Reactions of Bis(chloromethyl)phosphinic(-phosphinothioic) chlorides with silylated carbamates and trimethylsilyl N-trimethylsilylacetimidoate

Article abstract of DOI:10.1023/A:1012336429887

Bis(chloromethyl)phosphinic chloride reacts with trimethylsilyl methylcarbamate in benzene in the presence of a base to give trimethylsilyl bis(chloromethyl)phosphinate. The same reaction performed without a solvent and in the absence of a base yields trimethylsilyl bis(chloromethyl)phosphinate and bis(chloromethyl)phosphinic anhydride. Reaction of bis(chloromethyl)phosphinic chloride with trimethylsilyl diethylcarbamate yields N,N-diethylbis(chloromethyl)phosphinic amide. The reaction of bis(chloromethyl)phosphinic (-phosphinothioic) chlorides with trimethylsilyl N-trimethylsilylacetimidoate was studied.

Full text of DOI:10.1023/A:1012336429887

Russian Journal of General Chemistry, Vol. 71, No. 3, 2001, pp. 321 324. Translated from Zhurnal Obshchei Khimii, Vol. 71, No. 3, 2001,
pp. 354 357.
Original Russian Text Copyright
2001 by Kibardina, M. Pudovik, and A. Pudovik.
Reactions of Bis(chloromethyl)phosphinic(-Phosphinothioic)
Chlorides with Silylated Carbamates
and Trimethylsilyl N-Trimethylsilylacetimidoate
L. K. Kibardina, M. A. Pudovik, 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 Bis(chloromethyl)phosphinic chloride reacts with trimethylsilyl methylcarbamate in benzene in
the presence of a base to give trimethylsilyl bis(chloromethyl)phosphinate. The same reaction performed
without a solvent and in the absence of a base yields trimethylsilyl bis(chloromethyl)phosphinate and bis-
(chloromethyl)phosphinic anhydride. Reaction of bis(chloromethyl)phosphinic chloride with trimethylsilyl
diethylcarbamate yields N,N-diethylbis(chloromethyl)phosphinic amide. The reaction of bis(chloromethyl)-
phosphinic (-phosphinothioic) chlorides with trimethylsilyl N-trimethylsilylacetimidoate was studied.
Chloromethylphosphonic (-phosphinic) chlorides
exhibit a high phosphorylating power [1], and poly-
functional chloromethyl derivatives of four-coordinate
phosphorus show promise in synthesis of polyhetero-
phosphacyclanes [2 4]. Proceeding with these studies,
we performed reactions of bis(chloromethyl)phosphinic
chloride I and its thio analog with some silylated
carbamates and with mono- and disilylated acetamides.
We found that trimethylsilyl methylcarbamate
II reacts with bis(chloromethyl)phosphinic chloride
I in benzene in the presence of a base with heat
evolution and formation of triethylamine hydro-
chloride and trimethylsilyl bis(chloromethyl)phos-
phinate III.
(ClCH2)2P(O)OP(O)(CH2Cl)2
VII
MeNCO
O Me
(ClCH2)2P N C(O)OP(O)(CH2Cl)2
VI
Me
N
O
a
I
ClCH2P
Me3SiCl
C=O
O
Et3N
(ClCH2)2P(O)Cl + MeNHC(O)OSiMe3
[(ClCH2)2P(O)NMeC(O)OSiMe3]
IV
Et3N HCl
I
II
V
b
(ClCH2)2P(O)OSiMe3
MeNCO
III
However, cyclization of V into phospholidinone IV
with release of trimethylchlorosilane (pathway a)
does not occur. Owing to low stability, phosphinate V
even at 20 C undergoes fast -cleavage to give phos-
phinate III (pathway b). Such transformations were
observed previously in the series of functionally sub-
stituted chloromethylphosphonates (-phosphinates)
[5]. Reaction of I and II without a solvent and in the
absence of a base at 20 C, according to the 31P NMR
spectra, yields simultaneously silyl phosphinate III
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322
KIBARDINA et al.
and bis(chloromethyl)phosphinic anhydride VII,
which were isolated pure. Apparently, under these
conditions intermediate V, along with -cleavage to
silyl phosphinate III, undergoes phosphorylation with
reactive phosphinic chloride I. The resulting diphos-
phorylated carbamate VI decomposes to phosphinic
anhydride VII with release of methyl isocyanate,
which also was isolated and identified.
trimethylchlorosilane molecules and formation of
phospholine XV and with cleavage of intermediate
thiophosphinic amide XIV to trimethylsilyl phosphi-
nothioate XII. Actually on heating of equimolar
amounts of XI and XIII we obtained XII as a sole
product.
We also failed to detect the expected intermediates
in reaction of chloride XI with N-trimethylsilylacet-
This assumption is confirmed by the result of the
reaction of I with trimethylsilyl diethylcarbamate VIII:
OSiMe3
S
N
XI + MeC=NSiMe3
ClCH2P
C Me
Me3SiCl
XIII
CH2Cl
OSiMe3
XIV
N
ClCH2P
O
Me
XV
XII
MeCN
In this case the reactants contain no secondary
amino group, and their reaction at 20 C involves
cleavage of the O Si bond and intermediate formation
of unstable O-phosphorylated carbamate IX, which
eliminates CO2 to give N,N-diethylbis(chloromethyl)-
phosphinic amide X. It should be noted that the
methyl analog of IX, acetyl bis(chloromethyl)phosphi-
nate, decomposes differently, yielding phosphinic
anhydride VII and acetic anhydride [6]. Phosphinic
amide X was also prepared by independent synthesis
from phosphinic chloride I and diethylamine.
amide XVI performed under mild conditions (ben-
zene, 20 C):
O
B
XI + MeCNHSiMe3
XII + MeCN.
B HCl
XVI
The 31P NMR spectrum of the reaction mixture
after separation of triethylamine hydrochloride con-
tains only the signal from phosphinate XII (
74 ppm), indicating fast decomposition of the phosP-
phorylation product. Apparently, the initially formed
phosphinic amide undergoes 1,3-N O migration of the
trimethylsilyl group and reversibly transforms into
imide XIV, which undergoes -elimination with re-
lease of the acetonitrile molecule and formation of the
final product.
Reaction of silyl carbamate II with bis(chloro-
methyl)phosphinothioic chloride XI at 120 C for 2 h
also yielded the cleavage product, O-trimethylsilyl
bis(chloromethyl)phosphinothioate XII:
II + (ClCH2)2P(S)Cl
(ClCH2)2P(S)OSiMe3.
XI
XII
Reaction of phosphinic chloride I with silylacet-
amide XVI in diethyl ether in the presence of a base
at cooling yields siloxy phosphinic amide V. The
same reaction performed without a solvent and in the
absence of a base occurs with heat release and yields
phosphinic anhydride VII.
We also studied reactions of I and XI with silylated
acetamide derivatives. We expected that compound XI
would react with trimethylsilyl N-trimethylsilylacet-
imidoate XIII by two pathways: with release of two
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 71 No. 3 2001

REACTIONS OF BIS(CHLOROMETHYL)PHOSPHINIC(-PHOSPHINOTHIOIC) CHLORIDES
323
Apparently, the initially formed N-phosphorylated
acetamide XVII is phosphorylated with the initial
phosphinic chloride I to form compound XVIII,
which decomposes to anhydride VII and acetonitrile.
(30%) of VII, bp 145 149 C (0.08 mm), mp 65
67 C. 31P NMR spectrum:
38 ppm [9].
P
N,N-Diethylbis(chloromethyl)phosphinic amide
X. a. A mixture of 3.6 g of I and 3.8 g of VIII was
kept for 14 days at 20 C. Vacuum fractionation gave
2.9 g (67%) of X, bp 110 111 C (0.08 mm), mp
EXPERIMENTAL
The 31P NMR spectra were taken on a KGU-4
NMR spectrometer (10.2 MHz), external reference
56 58 C. 31P NMR spectrum:
36 ppm. Found, %:
N 6.31; Þ 13.99. C6H14Cl2NOPP. Calculated, %: N
6.42; P 14.22.
1
85% H3PO4. The H NMR spectra were obtained on
a Varian T-60 spectrometer (60 MHz, internal refer-
ence TMS).
b. To a solution of 7.3 g of diethylamine in 20 ml
of ether, we added dropwise 9.1 g of I. The reaction
mixture was left for 5 h at 20 C. Diethylamine hydro-
chloride was separated, the solvent was removed, and
the residue was vacuum-fractionated to give 7.5 g
(68%) of X, bp 84 C (0.08 mm), mp 57 C. 31P
Reaction of bis(chloromethyl)phosphinic chlo-
ride I with trimethylsilyl methylcarbamate II. a. To
a solution of 2.3 g of II and 1.5 g of triethylamine in
20 ml of benzene at 20 C we slowly added 2.7 g of
phosphinic chloride I. After 8 h, 1.8 g (86%) of tri-
ethylamine hydrochloride was separated, and the sol-
vent was removed. Vacuum fractionation gave 1.6 g
NMR spectrum:
36 ppm.
P
Trimethylsilyl bis(chloromethyl)phosphinothio-
ate XII. a. A mixture of 3.95 g of XI and 4.1 g of II
was heated for 2 h at 120 C. Fractionation gane 2.9 g
(44%) of silyl phosphinate III, bp 68 69 C (0.06 mm),
n2D0 1.4625. 31P NMR spectrum:
28 ppm [7]. H
1
P
(59%) of XII, bp 75 C (0.06 mm), n2D0 1.5070.
NMR spectrum (CCl4), , ppm: 0.65 s (9H, CH3Si),
3.85 d (4H, CH2P, JHP 7 Hz). Found P, %: 13.11.
3
31P NMR spectrum:
72 ppm. Found, %: P 11.86;
P
C5H13Cl2O2PSi. Calculated P, %: 13.18.
Si 10.63. C5H13Cl2OPSSi. Calculated, %: P 12.35; Si
11.15.
b. Phosphinic chloride I (3.6 g) was mixed with
carbamate II (2.9 g), and after 0.5 h the 31P NMR
spectrum of the reaction mixture was recorded; signals
b. To a solution of 3.9 g of silylamide XVI and 3 g
of triethylamine in 30 ml of benzene, we added 5.9 g
of XI. The mixture was left for 5 h, 3.4 g (81%) of
triethylamine hydrochlolride was separated, and the
solvent was removed. Vacuum fractionation gave
2.2 g (29%) of XII, bp 78 C (0.08 mm), nD20
from silyl phosphinate III ( 28 ppm), phosphinic
P
anhydride VII ( 38 ppm), and phosphinic chloride I
P
(
P 52 ppm) were observed. After 8 h the mixture was
fractionated, and 0.42 g (20%) of methyl isocyanate,
bp 43 C, n2D0 1.3825 [8], and 1.08 g (23%) of silyl
1.5063. 31P NMR spectrum:
72 ppm. Found P, %:
phosphinate III, bp 69 70 C (0.08 mm), nD20
Þ
12.01. C5H13Cl2OPSSi. Calculated P, %: 12.35.
1.4612, were obtained. 31P NMR spectrum:
P
28 ppm. Also we isolated 0.86 g (28%) of phosphinic
ACKNOWLEDGMENTS
anhydride VII, bp 145 150 C (0.08 mm), mp
1
65 C. 31P NMR spectrum:
38 ppm [9]. H NMR
P
The study was financially supported by the Russian
Foundation for Basic Research (project no. 00-03-
32837).
3
spectrum (CCl4), , ppm: 3.86 d (8H, CH2P, JHCP
9 Hz).
Trimethylsilyl bis(chloromethyl)phosphinate III.
To a solution of 2.6 g of XVI and 2.0 g of triethyl-
amine in 30 ml of ether we added dropwise 3.6 g of I
with cooling to 15 C. After 2 h triethylamine hydro-
chloride was separated, the solvent was removed, and
the residue was vacuum-fractionated. Yield of III
2.6 g (55%), bp 86 C (0.2 mm), n20 1.4645. 31P
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