Synthesis and characterization of novel alkyl-substituted aryl diphenylphosphinate esters

Article abstract of DOI:10.1080/10426507.2010.521472

In this work, the reactions of diphenylphosphinic chloride, (C ₆H₅)₂P(O)Cl, 1, with the sodium salts of sterically hindered phenol derivatives (2a-2j) were investigated. Novel alkyl-substituted aryl diphenyl phosphinate es

Full text of DOI:10.1080/10426507.2010.521472

Phosphorus, Sulfur, and Silicon, 186:1531–1537, 2011
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426507.2010.521472
SYNTHESIS AND CHARACTERIZATION OF NOVEL
ALKYL-SUBSTITUTED ARYL DIPHENYLPHOSPHINATE
ESTERS
Saliha Begec¸,1 Su¨meyya Alatas¸,1 and Adem Kılıc¸2
1Department of Chemistry, Science and Arts Faculty, Inonu University,
Malatya, Turkey
2Department of Chemistry, Gebze Institute of Technology, Gebze, Kocaeli, Turkey
GRAPHICAL ABSTRACT
Abstract In this work, the reactions of diphenylphosphinic chloride, (C6H5)2P(O)Cl, 1, with
the sodium salts of sterically hindered phenol derivatives (2a-2j) were investigated. Novel
alkyl-substituted aryl diphenyl phosphinate esters (C6H5)2P(O)OAr (3-12) were obtained from
these reactions. Satisfactory analytical and spectroscopic results were obtained for all the new
compounds.
Keywords Diphenylphosphinic chloride; phenol; phosphinic acid esters; phosphinate
INTRODUCTION
Organophosphorus compounds are an economically important class of chemical com-
pounds. These compounds have found a wide range of applications in the areas of industrial,
agricultural, and medicinal chemistry due to their biological and physical properties as well
as their utility as synthetic intermediates.1 Certain organophosphorus compounds are widely
used as pesticides, antimicrobicides, or antitumor active substances.2–7
Phosphinic acid derivatives are also used in protecting metal surfaces against cor-
rosion,8 to improve the performance of high-temperature greases,9 and for flame resis-
tance.10–12 These derivatives are important and intensively studied compounds.13–33
In this study, sterically hindered phenols have been selected as nucleophiles. Sterically
hindered phenols are widely used for the preparation of stable phenoxyl radicals and are of
Received 30 April 2010; accepted 31 August 2010.
We thank the Ino¨nu¨ University Research Fund for partial financial support (Project No: 2008/49).
Address correspondence to Saliha Begec¸, Department of Chemistry, Science and Arts Faculty, Inonu Uni-
versity, Malatya 44280, Turkey. E-mail: sbegec@inonu.edu.tr
1531

1532
S. BEGEC¸ ET AL.
interest as biologically active compounds.24,25 Steric properties of the substituents also play
a major role in determining the biological activity of these chemicals.26 In particular, phos-
phorus derivatives of 2,6-di-tert-butyl-4-methylphenol are effective antioxidants. They are
capable of inhibiting lipid peroxidation and lower the oxidative stress of the organism. Here
we report on the synthesis of sterically hindered phenol esters 3-12 of diphenylphosphinic
acid. It is anticipated that products 3-12 should show important biological activities.
RESULTS AND DISCUSSION
All compounds 3-12 were synthesized as described in the Experimental section.
Diphenylphosphinic chloride 1 was reacted in a 1:1 molar ratio with the sodium salts of
phenol derivatives 2a-j in tetrahydrofuran (THF). Aryl diphenylphosphinate compounds
3-12 were obtained from these reactions (see Scheme 1).
O
P
O
P
Na / THF
RT
Ph
O
Ph
Cl
HO
R
R
Ph
Ph
1
2a-2j
R
3-12
Mp oC
Yield %
Product
2,4-dimethyl
3
4
5
6
7
8
40
38
28
87-88
3,4-dimethyl
2,6-dimethyl
2,4,6-trimethyl
119-120
124-125
76-77
32
52
43
28
32
4-tert-butyl
168-170
138-139
4-tert-butyl-2-methyl
2-tert-butyl-4-methyl
2-tert-butyl-6-methyl
125-126
9
10
76-77
2,6-di-tert-butyl-4-methyl
2,4,6-tri-tert-butyl
24
37
149-150
11
12
196-198
Scheme 1 Synthesis and some properties of aryl diphenylphosphinate esters 3–12.
Products 3-12 were isolated from the reaction mixtures by column chromatography.
In all cases, the yields ranged from 52 to 24%. Using diethylether as a solvent instead of
THF resulted in significantly lower (from 27 to 9%) yields of products. Because the nature
of the reagents and the solvent affect the yield, the steric hindrance also plays an important
role in such reactions.
Compounds 3-12 were obtained as white crystals and are stable in air and moisture.
1
The structures of compounds 3-12 were determined initially by H-, 13C-, and 31P-NMR
spectroscopy, elemental analyses, and infrared spectroscopy. They were also characterized
by gas chromatography–mass spectrometry (GC-MS). The structures of compounds 3-12
are consistent with the analytical and spectroscopic data (see Experimental section and
Table 1). The composition of all compounds was confirmed by elemental analysis.

ALKYL-SUBSTITUTED ARYL DIPHENYLPHOSPHINATE ESTERS
1533
Table 1 1H-, 13C-, and 31P-NMR spectroscopic data (δ ppm, CDCl3) for compounds 3-12
31P
13C
1H
3
4
29.9
147.4 (d, JPC = 8.3 Hz), 133.9, 132.4, 130.5,
128.7 (d, JPC = 6.2 Hz), 127.4, 119.9 (d, JPC
3.6 Hz), 20.6, 16.8
2.23 (s, 3H, 4-CH3), 2.28 (s, 3H, 2-CH3),
7.28–7.94 (m, 10H, arom H),
6.73–6.96 (m, 3H, ArO H)
2.16 (s, 3H, 4-CH3), 2.18 (s, 3H, 3-CH3),
7.43–7.95 (m, 10H, arom H);
6.89–6.99 (m, 3H, ArO H)
=
30.1
29.5
148.8 (d, JPC = 8.3 Hz), 138.1, 132.3 (d, JPC
2.8), 131.9 (d, JPC = 10.3 Hz), 130.4 (d, JPC
4.5 Hz), 128.6 (d, JPC = 2.84), 121.8 (d, JPC
4.7 Hz), 117.7 (d, JPC = 4.8 Hz), 19.9, 19.0
=
=
=
5
6
148.3 (d, JPC = 9.8 Hz), 133.1, 132.3 (d, JPC
=
2.05 (s, 6H, 2,6-CH3), 7.45–7.95 (m, 10H,
arom H), 6.93–6.98 (m, 3H, ArO H)
2.8 Hz), 131.7 (d, JPC = 10.3), 131.3, 130.7 (d,
JPC = 2.83 Hz), 129.1 (d, JPC = 1.51 Hz),
128.6 (d, JPC = 7.2 Hz), 124.8 (d, JPC = 1.64
Hz), 18.2
30.0
146.0 (d, JPC = 9.8 Hz), 134.2 (d, JPC = 1.9 Hz),
2.00 (s, 6H, 2,6-CH3), 2.22 (s, 3H,
4-CH3), 7.47–7.94 (m, 10H, Ar-H),
6.78 (s, 3H, ArO H)
133.1, 132.3 (d, JPC = 2.8 Hz), 131.7 (d, JPC
10.3 Hz), 130.3 (d, JPC = 2.9 Hz), 129.7 (d,
=
JPC = 1.6 Hz), 128.6 (d, JPC = 13.4 Hz), 20.6,
18.1
7
8
9
30.3
29.8
29.5
148.5 (d, JPC = 8.3 Hz), 147.4, 132.4 (d, JPC
=
2.00 (s, 6H, 2,6-CH3), 2.22 (s, 3H,
4-CH3), 7.47–7.94 (m, 10H, arom H),
6.78 (s, 3H, ArO H)
2.9 Hz), 132.2, 131.9 (d, JPC = 10.4 Hz),
130.4, 128.7 (d, JPC = 13.4 Hz), 126.5, 120.1
(d, JPC = 4.7 Hz), 34.3, 31.4
147.1 (d, JPC = 0.8 Hz), 132.6, 132.4 (d, JPC
=
1.26 (s, 9H, 4-But), 2.33 (s, 3H, 2-CH3),
7.88–7.96 (m, 10H, arom H),
7.01–7.68 (m, 3H, ArO H)
2.8 Hz), 131.8 (d, JPC = 10.4 Hz), 128.7 (d,
JPC = 13.4 Hz), 123.8, 119.5 (d, JPC = 3.6
Hz), 34.2, 31.4, 17.2
148.5 (d, JPC = 8.4 Hz), 138.8 (d, JPC = 6.8 Hz),
1.49 (s, 9H, 2-But), 2.36 (s, 3H, 4-CH3),
6.84–7.46 (m, 3H, arom H)
132.9, 132.3, 132.4 (d, JPC = 2.9 Hz), 131.8
(d, JPC = 10.5 Hz), 130.6, 128.6 (d, JPC
=
13.5 Hz), 127.4, 119.8 (d, JPC = 5.2 Hz), 34.5,
30.0, 20.9
10
28.2
149.6 (d, JPC = 11.0 Hz), 141.4 (d, JPC
=
1.19 (s, 9H, 2-C(CH3)3), 2.15 (s, 3H,
6-CH3), 7.93–8.00 (m, 10H, arom H),
6.98–7.57 (m, 3H, ArO H)
4.7 Hz), 134.6, 132.7, 132.0 (d, JPC = 2.8 Hz),
131.6 (d, JPC = 10.2 Hz), 128.6 (d, JPC = 10.0
Hz), 125.6, 124.3 (d, JPC = 0.7 Hz), 34.7, 30.5,
21.2
11
12
29.9
31.9
142.8 (d, JPC = 3.6 Hz), 141.7, (d, JPC = 9.4 Hz),
132.5 (d, JPC = 10.0 Hz), 132.1 (d, JPC = 3.0
Hz), 130.1, 128.3 (d, JPC = 13.3 Hz), 36.8,
33.1, 21.0
145.2 (d, JPC = 1.9 Hz), 142.1 (d, JPC = 3.4 Hz),
141.9 (d, JPC = 9.3 Hz), 132.4 (d, JPC = 10.1
Hz), 132.1 (d, JPC = 2.8 Hz), 130.1, 128.2 (d,
JPC = 13.3 Hz), 124.3 (d, JPC = 2.0 Hz), 37.0,
34.4, 33.1, 31.5
1.19 (s, 18H, 2,6-But), 2.31 (s, 3H,
4-CH3); 7.28–7.63 (m, 10H, arom H),
7.00 (s, 2H, ArO H)
1.22 (s, 18H, 2,6-C(CH3)3), 1.33 (s, 9H,
4-C(CH3)3), 7.36–7.57 (m, 10H,
arom H); 7.20 (s, 2H, ArO H)
The characteristic bands in the infrared (IR) spectra of the phosphinates were assigned
and are provided in the Experimental section. The P O stretching vibrations of 3-12
between 1223 and 1238 cm−1 are characteristic of phosphinates. In the Fourier transform
infrared (FTIR) spectra of compounds 3-12, P Ph and P O Ph stretching bands are
observed between 1436–1440 and 1168–1238 cm−1, respectively. These data are in good
agreement with the literature.21,27–31 In the FTIR spectra of compounds 3-12, CH(aryl)

1534
S. BEGEC¸ ET AL.
and CH(aliphatic) stretching bands are observed between 3049–3437 and 2903–2984 cm−1
respectively.
,
The nuclear magnetic resonance (NMR) data for 3-12 are presented in the Exper-
1
imental section. The H-NMR spectral data of 3-12 are consistent with the structures
proposed. The methyl protons resonate at δ = 2.28 (2-CH3), 2.23 (4-CH3) (in a 1:1 ratio),
2.18 (3-CH3), 2.16 (4-CH3) (in a 1:1 ratio), and 2.05 (2,6-di-CH3) for compounds 3, 4, and
5, respectively. The methyl protons resonate at δ = 2.00 (2,6-di-CH3) and 2.22 (4-CH3) (in
a 2:1 ratio) in the case of compound 6. Signals are observed at δ = 1.26 (4-But) for 7; at
δ = 1.26 (4-But) and 2.33 (2-CH3) for 8; at δ = 1.49 (2-But) and 2.36 (4-CH3) for 9; at
δ = 1.19 (2-But) and 2.15 (6-CH3) for 10; at δ = 1.19 (2,6-di-But) and 2.22 (4-CH3) for 11;
and at δ = 1.22 (2,6-di-But) and 1.33 (4-But) for 12. These data are in good agreement with
the literature.32–34 The protons of the aromatic moiety of compounds 3-12 show multiplets
in the range of 6.84–7.97 ppm.
All compounds exhibited only a single absorption peak in the 31P-NMR spectrum
between 28.2 and 31.9 ppm, characteristic of phosphinate phosphorus.35–39 The 31P-NMR
signal appears at 29.9 for 3, 30.1 for 4, 29.5 for 5, 30.0 for 6, 30.3 for 7, 29.8 for 8, 29.5
for 9, 28.2 for 10, 29.9 for 11, and 31.9 for 12.
Compounds 3-12 were also characterized by GC-MS. In the GC-MS spectra of
compounds 3-10 the molecular ion peaks (M+) could be observed, except for compounds
11 and 12. In these cases only the important fragments at m/z 363 and 391 corresponding
to the loss of [(CH3)3] for 11 and [(CH3)3) + CH3] for 12 could be detected.
CONCLUSION
In this study, we described the synthesis of the substituted phenyl diphenylphosphinate
derivatives 3–12. Equimolar quantities of the corresponding sodium phenoxide derivatives
and diphenylphosphinic chloride were stirred together overnight at an ambient temperature
using THF as a solvent. Novel aryl diphenyl phosphinates 3–12 were successfully prepared.
EXPERIMENTAL
All synthetic steps were carried out under an inert atmosphere of N2 or Ar in pre-dried
glassware by using Schlenk techniques.40 THF was distilled over a sodium/potassium alloy
in the presence of benzophenone under a dry argon atmosphere. Starting materials were
commercially available and used without further purification. Reactions were monitored by
using silica gel 60 F254 precoated thin-layer chromatography (TLC) plates (Kieselgel 60,
0.25 mm thickness) and separating conditions were determined. The separation of products
was carried out by column chromatography using silica gel (Kieselgel 60, 230–400 mesh;
for 3 g crude mixture, 100 g silica gel was used in a column of 3 cm in diameter and 60 cm
in length).
The purity of compounds 3–12 was checked by TLC and characterized by elemental
analysis; 1H-, 13C-, 31P-NMR; and FTIR spectroscopy. Microanalysis was carried out with
a LECO 932 CHNS-O apparatus. Melting points were measured in open capillary tubes
with an Electrothermal-9200 melting point apparatus and are uncorrected. IR spectra were
recorded with an ATI Unicam Mattson 1000 FTIR spectrophotometer in KBr disks and are
reported in cm−1 units. 1H-, 13C-, and 31P-NMR spectra were recorded using a Bruker DPX-
300 spectrometer operating at 300.13 MHz (1H), 75.47 MHz (13C), and 121.49 MHz (31P).

ALKYL-SUBSTITUTED ARYL DIPHENYLPHOSPHINATE ESTERS
1535
Chemical shifts (δ) are given in ppm relative to tetramethylsilane (TMS). All data were
1
recorded for solutions in CDCl3. The H- and 13C-NMR chemical shifts were measured
using SiMe4 (δ = 0) as an internal standard, and the 31P chemical shifts were measured
using 85% H3PO4 as an external standard. Mass spectra were recorded with a Shimadzu
GCMS-QP2010 gas chromatograph spectrometer.
Aryl Diphenylphosphinate Esters (3-12): General Procedure
To a solution of the respective phenol (4.23 mmol) in THF (15 mL) at 20 ◦C during 0.5
h, small pieces of Na (0.25 g, 12 mmol) were slowly added with vigorous stirring, and argon
was passed over the reaction mixture. The excess of Na was removed by filtration and the
solution of the sodium phenoxide was cooled and then frozen with a liquid nitrogen–acetone
mixture. To this mixture (C6H5)2P(O)Cl 1 (4.23 mmol) in 10 mL of THF was slowly added
and the resulting mixture was allowed to come to an ambient temperature with constant
stirring. After the mixture was vigorously stirred (48 h) at room temperature, the precipitated
salt (NaCl) was filtered and the solvent was removed under reduced pressure. The resulting
white solid was subjected to column chromatography. The residue was chromatographed
on silica gel: 100 g (eluent: acetone/n-hexane 1:2 [for 3-10]; ethylacetate/n-hexane 1:3 [for
11 and 12]).
2,4-Dimethylphenoxy Diphenylphosphinoxide (3). White crystals; yield:
0.54 g (40%); m.p. 87–88 ◦C. (Rf = 0.324 acetone/n-hexane 1:2). IR (KBr): υ(CH
aryl) 3274–3059, υ(CH alkyl) 2962–2924, υ(P O) 1233, υ(P Ph) 1438, υ(P O Ph)
1197 cm−1; MS m/z (%): 322 (M+, 100). Anal. Calcd. for C20H19PO2: C, 74.60; H, 5.90.
Found: C, 74.47; H, 6.01%.
3,4-Dimethylphenoxy Diphenylphosphinoxide (4). White crystals; yield:
◦
0.51 g (38%); m.p. 119–120 C. (Rf = 0.459 acetone/n-hexane 1:2). IR (KBr): υ(CH
aryl) 3437–3054, υ(CH alkyl) 2984–2919, υ(P O) 1225, υ(P Ph) 1438, υ(P O Ph)
1192 cm−1; MS m/z (%): 322 (M+, 100). Anal. Calcd. for C20H19PO2: C, 74.60; H, 5.90.
Found: C, 74.49; H, 5.98%.
2,6-Dimethylphenoxy Diphenylphosphinoxide (5). White crystals; yield:
◦
0.38 g (28%); m.p. 124–125 C. (Rf = 0.540 acetone/n-hexane 1:2). IR (KBr): υ(CH
aryl) 3436–3057, υ(CH alkyl) 2953–2920, υ(P O) 1234, υ(P Ph) 1437, υ(P O Ph)
1168 cm−1; MS m/z (%): 322 (M+, 100). Anal. Calcd. for C20H19PO2: C, 74.60; H, 5.90.
Found: C, 74.72; H, 5.86%.
2,4,6-Trimethylphenoxy Diphenylphosphinoxide (6). White crystals; yield:
0.45 g (32%); m.p. 76–77 ◦C. (Rf = 0.388 acetone/n-hexane 1:2). IR (KBr): υ(CH
aryl) 3276–3058, υ(CH alkyl) 2961–2922, υ(P O) 1235, υ(P Ph) 1438, υ(P O Ph)
1193 cm−1; MS m/z (%): 336 (M+, 100). Anal. Calcd. for C21H21PO2: C, 75.04; H 6.52.
Found: C, 75.28; H, 6.76%.
4-tert-Butylphenoxy Diphenylphosphinoxide (7). White crystals; yield:
◦
0.76 g (52%); m.p. 168–170 C. (Rf = 0.516 acetone/n-hexane 1:2). IR (KBr): υ(CH
aryl) 3435–3057, υ(CH alkyl) 2960–2903, υ(P O) 1228, υ(P Ph) 1440, υ(P O Ph)
1176 cm−1; MS m/z (%): 350 (M+, 50), 335 (100). Anal. Calcd. for C22H23PO2: C, 75.49;
H, 6.57. Found: C, 75.47; H 6.78%.
4-tert-Butyl-2-methyl-phenoxy Diphenylphosphinoxide (8). White solid;
yield: 0.66 g (43%); m.p. 138–139 ◦C. (Rf = 0.441 acetone/n-hexane 1:2). IR (KBr,): υ(CH
aryl) 3435–3057, υ(CH alkyl) 2959–2903, υ(P O) 1223, υ(P Ph) 1439, υ(P O Ph)

1536
S. BEGEC¸ ET AL.
1188 cm−1; MS m/z (%): 364 (M+, 55), 349 (100). Anal. Calcd. for C23H25PO2: C, 75.52;
H, 6.86. Found: C, 75.42; H, 6.68%.
2-tert-Butyl-4-methypheno◦xy Diphenylphosphinoxide (9). White solid;
yield: 0.43 g (28%); m.p. 125–126 C. (Rf = 0.388 acetone/n-hexane 1:2). IR (KBr):
υ(CH aryl) 3435, υ(CH alkyl) 2950–2920, υ(P O) 1237, υ(P Ph) 1439, υ(P O Ph)
1204 cm−1; MS m/z (%): 364 (M+, 70), 349 (100). Anal. Calcd. for C22H23PO2: C, 72.52;
H, 6.86. Found: C, 75.02; H, 6.92%.
2-tert-Butyl-6-methylphenoxy Diphenylphosphinoxide (10). White crys-
tals; yield: 0.49 g (32%); m.p. 122–123 ◦C. (Rf = 0.388 acetone/n-hexane 1:2). IR (KBr):
υ(CH aryl) 3436–3055, υ(CH alkyl) 2962, υ(P O) 1238, υ(P Ph) 1439, υ(P O Ph)
1204 cm−1; MS m/z (%): 364 (M+, 60), 201 (100). Anal. Calcd. for C23H25PO2: C, 75.83;
H, 6.86. Found: C, 75.92; H, 6.98%.
2,6-Di-tert-butyl-4-methylphenoxy Diphenylphosphinoxide (11). White
◦
crystals; yield: 0.42 g (24%); m.p. 149–150 C. (Rf = 0.472 acetone/n-hexane 1:2). IR
(KBr): υ(CH aryl) 3436–3049, υ(CH alkyl) 2954–2907, υ(P O) 1228, υ(P Ph) 1436,
υ(P O Ph) 1196 cm−1; MS m/z (%): 363 [(M C(CH3)3)+, 100]. Anal. Calcd. for
C27H33PO2: C, 77.19; H, 7.86. Found: C, 76.99; H, 7.69%.
2,4,6-Tri-tert-butylphenoxy Diphenylphosphinoxide (12). White crystals;
yield: 0.71 g (37%); m.p. 196–198 ◦C. (Rf = 0.538 ethyl acetate/n-hexane 1:2). IR
(KBr): υ(CH aryl) 3436–3057, υ(CH alkyl) 2956–2903, υ(P O) 1235, υ(P Ph) 1438,
υ(P O Ph) 1197 cm−1; MS m/z (%): 391 [(M CH3)3 + CH3) 20], 201 (100). Anal.
Calcd. for C30H39PO2: C, 77.97; H, 8.44. Found: C, 77.03; H, 8.48%.
REFERENCES
1. Abou-Donia, M. B. Organophosphorus Pesticides. In: L. W. Chang and R. S. Dyer (Eds.),
Handbook of Neurotoxicology; Marcel Deccer, New York, 1994, pp. 419–447.
2. Yuan, C. Y.; Qi, Y. M. Synthesis 1988, 472–474.
3. Fest, C. K.; Schmidt, J. The Chemistry of Organophosphorus Pesticides, 2nd ed.; Springer:
Berlin, 1982.
4. Van Wager, J. R. Miscellaneous Phosphorus Applications—Phosphorus and Its Compounds;
Interscience: New York, 1961.
5. Schrader, G. Die Entwicklung Neuer Insektizider Phosphorsanreester, 3rd ed.; Verlag Chemie:
Weinheim, Germany, 1963.
6. Arnold, H.; Bourseaux, F.; Brock, N. Arzneim.-Forsch. 1961, 11, 143–158.
7. Friedman, O. M.; Bager, E.; Gublianskar, V.; Sommer, H. J. Med. Chem. 1963, 6, 50–58.
8. Zimmer, H.; Sill, A. Prog. Drug Res. 1964, 5, 1150.
9. Horner, L.; Roettger, F. Korrosion, 1963, 16, 57–71; Chem. Abstr. 1964, 61.
10. Gillman, H. D. U.S. Patent Application 946 265; Chem. Abstr. 1979, 91, 1238706.
11. Alco´n, M. J.; Ribera, G.; Galia`, M.; Ca´diz, V. Polymer 2003, 44, 7291–7298.
12. Maiti, S.; Banejee, S.; Palit, S. K. Prog. Polym. Sci. 1993, 18, 227–261.
13. Makhaeva, G. F.; Fomicheva, S. B.; Zhuravleva, L. V.; Yarkevich, A. N.; Kharitono, A. V.;
Malygin, V. V. Pharm. Chem. J. 2001, 35, 190–192.
ˇ
14. Kubicˇek, V.; Rehoˇr, I.; Havl´ıcˇkova´, J.; Kotek, J.; C´ısaˇrova´, I.; Hermann, P.; Lukesˇ, I. Eur. J.
Inorg. Chem. 2007, 24, 3881–3891.
15. Hoz, S.; Dunn, E. J.; Buncel, E.; Bannard, R. A. B.; Purdon, J. G. Phosphorus, Sulfur Silicon
Relat. Elem. 1985, 24, 321–326.
16. Dunn, E. J.; Bunsel, E. Can. J. Chem. 1989, 67, 1440–1448.

ALKYL-SUBSTITUTED ARYL DIPHENYLPHOSPHINATE ESTERS
1537
17. Dunn, E. J.; Moir, R. Y.; Buncel, E.; Purdon, J. G.; Bannard, R. A. B. Can. J. Chem. 1990, 68,
1837–1845.
18. Um, I. H.; Akhtar, K.; Shin, Y. H.; Han, J. Y. J. Org. Chem. 2007, 72, 3823–3829.
19. Onyido, I.; Albright K.; Buncel, E. Org. Biomol. Chem. 2005, 3, 1468–1475.
20. Douglas, K. T.; Williams, A. J. Chem. Soc. Perkin Trans. 2 1976, 515–521.
21. Quick J. E.; Venezky, D. L. J. Chem. Eng. Data 1970, 15, 377–378.
22. Haake, P.; Hurst, G. J. Am. Chem. Soc. 1966, 88, 2544–2550.
23. Douglas, K. T.; Williams, A. J. Chem. Soc. Perkin Trans. 2, 1975, 1010–1016.
24. Nonhebel, D. C.; Tedder, J. M.; Walton, J. C. Radicals; Cambridge University Press: Cambridge,
1979.
25. Denisov, E. Handbook of Antioxidants; CRC Press: Boca Raton, FL, 1995.
26. Abou-Donia, M. B. Arch. Environ. Health 2003, 58, 484–497.
27. Faghihi, K.; Hagibeygi, M. Turk. J. Chem. 2007, 31, 65–73.
28. Faghihi, K. J. Appl. Polym. Sci. 2006, 102, 5062–5071.
29. Lıu, Y.; Hsıue, G.; Lan, C.; Chıu, Y. J. Polym. Sci., Polym. Chem. 1997, 35, 1769–1780.
30. Lıu, Y.; Lıu, Y.; Jeng, R. J.; Chıu, Y. J. Polym. Sci., Polym. Chem. 2001, 39, 1716–1725.
31. Berlin, K. D.; Pagılagan, R. U. Chem. Commun. 1966, 19, 687–689.
32. Begec¸, S., Kılıc¸, A. Heteroatom Chem. 2005, 16, 308–310.
33. Begec¸, S. Heteroatom Chem. 2007, 18, 372–375.
34. Kılıc¸, A.; Begec¸, S.; C¸ etinkaya, B.; Hokelek, T.; Kilic, Z.; Gunduz, N.; Yildiz, M. Heteroatom
Chem. 1996, 7, 249–256.
35. Kingsley, S.; Vij, A.; Chandrasekhar, V. Inorg. Chem. 2001, 40, 6057–6060.
36. Kingsley, S.; Chandrasekhar, V.; Incarvito, C. D.; Lam, M. K.; Rheingold, A. Inorg. Chem. 2001,
40, 5890–5896.
37. Dunn, E. J.; Purdon, J. G.; Bannard, R. A. B.; Albright, K.; Buncel, E. Can. J. Chem. 1988, 66,
3137–3142.
38. Beletskaya, I. P.; Karlstedt, N. B.; Nifant’ev, E. E.; Khodarev, D. V.; Kukhareva, T. S.; Nikolaev,
A. V.; Ross, A. J. Russ. J. Org. Chem. 2006, 42, 1780–1785.
39. Ashkenazi, N.; Karton, Y.; Segall, Y. Tetrahedron Lett. 2004, 45, 8003–8006.
40. Shriver, F.; Drezdzon, M. A. The Manipulation of Air Sensitive Compounds, 2nd ed.; Wiley-
Intersience: New York, 1986.

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