Isomerization of 2-seleno-1,3,2-diazaphospholidine derivatives

Article abstract of DOI:10.1023/A:1015635804144

For the first time the isomerization of 1,3,2-diazaphospholidine-2-selenide derivatives in refluxing benzene in the presence of trace water was observed, and the structure of isomerized product was determined by X-ray diffraction, IR, ¹H NMR, <

Full text of DOI:10.1023/A:1015635804144

C
Journal of Chemical Crystallography, Vol. 31, Nos. 9–10, October 2001 ( 2002)
Isomerization of 2-seleno-1,3,2-diazaphospholidine
derivatives
Sheng Lou Deng,(1) Ru Yu Chen,(2) and Dong Zhi Liu(1)
Received April 20, 2001
For the first time the isomerization of 1,3,2-diazaphospholidine-2-selenide derivatives in
refluxing benzene in the presence of trace water was observed, and the structure of isomer-
ized product was determined by X-ray diffraction, IR, 1H NMR, 31P NMR, and elemental
analysis. The mechanism of isomerization was also proposed. The isomerized phospho-
roheterocycle (C26H38N3O5PSe, Mr = 582.52) is orthorhombic with space group Pbca,
3
˚
˚
˚
˚
a = 17.1010(9) A, b = 16.6404(9) A, c = 20.7517(11) A, V = 5905.3(5) A , Z = 8,
Dr = 1.310 g/cm3, = 0.71073 A, (Mo K ) = 1.363 mm 1, F(000) = 2432. The struc-
˚
ture was refined to R1 = 0.0482, wR2 = 0.1204 for 5214 unique reflections with I > 2 (I).
Intramolecular and intermolecular hydrogen bonds are observed in the crystal packing.
KEY WORDS: Isomerization; 2-seleno-1,3,2-diazaphospholidine derivatives; crystal structure; mechanism.
Introduction
stigated the isomerization of dioxaphospho-
rinane derivatives, which when treated with
PhCH2P+Ph3Br gives84%isomerized product,8
but, to our knowledge, the isomerization of phos-
phoroheterocycles 1,3,2-diazaphospholidine 2-
selenide derivatives which show highly selective
herbicidal activity9 has not been reported. This pa-
per describes the rearrangement of P Se to P Se
in 1,3,2-diazaphospholidine derivatives resulting
in the formation of the corresponding organic
ammonium salts. The pathway of the isomeriza-
tion is suggested to involve a three-step reaction.
The structure of the product was determined
by X-ray diffraction and characterized by micro-
analysis and other spectroscopic methods.
The thiono–thiolo rearrangement has
attracted considerable interest in the past
decades,1–4 which proved to be an important and
efficient method for the synthesis of phospho-
rothioates and their analogs from P S containing
precursors. Likewise, the selenone–selenol rear-
rangement of P Se to P Se in phosphorus com-
pounds has also been reported in the literature.5
Nuretdinov early reported the isomerization of ,
-unsaturated esters of selenophosphoric acids,6
and Dembinski also found the converse iso-
merization of selenol–selenone of the com-
pounds containing a selenium bridge between
two phosphoryl centers.7 Predvoditelev has inve-
(1) School of Chemical Engineering, Tianjin University, Tianjin
300072, People’s Republic of China.
Experimental
(2) Institute of Elemento-Organic Chemistry, Nankai University,
Tianjin 300071, People’s Republic of China.
* To whom correspondence should be addressed. E-mail:
shengloudeng@hotmail.com.
1H NMR and 31P NMR spectra were re-
corded with a BRUKER AC-P 200 Spectrometer
(CDCl3 as solvent, TMS as internal, 85% H3PO4
453
C
1074-1542/01/1000-0453/0 2002 Plenum Publishing Corporation

454
Deng, Chen, and Liu
Scheme 1.
as outside standard). Melting point was deter-
mined on THOMSHOOVER melting point ap-
paratus and the thermometer was uncorrected.
Elemental analysis was carried out with Yanaco
CHN CORDER MT-3 autoanalysis apparatus. IR
spectrum was performed on a SHIMADZU-435
spectrometer, and band positions were reported in
warmed to 80 C for another 2.5 h. The prod-
uct was obtained by flash chromatography (with
equalvolumesofethylacetateandpetroleumether
as eluant) and recrystallized from a mixture of
chloroform and petroleum ether (Scheme 1).
A1: R = p-Me, colorless crystal, mp: 120–
122 C, yield:37.6%, FM:C24H34N3O5PSe, FW=
553.96. Elemental Analysis. Calcd. (%) C: 51.98,
H: 6.13, N: 7.58. Found (%) C: 51.56, H: 5.90,
1
wave numbers (cm ).
1
N: 7.77. H NMR (CDCL3 as solvent, TMS as
Preparation of compound 1
internal) (ppm): 1.45 (t, 6H, JH = 7.26 Hz,
H
A total of 0.3 g (5 mmol) of ethylenediamine
and 1.5 mL Et3N were dropped into a 100 mL
three-necked flask containing 30 mL anhydrous
benzene, and there a solution of 10.5 mmol of phe-
noxy acetyl chloride in 10 mL anhydrous benzene
was added dropwise within 15 min in ice bath. The
mixture was stirred for 1 h, subsequently warmed
to room temperature, and stirred for another 2 h.
Thesolidformedwasfilteredandwashedwithwa-
ter several times. Acolorlessproduct wasobtained
by recrystallization of the solid from ethanol.
1a: R = p-Me, mp: 173–175 C, yield: 79.6%;
1b: R = 3,5-Me, mp: 198–199 C, yield: 72.5%.
N(CH2CH3)2), 2.24 (s, 3H, CH3), 2.26 (s, 3H,
CH3), 2.89–3.05 (m, 4H, N(CH2CH3)2), 3.78–
4.12 (dm, 4H, 2 CH2), 4.82–5.02 (m, 4H, 2
OCH2), 6.92 (dd, 8H, JH = 7.46 Hz, Ar H,
H
AA0BB0system), 9.56 (br, 2H, NH2). 31P NMR
(CDCL3 as solvent, 85% H3PO4 as out standard)
1
(ppm): 8.29. IR (KBr, cm ): 3060 (Ar H),
2979–2783
(CH2),
(CH3), 2513, 1989
(+NH2), (+NH2), 1683, 1652 (C O), 1610,
1510, 1435, 1388 (C C), 1216 (P O), 1079
(Ar O C).
A2: R = 3,5-Me2, colorless crystal, mp:145–
147 C, yield: 32.8%. FM = C26H38N3O5Pse,
FW = 581.96. Elemental Analysis. Calcd. (%) C:
53.61, H: 6.52, N: 7.21. Found (%) C: 53.15, H:
6.35, N: 7.08. 1H NMR (CDCl3 as solvent, TMS
Isomerization reaction
A total of 1.5 mmol of the dried com-
pound 1 was added to a two-necked flask
and heated directly with 2 mmol of tris(diethy-
lamino)phosphine at 180–190 C for 5 h under ni-
trogen, then the mixture was cooled to room tem-
perature. After addition of 15 mL of benzene, 0.3 g
of selenium was added and the mixture was
as internal) (ppm): 1.44 (t, 6H, JH = 7.12 Hz,
H
N(CH2CH3)2), 2.23 (s, 12H, 4 CH3), 2.95–3.15
(m, 4H, N(CH2CH3)2), 3.78–4.10 (dm, 4H, 2
CH2), 4.87–5.04 (m, 4H, 2 OCH2), 6.52 (s, 4H,
Ar H), 6.61 (s, 2H, Ar H), 9.52 (br, 2H, +NH2).
Compound A2 in a mixture of chloroform
and petroleum ether (1/3, v/v) was allowed to

Isomerization of 2-seleno-1,3,2-diazaphospholidine derivatives
455
Fig. 1. Molecule structure of compound A2 with 50% probability for ellipsoids.
stand at room temperature until colorless crystals
separated out gradually.
locatedtheoreticallyandrefinedwithridingmodel
position parameters and fixed isotropic thermal
parameters. A full-matrix least-squares refine-
ment gave final R1 = 0.0482 and wR2 = 0.1204.
Structure determination by X-ray diffraction
The maximum peak in the final difference Fourier
3
˚
maps was 0.303 e A and the minimum peak
was 0.401 e A .
A colorless crystal of the compound hav-
ing approximate dimensions of 0.20 mm
0.25 mm 0.3 mm was mounted on a glass fiber
in a random orientation. The determination of the
unit cell dimensions and the data collection were
3
˚
All calculations were carried out using
SHELXS97. The molecular structure of com-
pound A2 is shown in Fig. 1, together with the
packing of the molecules in a unit cell in Fig. 2.
˚
performed withMo K radiation( = 0.71073 A)
on a BRUKER SMART 1000 diffractometer
using ω scan mode. A total of 23,560 reflections
were collected in the range of 1.96 < < 25.02
at room temperature, of which 5214 reflections
with I > 2 (I) were considered to be observed
and used in the successive refinements. The cor-
rection for LP factors was applied.
Results and discussion
The isomerism of 2-seleno-1,3,2-diaza-
phosphoroheterocycles was discovered quite
accidentally when we worked on the synthesis of
some diazaphosphoroheterocycles. It was found
that such phosphoroheterocycle could readily iso-
merize into the selenolic compounds in reflux-
ing benzene in the presence of trace water. The
isomerization reaction starting from compound 1
possibly consisted of three steps: hydrolysis,
oxidation, and rearrangement (Scheme 2). On
reaction, the tervalent phosphoroheterocycle
was susceptible to hydrolysis, simultaneously
The structure was determined by direct
method (SHELX97). Most of the non-hydrogen
atoms were located from an E-map, the oth-
ers were determined with successive differential
Fourier syntheses. Then, the structure was re-
fined by full-matrix least-squares method with
anisotropic thermal parameters for all the non-
hydrogen atoms. The hydrogen atoms were
Scheme 2.

456
Deng, Chen, and Liu
Fig. 2. Packing of the molecules in a unit cell.
releasing diethylamine. In the presence of sele-
nium oxidation subsequently occured leading to
the formation of P Se bond. With the help of
diethylamine the P Se bond smoothly isomer-
ized to P Se bond resulting in organoammonium
salts. Besides the general spectroscopic meth-
ods, the product was directly identified by X-ray
diffraction study.
Table 1. Crystal Data and Structure Refinement for A2
Empirical formula
C26H38N3O5PSe
CCDC-1003/6077
Colorless
CCDC deposit no.
Color
Crystal size, mm3
Crystal system
Space group
0.20 0.25 0.30
Orthorhombic
Pbca
˚
Unit cell dimensions
a = 17.1010(9) A
˚
X-ray diffraction analysis was employed for
the confirmation of the isomerization of these
phosphoroheterocycles. X-ray data and refine-
ment are given in Table 1. The coordinates and
equivalent isotropic displacement factors of the
non-hydrogen atoms are given in Table 2. Se-
lected bond lengths and bond angles are listed in
Table 3.
b = 16.6404(9) A
˚
c = 20.7517(11) A
3
˚
Volume, A
5905.3(5)
Z
8
Formula weight
Density (calculated), Mg mm
Absorption coefficient, mm
F(000)
582.52
1.310
1.363
2432
3
1
Diffractometer used
Radiation/wavelength
SMART CCD 1000
Mo K (graphite mono
˚
˚
chrom.)/0.71073 A
The bond distance of 1.486 A for P(1) O(3)
Temperature, K
range for data collection, deg
Scan type
298(2)
1.96–25.02
ω
is shorter than that of a normal P O bond,
while the bond distance of P(1) Se(1) is longer
than that of a normal P Se bond. From this we
conclude that the bond P(1) O(3) exists in the
form of a double bond and the P(1), Se(1) atoms
are joined only by a single bond, which sup-
ports the isomerization of P Se to P Se in the di-
azaphosphoroheterocycle. On the other hand, the
Index ranges
20
k
h
20, 19
19, 24
l
17
Reflections collected
23560
Independent reflections
5214 [R = 0.0658]
int
(I 2 (I))
Absorption correction
Refinement method
None
Full-matrix least-squares
on F2
1.005
R1 = 0.0482, wR2 = 0.1204
0.303 and 0.401
5214/0/323
˚
Goodness of fit on F2
R, wR [I > 2 (I)]
Largest diff. peak and hole, e A
bond distance of Se(1) N(3) is 4.654 A, which
reveals that the two atoms interact by electrostatic
effect and also lead to the conclusion that the iso-
merized product is organic ammonium salt.
3
˚
Data/restraints/parameters

Isomerization of 2-seleno-1,3,2-diazaphospholidine derivatives
457
Table 2. Atomic Coordinates (104) and Isotropic
˚
Table 3. Selected Bond Angles (deg) and Bond Lengths (A)
3
2
˚
Displacement (10 A )
Bond
Angle (deg)
Bond
Length
Atom
x
y
z
U a
eq
O(3) P(1) N(1)
O(3) P(1) N(2)
N(1) P(1) N(2)
O(3) P(1) Se(1)
N(1) P(1) Se(1)
N(2) P(1) Se(1)
C(4) O(1) C(9)
C(15) O(5) C(14)
C(10) N(1) C(11)
110.76(18) Se(1) P(1)
109.89(17) P(1) O(3)
89.73(17) P(1) N(1)
118.52(13) P(1) N(2)
112.22(13) O(1) C(4)
112.08(13) O(1) C(9)
2.0931(12)
1.483(3)
1.708(3)
1.724(3)
1.374(6)
1.404(5)
Se(1)
P(1)
O(1)
O(2)
O(3)
O(4)
O(5)
N(1)
N(2)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
C(8)
5649(1)
6726(1)
7516(2)
7163(2)
7425(2)
6614(2)
6547(2)
6920(2)
6666(2)
6427(4)
6328(4)
6938(3)
6838(3)
6101(3)
5462(3)
5594(4)
4668(3)
7457(3)
7158(2)
6617(3)
6640(3)
6663(2)
6772(3)
5757(2)
5565(3)
4806(3)
4229(3)
4408(3)
5183(3)
3790(3)
4599(4)
8435(7)
9145(6)
7921(3)
7168(6)
6706(5)
5753(1)
6296(1)
4314(2)
5767(2)
6029(2)
8546(2)
7925(2)
6325(2)
7330(2)
2275(4)
2925(3)
3362(3)
3948(3)
4116(3)
3676(3)
3094(3)
3848(3)
4955(3)
5709(3)
7049(2)
7707(3)
7814(3)
7418(3)
7994(3)
8497(3)
8608(3)
8184(3)
7671(3)
7587(3)
7183(4)
9171(4)
5315(5)
5516(6)
4900(3)
4530(5)
5021(5)
5625(1)
5826(1)
7126(2)
7605(2)
5460(1)
5341(2)
4131(2)
6633(2)
5815(2)
8515(3)
8020(3)
7787(2)
7328(2)
7090(2)
7309(3)
7772(3)
7022(3)
6690(2)
7025(2)
6941(2)
6453(2)
5291(2)
4640(2)
4004(2)
3501(2)
3325(2)
3648(3)
4144(2)
4332(2)
4493(3)
2776(3)
4171(4)
4590(5)
4597(2)
4238(4)
3943(4)
82(1)
54(1)
78(1)
80(1)
64(1)
82(1)
75(1)
54(1)
55(1)
135(3)
83(2)
72(1)
66(1)
70(1)
79(2)
90(2)
105(2)
72(1)
57(1)
77(2)
83(2)
59(1)
68(1)
56(1)
61(1)
75(1)
82(2)
70(1)
64(1)
109(2)
121(2)
183(5)
190(4)
79(1)
170(4)
164(3)
118.3(4)
117.5(3)
117.6(3)
128.2(3)
112.6(3)
118.1(3)
127.2(3)
114.7(3)
123.2(5)
113.0(6)
107.4(4)
107.4(4)
117.2(4)
112.1(4)
110.8(4)
O(2) C(10) 1.206(5)
O(4) C(13) 1.225(5)
O(5) C(15) 1.381(5)
O(5) C(14) 1.406(5)
N(1) C(10) 1.372(5)
N(1) C(11) 1.457(5)
N(2) C(13) 1.353(5)
N(2) C(12) 1.465(5)
C(10) N(1) P(1)
C(11) N(1) P(1)
C(13) N(2) C(12)
C(13) N(2) P(1)
C(12) N(2) P(1)
C(6) C(7) C(2)
C(23) N(3) C(25)
N(1) C(11) C(12)
N(2) C(12) C(11)
N(2) C(13) C(14)
O(5) C(14) C(13)
O(1) C(9) C(10)
C(9) C(10)
1.523(6)
C(11) C(12) 1.492(6)
C(13) C(14) 1.515(6)
C(23) N(3) 1.425(9)
C(23) C(24) 1.530(12)
N(3) C(25) 1.609(9)
C(25) C(26) 1.291(9)
C(9)
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
N(3)
˚
(1.836 A), N3H32O3 = 165.89 ). Figure 1 illust-
ratesmoderateintramolecularhydrogenbond, and
Fig. 2 shows intramolecular and intermolecular
hydrogen bonds.
Based on the least-squares equation and
coplanar theory by Nordman,10 the five atoms
P(1), N(2), C(11), C(12), and N(1) deviate
from the least-squares plane by 0.0119 (0.0016),
0.0217 (0.0029), 0.0130 (0.0017), 0.0229
(0.0031), 0.4243 (0.0060), respectively, indicat-
ing that the atom N(1) deviates far from the ring
plane and the five-membered ring exists in an
envelope configuration. This accounts for the ob-
servation that the protons attached to C(11), C(12)
C(25)
C(26)
aU is defined as one third of the trace of the orthogonalized
eq
Ui j tensor.
1
Hydrogen bonds between atoms N(3) O(3)
in H NMR spectrum appeared to be not mag-
˚
˚
(2.730 A) and O(4) N(3) (2.845 A) (O(4)
N(3) O(3) (106 ) link organoammonium cations
and the anions. Atom N(3) simultaneously inter-
acts with the atom O(3) in one molecule and the
atom O(4) in another molecule, related by hy-
netically equivalent. In addition, according to
Paxton’s study on d–p bond of pentavalent phos-
phorus compounds,11 it can be stated that there are
no d–p bond properties between atom P and the
other two nitrogen atoms because the bond lengths
(P(1) N(1) (1.708 A), P(1) N(2) (1.724 A)) are
closetothatofanormalP Nbond(1.76A), while
its analogs such as 1,3,2-diazaphospholidine-4-
thione (one) 2-sulfide have strong d–p bonds
˚
˚
˚
drogen bond N3 H31
O4 (N3 H31 (1.077 A),
O4 (2.845 A), N3H31O4 = 165.80 ,
( x + 3/2, y 1/2, z)) and hydrogen bond
˚
˚
H31
˚
N3 H32
O3 (N3 H32 (0.913 A), H32
O3

458
Deng, Chen, and Liu
3. Poulter, C.D.; Mautz, D.S. J. Am. Chem. Soc. 1991, 113(13),
4895.
4. Sasaki, M.; Itoh, Y.; Yamamoto, N.; Yamada, Y. Chem. Lett.
1993, 11, 1835.
5. Mikolajczyk, M.; Kielbasinski, P.; Goszcozynska, Z. J. Org.
Chem. 1977, 42(22), 3629.
between atom P and the other two nitrogen atoms
in the molecules, which is of fundamental impor-
tance for their planar structures.12,13
6. Nuretdinov, I.A.; Buina, N.A. Zh. Obshch. Khim. 1969,
39(4), 930.
Acknowledgments
7. Dembinski, R.; Kaminski, R.; Michalski, J.; Skowronska, A.
J. Chem. Soc., Chem. Commun. 1986, 24, 1770.
8. Predvoditelev, D.A.; Rosadkina, E.N.; Bekker, A.R.; Nifantev,
E.E. Zh. Obshch. Khim. 1988, 58(7), 1504.
9. Deng, S.L.; Chen, Y.R.; Yang, X.F. Chem. J. Chinese Univ.
2001, 22(11), 1833.
10. Prade, M.D.; Nordman, C.E. Inorg. Chem. 1969, 8, 1669.
11. Paxton, K.; Hamor, T.A. J. Chem. Soc., Dalton Trans. 1978,
647.
We thank Dr Linhong Weng and her assistant
Xuebing Leng for X-ray diffraction performance.
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