(PPh3)2] at reflux in benzene in air led to the isolation of the rhenium(VI) complex [ReO2I2(PPh3)2] (1). The compound is centrosymmetric around the octahedrally coordinated rhenium center, and the ReO bond length of 1.797(2) Å is longer than in typical trans-dioxorhenium(V) complexes. The asymmetric ReO stretching frequency occurs at 744cm−1. Density functional theory has been used for the calculation of the vibrational spectrum density which confirms the experimental asymmetric ReO stretching frequency. DFT calculation within the polarizable continuum model shows that complex 1 is more stable in CH2Cl2 than in the gas phase. EPR spectroscopy confirms a single d electron in 1. The crystal structure was determined by X-ray single crystal diffraction. In addition, infra-red, redox and electronic properties are also reported.

Synthesis of 12-vertex mixed ligand closo-cobaltacarborane complexes and molecular structure of [3,3-(Ph2P(CH2)2PPh2)-3-Cl-closo-3,1,2-CoC2B9H11

A reaction of complexes CoCl2(dppe) (dppe is the 1,2-bis(diphenylphosphino)ethane) or CoCl2(dppp) (dppp is the 1,3-bis(diphenylphosphino)propane) with [K][7,8-nido-C2B9H12] upon reflux in benzene led to the mixed ligand closo-cobaltacarboranes [3,3-(Ph2P(CH2)nPPh2)-3-Cl-closo-3,1,2-CoIIIC2B9H11] (n = 2 and 3, respectively) in moderate yields (34 and 16%). The structure of the 18-electron complexes in solution and the solid state was studied by NMR and IR spectroscopy, the structure in the case of the closo-complex with dppe-ligand was confirmed by X-ray crystallography.

Synthesis and characterization of mixed-ligand ferracarboranes. Direct metalation of the nido-carborane [nido-7,8-C2B9H12]− mono-anion with 14-e [Ph2P(CH2)nPPh2]FeCl2 (n = 2, 3)

The heating of a mixture of 14-e [Ph2P(CH2)nPPh2]FeCl2 (n = 3 or 2) with the [K]+ salt of the [nido-7,8-C2B9H12]− mono-anion under gentle reflux in benzene affords either the paramagnetic (17-electron) complex [3,3-(dppp)-3-Cl-closo-3,1,2-FeC2B9H11] isolated in 15% yield or a mixture of the paramagnetic complex [3,3-(dppe)-3-Cl-closo-3,1,2-FeC2B9H11] (46% yield) and the diamagnetic complex [commo-8,8′-μ-(Ph2PCH2CH2PPh2)-3,3′-Fe{1,2-C2B9H10}2] (10% yield). All three novel ferracarboranes were characterized by spectroscopic (EPR or NMR) data and single-crystal X-ray diffraction.

On the Unique Reactivity of Pd(OAc)2 with Organic Azides: Expedient Synthesis of Nitriles and Imines

On the Unique Reactivity of Pd(OAc)₂ with Organic Azides: Expedient Synthesis of Nitriles and Imines

Synthesis, structure, and electronic study of some group VII furoyl substituted complexes

The reaction of fulvene 1 with TlOEt in THF affords [Tl{1,2-C 5H 3(COC 4H 3O) 2}] ( 2) in 60% yield. Treatment of 2 with [MBr(CO) 5] (M = Mn, Re) in benzene reflux gave [Mn{η 5-1,2-C 5H 3(COC 4H 3O) 2}(CO) 3] ( 3A) and [Re{η 5-1,2-C 5H 3(COC 4H 3O) 2}(CO) 3] ( 3B) in 61% and 66% yields, respectively. Diacyl complexes 3A and 3B were ring-closed to the pyridazine by treating with hydrazine hydrate in methanol at room temperature. Fulvene 1 and diacyl complexes 3A and 3B have been structurally characterized by X-ray crystallography. Additionally, the electronic structure of complexes 3A and 3B and their relaxed structures have been characterized with density functional calculations. Calculated vibrational frequencies are compared with the experimental characterizations.

Stoichiometric aryl nitrile formation from amides and aroyl isocyanates using high-valent early transition metal complexes and a catalytic process from the aroyl isocyanates

Reaction of PhCONH 2 with [WCl 6] under reflux in benzene gives a near quantitative yield of [WOCl 4(NCPh)] ( 1) which can be prepared directly by the reaction of PhCN and [WOCl 4]. PhCONH 2 reacts with [WOCl 4] under reflux in benzene to give [WO 2Cl 2(NCPh)] ( 2) and with [NbCl 5] under similar conditions to give [NbOCl 3(NCPh)] ( 3). PhCONH 2 and TiCl 4 give [TiCl 4(NH 2COPh) 2] ( 4). Reaction of the aroyl isocyanate PhCONCO with [WOCl 4] gave [WOCl 4(NCPh)] ( 1) and 4-Me 3CPhCONCO and [WOCl 4] gave [WOCl 4(NCPhCMe 3-4)] ( 5). PhCONCO reacts catalytically with [WOCl 4] or [WOCl 4(NCPh)] to give quantitative yields of PhCN. Similarly, 4-Me 3CPhCONCO and 2-ClCPhCONCO react catalytically with [WOCl 4] to give complete conversion to 4-Me 3CPhCN and 2-ClCPhCN. DFT studies show structures and intermediates in support of a possible catalytic mechanism. This involves initial complexation followed by formation of a metallocycle from the W O bond and the C N bond of the isocyanate. Rearrangement and elimination of CO 2 leads to an amidate complex that undergoes C–O bond scission and O migration to the W atom to give PhCN bound to the WOCl 4 moiety in a cis arrangement. This complex is unstable with respect to dissociation which completes the catalytic cycle. The overall reaction WOCl 4 + PhC(O)NCO → WOCl 4·PhCN + CO 2 is exothermic (Δ H = −20.7 kJ mol −1) and is favoured from free energy considerations (Δ G = −69.3 kJ mol −1).

Synthesis and spectroscopic characterization of tris( O, O′-ditolyl dithiophosphato) arsenic/antimony/bismuth(III) compounds: Crystal structures of [As{S 2P(OC 6H 4Me- m) 2} 3]·0.5C 6H 14, [Sb{S 2P(OC 6H 4Me- m) 2} 3] and [Bi{S 2P(OC 6H 4Me- m) 2} 3

Arsenic(III), antimony(III) and bismuth(III) compounds of the type, [M{S 2P(OR) 2} 3] (where M = As, Sb and Bi; R = o-, m-, p-C 6H 4Me) were obtained by reactions of MCl 3 with ammonium salts of the corresponding O, O′-ditolyl dithiophosphate on refluxing in benzene. These compounds were characterized by elemental analysis, IR, 1H NMR and 31P NMR spectroscopy. The single crystal X-ray structures of three representative compounds were determined. [As{S 2P(OC 6H 4Me- m) 2} 3]·0.5C 6H 14 crystallizes as triclinic in the space group P 1 ¯ with a = 10.9396(1), b = 14.1891(2), c = 17.5359(2) Å, α = 70.731(1), β = 84.734(1), γ = 74.205(1)° , Z = 4, V = 2472.37(5) Å 3. [Sb{S 2P(OC 6H 4Me- m) 2} 3] and [Bi{S 2P(OC 6H 4Me- m) 2} 3] both crystallize as monoclinic in the space group P2 1 with a = 12.4520(3), b = 22.8760(5), c = 16.2165(4) Å, β = 93.022(1)°, Z = 4, V = 4612.9(2) Å 3 and with a = 12.4903(2), b = 22.9554(4), c = 16.1032(3) Å, β = 92.4300(10)°, Z = 4, V = 4612.96(14) Å 3, respectively. In all three molecules, the central metal atom is surrounded by all six sulfur atoms of the three chelating anisobidentate O, O′-ditolyl dithiophosphate groups in a pseudo trigonally distorted octahedron with a lone pair positioned on one of the triangular octahedral faces. The three metal sulfur bonds adjacent to the lone pair (capped face) are longer than the three furthest from the lone pair (uncapped face). Inter-ligand angles between the longer bonds are greater than those between the shorter bonds.

Synthesis of novel ketoconazole derivatives as inhibitors of the human Pregnane X Receptor (PXR; NR1I2; also termed SXR, PAR)

PXR, pregnane X receptor, in its activated state, is a validated target for controlling certain drug–drug interactions in humans. In this context, there is a paucity of inhibitors directed toward activated PXR. Using prior observations with ketoconazole as a PXR inhibitor, the target compound 3 was synthesized from (s)-glycidol with overall 56% yield. (+)-Glycidol was reacted with 4-bromophenol and potassium carbonate in DMF to yield the ring opened compound 6. This was then heated to reflux in benzene along with 2′, 4′-difluoroacetophenone and catalytic amount of para-toluene sulfonic acid to yield 8. The resultant acetal 8 was then functionalized using Palladium chemistry to yield the target compound 3. The activity of the compound was compared with ketoconazole and UCL2158H. However, in contrast with ketoconazole (IC 50 ∼ 0.020 μM; ∼100% inhibition), 3 has negligible effects on inhibition of microsomal CYP450 (maximum ∼20% inhibition) at concentrations >40 μM. In vitro, micromolar concentration of ketoconazole is toxic to passaged human cell lines, while 3 does not exhibit cytotoxicity up to concentrations ∼100 μM (viability >85%). This is the first demonstration of a chemical analog of a PXR inhibitor that retains activity against activated PXR. Furthermore, in contrast with ketoconazole, 3 is less toxic in human cell lines and has negligible CYP450 activity.

The preparation and structural elucidation of uranium (VI) complexes and salts of the phosphorus ylides Ph 3PCHCOPh, Ph 3PC(COMe)(COPh) and Ph 3PCHCOOCH 2CH 3

The reaction in methanol of the phosphorus ylides Ph 3PCHCOPh, benzoylmethylenetriphenylphosphorane (BPPY), and Ph 3PC(COMe)(COPh), α-acetyl-α-benzoylmethylenetriphenylphosphorane (ABPPY) with UO 2(NO 3) 2 · 6H 2O at 273 K leads to the formation of O-coordinated bis(ylide)-uranium (VI) complexes of the type [UO 2(ylide) 2(NO 3) 2], whereas the reaction of BPPY and UO 2(NO 3) 2 · 6H 2O under reflux in benzene yields the salt [ H - BPPY ] 2 + [ U 2 O 4 ( NO 3 ) 4 ( OH ) 2 ] 2 - . The reaction of Ph 3PCHCOOCH 2CH 3, carbethoxymethylenetriphenylphosphorane (EPPY) with UO 2(CH 3COO) 2 · 2H 2O produces the salt [H-EPPY] +[UO 2(CH 3COO) 3] −. The structures of the free ylides ABPPY and EPPY are also discussed.

Some Stability and Stereochemical Considerations of Simple Bicyclo[4.2.0]octanols

Bicyclooctanols 3 and 4 were formed with control of the stereochemistry at C8 by using an aluminium enolate of cyclohexanone in 1,2-dimethoxyethane. Bicyclooctanols 1 and 3 were stable towards aqueous hydrochloric acid for short times (< 3.5 h), and ring open to a diastereomeric mix of monoalkylated 5 under protic or aprotic conditions in the presence of base (NaOH or lithium diisopropylamide). The rate of ring opening appears to be dependent on reaction temperature. Bicyclooctanols 1, 3, and 4 displayed remarkable stability when heated at reflux in benzene, whereas use of ethanol prompted stereoselective ring opening of 1 and 3 to give individual diastereomers of monoalkylated 5 and ring opening of 4 to give a 50 : 50 mix of diastereomers of 5. This unexpected result was attributed to the stereochemistry of the bicyclooctanol and placement of hydrogen-bonding sites.

A water‐dispersible conducting nanocomposite from suspension polymerisation of thiophene in presence of N‐vinylcarbazole

AbstractThe polymerisation of a mixture of thiophene and N‐vinylcarbazole was achieved in aqueous suspension in the presence of nanodimensional alumina and FeCl3 as oxidant. The resultant composite was found to contain both polythiophene (PTP) and poly(N‐vinylcarbazole) (PNVC) components even after reflux in benzene, which would remove any PNVC homopolymer. The presence of the individual polymer components was endorsed by FTIR spectroscopic analyses. Thermogravimetric analyses showed that the overall stabilities of the composite and the corresponding homopolymers were in the order: PTP–Al2O3 > PTP > PTP–PNVC–Al2O3 > PNVC. Differential thermal analyses studies showed the manifestation of two different exotherms corresponding to the presence of two different polymeric constituents in the PTP–PNVC–Al2O3 composite. Differential scanning calorimetry studies revealed two glass‐transition temperatures (Tg) suggesting the presence of two polymeric moieties in the PTP–PNVC composite. Scanning electron micrographs of the PTP–Al2O3 and PTP–PNVC–Al2O3 composites showed distinctive morphological patterns. Transmission electron microscopic images of the composite revealed that the average particle size varied between 20 and 80 nm. DC conductivities of the composites were of the order of 10−6 S cm−1. Copyright © 2003 Society of Chemical Industry

Novel access to cyclohexane-1,4-diones and 1,4-hydroquinones via radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones using cobaloxime-mediated electroreduction or tributyltin hydride

A new preparative access to synthetically useful cyclohexane-1,4-diones 2 and their oxidized analogues, hydroquinones 3 , with the option of introducing alkyl and aryl substituents, was developed by radical 1,2-acyl rearrangement on 2-(halomethyl)cyclopentane-1,3-diones 1 , accessible from 1,2-bis(trimethylsiloxy)cyclobutene and α-bromo ketone dimethyl acetals. The electroreduction of monoacetals of 1 in the presence of cobaloxime as a catalyst afforded the cyclohexane-1,4-dione monoacetals in good yields. The Bu 3SnH-reduction of 2-aryl 1 under refluxing in benzene effected the rearrangement, affording 2 , and when the reaction was prolonged, aromatization to 3 proceeded in moderate yields.

Electronic effects in migratory groups. [1,4]-versus[1,2]-rearrangement in rhodium carbenoid generated bicyclic oxonium ylides.

The variety of alpha-diazo beta-keto esters (3a-f, 8a-f) with varying substituents (ED/EW) on the phenyl ring of the O-benzyl group were prepared. The rhodium(II) acetate catalyzed decomposition of diazo compounds in benzene reflux conditions. The ratio of 1,4 versus 1,2 migration product was determined. It was found that an increase in electron density on the benzylic carbon of the migrating group prefers 1,4 migration products (4, 9) while a decrease in electron density leads to a preponderance of 1,2 migration products (5, 10). The results obtained were correlated to the mechanistic aspect of the product selectivity. The intermediacy of the intramolecular oxonium ylide formation was demonstrated by crossover experiments. The preference for the formation of 2,3 sigmatropic rearrangement product over 1,2 and 1,4 was demonstrated by performing the reaction with alpha-diazo beta-keto esters (13a, 13b) with O-allyl and O-propargyl at C3. The effect of solvent, temperature, and mole percentage of rhodium(II) acetate was also studied.

Formation of Novel Tetradentate Phosphine Ligand o-C6H4(PPhCH2CH2PPh2)2 by Coupling of Two Diphosphine Ligands Bound to Low-Valent Mo or W Center. Synthesis and Structure of [M{o-C6H4(PPhCH2CH2PPh2)2}(Ph2PCH2CH2PPh2)] (M = Mo, W)

Abstract A mixture of trans-[M(N2)2(dppe)2] (M = Mo or W; dppe = Ph2PCH2CH2PPh2) and dppe was heated to reflux in benzene or toluene to give the M(0) complex [M(P4)(dppe)], which contains the novel tetradentate phosphine o-C6H4(PPhCH2CH2PPhg2)2 (P4) arising from the coupling of two dppe ligands. The reaction of [Mo(P4)(dppe)] with CO afforded the carbonyl complex [Mo(CO)2(P4)].