Synthesis of Symmetric Diketones from Imidazolinium Salt and Bis-Grignard Reagents

The reaction of 2-substituted imidazolinium salt with bis-Grignard reagents is reported and a new method for the synthesis of symmetric diketones from carboxylic acids and bis-Grignard reagents is provided.

Characterization of Reaction of Primary Amine WithDiketones in Aqueous Solution

In this study,the interaction between primary amine and diketones was investigated.Three diketones with a general structure of—(CH2C(O)CH2C(O))-X-R(X is C,O or N and R is H and/or alkyl groups)were selected to react with primary amine in aqueous solutions.The reaction was in-situ monitored by Raman technique and the reaction products were identified by FTIR,NMR and LC-MS.It is found that the reaction products strongly depend on the structures of diketones.When X is nitrogen,the expected Schiff base or its analog can be obtained.However,Schiff base or its analog is not detected if X is C or O,instead,ion pairs or hydrolysis products are formed accordingly,suggesting critical impacts of acidity of CH2 inβ-diketone on the product formation.This study also shows that in-situ Raman is a powerful technique for reaction monitoring and structure characterization,which is useful for mechanism understanding.

Stereoselective synthesis of cis- and trans-4-acyl-β-lactams from vicinal diketones and ketoaldehydes

4-Acyl-β-lactams are important synthetic intermediates in both pharmaceutical and organic chemistry. Cis- and trans-4-acyl-β- lactams were synthesized stereoselectively from vicinal diketones via the formation of bulky and less bulky diimines as key intermediates, respectively. The diimines reacted with acyl chloride in the presence of triethylamine to give rise to the corre- sponding 4-imino-β-lactams, which were further hydrolyzed to afford 4-acyl-β-lactams. The cis- and trans selectivity is de- pended on the steric hindrance of the imine N-substituents. A series of cis-4-acyl-β-lactams were synthesized from vicinal ketoaldehydes via the formation of their monoimines and diimines as intermediates. Pyruvic aldehyde produced cis-4-acetyl-β- lactams and cis-4-formyl-β-lactams, respectively, through the reactions of its monoimine and diimine with acyl chlorides. Phenylglyoxal generated cis-4-benzoyl-β-lactams via its monoaldimine.

Catalyst-free Multicomponent Synthesis of β-Mercapto Diketones in Water

A simple, efficient and eco-friendly route has been developed for the synthesis of fl-mercapto diketones via a multicomponent reaction of an aldehyde, acetylacetone and thiol in water. This methodology affords a number of β-mercapto diketone derivatives in moderate to good yields.

Synthesis,luminescent properties,and theoretical study of novel Sm^(3+) and Dy^(3+) complexes containing β-diketone and 1,10-phenanthroline

Two new ternary complexes of 1-（2-thienyl）-3-（p-phenylethynylphenyl）-1,3-propanedione（HTPP） and 1,10-phenanthroline（phen） with Sm^3＋ and Dy^3＋ were synthesized.The composition of the ternary complexes was characterized as Sm（TPP）3phen and Dy（TPP）3phen,respectively,by infrared（IR） spectra,chemical analysis,elemental analysis,and thermodynamic analysis.At room temperature,under UV light excitation,the Sm^3＋ and Dy^3＋ complexes exhibit characteristic emissions of the central ions.It is found that the fluorescence intensity of Sm（TPP）3phen is stronger than that of Dy（TPP）3phen.In order to explain this phenomenon,an accurate quantum chemistry calculation was carried out,and the result is in good agreement with the experiment data.

Baker's Yeast Mediated Reduction of Optically Active Diketone

Baker's Yeast mediated reduction of optically active diketone has been described.

Synthesis and Crystal Structure of 1, 5-Bis( 1'-phenyl-3'-methyl- 5'-pyrazolone- 4') -1- ( 4'-aminobutand-1'-imino) -5-pentaneone

The title compound of PhCH_3C_3HN_2 (O )C (O) (CH_2) _3C [N (CH_2 )_4 NH_2]C_3HN_2 (O)CH_3Ph (L), a new Schiff-base containing diketone, has been synthesized. Its crystal structure has been determined by X-ray diffraction analysis. The crystal, C_(30)H_(41)N_6O_(5.5) (L·0. 5C_2H_5OH·2H_2O) , is triclinic, space group P1 ,a=11.544 (1) , b=11. 723(5) , c=12. 344(2) A , a=80. 61(2) . β=84. 17(1) ,γ=78. 80(2)°.V=1612. 6(9) A￣3, M_r=1147. 40, Z=2, D_x= 1. 18 g/cm￣3 . μ=0. 77 cm-1, F(000) = 614. The final agreement factor R=0. 079 for 1828 independent reflections with I≥ 3σ(I) considered to be observed. L contains three functional groups:β-diketone,β-ketoimine(Schiff-base) and NH_2. The β-diketone group has partially delocalized. The pyrazoline plane is not coplanar with its connected phenyl plane. The big πbond is not extended between these planes. There are one ethanol and four water molecules in the crystal. Intermolecular hydrogen bonds may exist between C=O and H_2O. NH_2 and H_2O, H_2O and EtOH, or H_2O and H_2O.

Synthesis of Lanthanide β-Diketonates by Solid State Reaction at Low Heating Temperature

Solid state reactions between β diketones (HPMBP, HDBM) and LnAc 3· x H 2O(La,Nd: x =3/2;Tb: x =4) have been investigated at low heating temperature. Pure compounds of Ln(PMBP) 3 and Ln(DBM) 3 are obtained by solid state reaction, and characterized by elemental analysis, infrared radiation (IR),X ray diffraction (XRD) and photoacoustic spectra. The solid state reaction properties of β diketones and their influences on the structures of products are discussed.

Synthesis, Structure and Photo- luminescence of Cu[(PPh_3)_2](acac) (PPh_3 = Triphenylphosphine, acac = Acetylacetone)

A novel complex Cu（PPh3）2（acac） 1 （PPh3 = triphenylphosphine, acac = acetylacetone） was obtained by a solution reaction and structurally characterized by X-ray diffraction. The crystal belongs to monoclinic, space group P21/n with a = 13.7361（8）, b = 12.8204（7）, c = 19.7638（13）A, β = 95.946（2）^o, C41H37CuO2P2, Mr= 687.19, V = 3461.7（4）A3, Z = 4, Dc = 1.319 g/cm^3, S = 1.067,μ（MoKa） = 0.758 mm^-l, F（000） = 1432, R = 0.0403 and wR = 0.0990. Complex 1 is characterized by an isolated structure. X-ray structure analysis of I shows that acac behaves as a chelating ligand and PPh3 coordinates as a monodentate ligand to the Cu（I） atoms. Photoluminescent investigation reveals that the title complex displays a strong green-light emission.

SYNTHESIS AND CHARACTERISTICS OF POLY(ARYLENE ETHER DIKETONE)S

Poly(arylene ether diketone)s were prepared by the aromatic nucleophilic displacement reaction of 4,4'-difluorobenzil with different bisphenols in the presence of anhydrous potassium carbonate in diphenylsulfone at elevated temperature. The polymers obtained had inherent viscosity of 0.51 similar to 0.63 dL/g, and exhibited glass transition temperature ranging from 136 similar to 217 degrees C mainly depending on the bisphenols used in the polymer synthesis. Thermogravimetry of these polymers showed excellent thermal stability, indicating that 10% weight losses of the polymers were observed in the range above 428 degrees C and 438 degrees C in air and nitrogen, respectively. The mechanical properties of these polymers were also described and the permeability of five polymers for H-2, O-2 and N-2 was determined at 30 degrees C.

Chemo- and regioselective hydroboration of Δ^(14,15) in certain cephalostatin analogue

The symmetrical diketone Ⅱ, which can be synthesized in gram scale using a well established method, was used as a starting material to prepare the 11α-methoxy ketomethylene Ⅵ. This is in continuation of our study aiming at the synthesis of multihydroxylated cephalostatin analogues, as for example cephalostatin 1Ⅰ, a potent anti-tumor natural product. Compound Ⅵ underwent chemo- and regioselective hydroboration reaction at only one of △14.15 double bonds furnishing compound Ⅸ as a major product in a fair yield.

Effects of Ligands in Novel Non-titanocene on Syndiotactic Polymerization of Styrene

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Combination of diketone and PAO to achieve macroscale oil-based superlubricity at relative high contact pressures

1-(4-ethylphenyl)-nonane-1,3-dione(0206)is an oil-soluble liquid molecule with rod-like structure.In this study,the chelate(0206-Fe)with octahedral structure was prepared by the reaction of ferric chloride and 1,3-diketone.The experimental results show that when using 0206 and a mixed solution containing 60%0206-Fe and 40%0206(0206-Fe(60%))as lubricants of the steel friction pairs,superlubricity can be achieved(0.007,0.006).But their wear scar diameters(WSD)were very large(532µm,370µm),which resulted in the pressure of only 44.3 and 61.8 MPa in the contact areas of the friction pairs.When 0206-Fe(60%)was mixed with PAO6,it was found that the friction coefficient(COF)decreased with increase of 0206-Fe(60%)in the solution.When the ratio of 0206-Fe(60%)to PAO6 was 8:2(PAO6(20%)),it exhibited better comprehensive tribological properties(232.3 MPa).Subsequent studies have shown that reducing the viscosity of the base oil in the mixed solution helped to reduce COF and increased WSD.Considering the COF,contact pressure,and running-in time,it was found that the mixed lubricant(Oil3(20%))prepared by the base oil with a viscosity of 19.7 mPa·s(Oil3)and 0206-Fe(60%)exhibited the best tribological properties(0.007,161.4 MPa,3,100 s).

Study on the tribological properties of metal rolling bearing under lubrication with diketone lubricants

In this article, 1-(4-ethylphenyl)-nonane-1,3-dione(0206) was prepared by Claisen condensation. By mixing 0206, chelate, and base oil in a ratio of 3.2:4.8:2, a diketone lubricant(PAO=14(20%)) that can achieve superlubricity was prepared and applied to bearing lubrication experiments. The experimental results show that when the bearing was lubricated by base oil, the friction coefficient(COF) and temperature rise decreased with the decrease of the viscosity of PAO. When PAO=14(20%) was used as the lubricant, the COF of the bearing was the lowest(0.001), and the wear morphology was comparable to that of the bearing lubricated with commercial lubricant. Compared with the base oil with the same viscosity, it is found that the COF and temperature rise of the bearing lubricated by PAO=14(20%) were lower under any experimental conditions. And when the amount of lubricant added was 10 μL, the COF of the bearing lubricated by PAO=14(20%) reached a very low value(0.0004).Bearing ball surface analysis identified the formation of diketone adsorption films. Combined with the previous PAO=14(20%)superlubricity mechanism, it was considered that the occurrence of tribochemical reaction and the bearing effect of chelates were the main reasons for the existence of ultra-low friction coefficient and low wear. In addition, when there were polar molecules in the lubricant, they were adsorbed on the metal surface through tribochemical reactions, resulting in many irregular pits on the surface.

How to improve superlubricity performance of diketone at steel interface:Effects of oxygen gas

Achievement of steady and reliable super-low friction at the steel/steel contact interface,one of the most tribological systems applied for mechanical moving parts,is of importance for prolonging machine lifetime and reducing energy consumption.Here we reported that the superlubricity performance of the steel/steel sliding interface lubricated with tiny amounts of diketone solution strongly depends on the oxygen content in surrounding environment.The increase of oxygen not only significantly shortens the initial running-in time but also further reduces the stable coefficient of friction in superlubricity stage due to the enhancement of tribochemical reactions.On the one hand,more severe oxidation wear occurring at higher oxygen content facilitates material removal of the contact interface,lowering the contact pressure and the corresponding initial friction.On the other hand,the growth of iron ions during the shear process in high oxygen environment promotes the formation of chelate which acted as an effective lubricated film chemisorbed at the steel/steel friction interface to further lower the interfacial friction.The results provide a new opportunity to further optimize the tribological performance of diketone superlubricity system,especially towards the lubrication of mechanical engineering materials.

Study on synthesis of lanthanide chelates of (l)-α- trifluoromethyl-polyfluoroalkyl-β-diketone and their application as chiral shift reagents

The lanthanide chelates of(l)-2,2-dimethyl-6-trifluoromethyl-7-oxa-6,8,8,9,9,10, 10,10-octafluoro-3,5-decanedione,Ln[(l)-CF_3CF_2CF_2OCF(CF_3)COCHCOC(CH_3)_3]_3(l-3a,Ln=Eu; 3b, Ln=Pr), are useful as ~1H NMR shift reagents for direct determination of enantiomeric composition of enantiomorphous alcohols. ketones and amines. With these substrates. l-3a induces shift difference similar to that induced by Eu(facam)_3 and Eu(hfbc)_3. However, due to the higher solubility of the chelates l-3a and l-3b in nonpolar organic solvent such as CHCl_3, CCl_4 and only one ~1H signal from l-3a and l-3b is observed. their application as the new chiral shift reagents seems promising. The spectral nonequivalence is also observed for dimethylsulfoxide in the presence of l-3a.