Cyclophosphorylation of polyphenols by diamidoarylphosphites

Article abstract of DOI:10.1016/S0040-4020(03)00111-X

It was found that the cyclophosphorylation of polyphenols by diamidoarylphosphites proceeds via the rupture of only one P-N bond and one P-O bond, the second P-N bond remaining intact. It is supposed that the unusual lack of reactivity of the P-N bond is due to the spatial arrangement of the amido group with respect to the reaction site in phosphorylated intermediates 5.

Full text of DOI:10.1016/S0040-4020(03)00111-X

Tetrahedron 59 (2003) 1753–1761
Cyclophosphorylation of polyphenols by diamidoarylphosphites
Vera I. Maslennikova,a Roman V. Merkulov,b Maria V. Dyagileva,a Larisa K. Vasyanina,a
Konstantin A. Lyssenko,b Mikhail Yu. Antipin,b Dirk Weber,c Ingmar Bauer,c
Wolf D. Habicherc and Eduard E. Nifantyeva
,
*
aDepartment of Chemistry, Moscow Pedagogical State University, 3 Nesvizhski per., 119021 Moscow, Russian Federation
bA.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 ul. Vavilova, 117813 Moscow,
Russian Federation
cInstitute of Organic Chemistry, Dresden University of Technology, Mommsenstr. 13, D-01062 Dresden, Germany
Received 11 June 2002; revised 18 December 2002; accepted 16 January 2003
Abstract—It was found that the cyclophosphorylation of polyphenols by diamidoarylphosphites proceeds via the rupture of only one P–N
bond and one P–O bond, the second P–N bond remaining intact. It is supposed that the unusual lack of reactivity of the P–N bond is due to
the spatial arrangement of the amido group with respect to the reaction site in phosphorylated intermediates 5. q 2003 Published by Elsevier
Science Ltd.
1. Introduction
The aim of this work was to elucidate the mechanism of the
anomalous cyclophosphorylation and to reveal the limits of
its synthetic applications.
This paper deals with the problem of expanding the
synthetic use of phosphorus acid amides. These compounds
are readily available and have a high phosphorylating
capacity of proton-bearing nucleophiles due to the rupture
of P–N bonds. They find wide application for the design of
different organophosphorus compounds, including complex
phosphocyclic systems.1 Note that phosphorus triamides
were predominantly used to obtain phosphocyclanes;
aliphatic diamidophosphites found fewer application, and
aromatic diamidophosphites were used very rarely.1 No
data are available on the cyclophosphorylation of
polyphenols.
2. Results and discussion
2.1. Cyclophosphorylation of calix[4]resorcinarenes
It was found previously that the cyclophosphorylation of
calix[4]resorcinarenes with triamides and aliphatic
diamidoesters of phosphorus acid is efficiently realized in
dioxane at room temperature.2 These factors favour the
stereoselective course of the reaction and convenient
separation of the target product from the reaction mixture.
Therefore, the reaction of calix[4]resorcinarenes with
diamidoarylphosphites was operated in analogous con-
ditions, varying the reagent ratio (1:4¼1:4–8). Calix[4]-
resorcinarenes 1a–e with different hydrocarbon substituents
(R) in the bridges between the aromatic rings were used as
substrates and diamidoarylphosphites 4a–g were used as
reagents (Table 1).
When studying the reaction of phosphorus amides with
calix[4]resorcinarenes 1, we found that phosphocyclization
of these compounds with aliphatic and aromatic diamido-
phosphites follows different pathways (Scheme 1).
In the former case, the reaction follows the classical
pathway with the rupture of two P–N bonds and formation
of phosphocavitands 2.2 In the latter case, an anomalous
course of the process is observed, which leads to the
formation of amidophosphocavitands 3.3
The process can conventionally be subdivided into two steps
(Scheme 1). The first step completely coincides with the
classical phosphorylation of alcohols and phenols by
phosphorus amides. It includes the rupture of a P–N bond
and is completed by the formation of intermediate 5. In
terms of the conventional concepts of diamidophosphite
reactivity, the second step, i.e. phosphocyclization of
intermediate 5, should include the rupture of the last P–N
bond and afford phosphitocavitands 6. However, an
Keywords: phenols; calixarenes; phosphoramidites; phosphorylation;
cyclization; regiospecificity.
*
Corresponding author. Tel.: þ7-095-246-5790; fax: þ7-095-246-7766;
e-mail: chemdept@mtu-net.ru, wolf.habicher@chemie.tu-dresden.de.
0040–4020/03/$ - see front matter q 2003 Published by Elsevier Science Ltd.
doi:10.1016/S0040-4020(03)00111-X

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V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
Scheme 1.
anomaly is observed in this case: the rupture of the P–O
bond takes place in intermediates 5 at the second step and
amidophosphitocavitands 3a–h are formed. Phospho-
cavitands 3a–h are crystallized directly from reaction
mixtures as individual symmetric stereoisomers with the
equatorial orientation of amide groups at all of the
phosphorus atoms.
It is noteworthy that a free phenol (naphthol) is released into
the reaction medium at the second stage of the cyclo-
phosphorylation of calix[4]resorcinarenes with diamido-
arylphosphites; therefore, the competitive phenolysis
(naphtholysis) of the initial diamidophosphite 4 should
also be considered (Scheme 1), phenolysis being more rapid
than naphtholysis. In our opinion, this is the main factor
responsible for the decreased yield of phosphocavitands
3e–h in the phosphorylation of calixarenes containing
phenyl (1e) and long alkyl (1c,d) groups in the lower rim of
the macrocycle, with diamidophenylphosphites 4a,b
(Table 1). In these cases, along with the signal of cavitand
3 (142–145 ppm), an intense singlet attributed to amido-
diarylphosphite 7 (140–141 ppm) is observed in the 31P
NMR spectra of reaction mixtures after the completion of
the process. It is interesting that no side reactions are
observed when calixarenes 1a and, b, which contain small
groups in the inter-nuclear bridges, are used. Phenol
probably forms inclusion compounds with phosphocavi-
tands 3a–d and becomes deactivated. The resulting
complexes are readily decomposed by ethanol or water.
This conclusion is based on the 1H NMR spectroscopic data:
along with the proton signals of cavitand 3, the spectra of
products crystallized from the reaction mixtures display
signals typical for the protons of free phenol, which
disappear after the adduct is decomposed.
The composition and structure of compounds 3a–f were
confirmed by the data of elemental analysis and NMR
spectroscopy, as well as by the counter synthesis.
All physicochemical characteristics of these amides
coincide with properties of cavitands 3a–f obtained by the
cyclophosphorylation of calix[4]resorcinarenes with phos-
phorus triamides (Scheme 1, Table 1). The structure and
symmetry of the new compounds 3g and, 3h were proved by
NMR spectroscopy. The spectra of these compounds are
typical for symmetric phosphocavitand stereoisomers:2d,4 a
narrow singlet in the 31P NMR spectrum and a set of signals
1
for all protons in the H NMR spectrum.
The X-ray structural study of compounds 3e3 and, 3f
showed that both molecules are crystallized as dioxane
solvates. The main geometrical parameters of 3e and, 3f are
similar to those of trivalent phosphorus derivatives studied
previously (Figs. 1 and 2).2b,c All phosphocine cycles exist
in a chair–boat conformation with the equatorial orientation
of amide groups at the phosphorus atoms. The conformation
of n-alkyl substituents in the lower rim of the macrocycle
deviates from the common all-trans conformation because
of packing effects. All intermolecular contacts correspond to
usual van der Waals interactions.
The reaction under study has both fundamental and
preparative importance. Note that the phosphocyclization
of calixarene 1a with hexaethylphosphorus triamide was
completed only when triamide was slowly added to 1a at
70–808C. The decrease of temperature and the increase in
the concentration of phosphorylating agent resulted in the

V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
1755
Table 1. Synthesis conditions, yields and physicochemical properties of amidophosphocavitands 3
Calixresorcinarene
Diamidoarylphosphite
R0
Reagent
ratio
Reaction duration
(days)
Cavitand
Yield
(%)
R
No.
Ar
No.
CH3
1a
CH3
4a
1:4
1:4
4
5
3a
3b
72
83
CH3
1a
C2H5
4b
C2H5
C2H5
4b
4c
1:8
1:4
5
5
40
80
C2H5
CH3
4d
4a
1:4
1:8
11
4
83
30
C3H7
C3H7
1b
1b
3c
C2H5
4b
1:4
6
58
C2H5
C2H5
4d
4e
1:4
1:4
6
84
35
10
3d
C2H5
C2H5
4f
1:4
1:4
14
17
13
4g
C6H13
1c
C2H5
4b
1:4
11
3e
13
C2H5
C2H5
4d
4b
1:4
1:4
7
42
12
C9H19
1d
1e
14
3f
C6H5
CH3
4a
4b
1:8
1:4
10
15
3g
3h
8
C2H5
18
Melting with decomposition.
formation of inseparable mixtures of products containing
acyclic (A) and cyclic (B) phosphorus fragments (Figure 3,
Table 2).2c
arylphosphites is also provided by the synthesis of C-phenyl
derivatives of calixarenes 3g and, h (Scheme 1, Table 1),
which could not be obtained using the classical scheme.2c
Using diamidoarylphosphites 4, we achieved the exhaustive
cyclophosphorylation of calixarene 1a by simply mixing the
reagents at room temperature. Moreover, phosphocycliza-
tion was the principal pathway of the reaction when a
double excess of phosphorylating agent was used
(1a:4¼1:8) (Table 2).
We suppose that the geometry of intermediates 5 is essential
for the realization of the effect considered. This supposition
is confirmed by the computer simulation of the process. Full
geometric optimization of plausible intermediates of the
reactions cyclophosphorylation of calixarenes 1 by
diamidophosphites has been carried out at semiempirical
method AM 1 using GAMESS program package.5 In
intermediates 5, the phosphorus-bearing group is arranged
An example of the preparative effectiveness of diamido-

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V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
Table 2. Composition of reaction mixtures in the phosphorylation of
calixarene 1a with phosphorus amides in dioxane at 208C
1a: Amide
(Et2N)3P
(Et2N)2POPh
A
(%) (ppm)
dp
B
dp
A
dp
B
dp
(%) (ppm) (%) (ppm) (%) (ppm)
1:4
1:8
64 126.3; 127.6 36 142.6
–
–
100 142.6
76 126.3; 127.6 24 142.6 30 139.5 70 142.6
Figure 1. The general view of 3e. The numbering of the carbon atom and
the disorder are omitted for clarity.
Figure 4. Geometry of a possible intermediate 5 in the cyclopho-
sphorylation of calixarene 1a by diamidopjosphite 1b.
the P–O bond alone, i.e. due to reetherification. The unusual
lack of reactivity of the P–N bond is due to its position.
Note that the substitution of the phenyl group in the
phosphorylating agent with a benzyl group affects the
relative arrangement of interacting groups in intermediates
5. Experiments on the phosphorylation of calixarene 1a by
diamidobenzylphosphite 8 showed that the reaction follows
the classical scheme involving the rupture of two P–N
bonds and the formation of phosphitocavitand 9 (Scheme 2).
The reaction was carried out in dioxane and acetonitrile at
258C. The duration of the reaction was 6 days in dioxane and
24 h in acetonitrile. In the latter case, tetrabenzyl-
phosphocavitand 9 was crystallized from the reaction
mixture (Scheme 3).
Figure 2. The general view of 3f. The numbering of the carbon atom and
the disorder are omitted for clarity.
The phosphite nature of phosphocine cycles, the identity of
the stereoisomer isolated and the symmetry of the
polycyclic skeleton of the molecule were proved by NMR
spectroscopy. The 31P NMR spectrum of cavitand 9
displayed a narrow singlet in the characteristic region of
1
neutral phosphites; in the H NMR spectrum, no protons
signals of diethylamide groups were found, but proton
signals of benzyl fragments at the phosphorus atoms were
observed with the integral intensities corresponding to the
theoretical values.
Figure 3. Acyclic (A) and cyclic (B) phosphorus-bearing fragments formed
in the reaction of calix[4]resorcinarenes with phosphorous amides.
2.2. Cyclophosphorylation of di- and trihydroxy-
aromatic compounds
in such a way that the phenoxyl group is approached to the
hydroxyl group of the adjacent benzene ring and the amido
group is moved to the periphery of the system (Fig. 4). This
conformation of the intermediate makes possible the
intermolecular phosphocyclization due to the rupture of
In order to determine the scope of the effect observed, we
studied the cyclophosphorylation, under the action of
diamidoarylphosphites, of some di- and trihydroxyaromatic

V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
1757
Scheme 2.
Scheme 3.
Scheme 4.
systems: 2,20-dihydroxy-1,10-bisnaphthyl 10, 2,20-
methylenebis(6-tert-butyl-4alkylphenols) 11a,b and 2,6-
bis(3-tert-butyl-2-hydroxy-5-methylphenol 12. Diamido-
phenylphosphite 4b and bis(N,N-diethylamido)-O-a-toco-
pherylphosphite 13 were used as phosphorylating agents. In
all cases, reactions were conducted at the equimolar reagent
ratio.
The cyclophosphorylation of trisphenol 12 with diamido-
phosphite 13 (Scheme 5) was carried out in toluene at
1208C. The reaction proceeded analogously to the above
processes due to the consecutive ruptures of P–N and P–O
bonds and completed by the formation of dioxaphosphocine
19. Intermediate 18 was not isolated because of its
instability.
Cyclophosphorylation of 10 with diamidophosphite 4b was
achieved in dioxane or acetonitrile in the temperature range
20–808C. At 20–258C, the duration of the process was 8
days in dioxane and 24 h in acetonitrile; at 808C, the
reaction was completed in 0.5 h. In all cases, phospho-
cyclization included the detachment of phenol and for-
mation of dioxaphosphepane 15. No accumulation of
intermediate 14 was observed even at room temperature.
The reaction of methylenebisphenol 11a with diamido-
phosphite 4b (Scheme 4) was conducted under analogous
conditions. In this case, monophosphorylated derivative 16a
was the main reaction product at 20–258C regardless of the
solvent. Phosphocyclization was very slow at room
temperature because of the presence of bulky tert-butyl
substituents in the ortho-positions of phenolic rings in 11a;
it was completed only when the reaction mixture was heated
to 80–1008C and gave dioxaphosphocine 17a.
When the sterically hindered diamidophosphite 13 was
used, the phosphorylation of methylenebisphenols 11a,b
proceeded under more severe conditions (1208C, toluene).
The reaction gave compounds 16b,c, which were isolated
by column chromatography with yields of 90 and
67%, respectively. Heating of monophosphorylated
derivatives 16b,c in xylene at 1408C resulted in the
detachment of a-tocopherol and formation of dioxa-
phosphocines 17a,b.
Scheme 5.

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V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
Thus, the revealed phenomenon of intramolecular
regulation of the cyclophosphorylation of polyphenols
with diamidoarylphosphites is promising for wide synthetic
application.
reagents used. The precipitate formed was filtered off,
washed with dioxane and dried in vacuo.
3.1.1. 1,21,23,25-Tetramethyl-5,9,13,17-tetrakis(di-
methylamino)-2,20:3,19-dimetheno-1H,21H,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i0]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3a).2a The
title compound 3a is a white solid, mp 270–2728C
(decomp.); dP (32.4 MHz, CDCl3) 141.3; dH (200 MHz,
3. Experimental
All syntheses were operated in dry solvents under argon. 1H
NMR spectra were recorded with Bruker AC-300 and
Bruker WM-200 spectrometers; 13C NMR spectra were
recorded with a Bruker AC-300 instrument (75.48 MHz);
31P NMR spectra were recorded with Bruker AC-300
(121.50 MHz) and Bruker WP-80 (32.4 MHz) instruments.
MALDI-TOF MS measurements were carried out with
Kratos Kompact MALDI II and Kratos Kompact MALDI
IV instruments (Shimadzu Europa GmbH). IR spectra were
recorded with Nicolet Magna-750 instrument.
CDCl3) 1.73 (d, JHH¼7.3 Hz, 12H, CH3), 2.80 (d,
3
3
3JPH¼10.2 Hz, 24H, NCH3), 4.80 (q, JHH¼7.3 Hz, 4H,
CH), 6.49 (s, 4H, Ho), 7.26 (s, 4H, Hm).
3.1.2. 1,21,23,25-Tetramethyl-5,9,13,17-tetrakis(diethyl-
amino)-2,20:3,19-dimetheno-1H,21H0,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i ]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3b).2a The
title compound 3b is a white solid, mp 272–2748C
(decomp.); dP (32.4 MHz, CDCl3) 142.6; dH (200 MHz,
3
CDCl3) 1.17 (t, JHH¼6.7 Hz, 24H, NCH2CH3), 1.73 (d,
3
Crystallographic data for 3f: at 110 K crystals of
C90H146N4O12P4 are monoclinic, space group C2/c,
3JHH¼7.4 Hz, 12H, CH3), 3.28 (m, JPH¼9.8 Hz, 16H,
3
NCH2CH3), 4.80 (q, JHH¼7.4 Hz, 4H, CH), 6.49 (s, 4H,
˚
˚
˚
a¼35.486(9) A,
b¼26.539(8) A,
c¼21.9412(2) A,
Ho), 7.24 (s, 4H, Hm).
3
˚
b¼121.17(1)8, V¼17680(9) A , Z¼8, M¼1599.99,
dcalc¼1.202 g cm23, m (Mo Ka)¼1.46 cm21, F(000)¼
6960. Intensities of 59191 were measured with a Smart
1000 CCD diffractometer at 110 K (l(Mo Ka)¼0.71073 A,
3.1.3. 1,21,23,25-Tetrapropyl-5,9,13,17-tetrakis(di-
methylamino)-2,20:3,19-dimetheno-1H,21H,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i0]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3c).2b The
title compound 3c is a white solid, mp 260–2628C; dP
(32.4 MHz, CDCl3) 141.1; dH (200 MHz, CDCl3) 1.02 (t,
12H, CH2CH2CH3), 1.41 (m, 8H, CH2CH2CH3), 2.20 (m,
˚
v-scans with 0.38 step in v and 30 and 30 s per frame
exposure, 2u,468) and 12,275 (Rint¼0.0720) independent
reflections were used in further refinement. The structures
was solved by direct method and refined by the full-matrix
least-squares technique against F 2 in the anisotropic–
isotropic approximation. All C9 substituents with the
exception of C62–C70 one, some of Et-groups and for
both dioxane solvate molecules are disordered. Due to
disorder the positions of oxygen atoms in dioxane molecule
have not been located. The refinement of the disordered
fragments was carried out in anisotropic (for some atom
isotropic) approximation with the restraints on the C–C
bond lengths (SAME, DFIX). The hydrogen atoms for the
undisordered part were located from electron density
synthesis while for the disordered the positions were
calculated geometrically. The refinement converged to
wR2¼0.3228 and GOF¼1.086 for all independent reflec-
tions R1¼0.1086 was calculated against F for 8760 observed
reflections with I.2s(I)). The number of the refined
parameters was 1178. All calculations were performed
using SHELXTL PLUS 5.1 on IBM PC AT.
3
8H, CH2CH2CH3), 2.85 (d, JPH¼10.5 Hz, 24H, NCH3),
3
4.68 (t, JHH¼8.0 Hz, 4H, CH), 6.58 (s, 4H, Ho), 7.20 (s,
4H, Hm).
3.1.4. 1,21,23,25-Tetrapropyl-5,9,13,17-tetrakis(diethyl-
amino)-2,20:3,19-dimetheno-1H,21H0,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i ]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3d).2b The
title compound 3d is a white solid, mp 245–2478C; dP
(32.4 MHz, CDCl3) 142.6; dH (200 MHz, CDCl3) 0.99 (t,
12H, CH2CH2CH3), 1.18 (t, 24H, NCH2CH3), 1.73 (m, 8H,
CH2CH2CH3), 2.19 (m, 8H, CH2CH2CH3), 3.27 (m,
3
3JPH¼10.6 Hz, 16H, NCH2CH3), 4.62 (t, JHH¼8.0 Hz,
4H, CH), 6.51 (s, 4H, Ho), 7.13 (s, 4H, Hm).
3.1.5. 1,21,23,25-Tetrahexyl-5,9,13,17-tetrakis(diethyl-
amino)-2,20:3,19-dimetheno-1H,21H0,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i ]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3e).2d The
title compound 3e is a white solid, mp 220–2238C; dP
(32.4 MHz, CDCl3) 142.6; dH (200 MHz, CDCl3) 0.91 (t,
12H, CH2(CH2)4CH3), 1.20 (t, 24H, NCH2CH3), 1.34 (br,
32H, CH2(CH2)4CH3), 2.23 (m, 8H, CH2(CH2)4CH3), 3.30
(m, 3JPH¼10.4 Hz, 16H, NCH2CH3), 4.61 (t, 3JHH¼7.8 Hz,
4H, CH), 6.53 (s, 4H, Ho), 7.14 (s, 4H, Hm).
Crystallographic data (excluding structure factors) for the
structure reported in this paper have been deposited with the
Cambridge Crystallographic Data Center as supplementary
nos. CCDC-177749. Copies of the data can be obtained free
of charge on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ UK (Fax: (internat.) þ44-1223/336-
033; e-mail: deposit @ccdc.cam.ac.uk.
3.1. Cyclophosphorylation of calix[4]resorcinarenes with
diamidoarylphosphites: general procedure
3.1.6. 1,21,23,25-Tetranonyl-5,9,13,17-tetrakis(diethyl-
amino)-2,20:3,19-dimetheno-1H,21H0,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i ]benzo[1,2-
d:5,4-d ]bis[1,3,2l3] benzodioxaphosphocine (3f).6 The
title compound 3f is a white solid, mp 162–1638C; dP
(32.4 MHz, CDCl3) 142.7; dH (200 MHz, CDCl3) 0.89 (t,
A solution of calix[4]resorcinarene 1 (0.4 mmol) and
diamidophosphite 4 (1.6 mmol) in dioxane (4 mL) was
maintained at 20–258C for 3–15 days, depending on the

V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
1759
12H, CH2(CH2)7CH3), 1.19 (t, 24H, NCH2CH3), 1.28 (br,
56H, CH2(CH2)7CH3), 2.20 (m, 8H, CH2(CH2)7CH3), 3.29
(m, 3JPH¼10.5 Hz, 16H, NCH2CH3), 4.60 (t, 3JHH¼7.8 Hz,
4H, CH), 6.51 (s, 4H, Ho), 7.12 (s, 4H, Hm).
246–2488C (decomp); [Found: C, 59.02; H, 4.43; P, 10.27.
C60H52O12P4S4 requires: C, 59.20; H, 4.31; P, 10.18%];
nmax (KBr) 2955, 2918, 2849, 1489, 1456, 1280, 1153,
1096, 1024, 997, 920, 885, 875, 755, 733, 694, 674 cm21; dP
(32.4 MHz, CDCl3) 58.7; dH (200 MHz, CDCl3) 1.79 (d,
3
3.1.7. 1,21,23,25-Tetraphenyl-5,9,13,17-tetrakis(di-
methylamino)-2,20:3,19-dimetheno-1H,21H,23H,25H-
bis[1,3,0 2l3]dioxaphosphocino[5,4-i:50,40-i0]benzo[1,2-
d:5,4-d ]bis[1,3,2l3]benzodioxaphosphocine (3g). The
title compound 3g is a rosy solid, mp 217–2198C;
[Found: C, 66.49; H, 5.62; N, 5.41; P, 11.19.
C60H56N4O8P4 requires: C, 66.42; H, 5.20; N, 5.16; P,
11.42 %]; nmax (KBr) 2969, 2849, 1485, 1455, 1151, 1095,
1024, 995, 889, 846, 798, 788, 750 cm21; dP (32.4 MHz,
CDCl3) 141.9; dH (200 MHz, CDCl3) 2.82 (d,
3JPH¼10.3 Hz, 24H, NCH3), 6.26 (s, 4H, CH), 6.72 (s,
4H, Ho), 6.90 (s, 4H, Hm), 7.14–7.29 (20H, C6H5); m/z
1085 [Mþ].
3JHH¼7.1 Hz, 12H, CH3), 4.85 (q, JHH¼7.1 Hz, 4H, CH),
3
5.37 (d, JPH¼9.4 Hz, 8H, CH2), 6.64 (s, 4H, Ho), 7.30 (s,
4H, Hm), 7.38–7.48 (20H, C6H5); m/z 1242.1 [MþNaþ].
3.1.11. Bis(N,N-diethylamide)-O-tocopherylphosphite
(13). A mixture of hexaethylphosphorus triamide (24.8 g,
100 mmol) and a-tocopherol (43.1 g, 100 mmol) was
heated at 90–1008C. The formed diethylamine was
continuously removed by distillation in a slow stream of
argon. After 5 h the formation of diethylamine was
completed and the reaction mixture was purified in vacuo
from residual hexaethylphosphorus triamide and diethyl-
amine and could be used for further reactions. The title
compound 13 (60.0 g, 100%) is a yellow oil; [Found: C,
73.54; H, 12.08; N, 4.88. C37H69N2O2P requires: C, 73.46;
H, 11.50; N, 4.43%]; dP (121.5 MHz C6D6) 130.33; dH
3.1.8. 1,21,23,25-Tetraphenyl-5,9,13,17-tetrakis(diethyl-
amino)-2,20:3,19-dimetheno-1H,210H0,23H,25H-
bis[1,30,2l3]dioxaphosphocino[5,4-i:50,4 -i ]benzo[1,2-
d:5,4-d ]bis[1,3,2l3]benzodioxaphos-phocine (3h). The
title compound 3h is a rosy solid, mp 230–2328C;
[Found: C, 68.44; H, 6.26; N, 4.64; P, 10.01.
C68H72N4O8P4 requires: C, 68.22; H, 6.06; N, 4.68; P,
10.35%]; nmax (KBr) 2973, 2930, 2877, 1485, 1455, 1151,
1095, 1024, 990, 889, 846, 798, 788, 745 cm21; dP
(32.4 MHz, CDCl3) 143.4; dH (200 MHz, CDCl3) 1.19 (t,
3
(300 MHz C6D6): 0.92 (t, JHH¼7.8 Hz, 12H, CH3 toco-
pherol side-chain), 1.03 (t, 3JHH¼7.0 Hz, 12H,
N(CH2CH3)2), 1.10–1.70 (m, br, 23H, CH and CH2 from
tocopherol), 1.20 (s, 3H, CH3), 2.32 (s, 3H, Ar–CH3), 2.34
3
(s, 3H, Ar–CH3), 2.35 (s, 3H, Ar–CH3), 2.45 (t, JHH
7.0 Hz, 2H, CH2), 3.04–3.18 (m, 8H, N(CH2CH3)2); dC
¼
3
(75.48 MHz C6D6) 12.91 (Ar–CH3), 14.33 (d, JPC
15.13
¼
7.3 Hz,
N(CH2CH3)2),
(d,
3JPC¼7.3 Hz,
3
3JHH¼7.3 Hz, 24H, CH3), 3.27 (m, JPH¼10.7 Hz, 16H,
N(CH2CH3)2), 15.80 (d, JPC¼7.3 Hz, Ar–CH3), 20.31–
20.49, 21.78 (CH2), 21.97 (CH2), 23.30, 23.40, 24.46, 25.42
(CH2), 25.78 (CH2), 28.83, 32.38 (CH2), 33.58, 33.71,
NCH2), 6.25 (s, 4H, CH), 6.71 (s, 4H, Ho), 6.86 (s, 4H, Hm),
7.06–7.36 (20H, C6H5).
38.23–38.55
(CH2),
40.39
3
(d,
3JPC¼19.9 Hz,
3.1.9. 1,21,23,25-Tetramethyl-5,9,13,17-tetrabenzoxy-
2,20:3,19-dimetheno0-1H,21H,23H,25H-bis[1,3,2l3]dioxa-
phosphocino[5,4-i:5 ,40-i0]benzo[1,2-d:5,4-d0]bis[1,3,2l3]
benzodioxaphosphocine (9). A solution of 1a (92.48 mg,
0.17 mmol) and 8 (115.04 mg, 0.68 mmol) in acetonitrile
(2 mL) was maintained at 258C for 24 h. The precipitate was
filtered off, washed with dioxane and dried in vacuo. The title
compound 9 (88.8 mg, 48%) is a white solid, mp 221–2228C
(decomp); [Found: C, 65.89; H, 4.92; P, 10.98. C60H52O12P4
requires: C, 66.18; H, 4.81; P, 11.3%]; nmax (KBr) 2959, 2923,
1488, 1455, 1156, 1096, 1021, 990, 886, 835, 736 cm21; dP
(32.4 MHz, CDCl3) 127.5; dH (200 MHz, CDCl3) 1.80 (d,
N(CH2CH3)2), 40.64 (d, JPC¼19.4 Hz, N(CH2CH3)2),
75.03 (tert.-C), 117.98 (d, JPC¼1.6 Hz), 123.33 (d,
JPC¼1.6 Hz), 126.00 (d, JPC¼3.8 Hz), 128.37 (overlapped
3
by signal of C6H6), 146.23 (d, JPC¼8.1 Hz), 148.02 (d,
JPC¼1.9 Hz, Ar–C); m/z 605 [MþHþ].
3.1.12. Diethylamido-(1,10-binaphthalen-2,20-yl)phos-
phite (15). A solution of 10 (57.2 mg, 0.2 mmol) and 4b
(53.6 mg, 0.2 mmol) in acetonitrile (1 mL) was maintained
at 808C for 0.5 h. The solvent was half removed by
distillation in vaccuo. The precipitate was filtered off,
recrystallized from acetonitrile and dried in vacuo. The title
compound 15 (63.5 mg, 82%) is a white solid, mp 183–
1848C; [Found: C, 74.49; H, 5.62; N, 3.41; P, 8.19.
C24H22NO2P requires: C, 74.41; H, 5.72; N, 3.62; P,
8.00%]; nmax (KBr) 2976, 2964, 2931, 1590, 1503, 1463,
3
3JHH¼7.7 Hz, 12H, CH3), 4.91 (q, JHH¼7.7 Hz, 4H, CH),
5.35 (d, 3JPH¼6.1 Hz, 8H, CH2), 6.70 (s, 4H, Ho), 7.32 (s, 4H,
Hm), 7.38–7.48 (20H, C6H5).
Tetrathion derivative 9a was obtained by the sulfurisation of
cavitand 9.
1376, 1327, 1235, 1205, 950, 936, 823, 798, 790, 755 cm21
;
dP (32.4 MHz, CDCl3) 150.2; dH (200 MHz, CDCl3) 1.05 (t,
3JHH¼7.2 Hz, 6H, NCH2CH3), 2.87 (m, 3JPH¼12.8 Hz, 2H,
2
3
3.1.10. 1,21,23,25-Tetramethyl-5,9,13,17-tetrabenzoxy-
5,9,13,17-tetrathion-2,20:3,19-dimetheno-1H,21H,
23H,25H-bis[1,3,2l3]dioxaphosphocino[5,4-i:50,40-
i0]benzo[1,2-d:5,4-d0]bis[1,3,2l3]benzodioxaphosphocine
(9a). A solution of sulfur (13.12 mg, 0.41 mmol) in benzene
(2 mL) was added to a solution of 9 (112.06 mg,
0.103 mmol) in chloroform (2 mL). The reaction mixture
was stirred at 808C for 3 h. Two thirds of solvent were
removed by distillation in vacuo. The precipitate was
filtered off, washed with dioxane and dried in vacuo. The
title compound 9a (110.2 mg, 88%) is a white solid, mp
NCH2CH3), 3.04 (m, JHH¼14.1 Hz, JPH¼9.0 Hz, 2H,
NCH2CH3), 7.23–7.50 (8H, H-arom.), 7.80–7.98 (4H,
H-arom).
3.1.13. Diethylamido-O-(2-[2-hydroxy-3-tert-butyl-5-
methylbenzyl]-4-methyl-6-tert-butyl-phenyl)-O-phenyl-
phosphite (16a). A solution of 11a (115.6 mg, 0.34 mmol)
and 4b (91.1 mg, 0.34 mmol) in acetonitrile (1 mL) was
maintained at 758C for 1.5 h. The solvent was removed by
distillation and the residue was dried in vacuo. The title
compound 16a (178.3 mg, 98%) is a yellow oil; [Found: C,

1760
V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
74.28; H, 8.97; N, 2.44; P, 8.61. C33H46NO3P requires: C,
73.99; H, 8.66; N, 2.61; P, 5.78%]; dP (32.4 MHz, CDCl3)
CH2), 1.72 (s, 3H, Ar–CH3), 1.78 (s, 3H, Ar–CH3), 1.94 (s,
3
3H, Ar–CH3), 2.41 (t, JHH¼6.6 Hz, 2H, CH2), 3.00–3.15
3
147.2; dH (200 MHz, CDCl3) 1.15 (t, JHH¼7.3 Hz, 6H,
(m, br., 2H, N(CH2CH3)2), 3.30–3.45 (m, br., 2H,
N(CH2CH3)2), 3.98 (d, 1H, JHH¼16.0 Hz, Ar–CH2–Ar),
2
NCH2CH3), 1.43 (s, 9H, C(CH3)3), 1.51 (s, 9H, C(CH3)3),
2.24 (s, 3H, CH3), 2.31 (s, 3H, CH3), 3.32–3.41 (br.m,
2
4.16 (d, 1H, JHH¼16.0 Hz, Ar–CH2–Ar), 5.90 (s, 1H,
3
3JPH¼9.4 Hz, JPH¼9.0 Hz, 4H, NCH2CH3), 3.97 (d,
OH), 6.80 (s, 1H, Ar–H), 6.91 (s, 1H, Ar–H), 7.08 (s, 1H,
Ar–H), 7.20 (s, 1H, Ar–H); dC (75.48 MHz, CDCl3) 11.88,
12.54, 13.80 (d, 3JPC¼4.6 Hz, N(CH2CH3)2), 14.74, 19.65–
19.75, 20.84 (CH2), 21.06 (CH2), 22.63, 22.72, 23.54, 23.93,
24.45 (CH2), 24.82 (CH2), 27.99, 29.65 (C(CH3)3), 30.07,
30.97, 31.32 (C(CH3)3), 31.53 (CH2), 31.59, 31.68
2
2JHH¼15.4 Hz, 1H, Ar–CH2–Ar), 4.36 (d, JHH¼15.4 Hz,
1H, Ar–CH2–Ar), 5.75 (br.s, 1H, OH), 6.84 (s, 1H,
H-arom.), 6.89 (s, 1H, H-arom.), 6.95–7.05 (3H, C6H5),
7.08 (br.s, 2H, H-arom.), 7.23–7.29 (2H, C6H5).
4
3.1.14. Diethylamido-O-(2-[2-hydroxy-3-tert-butyl-5-
methyl-benzyl]-4-methyl-6-tert-butyl-phenyl)-O-toco-
pherylphosphite (16b). A solution of 13 (6.05 g, 10 mmol)
in toluene (20 mL) was added dropwise to a solution of 11a
(3.40 g, 10 mmol) in toluene (30 mL) and the mixture was
refluxed for 24 h. The liquids were removed in vacuo and
the residue was purified by column chromatography (bas.
Alox, n-hexane; Rf¼0.4). The title compound 16b (5.80 g,
66.5%) is a yellow oil; [Found: C, 76.79; H, 10.14; N, 2.01.
C56H90NO4P requires: C, 77.11; H, 10.40; N, 1.61]; dP
(121.5 MHz, CDCl3) 147.64; dH (300 MHz, CDCl3) 0.78 (t,
3JHH¼6.9 Hz, 12H, CH3 from tocopherol side-chain), 1.02
(C(CH3)3), 32.22 (d, JPC¼5.9 Hz, C(CH3)3), 32.76, 33.79
(Ar–CH2–Ar), 34.15 (C(CH3)3), 34.31 (C(CH3)3), 34.62
(C(CH3)3), 35.30 (C(CH3)3), 37.31–37.63 (CH2), 39.13 (d,
2JPC¼22.9 Hz, N(CH2CH3)2), 39.39 (CH2), 74.68 (tert.-C),
117.45, 121.96, 123.80, 125.03, 125.44, 126.16, 127.89,
128.32, 129.04, 132.22, 135.25, 141.14, 141.42, 141.65,
145.77, 147.45, 147.67, 150.86 (Ar–C); m/z 957 [MþHþ].
3.1.16. 2-Diethylamino-4,5;7,8-dibenzo-9,90-di-tert-
butyl-11,110-dimethyl-1,3,2-dioxaphosphocin (17a).7 (a)
A solution of 11a (115.6 mg, 0.34 mmol) and 4b (91.1 mg,
0.34 mmol) in acetonitrile (1 mL) was maintained at
80–908C for 10 h.
3
(t, JHH¼6.7 Hz, 6H, N(CH2CH3)2), 1.10–1.50 (m, br.,
21H, CH and CH2 from tocopherol side-chain, 3H, CH3),
1.26 (s, 9H, C(CH3)3), 1.37 (s, 9H, C(CH3)3), 1.60–1.70 (m,
br., 2H, CH2), 1.79 (s, 3H, Ar–CH3), 1.85 (s, 3H, Ar–CH3),
1.95 (s, 3H, Ar–CH3), 2.11 (s, 3H, Ar–CH3), 2.16 (s, 3H,
Ar–CH3), 2.42 (t, br., 2H, CH2), 3.00–3.15 (m, br., 2H,
N(CH2CH3)2), 3.30–3.45 (m, br., 2H, N(CH2CH3)2), 84 (d,
(b) A solution of 16a (107.0 mg, 0.2 mmol) in acetonitrile
(1 mL) was maintained at 85–958C for 8 h.
(c) A solution of 16b (1.00 g, 0.114 mmol) in xylene
(15 mL) was heated under reflux for 8 h.
2
2
1H, JHH¼15.6 Hz, Ar–CH2–Ar), 4.16 (d, 1H, JHH
¼
15.6 Hz, Ar–CH2–Ar), 6.04 (s, 1H, OH), 6.67 (s, 1H, Ar–
H), 6.73 (s, 1H, Ar–H), 6.86 (s, 1H, Ar–H), 6.96 (s, 1H,
Ar–H); dC (75.48 MHz, CDCl3) 11.88, 12.90, 13.80 (d,
3JPC¼4.6 Hz, N(CH2CH3)2), 14.64, 19.65, 20.81, 20.99
(CH2), 22.62, 22.72, 23.56 (Ar–CH3 from bisphenol), 23.93
(Ar–CH3 from bisphenol and toc-CH), 24.45 (CH2), 24.81
(CH2), 27.98, 29.59 (C(CH3)3), 31.25, 31.40 (CH2), 32.04
The solvent was removed by distillation. The residue was
recrystallized from benzene and dried in vacuo. The title
compound 17a (72 (a), 48.5 (b), and 32.2 (c) mg, 48, 55, and
64% respectively) is a white solid, mp. 136–1378C; [Found:
C, 73.13; H, 9.44; N, 3.41. C27H40NO2P requires: C 73.44 H
9.13 N 3.17%]; dP (121.50 MHz, CDCl3) 144.42; d
3
H
(300.13 MHz, CDCl3) 1.29 (t, JHH¼7.1 Hz, 6 H,
4
(d, JPC¼5.81 Hz, C(CH3)3), 32.76, 33.79 (Ar–CH2–Ar),
N(CH2CH3)2),1.40 (s, 18 H, C(CH3)3), 2.28 (s, 6 H, CH3),
3.30 (d, 2JHH¼12.4 Hz, 1 H, e-CH2), 3.43 (p, 3JHH¼7.1 Hz,
4 H, N(CH2CH3)2), 4.35 (dd, 2JHH¼12.4 Hz, 5JPH¼2.8 Hz,
1 H, a-CH2), 7.00 (s, 2 H, Ar–H), 7.09 (s, 2 H, Ar–H); (C
(75.48 MHz, CDCl3) 14.28 (d, 3JPC¼4.2 Hz, N(CH2CH3)2),
20.94 (CH3), 30.86 (d, JPC¼4.2 Hz, C(CH3)3), 34.61 (CH2),
34.62 (C(CH3)3), 35.30 (C(CH3)3), 37.31–37.61 (CH2),
39.11 (d, 2JPC¼23.1 Hz, N(CH2CH3)2), 39.39 (CH2), 74.63
(tert.-C), 117.4, 122.84, 125.84 (2 s), 126.98, 127.70,
127.83 (d, JPC¼3.2 Hz), 127.93, 128.44, 129.09, 132.73,
132.83, 135.93, 141.70 (d, JPC¼4.9 Hz), 141.92 (d,
2
2
JPC¼2.2 Hz), 147.49 (d, JPC¼4.5 Hz), 147.68, 151.16
34.68 (C(CH3)3), 38.76 (d, JPC¼21.3 Hz, N(CH2CH3)2),
(Ar–C); m/z 873 [MþHþ], 912 [MþKþ].
126.28, 128.37, 132.57, 136.30 (d, JPC¼3.2 Hz), 141.57 (d,
JPC¼3.4 Hz), 148.13 (d, JPC¼7.9 Hz, Caryl); m/z 443
[MþHþ], 370 [M2HNEt2þHþ].
3.1.15. Diethylamido-O-(2-[2-hydroxy-3,5-di-tert-butyl-
benzyl]-4,6-di-tert-butyl phenyl)-O-tocopherylphosphite
(16c). A solution of 13 (12.10 g, 20 mmol) in toluene
(20 mL) was added dropwise to a solution of 11b (8.50 g,
20 mmol) in toluene (70 mL) and the mixture was refluxed
for 24 h. The liquids were removed in vacuo and the
residue was purified by column chromatography (bas. Alox,
n-hexane). The title compound 16c (17.3 g, 90.4%) is a
colourless oil; [Found: C, 77.69; H, 10.66; N, 1.75.
C62H102NO4P requires: C, 77.86; H, 10.75; N, 1.46%]; dP
(121.5 MHz, CDCl3) 147.66; dH (300 MHz, CDCl3) 0.78 (t,
3JHH¼7.2 Hz, 12H, CH3 from tocopherol side-chain), 1.02
3.1.17. 2-Diethylamino-4,5;7,8-dibenzo-9,90,11,110-tetra-
tert-butyl-1,3,2-dioxaphosphocine (17b).7 Was obtained
from 16c (1.00 g, 0.1 mmol) analogous to 17a (c). The title
compound 17b (37.8 mg, 72%) is a white solid, mp 162–
1638C; [Found: C, 75.76; H, 10.27; N, 2.74. C33H52NO2P
required: C 75.39 H 9.97 N 2.66%]; dP (121.1 MHz, CDCl3)
3
143.93; dH (300.13 MHz, CDCl3) 1.29 (t, JHH¼7.1 Hz, 6
H, N(CH2CH3)2), 1.31 (s, 18 H, C(CH3)3), 1.42 (s, 18 H,
C(CH3)3), 3.39 (d, JHH¼12.4 Hz, 1 H, e-CH2), 3.43 (p,
2
3JHH¼7.1 Hz, 6 H, N(CH2CH3)2), 4.41 (dd, 2JHH¼12.4 Hz,
3
(t, JHH¼7.0 Hz, 6H, N(CH2CH3)2), 0.90–1.50 (m, br.,
5JPH¼2.9 Hz, 1 H, a-CH2), 7.24 (d, 4JHH¼2.3 Hz, 2 H, Ar–
4
21H, CH and CH2 from tocopherol side-chain, 3H, CH3),
1.11 (s, 9H, C(CH3)3), 1.19 (s, 9H, C(CH3)3), 1.27 (s, 9H,
C(CH3)3), 1.39 (s, 9H, C(CH3)3), 1.60–1.70 (m, br., 2H,
H), 7.30 (d, JHH¼2.3 Hz, 2 H, Ar–H); dC (75.48 MHz,
3
CDCl3) 14.40 (d, JPC¼4.3 Hz, N(CH2CH3)2), 30.97 (d,
JPC¼5.1 Hz, C(CH3)3), 31.52 (C(CH3)3), 34.40, 35.08

V. I. Maslennikova et al. / Tetrahedron 59 (2003) 1753–1761
1761
2
2. Maslennikova, V. I.; Shkarina, E. V.; Bekker, A. R.; Vasyanina,
L. K.; Nifantyev, E. E. Phosphorus, Sulfur Silicon 1996, 113,
219–223. (b) Maslennikova, V. I.; Shkarina, E. V.; Vasyanina,
L. K.; Lysenko, K. A.; Sinicina, T. K.; Merkulov, R. V.;
Nifantyev, E. E. Phosphorus, Sulfur Silicon 1998, 139,
173–186. (c) Maslennikova, V. I.; Shkarina, E. V.; Vasyanina,
L. K.; Lysenko, K. A.; Antipin, M. Yu.; Nifantyev, E. E. Russ.
J. Gen. Chem. 1998, 68, 350–361. (d) Nifantyev, E. E.;
Maslennikova, V. I.; Rasadkina, E. N. Russ. J. Gen. Chem.
1999, 69, 1736–1758. (e) Antipin, I. S.; Kazakova, E. Kh.;
Habicher, W. D.; Konovalov, A. I. Russ. Chem. Rev. 1998, 67,
995–1012.
(C(CH3)3), 35.39 (CH2), 38.86 (d, JPC¼21.3 Hz,
N(CH2CH3)2), 122.62, 124.75, 135.97 (d, JPC¼3.3 Hz),
140.93 (d, JPC¼4.2 Hz), 145.69, 148.02 (d, JPC¼7.8 Hz,
Caryl); m/z 526 [MþHþ], 453 [M2HNEt2þHþ].
3.1.18. Reaction of diamidophosphite (13) with 2,6-bis(2-
hydroxy-3-tert-butyl-5-methyl-benzyl)-4-methylphenol
(12). A solution of 13 (12.10 g, 20 mmol) in toluene
(10 mL) was added dropwise to a solution of 12 (1.50 g,
3.30 mmol) in toluene (20 mL) and the mixture was
refluxed for 24 h. The liquids were removed in vacuo. The
residue was dissolved in 5 mL of methylene chloride and
yellowish crystals, identified by NMR as a mixture of 19
and tocopherol, were formed after 20 mL of acetonitrile was
added. NMR of compound 19: dP (121.5 MHz, CDCl3)
144.46; dH (300 MHz, CDCl3) 1.23 (t, 6H, N(CH2CH3)2),
1.30, 1.31 (s, 18H, C(CH3)3), 2.13, 2.18, 2.19 (s, 12H, CH3),
3. Nifantyev, E. E.; Maslennikova, V. I.; Merkulov, R. V.;
Lysenko, R. A.; Antipin, M. Yu. Mendeleev Commun. 2000,
195–196.
¨
4. Vollbrecht, A.; Neda, I.; Thonnessen, H.; Jones, P. G.; Harris,
R. K.; Crowe, L. A.; Schmutzler, R. Chem. Ber. Recueil 1997,
130, 1715–1720. (b) Moran, J. R.; Karback, S.; Cram, D. J.
J. Am. Chem. Soc. 1982, 104, 5826–5828.
2
3.35–3.44 (m, 4H, N(CH2CH3)2), 3.25 (d, JHH¼12.5 Hz,
1H, CH2), 4.27 (dd, 2JHH¼12.7 Hz, 5JPH¼3.0 Hz, 1H, CH2),
2
2
3.47 (d, JHH¼14.6 Hz, 1H, CH2), 3.93 (d, JHH¼14.6 Hz,
1H, CH2), 6.59 (1H, OH), 6.83–6.94 (6H, Ar–H).8
5. Schmidt, M. V.; Baldridge, K. K.; Boatz, J. A.; Elbert, S. T.;
Gordon, M. S.; Jonsen, J. H.; Koseki, S.; Matsnaga, N.; Nguyen,
K. A.; Su, S. J.; Windus, T. L.; Dupuis, J. A.; Montgomery, J. A.
J. Comput. Chem. 1993, 14, 1347–1363.
Acknowledgements
6. Sinicina, T. K.; Maslennikova, V. I.; Vasyanina, L. K.;
Dyagileva, M. V.; Nifantyev, E. E. Russ. J. Gen. Chem. 2000,
70, 714–720.
This work was supported in part by the Russian Foundation
for Basic Research (grant no. 00-03-32844a), the German
Ministry of Education and Research (BMBF, grant no. RUS
00/216), the Fonds der Chemischen Industrie and the BASF
Schwarzheide GmbH.
7. Danilova, O. I.; Arshinova, R. P.; Kadirova, V. Kh.;
Mukmeneva, N. A.; Arbuzov, B. A. Zh. Obshch. Khim. 1987,
57, 2671–2679.
8. Weber, D.; Habicher, W. D.; Nifantev, E. E.; Teleshev, A. T.;
Zhdanov, A. A.; Belsky, V. K. Phosphorus, Sulfur Silicon 1999,
149, 143–165.
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