New phosphorus-containing quinone derivatives ii: Tri- and tetraphosphorylated quinone derivatives

Article abstract of DOI:10.1002/hc.21089

A new synthetic approach to aromatic diols substituted with two, three, and four (similar or different) phosphorus groups via the Michael-type addition of the P-H bond containing reagents to p-benzoquinone derivatives, reoxidation, and subsequent addition

Full text of DOI:10.1002/hc.21089

Heteroatom Chemistry
Volume 24, Number 4, 2013
New Phosphorus-Containing Quinone
Derivatives II: Tri- and Tetraphosphorylated
Quinone Derivatives
Patrick Mu¨ller,1 Olaf Fuhr,2 and Manfred Do¨ring3
1Institute of Catalysis Research and Technology, Karlsruhe Institute of Technology, 76344
Eggenstein-Leopoldshafen, Germany
2Institute of Nanotechnology, Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology,
76344 Eggenstein-Leopoldshafen, Germany
3Fraunhofer Institute for Structural Durability and System Reliability LBF, Division Plastics,
64289 Darmstadt, Germany
Received 5 December 2012; revised 7 March 2013
such, a great variety of recent studies focus on the
ABSTRACT: A new synthetic approach to aro-
phospha-Michael reaction [4–11]. Specifically, addi-
matic diols substituted with two, three, and four
tion reactions of phosphorus-containing compounds
(similar or different) phosphorus groups via the
to quinones have been investigated thoroughly
Michael-type addition of the P H bond containing
[12–14] as a result of the significance of quinone
reagents to p–benzoquinone derivatives, reoxidation,
derivatives as dyes and biologically active com-
and subsequent addition of another phosphorus
pounds [15]. Recently, phosphorus-carrying hydro-
unit is presented. A variety of new phosphorus-
quinones also gained importance as flame-retardant
containing
p–hydroquinone
derivatives
were
additives or comonomers for polymers, especially
epoxy resins and polyesters [16–23].
In general, the majority of phosphorus-
containing compounds react with, i.e. p-
ꢀC
synthesized and fully characterized. 2013 Wiley Pe-
riodicals, Inc. Heteroatom Chem. 24:252–262, 2013;
View this article online at wileyonlinelibrary.com.
DOI 10.1002/hc.21089
benzoquinone via/via
a Michael-type addition,
resulting in C-phosphorylated p-hydroquinone
derivatives, whereas some reagents also undergo
O-phosphorylation [12]. Phosphine- and phosphine
oxide-type compounds perform mono-C-addition
in most cases, with the exception of primary phos-
phines (H2P-R), which undergo a redox reaction
with p–benzoquinone, resulting in p–hydroquinone
and RPH-HPR [24]. Phosphite-type reagents
perform mono- and di–C- addition as well as
O-phosphorylation, depending on the conditions
[12]. As a special case, the formation of tetraphos-
phorylated quinone derivates was reported for the
reaction of chloranil with certain phosphites of
secondary alcohols [25] whereas in the case of
most phosphorus reagents chloranil undergoes
INTRODUCTION
The reaction behavior of phosphorus reagents to-
ward unsaturated systems has been thoroughly in-
vestigated throughout the past decades [1–4]. As
Correspondence to: Manfred Do¨ring; e-mail: manfred.
doering@lbf.fraunhofer.de.
Contract grant sponsor: German Research Foundation.
Contract grant numbers: DFG SCHA 730/10-1, DFG DO 453/6-1,
DFG AL 474/14-1; SCHA 730/11-1, DO 453/7-1, PO 575/11-1.
Supporting Information is available in the online issue at
www.wileyonlinelibrary.com.
ꢀC
2013 Wiley Periodicals, Inc.
252

New Phosphorus-Containing Quinone Derivatives II 253
SCHEME 1 Oxidation of monosubstituted phosphorus-containing p-hydroquinone derivatives DPhPO-HQ (1a), DOPO-HQ
(1b), DDPO-HQ (1c), and (PhO)2PO-HQ (1d) with activated MnO2. Compounds 2a, c, and d were not isolated as original
substances.
mono-C-phosphorylation [26] or O-phosphorylation
[27]. For phosphate-type compounds, no reaction
with p-benzoquinone takes place [13].
In summary, the existing work focuses on
quinones carrying one, two, or in rare cases four
similar phosphorus substituents.
RESULTS AND DISCUSSION
The p-hydroquinone derivatives DPhPO-HQ (1a),
DOPO-HQ (1b), DDPO-HQ (1c), and (PhO)2PO-BQ
(1d), monosubstituted with phosphorus groups of
different chemical environments regarding the phos-
phorus atom, all readily underwent oxidation as in-
dicated by the intense reddish colored solutions af-
ter a few minutes of treatment at room temperature
(Scheme 1). As different methods of oxidation, 1b
was treated with aqueous H2O2 and with tert-butyl
hydroperoxide in toluene [36], respectively. How-
ever, in both cases no reaction was observed after
24 h of treatment at room temperature.
While DOPO-BQ (2b) was obtained as a bright
orange solid as shown in our previous work [28],
DPhPO-BQ (2a), DDPO-BQ (2c), and (PhO)2PO-BQ
(2d) could not be isolated as original substances
due to their higher solubility (attempts to precipitate
them were not successful; also drying in melt could
not be attempted due to the limited thermal stability
of the p-benzoquinone derivates). Hence, secondary
products of the latter were prepared by process-
ing them in situ with a [P]-H reactant (Scheme 2).
Treatment of DPhPO-HQ (1a) with activated MnO2
and subsequent addition of diphenylphosphine ox-
ide yielded DPhPO-2-HQ (5a). A similar synthesis
for 5a using Ag2O as an oxidant is described in
[37] but could not be reproduced. X-Ray analy-
sis of 5a (Fig. 1) revealed the addition of the sec-
ond phosphorus group to take place in ortho po-
sition as was expected [28] (it should be noted
that the para-substituted isomer of 5a was recently
described by Howell and Carter via lithium diiso-
propylamide catalyzed rearrangement of the corre-
spondent O-phosphorylated p-hydroquinone deriva-
tive [38]). The synthesis of 5a was carried out in
three different solvents for comparison. While the
properties of the product did not alter, the yield was
In our previous study, we presented a novel syn-
thetic approach to twofold phosphorylated quinone
derivatives that is not limited to identical P-
units [28]. A phosphorus carrying p–benzoquinone
derivative was synthesized by oxidation of DOPO-
HQ, a common flame retardant [17, 18, 22, 23],
which is easily synthesized via the Michael-
type addition of p–benzoquinone and 6-oxido-6H-
dibenzo[c,e][1,2]oxaphosphinine (DOPO; a widely
used flame retardant by itself and building block
for advanced flame retardants [29–32]). Treat-
ment of DOPO-HQ with activated manganese diox-
ide, a quick and easy laboratory-scale procedure
known to oxidize a large variety of hydroxy com-
pounds to ketones [33], provided the correspon-
dent compound DOPO-BQ in good yield and
purity. Several new p–hydroquinone derivatives car-
rying two different phosphorus groups were syn-
thesized by addition of a second [P]-H reactant to
DOPO-BQ.
In this study, the concept described above
was at first applied to further starting materi-
als, as the addition products of p–benzoquinone
with diphenylphosphine oxide (DPhPO) [20, 23,
34], diphenyl phosphite, and 5,5-dimethyl-2-oxido-
1,3,2-dioxaphosphinan (DDPO; another phosphite-
type reactant) [21, 35]. Subsequently, the obtained
twofold phosphorylated quinone derivatives were
further processed in the same manner to open a
novel pathway to new tri- and tetraphosphorylated
quinone derivatives that is not limited to identical
P-units.
Heteroatom Chemistry DOI 10.1002/hc

254 Mu¨ller, Fuhr, and Do¨ring
SCHEME 2 Preparation of DPhPO-2-HQ (5a) and DPhPO-HQ-DOPO (6) from DPhPO-HQ (1a).
FIGURE 1 Structure of DPhPO-HQ (1a) and DPhPO-2-HQ (5a), validated by X-ray analysis (5a shown as one of two
conformations. Hydrogens are omitted except on heteroatoms for reasons of clarity). In compound 5a, one hydroxyl group
forms in intramolecular hydrogen bond with the neighboring P O unit, while 2 out of 4 phenyl units exhibit intramolecular
π–stacking.
significantly different: Although only 31% yield was
obtained processing the raw materials in toluene and
46% in chloroform, respectively, the reaction in 1,4-
dioxane gave 83% yield. This can be attributed to
the different polarities of the solvents and the sol-
ubility of the intermediate DPhPO-BQ (2a), respec-
tively (vs. the absorption of the latter to the activated
MnO2). Furthermore, DPhPO-HQ-DOPO (6) was ob-
tained exemplarily from DPhPO-HQ (1a) and DOPO
(Scheme 2), as already previously synthesized vice
versa from the isolated compound DOPO-BQ (2b)
and diphenylphosphine oxide [28]. Using the in situ
procedure, the yield of 6 was slightly lower (38%) as
compared to the two-step procedure (45% starting
from DOPO-HQ (1b)).
Compounds 5a and a variety of other twofold
phosphorylated p-hydroquinone derivates presented
in our previous work were investigated regard-
ing a new reoxidation with manganese dioxide
(Scheme 3). A brisk reaction after few minutes of
treatment with activated MnO2 was exhibited by
DPhPO-2-HQ (5a), DOPO-2-HQ (5b), and DDPO-2-
HQ (5c). DDPO-2-BQ (7c, X-ray structure in Fig. 2)
was obtained as a bright orange solid; the correspon-
dent compounds 7b and 7c could not be isolated as
original substances due to the aforementioned rea-
sons. For DPhPO-HQ-DOPO (6), DOPO-HQ-DDPO
(8), and DOPO-HQ-(PhO)2PO (9), no reaction with
manganese dioxide was observed, even after pro-
longed processing time (24 h at room temperature).
In summary, in all cases studied, all derivatives car-
rying two similar phosphorus groups (regardless
of their chemical environment) readily underwent
reoxidation whereas all compounds with different
phosphorus substituents did not. Besides, it is worth
mentioning that the P C bond in DDPO-2-BQ (7c)
is significantly longer than in the non-oxidized form
5c (Table 1).
Trifunctional phosphorus containing quinone
derivatives was synthesized from DDPO-2–BQ (7c).
The reaction of 7c with diphenylphosphine oxide
yielded DDPO-2-HQ-DPhPO (10; Scheme 4) as a
2,3,5-triphosphorylated p-hydroquinone derivative,
as was expected (see X-ray structure in Fig. 2). For
Heteroatom Chemistry DOI 10.1002/hc

New Phosphorus-Containing Quinone Derivatives II 255
SCHEME 3 Reaction behavior of several disubstituted phosphorus-containing p-hydroquinone derivates toward activated
manganese dioxide. The synthesis of 5b, 5c, 6, 8, and 9 was presented in our previous work [28]. Compounds 7a and 7b were
not isolated as original substances.
FIGURE 2 Structure of DDPO-2-BQ (7c) and DDPO-2-HQ-DPhPO (10), validated by X-ray analysis (hydrogens are omitted
except on heteroatoms for reasons of clarity. 7c shown as one of two conformations).
diphenyl phosphite, no similar product was formed
due to the limited reactivity of phosphite-type re-
actants; prolonged processing led to decomposi-
tion (according to 31P NMR). In the case of the
phosphinate-type [P]-H-reactant, DOPO, an addition
reaction with 7c took place, however, exhibited a
rather unexpected regiochemistry, yielding DDPO-2-
HQ-DOPO (11) as a 2,2,3-triphosphorylated quinone
derivative (Scheme 4). An explanation can be pro-
vided by consideration of the mesomeric struc-
tures for an ortho-diphosphorylated p-benzoquinone
derivative. As shown in Scheme 5, a negative charge
can be localized not only at the C O units, but at the
P O units as well, resembled by an additional me-
someric structure with a localized positive charge at
ortho-position. In the case of a monophosphorylated
derivative, the nucleophilic addition of a second [P]-
H unit therefore leads to 2,3-substituted derivatives
with a high selectivity, as evident from our previous
work [28]. In the case of an ortho-diphosphorylated
p-benzoquinone derivative, however, a localization
of a positive charge at the ortho position is much
less favored due to the second P O unit that is al-
ready deprived of electron density, especially in the
case of a phosphite-type substituent as in DDPO-2-
BQ (7c). Hence, in the reaction with a third [P]-H
compound, the selectivity toward the 2,2,3- and the
2,3,5-triphosphorylated product is more dependent
Heteroatom Chemistry DOI 10.1002/hc

256 Mu¨ller, Fuhr, and Do¨ring
TABLE 1 Lengths of P C and P O bonds between quinone and phosphorus units.
Compound
P–C (DPhPO Unit)
P–C (DDPO Unit)
DPhPO-HQ (1a)
1.801
1.814–1.825
–
–
DPhPO-2-HQ (5a)
DDPO-2-HQ (5c)a
DDPO-2-BQ (7c)
DDPO-2-HQ-DPhPO (10)
DDPO-2-HQ-DOPO (11)
–
–
1.804–1.805
1.819–1.834
1.811–1.821
1.811 (vicinal)
1.857 (geminal)
1.81 (P–C)
1.601 (P–O)
–
1.816
b
DDPO-2-HQ-DOPO-rear (12)c
DPhPO-3-HQ (13)
d
1.822–1.847 (vicinal)
1.808 (opposing site)
1.823–1.858
DPhPO-4-HQ (15)
–
˚
All values given in A (standard deviation < 0.005).
aX-Ray analysis given in our previous work [28].
bP–C DOPO (geminal): 1.907.
cStandard deviation 0.01 is due to crystal quality.
d P–C DOPO (vicinal): 1.79.
SCHEME 4 Reaction of DDPO-2-BQ (7c) with DOPO and diphenylphosphine oxide.
on the [P]-H reactant and the stability of the poten-
tial products, respectively. Likewise, the solubility
of the latter is of importance due to the reversibil-
ity of the phospha-Michael addition, influencing the
equilibrium by precipitation of one component, as
both 10 and 11 precipitated from the correspondent
reaction mixture.
It should be noted that, regarding the C-4 posi-
tion, 11 emerged distinctively in the enolic form as
evident from 1H NMR (singlet at 12.94 ppm, 1-OH),
13C NMR (161.9 ppm, 1C–OH) and X-ray analysis
(Fig. 3). Although a 1,4-diketo compound would be
expected for reasons of keto-enol tautomerism, the
enolic form is stabilized via an intramolecular hy-
drogen bond. As further expected, the P C bond of
the DDPO unit in the geminal position to the DOPO
unit is significantly longer than the less sterically
hindered one in the vicinal position (Table 1). Fur-
thermore, prolonged processing of DDPO-2-BQ (7c)
and DOPO led to a 1,3–rearrangement of one DDPO
unit in 11, yielding DDPO-2-HQ-DOPO-rear (12;
Scheme 4 and X-ray structure shown in Fig. 3). It is
worth mentioning that treatment of the first isolated
intermediate 11 under same conditions (toluene,
4 h, 110◦C) did not lead to rearrangement, and the
latter was found to be unchanged. Treatment of 11 in
the presence of a small amount of triethylamine led
to formation of some 12, but was accompanied by a
large amount of decomposition products (as evident
from 31P NMR).
Heteroatom Chemistry DOI 10.1002/hc

New Phosphorus-Containing Quinone Derivatives II 257
SCHEME 5 Mesomeric structures for [P]-2-BQ and nucleophilic attack of a third [P]-H reactant.
FIGURE 3 Structure of DDPO-2-HQ-DOPO (11) and DDPO-2-HQ-DOPO-rear (12), validated by X-ray analysis (hydrogens
are omitted except on heteroatoms for reasons of clarity). In both cases, the hydroxyl group forms an intramolecular hydrogen
bond. 11 exhibits intramolecular π-stacking.
910.2025). The chemical shift of 15 in 31P NMR was
determined as 52.90 ppm (s) in CDCl3, as evident
from analysis of the mixture after complete removal
of the solvent. Small crystals were obtained by re-
crystallization of the residue from ethyl acetate that
allowed X-ray analysis of 15 (Fig. 4). The sole re-
maining by-product was identified as diphenylphos-
phinic acid Ph2POOH by 31P NMR. However, a
complete separation of the latter and compound 15
was not possible due to the formation of a charge-
transfer complex, as indicated by the fluorescent yel-
lowish color of the solution or the residue, respec-
tively.
The average P C bond lengths between the
quinone moiety and the phosphorus units in DPhPO-
HQ (1a), DPhPO-2-HQ (5a), DPhPO-3-HQ (13), and
DPhPO-4-HQ (15) increased with the number of
phosphorus substituents, as was expected due to
steric hindrance. Also, in DPhPO-3-HQ (13), the two
Furthermore, DPhPO-3-HQ (13; Scheme 6, X-
ray structure shown in Fig. 4) was synthesized from
DPhPO–2–HQ (5a) and diphenylphosphine oxide in
a similar manner as 5a. While compound 13 was iso-
lated via precipitation as a 2,3,5-triphosphorylated
p-hydroquinone derivative exclusively, the relatively
low yield of 36% indicates the formation of by-
products.
Compound 13 readily underwent reoxidation
with activated MnO2. The resulting DPhPO-3-BQ
(14) could again not be isolated as an original sub-
stance and was processed in situ with diphenylphos-
phine oxide, to synthesize DPhPO-4-HQ (15) as a
2,3,5,6–tetraphosphorylated p-hydroquinone deriva-
tive conclusively (Scheme 6). Although a mixture of
products was obtained and DPhPO-4-HQ (15) could
not be isolated as the original substance, the pres-
ence of 15 was confirmed by HRMS of the mixture
(EI, calculated for [12C54H42O6P4]+ 910.1932, found
Heteroatom Chemistry DOI 10.1002/hc

258 Mu¨ller, Fuhr, and Do¨ring
SCHEME 6 Synthesis of DPhPO-3-HQ (13) and DPhPO-4-HQ (15). Compound 15 was not isolated as the original substance.
FIGURE 4 Structure of DPhPO-3-HQ (13) and DPhPO-4-HQ (15), validated by X-ray analysis (hydrogens are omitted except
on heteroatoms for reasons of clarity). In 15, both hydroxyl groups form an intramolecular hydrogen bond, whereas in 13 only
the enclosed one does. For both compounds, no intramolecular π-stacking is evident.
vicinal P C bonds were significantly longer than the
opposing one (Table 1). In addition, X–ray analysis
revealed the planarity of the p-hydroquinone unit
in DPhPO-4-HQ (15) to be undeformed despite the
presence of four bulky substituents, in consistence
with the results reported for p-hydroquinone 2,3,5,6-
tetrakis(diisopropyl phosphonate) [39].
and a ratio of always about 1:1, with the exception
of 5b, where the effect was most distinct with 1.15
ppm deviation and a ratio of 1:1.5, at which the two
isomers were successfully separated as shown in our
previous work [28]. For the derivatives 8–12, no sep-
aration of isomers was attempted.
Also, all p-benzoquinone derivatives not isolated
as original substances (2a, 2c, 2d, 7a, 7b, and 14)
were characterized in situ via HRMS and 31P NMR
of their concentrated solutions (Table 2).
CONCLUSIONS
A new synthetic approach to di-, tri-, and tetrafunc-
tional phosphorus-containing quinones and a vari-
ety of corresponding derivatives was presented. In
contrast to previous methods, the new approach is
not limited to similar phosphorus units and, there-
fore, offers a convenient pathway to tailor-made aro-
matic diols regarding the number and kind of phos-
phorus substituents for multiple purposes, for in-
stance as comonomers, dyes, or ligands.
It should be noted that most of the presented
derivatives emerge as a mixture of different diastere-
omers due to the bulkiness of the phosphorus sub-
stituents in sterically hindered positions and the
chirality regarding the phosphorus atom in DOPO
moieties, given that the formation of different di-
astereomers is a known effect for compounds carry-
ing two or more DOPO substituents and was well de-
scribed, i.e., in [40]. As evidence, the correspondent
signals in 31P NMR (measured proton-decoupled)
appeared as two separated peaks, exhibiting a small
difference in chemical shift. The phenomenon was
observed in the case of the derivatives 5b and 8–12
with a deviation in chemical shift of about 0.2 ppm
EXPERIMENTAL
Materials and Measurements
Unless stated otherwise, solvents and chemicals
were obtained from commercial sources and used
Heteroatom Chemistry DOI 10.1002/hc

New Phosphorus-Containing Quinone Derivatives II 259
TABLE 2 Chemical Shift in 31P NMR in CDCl3 and HRMS (EI) for Phosphorylated p-Benzoquinone Derivatives Not Isolated
as Original Substances 2a, 2c, 2d, 7a, 7b. and 14.
Compound
31P NMR (CDCl3)
HRMS (EI)
DPhPO-BQ (2a)
DDPO-BQ (2c)
(PhO)2PO-BQ (2d)
DPhPO-2-BQ (7a)
DOPO-2-BQ (7b)
DPhPO-3-BQ (14)
43.84 ppm (s)
1.85 ppm (s)
1.82 ppm (s)
calcd. [12C18H13O3P]+ 308.0602, found 308.0563
calcd. [12C11H13O5P]+ 256.0501, found 256.0507
calcd. [12C18H13O5P]+ 340.0501, found 340.0482
calcd. [12C30H22O4P2]+ 508.0993, found 508.0952
calcd. [12C30H18O6P2]+ 536.0579, found 536.0663
calcd. [12C42H31O5P3]+ 708.1384, found 708.1339
28.32 ppm (s)
15.47 ppm (s)a
28.15 ppm (s, 1 P), 27.76 ppm
(s, 1 P), 21.81 ppm (s, 1 P)
aDOPO-2-HQ (7b) was processed as a mixture of both diastereomers (see [28]). However, only the less stable isomer underwent reoxidation
within 30 min, exhibiting roughly 50% conversion as evident from 31P NMR.
as received. DDPO was synthesized from neopentyl
glycol and dimethyl phosphite according to the liter-
ature method [41]. Compounds 1c, 1d, 5b, 5c, 8, and
9 were synthesized as shown in our previous work
[28].
the Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
Synthesis
(2,5-Dihydroxyphenyl)diphenylphosphine Oxide
NMR spectra were recorded with a Bruker (Bel-
lerica, MA) Analytical BZH 250/52 (250 MHz) and a
Varian (Palo Alto, CA) Inova-400 (400 MHz). Chem-
ical shifts are given as δ values with internal stan-
dard via a solvent. 31P NMR spectra were mea-
sured proton decoupled, 13C NMR proton decoupled
(DPhPO-HQ,
1a). Diphenylphosphine
oxide
(101.1 g, 0.50 mol) was dissolved in 300 mL of
toluene in a three-necked flask equipped with a
condenser, argon inlet, thermometer, and magnetic
stirrer. p-Benzoquinone (54.1 g, 0.50 mol) was
added in small portions at 75◦C, and the mixture
was refluxed at 110◦C for 1 h. After cooling down,
the product was filtered off at reduced pressure,
washed with acetone, and air-dried. Light brown
solid, yield: 132.94 g (86%). mp: 214◦C. 31P NMR
(101 MHz, DMSO-d6, ppm): 28.30 (s). 13C NMR
(63 MHz, DMSO-d6, ppm): 152.5 (d, J = 2.8 Hz, 1
C-OH); 150.2 (d, J = 14.2 Hz, 1 C-OH); 133.5 (d,
J = 105.3 Hz, 2C-P); 132.1 (s, 2C); 131.7 (d, J =
10.2 Hz, 4 C); 128.7 (d, J = 12.1 Hz, 4C); 121.8 (s,
1C); 118.9 (d, J = 8.1 Hz, 1C); 117.9 (d, J = 8.6
Hz, 1C); 116.4 (d, J = 102.5 Hz, 1C-P). 1H NMR
(250 MHz, DMSO-d6, ppm): 9.75 (s, 1 H, OH); 9.10
(s, 1 H, OH); 7.70–7.45 (m, 10 H, P(O)Ph2); 6.94
(dd, J = 13.92 Hz, J = 2.75 Hz, 1H, C H); 6.85 (dd,
J = 8.64 Hz, J = 2.63 Hz, 1H, C H); 6.70 (dd, J =
8.52 Hz, J = 6.12 Hz, 1H, C H). IR (KBr) ν 3142 (br,
1
and phosphorus coupled, and H NMR phosphorus
coupled. IR spectra were recorded with a Varian
660-IR (FT-IR). Melting points were measured with
a Bu¨chi (Flawil, Switzerland) B-545 (uncorrected).
High-resolution mass spectra were obtained with a
MicroMass (Beverly, MA) GCT (EI, 70 eV). Elemen-
tary analysis (CHNS) was performed with an Ele-
mentar (Hanau, Germany) VarioEL.
Crystallographic Data
Single crystal X-ray diffraction data were col-
lected on a STOE IPDS2T diffractometer with
graphite monochromated Mo Kα radiation (0.71073
˚
A) equipped with an Oxford Cryostream unit for
low-temperature measurements (T = 180 K). Struc-
ture solution and refinement against F2 were carried
out using SHELXS and SHELXL software [42]. Re-
finement was performed with anisotropic tempera-
ture factors for all non-hydrogen atoms (disordered
atoms were refined isotropically); hydrogen atoms
were calculated on idealized positions. The crystal-
lographic data of 1a, 5a, 7c, 10–13, and 15 are sum-
marized in Table 3 (continued) in the Supporting
Information. Visualization for evaluation was per-
formed with XPMA [43], and figures were created
with Mercury [44].
O
H); 1606 (w); 1590 (w); 1512 (w) 1486 (w); 1431
(vs, P Ph); 1359 (w); 1252 (m); 1230 (m); 1206 (m);
1130 (vs, P O); 1088 (s); 1053 (s); 1027 (w); 998 (w);
875 (w); 826 (m); 752 (m); 734 (s); 716 (m); 691 (s);
584 (w); 569 (m); 534 (m); 520 (s); 489 (w); 450 (w).
HRMS (EI) calcd. [12C18H15O3P]+ 310.0759; found
310.0768. Anal calcd. for: C18H15O3P: C 69.68, H
4.87; found: C 69.49, H 4.98.
(3,6-Dihydroxy-1, 2-phenylene)bis(diphenylphos-
phine Oxide) (DPhPO-2-HQ, 5a). DPhPO–HQ (1a,
6.21 g, 20 mmol) and activated manganese diox-
ide (25.0 g) were suspended in 1,4-dioxane and
vigorously stirred at room temperature for 1 h.
CCDC numbers 905545–905552 contain the sup-
plementary crystallographic data for this paper.
These data can be obtained free of charge from
Heteroatom Chemistry DOI 10.1002/hc

260 Mu¨ller, Fuhr, and Do¨ring
The mixture was filtered off, and the residue thor-
oughly washed with 1,4-dioxane. The combined liq-
uid phases were filtered again using particularly fine-
pored paper to separate remaining traces of MnO2.
Diphenylphosphine oxide (4.04 g, 20 mmol) was
added, and the mixture was heated to 90◦C for 2 h
until the reddish color faded. The mixture was con-
centrated under reduced pressure. The product was
collected by filtration at reduced pressure, washed
with 1,4-dioxane, and dried at 0.2 mbar. White solid,
yield: 8.48 g (83%). mp: 217–218◦C. 31P NMR (101
MHz, TFA-d, ppm): 56.28 (s). 13C NMR (63 MHz,
TFA-d, ppm): 155.9 (d, J = 16.8 Hz, 2C OH); 135.1
(s, 4CPh); 132.8 (d, J = 11.9 Hz, 8CPh); 129.6 (d, J
= 14.2 Hz, 8CPh); 126.7 (d, J = 5.9, 2C H); 126.2
(d, J = 114.9 Hz, 4P CPh); 115.6 (dd, J = 104.9 Hz, J
= 5.4 Hz, 2P C). 1H NMR (250 MHz, TFA-d, ppm):
8.94–8.78 (m, 12H, arom.); 8.72–8.62 (m, 8H, arom.);
8.34 (t, J = 3.11 Hz, 2H, C H quinone). IR (KBr) ν
3058 (C H aryl.); 1573 (w); 1461 (s); 1437 (s, P Ph);
1267 (s); 1207 (w); 1151 (vs, P O); 1120 (m); 1087
(m); 1062 (m); 932 (w); 833 (w); 731 (m); 702 (m);
689 (s); 588 (s); 573 (m); 548 (w); 527 (s); 503 (w).
HRMS (EI) calcd. [12C30H24O4P2]+ 510.1150, found
510.1157. Anal calcd. for C30H24O4P2: C 70.59, H
4.74; found: C 70.20, H 4.86.
2,2ꢁ-(4-(Diphenylphosphoryl)-3,6-dihydroxy-1,2-
phenylene)bis(5,5-dimethyl-1,3,2-dioxaphosphinane
2-oxide), (DDPO-2-HQ-DPhPO, 10). In a flame-
dried flask equipped with a condenser and an argon
inlet, DDPO-2-BQ (7c; 404 mg, 1.0 mmol) and
diphenylphosphine oxide (202 mg, 1.0 mmol) were
refluxed in 20 mL of dry toluene for 1 h until the
orange color of the mixture faded. The mixture was
cooled with an ice bath for 30 min. The product was
collected by filtration at reduced pressure, washed
with cold toluene, and dried at 0.2 mbar. White
solid, yield: 410 mg (68%). mp: 178◦C. 31P NMR
(101 MHz, CDCl3, ppm): 37.46 (s, 1 P DPhPO); 9.82
+ 9.66 (isomers, 1P DDPO); 7.67 + 7.59 (isomers,
1P DDPO). 13C NMR (101 MHz, CDCl3, ppm):
158.3 (d, J = 17.2 Hz, 1Carom OH); 154.6 (td, J =
15.8 Hz, J = 4.8 Hz, 1Carom OH); 133.2 (d, J = 2.6
Hz, 2CPh); 132.3 (d, J = 10.7 Hz, 4CPh); 130.1 (d,
J = 107.5 Hz, 2CPh P); 129.1 (d, J = 12.8 Hz, 4CPh);
128.4 (t, J = 10.2 Hz, 1C); 122.0 (dd, J = 99.8 Hz,
J = 9.6 Hz, 1C P); 119.2 (dd, J = 182.9 Hz, J =
10.8 Hz, 1 C P); 116.6 (dt, Jd = 178.6 Hz, Jt = 9.2 Hz,
1 C P); 79.1 (d, J = 7.1 Hz, 2 CH2
O ) 78.5 (d,
J = 7.0 Hz, 2 CH2
O
); 33.0 (d, 10.0 Hz, 1Cquart);
32.7 (d, J = 8.4 Hz, 1Cquart); 23.3 (s, 1 CH3 ax.);
23.1 (s, 1 CH3 ax.); 21.3 (s, 1 CH3 equ.); 21.2 (s,
1
CH3 equ.). 1H NMR (250 MHz, CDCl3, ppm):
11.48 (s, 1 H, Ar OH); 10.43 (s, 1 H, Ar OH); 7.71
(dd, J = 12.7 Hz, J = 7.3 Hz, 4 H, arom.); 7.61 (d,
J = 7.1 Hz, 2H, arom.); 7.53 (dd, J = 7.2 Hz,
J = 2.7 Hz, 4H, arom.); 7.19 (m, 1H, C H quinone
unit); 4.34 (dd, J = 41.3 Hz, J = 10.4 Hz, 4H,
2,3-Bis (5,5-dimethyl-2-oxido-1,3,2-dioxaphos-
phinan-2-yl)cyclohexa-2,5-diene-1,4-dione (DDPO-
2-BQ, 7c). DDPO-2-HQ (5c, 4.06 g, 10 mmol)
and activated manganese dioxide (32.0 g) were
suspended in acetone and vigorously stirred at room
temperature for 1 h. The mixture was filtered off,
and the residue thoroughly washed with acetone.
The solution was dried over MgSO4 and filtered
off. The product was obtained by complete removal
of the solvent at reduced pressure and dried at
0.2 mbar. Bright orange solid, yield: 2.26 g (56%).
mp: decomp. >190◦C. 31P NMR (101 MHz, CDCl3,
ppm): –1.71 (s). 13C NMR (63 MHz, CDCl3, ppm):
184.3 (t, J = 11.6 Hz, 2C O); 144.2 (d, J = 167.8
Hz, 2C P); 136.8 (t, J = 4.5 Hz, 2C, CH CH );
CH2
CH2
O
O
); 4.00 (dd, J = 10.5 Hz, J = 4.9 Hz, 2H,
); 3.92 (t, J = 8.9 Hz, 2 H, CH2
O );
1.44 (s, 3H, CH3 ax.); 1.40 (s, 3 H, CH3 ax.);
0.82 (s, 6H, CH3 equ.). IR (KBr) ν 3061 (w, C
H
aryl); 2965 (w, C H alkyl); 2884 (w, C H alkyl);
1580 (w); 1474 (w); 1439 (m; P Ph); 1359 (m); 1284
(s, P O); 1234 (s, P O); 1208 (m); 1148 (m); 1122
(m); 1061 (vs, P OCalkyl); 1009 (s, P OCalkyl); 943
(w); 812 (s); 793 (m); 753 (w); 728 (w); 697 (m); 651
(m); 582 (s); 564 (m); 507 (s); 474 (w). HRMS (EI)
calcd. [12C28H33O9P3]+ 606.1337, found 606.1343.
Anal calcd. for C28H33O9P3: C 55.45, H 5.48; found:
C 55.45, H 5.85.
78.1 (t, J = 3.8 Hz, 4
O
CH2 ); 32.0 (t, J = 3.4
Hz, 2Cquart); 21.7 (s, 2 CH3 ax.); 20.3 (s, 2 CH3,
equ.). 1H NMR (250 MHz, CDCl3, ppm): 6.92 (t,
J = 3.11 Hz, 2H, HC CH ); 4.05–3.96 (m, 8H,
5,6-Bis(5,5-dimethyl-2-oxido-1,3,2-dioxaphos-
phinan-2-yl)-4-hydroxy-6-(6-oxido-6H-dibenzo[c,e]
[1,2]oxaphosphinin-6-yl)cyclohexa-2,4-dienone
(DDPO-2-HQ-DOPO, 11). In a flame-dried flask
equipped with a condenser and an argon inlet,
DDPO-2-BQ (7c; 404 mg, 1.0 mmol) and DOPO
(216 mg, 1.0 mmol) were refluxed in 20 mL of dry
toluene for 1.5 h, not longer. After cooling down,
the product was collected by filtration at reduced
CH2
O ); 1.31 (s, 6H, CH3 ax.); 0.83 (s, 6H,
CH3 equ.). IR (KBr) ν 2974 (w, C H alkyl); 2883
(w, C H alkyl); 1657 (s, C O); 1479 (m, P C); 1290
(vs, P O); 1060 (vs, P OCalkyl); 1007 (s, P OCalkyl);
986 (m); 864 (m); 778 (m); 488 (s). HRMS (EI)
calcd. [12C16H22O8P2]+ 404.0790, found 404.0869.
Anal calcd. for C16H22O8P2: C 47.53, H 5.48; found:
C 47.59, H 5.69.
Heteroatom Chemistry DOI 10.1002/hc

New Phosphorus-Containing Quinone Derivatives II 261
731 mg (59%). mp: decomp. >212◦C. 31P NMR
(101 MHz, CDCl3, ppm): 19.21 + 19.07 (isomers,
1P DOPO); 14.04 + 13.90 (isomers, 1P C DDPO);
14.95 (s, 1 P O DDPO). 13C NMR (63 MHz,
CDCl3, ppm): 162.0 (dd, J = 14.6 Hz, J = 7.2 Hz,
1C); 149.2 (d, J = 8.2 Hz, 1C); 147.0 (dd, J = 18.7
Hz, J = 5.3 Hz, 1C); 134.5 (d, J = 5.6 Hz, 1C); 132.8
(d, J = 2.6 Hz, 1C); 130.4 (s, 1C); 129.5 (d, J = 13.7
Hz, 1C); 128.6 (d, J = 15.3 Hz, 1C); 127.2 (d, J = 15.7
Hz, 1C); 125.9 (d, J = 134.0 Hz, 1C P); 125.8 (d, J
= 8.8 Hz, 1C); 124.7 (s, 1C); 124.4 (s, 1C); 123.2 (d, J
= 10.1 Hz, 1C); 121.2 (d, J = 12.1 Hz, 1C); 120.7 (d,
J = 6.7 Hz, 1C); 117.7 (dm, Jd = 183.0 Hz, 1C P);
113.9 (dd, J = 195.9 Hz, J = 9.5 Hz, 1C P); 79.8 (d,
J = 7.5 Hz, 1C); 79.2 (d, J = 7.7 Hz, 1C); 77.9 (d, J =
7.2 Hz, 2C); 33.2 (d, J = 15.5 Hz, 1C); 31.4 (d, J =
6.1 Hz, 1C); 24.4 (s, 1C); 22.1 (s, 1C); 21.2 (s, 1C);
19.5 (s, 1C). 1H NMR (250 MHz, CDCl3, ppm): 12.66
(s, 1H, Aryl-OH); 8.09 (t, J = 7.10 Hz, 2H, arom.);
7.72 (m, 2H, arom); 7.48 (m, 2H, arom.); 7.39 (d,
J = 6.97 Hz, 1H, arom.); 7.30 (d, J = 8.74 Hz, 2H,
arom); 7.22 (m, 1H, arom.); 4.96 (dd, J = 9.42 Hz, J
= 3.94, 1H, CH2 ); 4.79 (dd, J = 9.33 Hz, J = 4.35
Hz, 1 H, CH2 ); 4.01 (dq, Jq = 12.31 Hz, Jd = 2.4
Hz, 2 H, CH2 ); 3.56 (m, 2 H, CH2 ); (dd, J =
24.3 Hz, J = 10.9 Hz, 1 H, CH2 ); 3.13 (d, J = 11.0
Hz, 1 H, CH2 ); 1.64 (s, 3 H, CH3 ax.); 1.05 (s, 3
H, CH3 ax.); 0.83 (s, 3H, CH3 equ.); 0.48 (s, 3 H,
CH3 equ.). IR (KBr) ν 3075 (w, C H aryl); 2967
(w, C H alkyl); 2885 (w, C H alkyl); 1595 (w); 1584
(w); 1479 (m, P Caryl); 1432 (m, P Caryl); 1375 (w);
1316 (m); 1296 (m, P O); 1255 (s, P O); 1215 (m);
1170 (m, P OCaryl); 1119 (w); 1062 (s, P OCalkyl);
1009 (m, P OCalkyl); 991 (m); 969 (m); 940 (m); 909
(m); 836 (m); 813 (m); 792 (m); 757 (m); 734 (w);
715 (w); 632 (m); 524 (w); 508 (w); 492 (m). HRMS
(EI) calcd. for [12C28H31O10P3]+ 620.1130, found
620.1126. Anal calcd. for C42H33O5P3: C 70.99, H
4.68; found: C 70.66, H 4.84.
pressure, washed with toluene, and dried at 0.2
mbar. Yellowish solid, yield: 403 mg (65%). mp:
197◦C. 31P NMR (101 MHz, CDCl3, ppm): 32.41
+ 32.35 (isomers, 1P DOPO); 13.10 (s, 1P DDPO
vicinal), 1.70 + 1.64 + 1.59 (isomers, 1P DDPO
geminal). 13C NMR (63 MHz, CDCl3, ppm): 188.1
(m, 1C O); 161.9 (m, 1C OH); 147.1 (d, J = 8.6 Hz,
1C); 140.4 (dt, Jd = 18.3 Hz; Jt = 3.0 Hz, 1C); 135.9
(d, J = 6.9 Hz, 1Cquart); 133.8 (d, J = 2.5 Hz, 1C);
132.9 (d, J = 8.7 Hz, 1C); 130.8 (s, 1C); 130.0 (d, J =
2.8 Hz, 1C); 128.5 (d, J = 50.9 Hz, 1C P); 128.4 (d,
J = 14.3 Hz, 1C); 125.5 (s, 1C); 125.2 (s, 1C); 124.8 (d,
J = 42.6 Hz, 1C P); 123.8 (d, J = 12.1 Hz, 1Cquart);
123.5 (d, J = 11.0 Hz, 1C); 122.5 (d, J = 6.5 Hz, 1C);
97.7 (dt, Jd = 200.4 Hz, Jt = 7.8 Hz, 1 P
C P); 80.2
(d, J = 6.4 Hz, 1 CH2 ); 79.9 (d, J = 8.4 Hz, 1
CH2 ); 79.5 (d, J = 8.5 Hz, 1 CH2 ); 79.1 (d, J
= 7.3 Hz, 1 CH2 ); 33.3 (d, J = 13.3 Hz, 1Cquart);
32.9 (d, J = 11.6 Hz, 1Cquart); 23.8 (s, 1 CH3 ax.);
22.7 (s, 1 CH3 ax.); 21.2 (s, 1 CH3 equ.); 20.4 (s,
1
CH3 equ.). 1H NMR (250 MHz, CDCl3, ppm):
12.94 (s, 1 H, OH); 8.16 (dd, J = 13.40 Hz, J =
7.48 Hz, 1H, arom.); 7.72 (s, 2H, arom.); 7.59 (d,
J = 7.15 Hz, 2H, arom.); 7.29 (s, 1H, arom.); 7.26 (t,
J = 16.20 Hz, 2H, arom.); 7.17 (m, 1H, arom.); 6.39
(m, 1H, CH ); 5.50 (d, J = 9.69, 1H, CH CH );
5.33 (d, J = 9.83, 1H, CH CH ); 5.02 (d, J =
6.52 Hz, 1H, CH2
CH2
3.99 (t, J = 11.36 Hz, 2H, CH2
CH2
); 3.59 (d, J = 9.37 Hz, 1H, CH2
O
);4.45 (d, J = 9.32 Hz,
);
); 3.78 (t, 1H,
);
O
); 4.10 (t, J = 14.80 Hz, 2H, CH2
O
O
O
O
1.56 (s, 3H, CH3 ax.); 1.35 (s, 3H, CH3 ax.); 0.92
(s, 3H, CH3 equ.); 0.74 (s, 3H, CH3 equ.). IR
(KBr) ν 3070 (w, C H aryl); 2960 (w, C H alkyl);
2932 (w, C H alkyl); 1658 (m); 1638 (m); 1546
(m); 1475 (m); 1430 (m); 1283 (s, P O); 1238 (m,
P O); 1199 (w); 1147 (m, P OCaryl); 1116 (w); 1071
(s, P OCalkyl); 1065 (s, P OCalkyl); 1032 (w); 1013
(m); 989 (w); 939 (w); 909 (m); 887 (w); 852 (m);
790 (w); 768 (m); 625 (m); 529 (m); 511 (m); 497
(m). HRMS (EI) calcd. [12C28H31O10P3]+ 620.1130,
found 620.1190. Anal calcd. for C28H31O10P3: C
54.20, H 5.04; found: C 53.97, H 5.03.
(3,6-Dihydroxybenzene-1,2,4-triyl)tris(diphenyl-
phosphine oxide) (DPhPO-3-HQ, 13). DPhPO-2-
HQ (5a, 5.10 g, 10 mmol), activated manganese
dioxide (20.0 g), and diphenylphosphine ox-
ide (2.02 g, 10 mmol) were processed in the
manner described for 5a. White solid, yield:
2.58 g (36%). mp: decomp. >220◦C. 31P NMR
(101 MHz, CDCl3, ppm): 52.86 (s, 1P); 38.97 (s,
1P); 32.80 (s, 1P). 13C NMR (101 MHz, CDCl3,
ppm): 156.6 (m, 1C OH); 152.5 (m, 1 C OH);
131.3–123.2 (37C);* 118.1 (d, J = 116.0 Hz, 1C P);
116.0 (d, J = 101.0 Hz, 1C P); 115.9 (d, J = 100.1
Hz, 1C P). 1H NMR (250 MHz, CDCl3, ppm): 13.52
(s, 1H, Aryl-OH); 11.09 (s, 1H, Aryl-OH); 7.83 (dd,
2,2ꢁ-(3-Hydroxy-6-((6-oxido-6H-dibenzo[c,e]
[1,2]oxaphosphinin-6-yl)oxy)-1,2-phenylene)bis(5,5-
dimethyl-1,3,2-dioxaphosphinane 2-oxide) (DDPO-
2-HQ-DOPO-rear, 12). In
a
flame-dried flask
equipped with a condenser and an argon inlet,
DDPO–2-BQ (7c, 808 mg, 2.0 mmol) and DOPO
(432 mg, 2.0 mmol) were refluxed in 20 mL of dry
toluene for 4 h. The mixture was cooled with an
ice bath for 30 min. The product was collected by
filtration at reduced pressure, washed with cold
toluene, and dried at 0.2 mbar. White solid, yield:
Heteroatom Chemistry DOI 10.1002/hc

262 Mu¨ller, Fuhr, and Do¨ring
[16] Rakotomalala, M.; Wagner, S.; Do¨ring, M. Materials
2010, 3, 4300–4327.
[17] Wang, C. S.; Lin, C. H.; Chen, C. Y. J Polym Sci, Part
A: Polym Chem 1998, 36, 3051–3061.
[18] Wang, C. H.; Lin, C. S. Polymer 1999, 40, 747–757.
[19] Xia, X.-N.; Lu, Y.-B.; Zhou, X.; Xiong, Y.-Q.; Zhang,
X.-H.; Xu, W.-J. J Appl Polym Sci 2006, 102, 3842–
3847.
[20] Sponto´n, M.; Ronda, J. C.; Galia`, M.; Ca´diz, V. J
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[21] Worku, A.; Bharadwaj, A.; Thibault, R.; Wilson, M.;
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[22] Brehme, S.; Schartel, B.; Goebbels, J.; Fischer, O.;
Pospiech, D.; Bykov, Y.; Do¨ring, M. Polym Deg Stab
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[23] Fischer, O.; Pospiech, D.; Korwitz, A.; Sahre, K.;
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J = 12.8 Hz, J = 7.4 Hz, 3H arom.); 7.75–7.61 (m,
5H, arom.); 7.61–7.52 (m, 4H, arom.); 7.40–7.08 (m,
18H, arom.); 7.00 (dd, J = 14.2 Hz, J = 4.2 Hz, 1H,
arom.). IR (KBr) ν 3054 (C H aryl.); 1572 (w); 1483
(w); 1437 (s, P Ph); 1353 (m); 1266 (w); 1196 (m);
1165 (s, P O); 1122 (s); 1094 (m); 1042 (w); 998
(w); 910 (w); 801 (w); 745 (m); 729 (s); 701 (s); 687
(s); 655 (m); 618 (w); 590 (s); 563 (s); 531 (w); 517
(s). HRMS (EI) calcd. [12C42H33O5P3]+ 710.1541,
found 710.1592. Anal calcd. for C42H33O5P3: C
70.99, H 4.68; found: C 70.66, H 4.84. *detailed
assignment not possible due to limited resolution of
the available NMR technology. The structure of 13
was confirmed by X-Ray analysis and HR-MS.
[24] Pudovik, A. N.; Romanov, G. V.; Pozhidev, V. M. Russ
Chem Bull 1978, 27(7), 1450–1452.
ACKNOWLEDGMENTS
[25] Reetz, T.; Groves, W. US Patent 2935518, 1960.
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[28] Mu¨ller, P.; Bykov, Y.; Walter, O.; Do¨ring, M. Het-
eroatom Chem 2012, 23(4), 383–394.
The authors thank Mr. Gilbert Zwick for measuring
HRMS, Ms. Ilona Schmelcher for performing ele-
mentary analysis, and Ms. Rebecca Lauber and Mr.
Christoph Schulten for measurement of IR spectra.
[29] Saito, T. US Patent 3702878, 1972.
[30] Schartel, B.; Balabanovich, A. I.; Braun, U.; Knoll, U.;
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Heteroatom Chemistry DOI 10.1002/hc