3-(5-(2.4-dichlorophyenyl)-4.5-dihydro-1 H-pyrazol-3-yl)-4hydroxy-1-methylquinolin(1 H)-one, 5-((4-hydroxy-8-methyl-2-oxo-1.2-dihydroquinolin-3-yl)methylene)-1-phenyl-2-hioxodihydropyrimidine-4.6(1 H.5 H)-dione, and 1-butyl-4-hydroxy-3-(5-styryl-4.5-dihydro-1 H-pyrazol-3yl)quinolin-2(1 H)-one were synthesized and characterized by spectroscopy analysis. These compounds are designated I, II and III, respectively. The antioxidants efficiency of the synthesized compounds in lubricating greases had been investigated using ASTM d-942 and ASTM d-664. The obtained data showed that the total acid number and oxygen pressure drop of these compounds in lubricating greases decrease in the order: Comp.III. < Comp.I. < Comp.II. The antioxidant efficiency of the prepared quinolinones derivatives was discussed. Acceptable correlations were obtained between the obtained oxidation inhibition and the calculated quantum chemical parameters.
Oxidative stability and consistency of the grease matrix control a wide variety of performance properties in grease lubrication [
This fact motivates us to study the relationship between the structure of 4-hydroxy- quinoline with various substituents and its antioxidant effect against free-radical-in- itiated peroxidation.
The 4-hydroxyquinoline-3-carboxylic acid ester with the S-alkyl subsistent was invented by Stharfeldt et al. [
2,2,4-trialkyl-1,2-dihydroquinoline and other compounds as lubricant antioxidants were invented by Cyril A. Migdal [
Recently, antioxidant publications contain substantial chemical calculations [
The aim of this paper is a study on the preparation of three 4-hydroxy quinolinone derivatives. The ultimate objective was to explore the efficiency of these derivatives as antioxidant additives to the prepared lubricating grease. Also, the correlation between quantum chemical calculations for the quinolone compounds and their oxidation stability data was investigated.
3-(5-(2,4-dichlorophenyl)-4,5-dihydro-1H-pyrazol-3-yl)-4-hydroxy-1-methylquinolin-2(1H)-one was prepared in the following steps.
Step 1
A mixture of 3-acetyl-4-hydroxy-N-methyl-2 (1H) quinoline (0.01 mol), 2-4-dichlorobenzal (0.01 mol) and one drop of pipridine was heated on a boiling water bath for 4 hr. The reaction mixture was triturated with ethanol and the solid so obtained was filtered off, washed with diethyl ether and crystallized from acetic.
Step 2
To a solution of the compound a (0.01 mol) in DMF (10 cm3) hydrazine hydrate (0.01 mol) was added. The reaction mixture was refluxed for 5 h, then cooled and poured into water; the solid that deposited was filtered off and crystallized from DMF (Scheme 1).
2-hydrazono-5-((4-hydroxy-8-methyl-2-oxo-1,2-dihydroquinolin-3yl) methylene)-1-ph- enyldihydropyrimidine-4,6(1H.5H)-dione (II). It was prepared by a mixture of pyrimidinethione (0.01 mol) and hydrazine hydrate (0.01 mol) in absolute ethanol (20 cm3) and then the mixture was refluxed for 4 h. The solid product that obtained was filtered off and crystallized from DMF: (Scheme 2).
1-butyl-4-hydroxy-3-95-styryl-4,5-dihydro-1H-pyrazol-3-yl)quinoline-2(1H) (Scheme 3).
Scheme 1. Synthesis of Compound I.
Scheme 2. Synthesis of Compound II.
Scheme 3. Synthesis of Compound III.
Using the same method as for preparation of 1, 4, we used cinnamaldehyde with the some acetyl instead of thiophene-2-carboxaldehyde to produce III.
All melting points for the prepared compounds were determined using Gallenkamp electric melting point apparatus. The compounds I, II and III were identified and confirmed by microanalysis of carbon, hydrogen, oxygen and nitrogen. The IR spectra were recorded on Perkin-Elmer infrared spectrophotometer model 157, Grating. Also, the 1H NMR spectra were recorded on a Varian Spectrophotometer at 200 MHz using TMS as an internal reference and DMSO-das solvent. The mass spectra (EI) were recorded on 70 ev with Kratos MS equipment and/or a Varian MAT 311 Spectrometer.
The prepared grease under investigation was prepared, according to the procedure previously described [
The micro analysis of carbon, hydrogen, nitrogen and oxygen of prepared compound I, II and III are shown in
Ingredient, wt% | G1 blank | G2 | G3 | G4 |
---|---|---|---|---|
Base oil, | 80 | 80 | 80 | 80 |
12-Hydroxy stearic acid, | 15 | 15 | 15 | 15 |
LiOH | 3.0 | 3.0 | 3.0 | 3.0 |
Compound I | 0 | 0.3 | 0 | 0 |
Compound II | 0 | 0 | 0.3 | 0 |
Compound III | 0 | 0 | 0 | 0.3 |
Comp.no. | Chemical analysis Calc/found | |||
---|---|---|---|---|
C, % | H, % | N, % | O, % | |
I | 58.73/58.78 | 3.86/3.89 | 10.82/10.82 | 8.24/8.24 |
II | 62.53/62.53 | 4.22/4.25 | 17.38/17.36 | 15.88/15.86 |
III | 74.32/74.39 | 6.45/6.50 | 10.84/10.84 | 8.26/8.26 |
Comp.no. | M.P., ˚C | MW | solvent | Yield, % | Mol. Formula. |
---|---|---|---|---|---|
I | 310 | 387 | DMF | 80 | C19 H15 Cl2 N3 O2 |
II | 290 | 403 | DMF | 85 | C21 H17 N5 O4 |
III | 220 | 387 | acetic | 87 | C24 H25 N3 O2 |
Compound | Spectral data |
---|---|
I | IR (KBr), ν max :Cm-1 3200 ν (N-H), 2920ν(C-H ali), 2600 ν(H-bonded OH), 1645 ν (C=O) 1HNMR, S(ppm) 3.44(S,3H,CH3), 3.80(S,2H,CH2 pyratozole), 7 - 8.11 (m,7H,Ar-, 9.13(S,1H,N-H), 12.5(bs,1H,OH). |
II | IR (KBr), ν max :Cm-1 3340, 3310, 3180 ν(NH2,NH), 2500 ν(H-bonded OH), 1635 - 1660 ν(C=O) 1HNMR,S(ppm) 2.12 (s,3H,CH3), 5.98 (bs,2H,NH2), 6.88 - 792 (m,9H,olefinic H and Ar-H), 8.00 (s,1H,N-H quinolinone), 11.24 (s,1H,NH), 13.20 (bs,1H,OH). |
III | IR (KBr), ν max :Cm-1 3190 ν(N-H), 2900-2820 ν (C-H ali), 2500 ν (H-bonded OH), 1635(C=O) 1HNMR,S(ppm) 3.50 (s,2H,CH2,pyrazole), 3.97 (t,2H,N-CH2), 0.9 - 1.60 (m,7H,CH2CH2CH3), 6.19 - 656 (2H,alefinic H), 724 - 811 (m,9H,Ar-H), 9.13 (s,1H,N-H) 13.2 (bs,1H,OH). |
Ingredient | G1 blank | G2 | G3 | G4 | Test method |
---|---|---|---|---|---|
Penetration Un worked worked | 280 295 | 278 290 | 279 292 | 276 287 | ASTM D-217 |
Dropping point, ˚C | 174 | 177 | 175 | 179 | ASTM D-566 |
Copper Corrosion 3 h/100˚C | Ia | Ia | Ia | Ia | ASTM D-4048 |
Oxidation Stability 99 ± 96 h, pressure drop, Kpa | 35 | 30 | 32 | 25 | ASTM D-942 |
TAN, mg KOH/gm @ 72 h | 1.89 | 1.63 | 1.72 | 1.5 | ASTM D-664 |
Oil Separation, Wt% | 2.3 | 2.1 | 2.2 | 2.0 | ASTM D-1724 |
Code grease according to NLGI | 2 | 2 | 2 | 2 | |
Egyptian standard | LB | LB | LB | LB | |
Apparent Viscosity, cP, @60˚C | 39,680 | 40,126 | 40,058 | 40580 | ASTM D-189 |
Consistency Index | 6200 | 6400 | 6470 | 6500 | ASTM D- 189 |
Yield stress, D/cm2 | 67.5 | 70.5 | 69.5 | 71.3 | ASTM D-189 |
dients that’s needed to prepare obtained greases (G1, G2, G3 and G4) is a good selection.
The prepared compounds ( I, II and III) were evaluated as antioxidants for lubricating greases using ASTM D-942 and ASTM d 664 to determine the oxygen pressure drop and total acid number, respectively (
Comparison of the antioxidant activity of the compounds I, II and III reveals the following order Comp. III. < Comp. I < Comp. II. This indicates that the oxidation inhibition efficiency is dependent on the structure of the quinolinone compound. It appears, therefore, that the introduction of hydroxyl group with butyl group in quinolinones (compound III) leads to increasing the efficiency of inhibiting the oxidation chain reactions.
Quantum chemical calculations were performed to investigate the relationships between the molecular structure of the prepared compounds and their oxidation stabilities. Quantitative structure activity relationship (QSAR) has been performed on the activity of antioxidants [
The full geometry-optimized structures with Mulliken charges of three prepared quinolone derivatives are shown in Figures 3-8. Also, the theoretical value of the prepared compounds was tabulated in
E HOMO (the highest occupied molecular orbital) and E LUMO (the lowest unoccupied molecular orbital) values were calculated. The charges representative atoms and other relevant quantum parameters were listed in
the molecules and the electric/orbital density distributions of HOMO and LUMO illustrated in Figures 3-8. Mulliken population analysis is mostly used for the calculation of the charge distribution in a molecule. These numerical quantities are easy to obtain and they provide at least a qualitative understanding of the structure and reactivity of molecules [
Highest occupied molecular orbital energy (E HOMO) and lowest unoccupied molecular orbital energy ( E LUMO ) are very popular quantum chemical parameters. These orbitals, also called the frontier orbitals, determine the way the molecule interacts with other species.
The HOMO is the orbital that could act as an electron donor, since it is the outermost (highest energy) orbital containing electrons. The LUMO is the orbital that could act as the electron acceptor, since it is the innermost (lowest energy) orbital that has room to accept electrons. According to the frontier molecular orbital theory, the formation of a transition state is due to an interaction between the frontier orbitals (HOMO and LUMO) of reactants [
From
Gaussian 05 (HF/3-21G) | |||
---|---|---|---|
Compounds | E HOMO | E LUMO | ΔE |
I | −0.26631 | −0.22724 | 0.03907 |
II | −0.29445 | −0.21467 | 0.7978 |
III | −0.21113 | −0.18597 | 0.02516 |
1) There may be concluded that, the optimum structure for the maximum efficiency of the 4-hydroxy quinolinones derivatives as antioxidants requires the following items:
a) The presence of butyl group (donating group) and hydroxyl group in quinolone to give compounds III. Such structure stabilized radical resulting from the oxidation reactions, therefore inhibiting the deterioration of the lithium lubricating grease G4.
b) The presence of hydroxyl group and imide group in quinolone to give compounds II. It also inhibits the deterioration of the lithium lubricating grease G3.
c) The Presence of extensive conjugation through the 4-hydroxy quinolinones derivatives (I, II, and III).
2) The obtained quantum chemical calculations using Gaussian model showed good agreement with experimental data.
Hussein, M.F., Ismail, M.A. and El-Adly, R.A. (2016) Synthesis and Evaluation of 4-Hydroxy Quinolinone Derivatives as Antioxidants of Lubricating Grease. International Journal of Organic Chemistry, 6, 207-219. http://dx.doi.org/10.4236/ijoc.2016.64021