Reactions of N,N′-dimethyl-N,N′-bis(trimethylsilyl)-methylphosphonic diamide with chloral and chloromethyldimethylchlorosilane

Article abstract of DOI:10.1023/A:1012340630796

N,N′-Dimethyl-N,N′-bis(trimethylsilyl)methylphosphonic diamide reacts with chloral to form 1,2,3-trimethyl-4,4-dichloro-5-trimethylsiloxy-1,3,2-diazaphospholidine 2-oxide and with chloromethyldimethylchlorosilane to form 1,2,3,4,4-pentamethyl-1,3-diaza-2-

Full text of DOI:10.1023/A:1012340630796

Russian Journal of General Chemistry, Vol. 71, No. 3, 2001, pp. 327 329. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 3, 2001,
pp. 360 362.
Original Russian Text Copyright
2001 by M. Pudovik, Kibardina, Zyablikova, A. Pudovik.
Reactions of N,N -Dimethyl-N,N -bis(trimethylsilyl)-
methylphosphonic Diamide with Chloral
and Chloromethyldimethylchlorosilane
M. A. Pudovik, L. K. Kibardina, T. A. Zyablikova, and A. N. Pudovik
Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Center,
Russian Academy of Sciences, Kazan, Tatarstan, Russia
Received December 21, 1999
Abstract N,N -Dimethyl-N,N -bis(trimethylsilyl)methylphosphonic diamide reacts with chloral to form
1,2,3-trimethyl-4,4-dichloro-5-trimethylsiloxy-1,3,2-diazaphospholidine 2-oxide and with chloromethyldi-
methylchlorosilane to form 1,2,3,4,4-pentamethyl-1,3-diaza-2-phospha-4-silacyclopentane 2-oxide.
A promising route to polyheterophosphacyclanes
involves the use of polyfunctional derivatives of four-
coordinate phosphorus in which two or more structur-
al fragments can interact intramolecularly to form ring
systems. This approach was successful in synthesis of
chloromethylphosphonates (-phosphinates) containing
urea, thiourea, and other groups at the phosphorus
atom; it allowed synthesis of various saturated and
unsaturated phosphacyclanes [1 3]. By phosphoryla-
tion of heptamethyldisilazane with chloromethylphos-
phonic chloride derivatives we prepared (N-trimethyl-
silyl)chloromethylphosphonic amides which were con-
verted to 1,4,2-diazaphospholidin-5-ones [4]. Proceed-
ing with these studies, we attempted to prepare N,N -
dimethyl-N,N -bis(trimethylsilyl)methylphosphonic
diamide I with the aim of its further transformation
into new cyclic compounds. However, the reaction of
methylphosphonic dichloride with heptamethyldisila-
zane (1 : 2 ratio) occurs by several pathways and gives
a mixture of products. We were able to prepare I by
silylation of N,N -dimethylmethylphosphonic diamide
with trimethylchlorosilane in the presence of a base
(1 : 2 : 2 ratio):
good grounds to expect that the reaction of I with
chloral would yield the insertion product II in which
there are two possibilities of ring closure: elimination
of siloxane to form diazaphosphetidine III and elim-
ination of trimethylchlorosilane to form phosphacy-
clane IV. The reaction readily occurs at room temper-
ature and yields 1,2,3-trimethyl-4,4-dichloro-5-tri-
methylsiloxy-1,3,2-diazaphospholidine 2-oxide IV.
CH3
CH3P(O)(NSiMe3)2 + CCl3CHO
I
O Me
CH3P N CH OSiMe
CCl3
MeN
SiMe3
II
Me
O
1
N
CH3P
CCl3
N
(Me3SiO)2O
MeP(O)(NHMe)2 + 2Me3SiCl
Me
III
2B
MeP(O)(NSiMe3)2.
B HCl
Me
O
Me
2
I
CH3P
N
Me3SiCl
CH OSiMe3
CCl2
N
The only example of the reaction of chloral with
a four-coordinate phosphorus compound containing
a P NR SiMe3 fragment is reported in [5]. It was
concluded that chloral is not inserted into the N Si
bond; instead, the Wittig reaction occurs with the
tautomeric imide form [5]. Nevertheless, there were
Me
IV
According to the NMR spectra, diazaphospholidine
IV exists in solution in the form of cis and trans iso-
1070-3632/01/7103-0327$25.00 2001 MAIK Nauka/Interperiodica

328
PUDOVIK et al.
1H, 13C, and 31P NMR spectra of 1,2,3-trimethyl-4,4-dichloro-5-trimethylsiloxy-1,3,2-diazaphospholidine 2-oxide IV:
chemical shifts ( , ppm) and coupling constants (J, Hz)
cis-IV
trans-IV
Nucleus
J
J
P
30.46
27.95
31.31
27.30
C6
2.4 (PNC6)
138.6 (C6H)
116.6 (PC7)
127.0 (C7H)
0 (PNC8)
3.3 (PNC6)
138.6 (C6H)
3.3 (PC7)
C7
C8
C4
12.42
26.63
27.30
26.0
127.0 (C7H)
0 (PNC8)
138.0 (C8H)
6.4 (PC4)
138.0 (C8H)
6.4 (PC4)
104.28
87.24
104.28
87.90
9.9 (PC5)
9.6 (PC5)
162.0 (C5H)
119.0 (C9H)
12.0 (P NC6H)
15.0 (P C7H)
9.0 (P NC8H3)
8.0 (P NC5H)
162.0 (C5H)
119.0 (C9H)
12.0 (P NC6H)
15.0 (P C7H)
9.0 (P NC8H3)
8.0 (P NC5H)
C9
0.84
2.73
1.57
2.85
5.79
0.41
1.01
2.70
1.60
2.85
5.85
0.41
C6H3
C7H3
C8H3
C5H
C9H3
mers (see the table) differing in the relative orientation
of the OSiMe3 group and methyl substituent at phos-
phorus. Both methyl substituents at nitrogen atoms
probably occupy the equatorial position, as the param-
pected. Indeed, we isolated from the reaction mixture
1,2,3,4,4-pentamethyl-1,3-diaza-2-phospha-4-silacy-
clopentane 2-oxide V, with release of two trimethyl-
chlorosilane molecules:
1
eters of their H and 13C NMR signals are close in
6
both isomers. On the other hand, it is known that the
configuration of the nitrogen atom bound to four-
coordinate phosphorus becomes approximately planar
[6]. Assignment of the doubled signals in the NMR
spectra was made on the basis of the contraction
effect.
CH
3 H
O
H
N
5
H3C P 21
7
+ 2Me3SiCl.
I + ClCH2SiMe2Cl
1C0 H3
3 4
N Si9
CH3
8CH3
7
V
6
6
O
9
H3C
9
CH3
CH3
The 31P NMR chemical shift in V is
39.0 ppm.
2
P
2
P
OSi(CH3)3
7
OSi(CH3)3
1
5
1
5
P
H3C
In the 13C NMR spectrum the signal from the P CH3
3N C
3N C
O
H
N 4C Cl
Cl
H
N 4C Cl
Cl
8
carbon atom is observed at
12.42 ppm (1JPC
8
7 7
C
1
H3C
H3C
113.4, JC H 126.3 Hz). The methyl groups at the
nitrogen a7toms are nonequivalent:
25.82,
137.3, JC H
6 8
C H
6
8
C
C
2
1
1
35.64 ppm (2JPNC 2.4, J
7.7, J
cis-IV
trans-IV
6
8
PNC
135.9 Hz). The highest-field signals are those from
the methyl groups at the silicon atom, which are also
In the sterically strained cis isomer of IV the NMR
nonequivalent:
2.36 and
1.88 ppm (1JC H
9
signals of the exocyclic (
12.42,
0.84 ppm)
7
9
C
C
9
10
C
C
and endocyclic (
87.24,
30.46 ppm) atoms are
1
5
P
C
119.7, JC
119.5 Hz). In the low field are observed
signals from the endocyclic methylene carbon atom,
10
H
observed in the higher field as compared to the less
37.97 ppm (2JPNC 9.7, JC H 127.5 Hz). In the
1
strained trans isomer (
13.42,
1.01,
87.90,
5
C
7
9
C
31.31 ppm). According to the 31CP NMR spectrum,
5
5
5
C
1H NMR spectrum, the proton signal of the methyl
group at phosphorus is a doublet at 1.30 ppm (2JCH
15 Hz). The protons of the methyl groups at nitrogen
P
the ratio of cis-IV to trans-IV in chloroform is 74 : 26.
In silylation of I with chloromethyldimethylchloro-
silane, formation of a cyclic structure could be ex-
atoms are nonequivalent:
2.62,
2.58 ppm
6
C H
8
C H
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 3 2001

REACTIONS OF N,N -DIMETHYL-N,N -BIS(TRIMETHYLSILYL)METHYLPHOSPHONIC DIAMIDE
329
3
(3JPNC H 8, J
12 Hz). The protons of two meth-
chlorosilane was heated for 2 h at 120 C. Vacuum
fractionation gave 1.2 g (72%) of III, bp 80 82 C
8
yl gro6ups at tPhNeCsHilicon atom are also nonequivalent:
0.17 and 0.26 ppm; methylene protons give a multi-
(0.09 mm), mp 34 C.
39 ppm. Found, %: P 15.85;
plet in the range
2.18 2.58 ppm.
Si 14.04. C6H17N2OPSPi. Calculated, %: P 16.12; Si
14.58.
EXPERIMENTAL
ACKNOWLEDGMENTS
The NMR spectra were taken on Bruker MSL-400
(13C, 13C {1H} 100.6 MHz, 31P {1H} 161.8 MHz)
and Varian T-60 (1H, 60 MHz) spectrometers, refer-
ences TMS and H3PO4.
The study was financially supported by the Russian
Foundation for Basic Research (project no. 00-03-
32837).
N,N -Dimethyl-N,N -bis(trimethylsilyl)methyl-
phosphonic diamide II. To a mixture of 12.2 g of
phosphonate I and 20.2 g of triethylamine in 100 ml
of anhydrous chloroform, we added dropwise 21.8 g
of trimethylchlorosilane. The mixture was allowed to
stand for 12 h. Triethylamine hydrochloride was sep-
arated, the solvent was removed, and the residue was
vacuum-fractionated to give 6.5 g (25%) of phospho-
nate II, bp 72 C (0.009 mm Hg), d240 0.9609, nD20
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of ether was heated for 1 h, and the crystals that pre-
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9.03. C8H19Cl2N2O2PSi. Calculated, %: P 10.16; Si
9.18.
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1,2,3,4,4-Pentamethyl-1,3-diaza-2-phospha-4-
silacyclopentane 2-oxide V. A mixture of 2.3 g of
phosphonate II and 1.2 g of chloromethyldimethyl-
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 3 2001