Novel heterocyclic selenazadiphospholaminediselenides, zwitterionic carbamidoyl(phenyl)-phosphinodiselenoic acids and selenoureas derived from cyanamides

Article abstract of DOI:10.1016/j.tet.2009.05.056

2,4-Bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide (Woollins' reagent, WR) reacts with cyanamides (1a-h) in refluxing toluene to afford a series of novel selenazadiphospholaminediselenides (RR′NC{double bond, long}N(PhP(Se)SeP(Se)Ph, R=C₆

Full text of DOI:10.1016/j.tet.2009.05.056

Tetrahedron 65 (2009) 6074–6082
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Novel heterocyclic selenazadiphospholaminediselenides, zwitterionic
carbamidoyl(phenyl)-phosphinodiselenoic acids and selenoureas
derived from cyanamides
*
Guoxiong Hua, Qingzhi Zhang, Yang Li, Alexandra M.Z. Slawin, J. Derek Woollins
School of Chemistry, University of St. Andrews, Fife, Scotland KY16 9ST, UK
a r t i c l e i n f o
a b s t r a c t
Article history:
2,4-Bis(phenyl)-1,3-diselenadiphosphetane-2,4-diselenide (Woollins’ reagent, WR) reacts with cyan-
amides (1a–h) in refluxing toluene to afford a series of novel selenazadiphospholaminediselenides
(RR0NC]N(PhP(Se)SeP(Se)Ph, R¼C6H5(CH2)1–3, 4-n-C10H21C6H4 and 4-BrC6H4CH2; R0¼H, CH3, C2H5 and
C(O)OC2H5 2a–g). Post-treatment of the reaction mixture with water led to the formation of carbami-
doyl(phenyl)phosphinodiselenoic acids (RR0NC(NH2)P(SeH)2Ph, R¼C6H5(CH2)2–3, 4-n-C10H21C6H4 and 4-
BrC6H4CH2; R0¼H and CH3, 3b, 3c, 3e and 3f) and selenoureas (RR0NC(Se)NH2, R¼C6H5(CH)1–2; R0¼CH3
and OC(O)C2H5, 4f and 4h) in moderate to excellent yields. All new compounds are characterised
spectroscopically and five X-ray crystal structures are reported.
Received 12 February 2009
Received in revised form 5 May 2009
Accepted 21 May 2009
Available online 27 May 2009
Keywords:
Woollins’ reagent
Cyanamides
Carbamidoyl(phenyl)phosphino-
diselenoic acids
Ó 2009 Elsevier Ltd. All rights reserved.
Selenazadiphospholaminediselenides
Selenoureas
1. Introduction
the synthesis of 8-, 9- and 10-membered diselenides bearing P–Se–
Se–P linkage.16
Cyanamides, cyanates, thiocyanates and their derivatives are
known as tumour inhibitors1 and important intermediates for
herbicides2 as well as N-alkyl or N-aryl imides.3 Conversion of the
cyano group to selenocarbonyl by selenation is a useful approach to
organoselenium derivatives. Typical selenium reagents include
SeO2, PhSeO2H, PhSeCl, PhSeꢀ,4–6 selenoethers and phosphine
As part of our broader study into the reactivity of WR here we
report the preparation of a series of novel selenazadiphosphol-
aminediselenides, carbamidoyl(phenyl)phosphinodiselenoic acids
and selenoureas from the selenation of cyanamides (RR0NC^N,
R¼C6H5(CH2)1–3, 4-BrC6H4CH2 and 4-n-C10H21C6H4; R0¼H, CH3,
CH2CH3 and C(O)OC2H5) with WR.
selenides.7
selenide [PhP(Se)(
known Lawesson’s reagent [p-MeOC6H4P(S)(
2,4-Bis(phenyl)-1,3-diselenadiphosphetane-2,4-di-
-Se)]2, the selenium counterpart of the well-
-S)]2, known as
m
2. Results and discussion
m
Woollins’ reagent (WR), has become of increasing interest in sele-
nium chemistry due to its high efficiency and broad utility.8 Com-
pared with other selenium reagents, WR has less unpleasant
properties and can be prepared readily and handled safely in air.9
Selenoamides and selenoaldehydes have been obtained by simple
oxygen/selenium exchange using WR and corresponding carbonyl
compounds or ArCN followed by hydrolysis.10–13 WR has been used
as an efficient coupling reagent for syntheses of symmetrical and
unsymmetrical (E)-olefins from the corresponding ketones or al-
dehydes.14 As a deoxygenating agent, WR has converted phenyl-
sulfoxides into phenylsulfides.15 WR was also found application in
Cyanamides 1a–h were prepared from cyanogen bromide with
primary or secondary amines in dry methanol in the presence of
excess of anhydrous CH3COONa at room temperature in almost
quantitative yields.17
As shown in Scheme 1 and Table 1, heating the mixture of equal
molar amount of WR and cyanamides 1a–g in toluene under an-
hydrous condition led to the formation of selenazadiphosphoami-
nediselenides 2a–g in moderate to good yields (28–71%) after
column chromatography (silica gel, 9:1 toluene/ethyl acetate elu-
ent) and recrystallisation by diffusion of a dichloromethane solu-
tion to n-hexane.
Modification of the reaction by post-treatment of the mixture of
WR and cyanamides in refluxing toluene with water showed a di-
verse product distribution. The selenazadiphosphoaminedisele-
nides 2a, 2d and 2g seem very stable as the addition of water did
* Corresponding author. Tel./fax: þ44 1334 463384.
E-mail address: jdw3@st-and.ac.uk (J.D. Woollins).
0040-4020/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tet.2009.05.056

G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
6075
Se
Se
Ph
Se
NH2
R'
N
WR
R'
N
or
Se
C
R'
N
Se
WR/H2O
P
P
R
C
P
+
R
+
NH2
R
C
N
Ph
toluene,reflux
C
N
SeH
Ph
3a-h
RR'N
4a-h
1a-h
2a-h
Scheme 1. Reaction of cyanamides and WR in toluene at reflux with or without post-water-treatment.
Table 1
Ph
Se
Se
Se
Ph
NH
C
2Se
Products of the reaction of WR and cyanamides in toluene at reflux with or without
post-water-treatment
R'
R N
P
P
THF, reflux
H2O
(PhPO2)3
+
Se
+
P
Se
C N
Ph
R N R'
2b, 2c, 2e, 2f
Reactant Products in Products in reaction B
reaction A
3b E/Z = 100 :0
3c E/Z = 100 :0
3e E/Z = 100 :0
3f E/Z = 70 : 30
R
R0
1
2
Yield
(%)
2
Yield
(%)
3
Yield
(%)
4
Yield
(%)
Scheme 2. Hydrolysis of selenazadiphospholaminediselenides to zwitterionic carba-
midoyl(phenyl)-phosphinodiselenoic acids 3b, 3c, 3e and 3f.
C6H5CH2CH2
4-n-C10H21C6H4
4-BrC6H4CH2
C6H5CH2
C6H5(CH2)3
C6H5CH2CH2
C6H5CH2
H
H
H
H
1a
1b
1c
1d
1e
1f
2a
45
2a 30
2b 41
2c 11
2d 15
2e 25
2f 31
2g 38
2h
3a
3b 57
3c 47
2b 71
2c 29
2d 28
2e
2f
H
CH3
CH3CH2 1g
EtCO2 1h
43
42
50
3e 29
3f 48
3g
Therefore, we propose possible pathways for the formation of
2a–g, 3b, 3c, 3e, 3f, 4f and 4h as shown in Scheme 3. WR at elevated
4f 20
4h 91
2g
temperature is in equilibrium with
a diselenaphosphorane
C6H5CH2CH2
3h
PhP(Se)2, which is believed to be a true reactive species in refluxing
toluene.8 The initial step for the formation of 2a–g, 3b, 3c, 3e, 3f, 4f
and 4h is a typical [2þ2] cycloaddition of a P]Se bond from dis-
elenaphosphorane PhP(Se)2 across the C^N bond of cyanamide to
give an intermediate I, which is in equilibrium in solution in three
tautomeric forms: the 1,2-selenaphospacyclobutene Ia, the selone
Ib and the dipolar species Ic. The intermediate Ic reacts further
with another molecule of PhP(Se)2 to generate a second dipolar
intermediate II, which extrudes selenium to afford selenazadi-
phospholaminediselenides 2a–g. Furthermore, reaction of selena-
zadiphospholaminediselenides with one molecule of H2O gives rise
to carbamidoyl(phenyl)phosphinodiselenoic acids 3b, 3c, 3c and 3f
with unusual zwitterionic structures via the intermediates IV and V
while eliminating PhP(Se)(O), the latter can readily decompose to
give (PhPO2)3 and Se. On the subject of the formation of 4f and 4h,
the hydrolysis of the intermediate Ib with one molecule of H2O can
afford selenoureas via the intermediate III by further loss of
(PhPO2)3 and Se.
Reaction A: WR, toluene, reflux for 10 h; reaction B: WR, toluene, reflux for 10 h,
then addition of water, further reflux for 1 h.
not lead to any hydrolysed products. However, similar post-treat-
ment of the reaction mixture of cyanamides 1b, 1c and 1e and WR
with water resulted in carbamidoyl(phenyl)phosphinodiselenoic
acids 3b (57%), 3c (47%), 3e (29%) and 3f (48%), and the hydrolysed
products of heterocyclic compounds 2b, 2c and 2e. In the case of 1f,
water led to the formation of the third product 4f (20%) apart from
the selenazadiphosphoaminediselenide 2f (31%) and carbami-
doyl(phenyl)phosphinodiselenoic acids 3f (48%). Meanwhile
treatment of the refluxing mixture of 1g and WR in toluene with
water gave selenourea 4h as the only product in 91% yield.
In order to gain mechanistic insight, the hydrolysis of isolated
selenazadiphospholaminediselenides 2b, 2c, 2e and 2f was carried
out straightforwardly in refluxing tetrahydrofuran with excess of
water, giving the corresponding zwitterionic carbamidoyl(phenyl)-
phosphinodiselenoic acids 3b, 3c, 3e and 3f in almost quantitative
yields (Scheme 2).
Preparation and characterisation of the compounds 2e, 2f, 3e
and 3f have been reported in our recent communication,18 thus, the
Ph
Se
Se
Ph
Ph
Se
RR'NC
Se
Se
Se
RR'NC
[2 + 2]
N
P
N
PhP
P
N
WR
P
N
Se
Se
RR'NC
Ia
RR'NC
Ib
Ic
O
H 2
[PhPSe2]
Ph
Ph
Se
Se
RR'NC
Se
OH
Se
Se
Ph
P
P
Se
RR'NC
P
NH2
- [(PhPO2)3 + Se]
Se
NH
4f and 4h
RR'NC
N
III
II
-Se
Se
SeH
Ph
NH SeH
NH2
Se
P
Se
Se
Se
Se
H2O
Se
RR'N
P
C
P
P
R'RN
P
P
Se
C
Ph
RR'NC
Ph
RR'NC
Ph
OH
Ph
N
IV
N
Ph
V
3b, 3c, 3e, 3f
(PhPO2)3 + Se
2a-g
Scheme 3. Suggested mechanism for the formation of selenazadiphospholaminediselenides, carbamidoyl(phenyl)phosphinodiselenoic acids and selenoureas.

6076
G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
vibrations (1512 and 1557 cmꢀ1) and the
and 559 cmꢀ1). However, the IR spectra of 4f and 4h show asym-
metrical and symmetrical (NH2) vibration in the range 3375–
3166 cmꢀ1 along with strong bands at 1612 and 1598 cmꢀ1
n(P]Se) vibrations (551
Table 2
31P and 77Se NMR data for compounds 2a–d and 2g
1J(Se–P)
1J(Se]P)
d(Se)
1J(Se–P)
[Hz]
1J(Se]P)
[Hz]
n
Compound
d(P)
[ppm]
[Hz]
[Hz]
[ppm]
resulting from the n(N–H) vibrations and medium bands at 699 and
2a
76.4
74.8
475
477
792
825
414.1
11.8
465/477
310/484
310/420
486/477
656 cmꢀ1 characteristic of the C]Se group.11,19
825
792
31P NMR characteristics of 2a–d and 2g exhibit two sets of
double resonances with two sets of satellites for the endocyclic and
exocyclic selenium atoms as showed in Table 2. Slightly different
chemical shifts indicate the presence of two slightly different single
P–Se and two slightly different double P]Se bonds in each com-
pounds due to the two different phosphorus atoms. The difference
is further substantiated by the 77Se NMR spectra, which exhibit
a doublet of doublets. One pair of diastereomers with the same
intensity was identified in compound 2g. Detailed NMR spectro-
scopic analysis and iterative simulation reveal the coupling con-
stant between phosphorus atoms and exocyclic selenium atoms
ꢀ126.7
2b
2c
2d
2g
89.1
74.9
484
310
789
831
391.4
14.3
831
789
ꢀ126.2
80.7
75.3
420
310
789
833
391.9
13.6
833
789
ꢀ124.5
76.5
74.4
486
477
825
791
419.1
15.3
825
791
822
[822]
794
ꢀ126.4
499.66
[492.6]
17.54
76.1
[75.7]
59.8
458
[460]
458
794
[794]
822
458/455
[460/458]
[59.6]
[455]
[822]
[8.1]
[794]
3
(2J(P,P)¼9.4–16.4 Hz and J(P,Seexo): ca. 9.0 Hz) in 2a–d and 2g. The
ꢀ70.57
chemical shifts and coupling constants are comparable to those in
the literature.20 Molecular structures of 2a, 2d and 2g are also
confirmed by single crystal X-ray analysis.
[ꢀ74.5]
Dimension for another diastereomeric molecule in square parentheses.
31P NMR spectra of 3b and 3c display sharp singlets at 30.2 and
30.5 ppm, respectively, flanked by selenium satellites with 31P–77Se
coupling constants of 702 and 695 Hz, indicating a single P–Se bond
order of approximately 1.5. However, the values are slightly bigger
than that in phosphonodiselenoate salts (ca. 657–680 Hz),21 in-
dicating the presence of the zwitterionic structures for both com-
pounds. 77Se NMR spectra show doublets at ꢀ83.7 ppm for 3b and
ꢀ78.2 ppm for 3c with matching coupling constants. All NMR
spectroscopic characterisations in 3b and 3c are comparable with
those documented in 3e and 3f.18 For 4f and 4h, 77Se NMR spectra
show single signals at 607.7 and 382.1 ppm, respectively, while 13C
NMR spectra contain signals for the group C]Se at 207.1 and
186.7 ppm, respectively, together with the expected signals for
related carbon atoms.
four compounds will not be discussed here in details. The charac-
terisation of 2a–d, 2g, 3b, 3c, 4f and 4h is based on elemental mi-
croanalysis, 1H, 13C, 31P and 77Se NMR spectra, IR spectroscopy and
mass spectrometry. The elemental microanalyses for all com-
pounds were satisfactory, and all compounds showed the antici-
pated [M]þ or [MꢀH]þ or [MþH]þ or [MþNa]þ peak in their mass
spectra. The n(C]N) vibrations are observed in the range 1503–
1549 cmꢀ1, while the range 550–557 cmꢀ1 shows the presence of
(P]Se) vibrations for compounds 2a–d and 2g, these values are
comparable with similar heterocycles.12c,d For compounds 3b and
3c, the strong bands in the range 1636–1639 cmꢀ1, from the
(N–H)
vibration were observed together with the typical (C]N)
n
n
n
Figure 1. (A) Crystal structure of 2a (C–H bonds omitted for clarity); (B) X-ray structure showing the intramolecular hydrogen bonding interactions of P]Se/H–N leading to chains
of the polymer.

G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
6077
Figure 2. (A) Crystal structure of 2d (C–H bonds omitted for clarity); (B) X-ray structure showing the intramolecular hydrogen bonding interactions of P]Se/H–N leading to chains
of the polymer.
2.1. X-ray crystal structures
interactions in the second independent molecule. The frame works
of all compounds contain a five-membered P2SeCN ring bearing
a P(Se)–Se–P(Se) linkage with the exocyclic P]Se groups orientated
trans to each other. The P]Se bond lengths and angles are normal
and comparable with those found in the literature.8,12c,13,22 The ge-
ometry around P(1) [Se(1)–P(1)–Se(2): 117.24(9)ꢁ [116.66(9)ꢁ] for
Perspective views of the X-ray crystallographic structures of the
compounds 2a, 2d and 2g with selected parameters are shown in
Figures 1–3. Crystal data and details of the structure determination
are given in Tables 3 and 4. The structure of 2a contains two in-
dependent molecules within the unit cell, the differences in metric
parameters in the two molecules resulting from the rotation of aryl–
alkyl group [C6H5CH2CH2) C(14)–C(21)] leading to some steric
Table 3
Details of the X-ray data collections and refinements for compounds 2a, 2d and 2g
Compound
2a
2d
2g
Formula
M
C21H20N2P2Se3
599.21
C20H18N2P2Se3
585.18
C22H22N2P2Se3
613.24
Crystal system
Space group
Triclinic
P-1
Monoclinic
P21/n
Monoclinic
P21/n
a/Å
b/Å
c/Å
a
8.8864(5)
9.7663(14)
13.739(2)
84.651(13)
74.529(12)
73.472(12)
1101.5(2)
2
9.7105(8)
16.3577(13)
13.5571(11)
90
98.815(2)
90
2128.0(3)
4
5.344
14.7395(18)
10.6811(10)
15.6539(18)
90
109.845(2)
90
2318.1(4)
4
4.910
b
g
U/Å3
Z
m
/mmꢀ1
5.165
Reflections collected
Independent
7616
0.0541
14,859
0.0253
16,162
0.0418
reflections (Rint
R1, wR2 [I>2 (I)]
)
s
0.0422, 0.0987
0.0478, 0.0611
0.0613, 0.0762
Figure 3. Crystal structure of 2g (C–H bonds omitted for clarity).

6078
G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
Table 4
two independent molecules within the unit cell. The C–Se bond
lengths in 4f and 4h are 1.877(7) [1.872(7)] and 1.850(4) Å, re-
spectively, which are slightly longer than the values in aryseleno-
amides [1.820(4)–1.848(2)],11 while the shortness of the C–N bond
lengths in which the C–N bonds are adjacent to the C]Se double
bond [C(1)–N(1) and C(1)–N(2): 1.342(8) [1.351(8)] and 1.325(8)
[1.311(8)] Å for 4f, 1.319(5) and 1.400(5) Å for 4h], compared to the
normal C–N bond distances [N(2)–C(2) and N(2)–C(3): 1.459(8)
[1.460(8)] and 1.480(7) [1.454(7)] Å for 4f, 1.401(5) and 1.490(5) Å
for 4h], suggests some multiple bonding character. It should be
noted that the C(1)–N(1) bond length [1.342(8) [1.351(8)] Å] in 4f is
slightly longer than that [1.319(5) Å] in 4h, meanwhile C(1)–N(2)
bond distance [1.325(8) [1.311(8)] Å] in 4f is much shorter than that
[1.400(5) Å] in 4h, indicating the effect of the presence of C(O)OC2H5
versus CH3. In both structures, N(1)–N(2)–C(1)–Se(1) is approxi-
mately planar, while Se(1) lies 0.04 Å [0.03 Å for molecule 2] for 4f
and 0.02 Å for 4h out of this plane. Furthermore, the aryl and N(1)–
N(2)–C(1)–Se(1) interplanar angle in 4f and 4h is 15.30ꢁ [15.21ꢁ] and
17.44ꢁ, respectively. There are weak C]Se/H–N hydrogen bonding
interactions in the structure of 4f [the hydrogen bonding Se(1)/
H(1A), Se(11)/H(1B), Se(11)/H(11A) and Se(1)/H(11B) distances
are 2.79(6), 2.61(4), 2.80(6) and 2.59(4) Å, respectively, along with
N(1)–H(1A)/Se(1), N(1)–H(1B)/Se(11), N(11)–H(11A)/Se(11)
and N(11)–H(11B)/Se(1) angles of 129(5)ꢁ, 147(6)ꢁ, 126(5)ꢁ and
152(6)ꢁ]. However, in 4f, apart from the weak C]Se/H–N hydrogen
bonding interactions [Se(1)/H(1B) distance is 2.638(11) Å with
N(1)–H(1B)/Se(1) angle of 162(4)ꢁ], there is another stronger hy-
drogen bonding interaction between C]O/H–N [H(1A)/O(1) and
H(1A)/O(1i) distances are 1.88(4) and 2.38(3) Å, respectively, with
N(1)–H(1A)/O(1) and N(1)–H(1A)/O(1i) angles of 129(4)ꢁ and
146(4)ꢁ]. For both compounds, the hydrogen bonding interactions
result in discrete dimeric pairs, with additional secondary
Details of the X-ray data collections and refinements for compounds 4f and 4h
Compound
4f
4h
Formula
M
Crystal system
Space group
a/Å
b/Å
c/Å
a
C10H14N2Se
241.19
C12H16N2O2Se
299.23
Monoclinic
C2/c
17.695(3)
6.7719(10)
24.199(4)
90
109.772(4)
90
2728.7(7)
8
2.745
8634
0.0406
Orthorhombic
Pca2(1)
12.067(2)
5.9432(13)
29.023(6)
90
90
90
2081.5(7)
8
3.564
b
g
U/Å3
Z
m
/mmꢀ1
Reflections collected
Independent reflections (Rint
R1, wR2 [I>2
9033
0.0961
0.0623, 0.1348
)
s(I)]
0.0710, 0.1819
2a, 118.16(4)ꢁ for 2d and 114.12(4)ꢁ for 2g, respectively] and around
P(3) [Se(2)–P(3)–Se(3): 113.06(9)ꢁ [112.92(9)ꢁ] for 2a,112.93(3)ꢁ for
2d and 113.06(9)ꢁ for 2g, respectively] are distorted tetrahedral due
to the effects of the steric hindrance of phenyl groups.12e The
transannular P/P bond distances are 3.24, 3.24 and 3.21 Å for 2a, 2d
and 2g, respectively, being marginally longer than those observed in
the four-membered P2Se2 ring system (3.1 Å) and considerably
shorter than those measured in six-membered ring system P2Se4
ring system (4.3 Å).23 It should be noted that there is a intra-
molecular N–H/Se]P hydrogen bonding interaction to form
chains of polymer in the solid state in 2a and 2d.
The X-ray crystal structures of selenoureas 4f and 4h are shown
in Figures 4 and 5. The crystallographic data, selected bond lengths
and bond angles are listedinTables 5 and 6. Thestructure of 4f shows
Figure 4. (A) Crystal structure of 4f (C–H bonds omitted for clarity); (B) X-ray structure showing hydrogen bonding interaction of Se/H–N leading to clusters of the polymer.

G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
6079
Table 6
Selected bond lengths (Å) and angles (ꢁ) for compounds 4f and 4h
4fa
4h
N(1)–C(1)
N(2)–C(1)
N(2)–C(2)
N(2)–C(3)
Se(1)–C(1)
1.342(8) [1.351(8)]
1.325(8) [1.311(8)]
1.459(8) [1.460(8)]
1.480(7) [1.454(7)]
1.877(7) [1.872(7)]
1.319(5)
1.400(5)
1.401(5)
1.490(5)
1.850(4)
C(1)–N(2)–C(2)
C(1)–N(2)–C(3)
C(2)–N(2)–C(3)
N(2)–C(1)–N(1)
N(2)–C(1)–Se(1)
N(1)–C(1)–Se(1)
121.0(5) [120.5(5)]
122.7(5) [121.9(6)]
116.2(5) [116.9(5)]
117.6(6) [117.8(6)]
124.6(5) [124.6(5)]
117.8(5) [117.6(5)]
122.5(3)
119.5(3)
117.8(3)
119.1(3)
120.7(3)
120.1(3)
a
Dimensions for second independent molecule in square parentheses.
interactions of the same type between dimeric pairs to finally give
a polymeric structure in the solid state.
In summary, a convenient and efficient approach to synthesise
a series of new heterocyclic selenazadiphospholaminediselenides,
zwitterionic carbamidoyl(phenyl)phosphinodiselenoic acids and
selenoureas has been developed from the reaction of Woollins re-
agent with the corresponding cyanamide following with or without
further treatment with H2O. The biological activity of 2a–2h will be
investigated in due course.
3. Experimental section
3.1. General
Unless otherwise stated, all reactions were carried out under an
oxygen free nitrogen atmosphere using pre-dried solvents and
standard Schlenk techniques, subsequent chromatographic and
work up procedures were performed aerobically. Solvents were
dried, purified, and stored according to common procedures. 1H
(270 MHz), 13C (67.9 MHz), 31P–{1H} (109 MHz) and 77Se–{1H}
(51.4 MHz referenced to external Me2Se) NMR spectra were recor-
ded at 25 ꢁC (unless stated otherwise) on a JEOL GSX 270. IR spectra
were recorded as KBr pellets in the range of 4000–250 cmꢀ1 on
a Perkin–Elmer 2000 FTIR/Raman spectrometer. Microanalysis was
performed by the University of St. Andrews microanalysis service.
Mass spectrometry was performed by the EPSRC National Mass
Spectrometry Service Centre, Swansea (UK) and the University of
St. Andrews Mass Spectrometry Service. X-ray crystal data for
compounds 2a, 2d, 2g, 4f and 4h were collected at 93 K by using
a Rigaku MM007 High brilliance RA generator/confocal optics and
Mercury CCD system. Intensities were corrected for Lorentz-
polarisation and for absorption. The structure was solved by direct
methods. Hydrogen atoms bound to carbon were idealised. Struc-
tural refinement was obtained with full-matrix least-squares based
on F2 by using the program SHELXTL.24 CCDC 720091–720095
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge via www.ccdc.cam.ac.uk/
conts/retrieving.html or from the Cambridge Crystallographic Data
centre, 12 Union Road, Cambridge CB2 1EZ, UK; fax: þ44 1223 336
033; E-mail: deposit@ccdc.cam.ac.uk.
Figure 5. (A) Crystal structure of 4h (C–H bonds omitted for clarity); (B) X-ray
structure showing hydrogen bonding interactions of C]Se/H–N and C]O/H–N
leading to clusters of the polymer.
Table 5
Selected bond lengths (Å) and angles (ꢁ) for compounds 2a, 2d and 2g
2aa
2d
2g
Se(1)–P(1)
Se(2)–P(1)
Se(2)–P(3)
Se(3)–P(3)
P(3)–N(4)
P(1)–C(5)
N(5)–C(5)
N(4)–C(5)
2.098(2) [2.089(2)]
2.236(2) [2.247(2)]
2.311(2) [2.291(2)]
2.096(2) [2.104(2)]
1.647(6) [1.636(6)]
1.882(8) [1.889(8)]
1.326(9) [1.336(10)]
1.303(9) [1.301(10)]
2.0892(8)
2.2409(8)
2.2883(8)
2.1031(8)
1.652(2)
1.889(3)
1.339(3)
1.283(3)
2.0976(10)
2.2288(10)
2.2791(10)
2.0865(10)
1.644(3)
1.890(3)
1.337(4)
1.304(4)
P(1)–Se(2)–P(3)
N(4)–P(3)–Se(3)
N(4)–P(3)–Se(2)
Se(3)–P(3)–Se(2)
C(5)–P(1)–Se(1)
C(5)–P(1)–Se(2)
Se(1)–P(1)–Se(2)
C(5)–N(4)–P(3)
90.70(8) [91.03(7)]
116.3(3) [114.9(3)]
102.2(3) [104.1(3)]
113.06(9) [112.92(9)]
114.0(2) [114.6(2)]
97.9(3) [98.1(2)]
91.44(3)
115.71(9)
103.22(8)
112.93(3)
112.60(9)
97.80(9)
90.91(3)
115.41(11)
103.41(10)
112.59(4)
112.71(11)
99.49(11)
114.12(4)
125.6(2)
3.2. Reaction of cyanamides with WR (method A)
A mixture of cyanamide (4.0 mmol) and WR (2.15 g, 4.0 mmol) in
50.0 mL of dry toluene was heated at 130 ꢁC for 10 h. The red sus-
pension disappeared and a pale yellow solution was formed along
with a small amount of grey selenium after cooling to room temper-
ature. The resulting mixture was concentrated to ca. 5.0 mL and pu-
rified by silica gel (1:9¼ethyl acetate/toluene as eluent) to give 2a–g.
117.24(9) [116.66(9)]
124.0(6) [123.9(6)]
118.16(4)
123.95(19)
a
Dimensions for second independent molecule in square parentheses.

6080
G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
3.3. Reaction of cyanamides with WR/H2O (method B)
J(P,Se)¼310, 484 Hz),14.3 (d, J(P,Se)¼831 Hz), ꢀ126.2 (d, J(P,Se)¼789 Hz).
MS (EI, m/z), 713 [M]þ.
A red toluene (30 mL) suspension of WR (2.0 mmol) and cyan-
amide (2.0 mmol) were refluxed for 10 h. The red suspension dis-
appeared and a pale yellow solution was formed. After cooling to
90 ꢁC to the mixture was added 2.0 mL of water and refluxing
continued for another 1 h. A yellow suspension was obtained along
with a mixture of dark and white precipitate. Toluene and excess
water were removed in vacuo, the residue was then extracted by
dichloromethane (3ꢂ30 mL). The organic layers were dried over
MgSO4, concentrated in vacuo and further purified by silica gel
chromatography to give selenazadiphospholaminediselenides 2a–
g (1:9¼ethyl acetate/dichloromethane as eluent), carbamidoyl
(phenyl)phosphinodiselenoic acids 3b, 3c, 3e and 3f (1:5¼ethyl
acetate/dichloromethane as eluent), and selenoureas 4f and 4h
(1:5¼ethyl acetate/dichloromethane as eluent).
3.4.3. N-(4-Bromobenzyl)-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2c)
Green solid (29% yield from method A and 11% yield from
method B); mp 163–164 ꢁC. Elemental analysis: Found C, 36.01; H,
2.43; N, 4.11. C20H17BrN2P2Se3 requires C, 36.17; H, 2.58; N, 4.22. IR
(KBr, nmax/cmꢀ1): 3264 (w), 3047 (w), 1596 (s), 1565 (s), 1525 (m,
C]N), 1486 (m), 1434 (m), 1395 (m), 1306 (m), 1180 (m), 1084 (m),
943 (m), 819 (m), 744 (m), 702 (m), 702 (m), 683 (m), 551 (s, P]Se).
3
1H NMR (CDCl3, ppm): 8.32 (d, J(H,H)¼7.2 Hz, 2H, ArH), 8.28 (dd,
3
3
3J(H,H)¼7.2 Hz, J(P,H)¼10.1 Hz, 2H, ArH), 8.00 (dd, J(H,H)¼7.2 Hz,
3J(P,H)¼10.1 Hz, 2H, ArH), 7.59 (dd, 3J(H,H)¼7.2 Hz, 4J(P,H)¼3.7 Hz, 2H,
3
4
ArH), 7.57 (dd, J(H,H)¼7.2 Hz, J(P,H)¼3.0 Hz, 2H, ArH), 7.52 (dd,
3J(H,H)¼7.2 Hz, 1H, ArH), 7.41 (dd, J(H,H)¼7.2 Hz, 1H, ArH), 7.22 (d,
3
3J(H,H)¼7.2 Hz, 2H, ArH), 2.35 (s, 2H, CH2), 0.07 (s, 1H, NH). 13C NMR
1
3
(CDCl3, ppm): 165.0 (d, J(P,C)¼32.6 Hz), 136.2 (d, J(P,C)¼9.3 Hz),
4
4
3.4. Hydrolysis of selenazadiphospholaminediselenides to
carbamidoyl(phenyl)phosphinodiselenoic acids (method C)
133.5 (d, J(P,C)¼4.2 Hz), 132.9 (d, J(P,C)¼3.1 Hz), 132.5 (d,
2J(P,C)¼14.5 Hz), 132.4, 131.6 (d, 2J(P,C)¼13.5 Hz), 129.3 (d,
2J(P,C)¼13.5 Hz), 129.1, 128.7 (d, J(P,C)¼14.5 Hz), 128.3, 125.4, 121.8,
2
2
A solution of selenazadiphospholaminediselenides (1.0 mmol)
and 1.0 mL of water in 20.0 mL of tetrahydrofuran was refluxed for
3 h. Upon cooling to room temperature the resulting mixture was
extracted with dichloromethane (2ꢂ25 mL). The organic layers
were dried over MgSO4 overnight. After concentration in vacuo the
residue was purified by silica gel chromatography (1:5¼ethyl ace-
tate/dichloromethane as eluent) to afford the corresponding carb-
amidoyl(phenyl)phosphinodiselenoic acids.
40.8. 31P NMR (CDCl3, ppm): 80.7 (d, J(P,P)¼14.1 Hz, J(P,Se)¼420,
789 Hz), 75.3 (d, J(P,P)¼14.1 Hz, J(P,Se)¼310, 833 Hz). 77Se NMR
2
(CDCl3, ppm): 391.9 (dd, J(P,Se)¼310, 420 Hz), 13.6 (d, J(P,Se)¼833 Hz),
ꢀ124.5 (d, J(P,Se)¼789 Hz). MS (EI, m/z), 666 [M]þ.
3.4.4. N-Benzyl-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2d)
Yellowsolid(28% yieldfrom method A and15% yieldfrommethod
B); mp 108–110 ꢁC. Elemental analysis: Found C, 40.90; H, 3.03; N,
3.4.1. N-(Phenylpropyl)-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2a)
Yellow solid (45% yield from method A and 30% yield from method
B); mp 133–134 ꢁC. Elemental analysis: Found C, 41.81; H, 3.05; N,
4.65. C20H18N2P2Se3 requires C, 41.05; H, 3.10; N, 4.79. IR (KBr, nmax/
cmꢀ1): 3249 (m), 1580 (vs), 1511 (m, C]N), 1433 (m), 1085 (m), 1017
(m), 882 (m), 550 (vs, P]Se). 1H NMR (CDCl3, ppm): 8.26 (dd,
3
3
3J(H,H)¼8 Hz, J(P,H)¼16 Hz, 4H, ArH), 7.93–7.89 (m, J(H,H)¼8 Hz, 6H,
ArH), 7.59–7.15 (m, 5H, ArH), 4.79–4.57 (m, 2H, CH2),1.56 (s,1H, NH).
13C NMR (CDCl3, ppm): 136.0 (d, 1J(P,C)¼30 Hz),133.3 (d, 4J(P,C)¼3 Hz),
4.55. C21H20N2P2Se3 requires C, 42.09; H, 3.36; N, 4.67. IR (KBr, nmax
/
cmꢀ1): 3226 (w), 1579 (vs), 1503 (w, C]N), 1434 (m), 1357 (w), 1260
(m), 1095 (m), 1084 (m), 920 (m), 747 (m), 549 (s, P]Se). 1H NMR
(CDCl3, ppm): 8.19 (dd, J(H,H)¼8.2 Hz, J(P,H)¼16.1 Hz, 2H, ArH), 7.96 (dd,
J(H,H)¼8.4 Hz,J(P,H)¼9.6 Hz, 2H, ArH),7.56–7.52(m, 3H, ArH), 7.52–7.50
(m, 3H, ArH), 7.21–7.19 (m, 2H, ArH), 7.00–6.96 (m, 3H, ArH), 3.73 (t,
J(H,H)¼6.7 Hz, 2H, ArCH2), 2.82 (t, J(H,H)¼6.7 Hz, 2H, NCH2), 0.06 (s,1H,
NH). 13C NMR (CDCl3, ppm): 166.58 (d, J(P,C)¼34.3 Hz), 137.4, 133.2,
132.6, 132.4, 131.5 (d, J(P,C)¼14.3 Hz), 129.2, 129.0, 128.9, 128.7, 128.5,
127.0, 47.2, 47.1, 34.8. 31P NMR (CDCl3, ppm): 76.4 (d, 2J(P,P)¼14.1 Hz,
3
3
132.5 (d, J(P,C)¼14 Hz), 131.4 (d, J(P,C)¼14 Hz), 129.3, 129.1, 128.6,
128.4, 128.3, 127.7, 49.7 (s, CH2). 31P NMR (CDCl3, ppm): 76.5 (d,
2J(P,P)¼14 Hz, J(P,Se)¼486, 825 Hz), 74.4 (d, J(P,P)¼14 Hz, J(P,Se)¼477,
2
791 Hz). 77Se NMR (CDCl3, ppm): 419.1 (dd, J(P,Se)¼486, 477 Hz), 15.3
(d, J(P,Se)¼825 Hz), ꢀ126.4 (d, J(P,Se)¼791 Hz). MS (EIþ, m/z), 588 [M]þ.
3.4.5. N-(3-Phenylpropyl)-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2e)
2
J(P,Se)¼475, 792 Hz), 74.8 (d, J(P,P)¼14.1 Hz, J(P,Se)¼477, 825 Hz). 77Se
Pale green solid (43% yield from method A and 25% yield from
method B); mp 122–123 ꢁC. Elemental analysis: Found C, 43.01; H,
3.45; N, 4.51. C22H22N2P2Se3 requires C, 43.09; H, 3.62; N, 4.57. IR (KBr,
nmax/cmꢀ1): 3225 (dw), 2924 (w),1586 (vs, C]N),1508 (m),1434 (m),
1354 (m),1252 (m),1181 (m),1093 (m), 935 (m), 910 (m), 748 (m), 678
(m), 549 (m, P]Se). 1H NMR (CDCl3, ppm): 8.28 (dd, J(H,H)¼6.2 Hz,
NMR (CDCl3, ppm): 414.1 (dd, J(P,Se)¼475, 477 Hz), 11.8 (d,
J(P,Se)¼825 Hz), ꢀ126.7 (d, J(P,Se)¼792 Hz). MS (EI, m/z), 602 [M]þ.
3.4.2. N-(4-Decylphenyl)-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2b)
3
Yellow oil (71% yield from method A and 41% from method B); mp
158–159 ꢁC. Elemental analysis: Found C, 49.10; H, 4.81; N, 3.65.
C29H35N2P2Se3 requires C, 49.03; H, 4.97; N, 3.94. IR (KBr, nmax/cmꢀ1):
2922 (s), 2850 (m),1581 (s),1511 (m, C]N),1434 (m),1411 (m),1305
(w), 1260 (w), 1180 (w), 1087 (m), 940 (s), 821 (m), 745 (m), 685 (m),
554 (s, P]Se). 1H NMR (CDCl3, ppm): 8.67 (ws,1H, NH), 8.65 (ws,1H,
3J(P,H)¼9.9 Hz, 2H, ArH), 8.05 (dd, J(H,H)¼6.8 Hz, J(P,H)¼15.1 Hz, 2H,
ArH), 7.58–7.56 (m, 3H, ArH), 7.52–7.49 (m, 3H, ArH), 7.22 (d,
J(H,H)¼7.7 Hz, 2H, ArH), 7.04(d, J(H,H)¼7.7 Hz, 2H, ArH), 6.55(s,1H, NH),
3.52 (m, 2H, NCH2), 2.54 (m, 2H, CH2), 1.88 (m, 2H, CH2). 13C NMR
(CDCl3, ppm): 166.8 (d,1J(P,C)¼33.2 Hz),140.5,137.0 (d,1J(P,C)¼91.4 Hz),
133.2 (d, 4J(P,C)¼3.1 Hz),132.6,132.4,131.6 (d, 3J(P,C)¼13.5 Hz), 129.2 (d,
3
3
4
NH), 8.34 (dd, J(H,H)¼7.4 Hz, J(P,H)¼15.6 Hz, 4H, ArH), 8.05 (m, 6H,
ArH), 7.58 (d, 3J(H,H)¼8.2 Hz, 2H, ArH), 7.11 (d, 3J(H,H)¼8.2 Hz, 2H, ArH),
2.54 (t, 3J(H,H)¼7.2 Hz, 2H, CH2),1.53–1.50 (m, 3J(H,H)¼7.2 Hz, 2H, CH2),
3J(P,C)¼13.5 Hz), 128.7, 128.4 (d, J(P,C)¼2.1 Hz), 126.4, 45.4, 32.7, 30.1.
2
31P NMR (CDCl3, ppm): 76.4 (d, J(P,P)¼14.1 Hz, J(P,Se)¼479, 789 Hz),
74.9 (d, 2J(P,P)¼14.1 Hz, J(P,Se)¼308, 825 Hz). 77Se NMR (CDCl3, ppm):
414.7 (dd, J(P,Se)¼479, 308 Hz), 10.9 (d, J(P,Se)¼825 Hz), ꢀ125.8 (d,
J(P,Se)¼789 Hz). MS (CI, m/z), 617 [MþH]þ.
3
1.24–1.22 (m, 14H, CH2), 0.88 (t, J(H,H)¼7.2 Hz, 3H, CH3). 13C NMR
(CDCl3, ppm): 161.5 (d, 1J(P,C)¼34.3 Hz, P–C), 141.5, 137.3, 136.0, 134.9
2
4
3
(d, J(P,C)¼9.3 Hz), 133.4 (d, J(P,C)¼3.1 Hz), 132.8 (d, J(P,C)¼4.2 Hz),
132.5 (d, 1J(P,C)¼13.5 Hz), 131.6 (d, 1J(P,C)¼13.5 Hz), 129.4, 129.2, 128.7,
128.4, 120.1, 35.5, 32.0, 31.5, 29.7, 29.6, 29.4, 29.3, 22.8,14.3. 31P NMR
3.4.6. N-Phenethyl-N-methyl-2,5-diphenyl-2,5-dihydro-1,2,3,5-
selenazadiphosphol-4-amine-2,5-diselenide (2f)
2
(CDCl3, ppm): 81.0 (d, J(P,P)¼16.4 Hz, J(P,Se)¼484, 789 Hz), 74.9 (d,
Pale green solid (42% yield from method A and 31% yield from
2J(P,P)¼16.4 Hz, J(P,Se)¼310, 831 Hz). 77SeNMR(CDCl3, ppm):391.4(dd,
method B); mp 149–150 ꢁC. IR (KBr, nmax/cmꢀ1): 3425 (dw), 2921

G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
6081
(w), 1561 (vs, C]N), 1434 (s), 1355 (m), 1094 (s), 869 (m), 746 (m),
687 (m), 554 (m, P]Se), 539 (m, P]Se). 1H NMR (CD2Cl2, ppm):
8.16–8.08 (m, 4H, ArH), 7.72–7.53 (m, 6H, ArH), 7.22–7.19 (m, 7H,
ArH). 13C NMR (CD2Cl2, ppm): 137.8, 137.0, 133.4, 133.1, 132.4, 132.2,
132.0, 131.9, 131.3, 131.1, 129.6, 129.4, 129.2, 129.0, 128.7, 128.6,
128.5, 128.3, 126.7, 57.9, 38.8, 33.6. 31P NMR (CD2Cl2, ppm): 76.7 (d,
2J(P,P)¼11.7 Hz, J(P,Se)¼455, 793 Hz), 75.1 (d, 2J(P,P)¼11.7 Hz,
J(P,Se)¼477, 798 Hz). 77Se NMR (CD2Cl2, ppm): 502.0 (dd, J(P,Se)¼455,
479 Hz), 13.4 (d, J(P,Se)¼827 Hz), ꢀ79.5 (d, J(P,Se)¼792 Hz). MS (EIþ,
m/z), 616 [M]þ, 536 [MꢀSe]þ. Accurate mass measurement (EI,
m/z): 615.8745, calculated mass for C22H22N2P2Se3: 615.8748.
cmꢀ1): 3045 (m), 1636 (vs, C]N), 1557 (s, C]N), 1486 (m), 1434
(m), 1399 (w), 1249 (w), 1072 (m), 1010 (m), 809 (m), 747 (m), 689
(m), 624 (m), 559 (s, P–Se). 1H NMR (CDCl3, ppm): 8.52 (s, 2H, NH2),
8.22 (d, J(H,H)¼6.9 Hz, 2H, ArH), 8.17 (dd, J(H,H)¼7.2 Hz,
3J(P,H)¼15.6 Hz, 2H, ArH), 8.05 (s, 1H, NH), 7.55–7.50 (m, 3H, ArH),
7.05 (d, J(H,H)¼6.9 Hz, 2H, ArH). 13C NMR (CDCl3, ppm): 166.9 (d,
2
1J(P,C)¼24.9 Hz), 135.2, 134.2, 134.0, 132.2 (d, J(P,C)¼19.7 Hz), 131.9,
3
131.8, 128.6 (d, J(P,C)¼13.5 Hz), 126.2, 123.7, 60.5. 31P NMR (CDCl3,
ppm): 30.5 (s, J(P,Se)¼695 Hz). 77Se NMR (CDCl3, ppm): ꢀ78.2 (d,
J(P,Se)¼695 Hz). MS (ESþ, m/z), 505 [MþNa]þ; (ESꢀ, m/z), 481
[MꢀH]þ.
3.4.7. N-Benzyl-N-ethyl-2,5-diphenyl-2,5-dihydro-1,2,3,5-
3.4.10. N0-(3-Phenylpropyl)carbamidoyl(phenyl)-
selenazadiphosphol-4-amine-2,5-diselenide (2g)
phosphinodiselenoic acid (3e)
Pale green solid (50% yield from method A and 38% yield form
method B); mp 140–142 ꢁC. Elemental analysis: Found C, 42.85; H,
3.44; N, 4.50. C22H22N2P2Se3 requires C, 43.09; H, 3.62; N, 4.57. IR
(KBr, nmax/cmꢀ1): 3432 (w), 2927 (w), 1549 (vs, C]N), 1433 (m),
1352 (m), 1302 (w), 1237 (m), 1177 (m), 1088 (m), 980 (m), 899 (m),
899 (m), 822 (m), 741 (m), 687 (m), 596 (m), 557 (s, P]Se), 554 (s,
P]Se). 1H, 31P and 77Se NMR confirmed that the product is one pair
of diasteroisomers with the same intensity. 1H NMR (CDCl3, ppm):
8.25 (dd, J(H,H)¼6.4 Hz, J(P,H)¼20.0 Hz, 2H, ArH), 7.93 (dd,
J(H,H)¼6.4 Hz, J(P,H)¼16.8 Hz, 2H, ArH), 7.59 (dd, J(H,H)¼6.4 Hz,
J(P,H)¼12.6 Hz, 2H, ArH), 7.50 (dd, J(H,H)¼6.4 Hz, J(P,H)¼13.6 Hz, 2H,
ArH), 7.47 (m, 1H, ArH), 7.40 (m, 1H, ArH), 7.25 (m, 2H, ArH), 7.17 (d,
J(H,H)¼6.9 Hz, 2H, ArH), 6.77 (d, J(H,H)¼6.9 Hz, 2H, ArH), 5.10 (d,
J(P,H)¼14.8 Hz, 2H, ArCH2), 4.57 (d, J(P,H)¼14.8 Hz, 2H, ArCH2), 3.97
(q, J(P,H)¼6.9 Hz, 2H, NCH2), 3.66 (q, J(P,H)¼6.9 Hz, 2H, NCH2), 1.07 (t,
J(P,H)¼6.9 Hz, 3H, CH3), 0.63 (t, J(P,H)¼6.9 Hz, 3H, CH3). 13C NMR
(CDCl3, ppm): 163.8 (d, J(P,C)¼29.1 Hz),162.7 (d, J(P,C)¼29.1 Hz),138.0
(d, J(P,C)¼4.2 Hz), 136.7 (d, J(P,C)¼4.2 Hz), 135.2, 134.0, 133.2 (d,
J(P,C)¼3.1 Hz), 133.1 (d, J(P,C)¼3.1 Hz), 132.6, 132.5, 132.3, 132.2, 131.5
(d, J(P,C)¼13.5 Hz), 131.2 (d, J(P,C)¼14.5 Hz), 129.5, 129.3, 128.9, 128.6,
128.4, 128.2, 128.0, 127.6, 127.5, 54.9, 53.6, 47.8, 45.0, 12.4, 11.3. 31P
NMR (CD2Cl2, ppm): 76.1 (d, 3J(P,P)¼9.4 Hz, J(P,Se)¼458, 794 Hz), 75.7
Green solid (0.51 g), 29% yield form method B and 98% yield
from method C; mp 140–141 ꢁC. Elemental analysis: Found C,
44.67; H, 4.50; N, 6.19. C16H19N2PSe2 requires C, 44.88; H, 4.47; N,
6.54. IR (KBr, nmax/cmꢀ1): 3243 (s), 3150 (s), 3117 (s), 1642 (vs,
C]N), 1577 (s, C]N), 1490 (m), 1454 (m), 1434 (m), 1346 (m), 1303
(m), 1233 (m), 1083 (m), 1010 (m), 743 (s), 697 (s), 557 (s, P]Se). 1H
NMR (CD2Cl2, ppm): 8.75 (br s, 2H, NH2), 8.24–8.15 (m, 2H, ArH),
7.52–7.43 (m, 3H, ArH), 7.23 (d, J(H,H)¼7.2 Hz, 2H, ArH), 7.05 (d,
J(H,H)¼7.2 Hz, 2H, ArH), 6.89 (ds, H, NH), 3.27 (t, J(H,H)¼6.4 Hz, 2H,
NCH2), 2.60 (t, J(H,H)¼6.4 Hz, 2H, ArCH2), 2.03–1.94 (m, 2H, CH2). 13
C
1
NMR (CD2Cl2, ppm): 167.3 (d, J(P,C)¼29.1 Hz), 139.7, 131.8, 131.6,
131.5, 128.7, 128.4, 128.2, 126.6, 43.7, 32.2, 29.0. 31P NMR (CD2Cl2,
ppm): 29.9 (s, J(P,Se)¼703 Hz). 77Se NMR (CD2Cl2, ppm): ꢀ95.2 (d,
J(P,Se)¼703 Hz). MS (ESþ, m/z), 453 [MþNa]þ; (ESꢀ, m/z), 429
[MꢀH]þ.
3.4.11. N0-Phenethyl-N0-(methyl)carbamidoyl(phenyl)-
phosphinodiselenoic acid (3f)
Greenish white solid (0.52 g), 48% yield from method B and 99%
yield from method C; mp 94–96 ꢁC. Elemental analysis: Found C,
44.55; H, 4.59; N, 6.45. C16H19N2PSe2 requires C, 44.88; H, 4.47; N,
6.54. IR (KBr, nmax/cmꢀ1): 3202 (w), 3091 (w), 1613 (vs, C]N), 1562
(m, C]N), 1453 (w), 1435 (m), 1088 (m), 748 (m), 702 (m), 552 (s,
P]Se). One pair of diastereomers: 1H NMR (CD3CN, ppm): 9.22 (s,
2H, NH2), 8.01–7.94 (m, 2H, ArH), 7.47–7.45 (m, 3H, ArH), 7.28–7.16
(m, 3H, ArH), 6.95–6.93 (m, 2H, ArH), 3.77 (t, J(H,H)¼8.4 Hz, 2H,
PhCH2), 3.15 (s, 3H, CH3), 2.47 (t, J(H,H)¼8.4 Hz, 2H, NCH2). 13C NMR
(CDCl3, ppm): 137.4, 131.2, 130.4, 130.2, 129.1, 128.8, 128.5, 126.7,
117.4, 54.8, 39.4, 32.2. 31P NMR (CD3CN, ppm): 27.4 (30%) (s,
J(P,Se)¼700 Hz), 24.9 (70%) (s, J(P,Se)¼700 Hz). 77Se NMR (DMF-d7,
ppm): 31.6 (70%) and 29.9 (30%) (d, J(P,Se)¼700 Hz). MS (ESþ, m/z),
453 [MþNa]þ; (ESꢀ, m/z), 429 [MꢀH]þ.
3
3
(d, J(P,P)¼9.4 Hz, J(P,Se)¼460, 794 Hz), 59.8 (d, J(P,P)¼9.4 Hz,
J(P,Se)¼458, 822 Hz), 59.5 (d, 3J(P,P)¼9.4 Hz, J(P,Se)¼455, 822 Hz). 77Se
NMR (CD2Cl2, ppm): 499.7 (dd, J(P,Se)¼458, 455 Hz), 492.6 (dd,
J(P,Se)¼460, 458 Hz), 17.5 (d, J(P,Se)¼822 Hz), 8.1 (d, J(P,Se)¼822 Hz),
ꢀ70.6 (d, J(P,Se)¼794 Hz), ꢀ74.5 (d, J(P,Se)¼794 Hz). MS (EI, m/z), 616
[M]þ.
3.4.8. N0-(4-Decylbenzyl)carbamidoyl(phenyl)phosphinodiselenoic
acid (3b)
Yellow oil (310 mg) in 57% yield from method B; mp 147–148 ꢁC.
Elemental analysis: Found C, 52.39; H, 5.88; N, 5.40. C23H31N2PSe2
requires C, 52.68; H, 5.96; N, 5.34. IR (KBr, nmax/cmꢀ1): 2923 (s),
2852 (m), 1639 (s, C]N), 1512 (s, C]N), 1463 (m), 1436 (m), 1141
(s), 1019 (m), 938 (m), 695 (m), 551 (m, P–Se). 1H NMR (CDCl3,
ppm): 10.10 (ws,1H, NH), 8.43 (ws, 1H, NH), 8.25 (dd, 3J(H,H)¼7.4 Hz,
3J(P,H)¼15.6 Hz, 2H, ArH), 7.44–7.42 (m, 3H, ArH), 7.26 (d,
3.4.12. 1-Methyl-1-phenethylselenourea (4f)
Pink white solid, 20% yield from method B and 99% yield from
method C; mp 167–169 ꢁC. IR (KBr, nmax/cmꢀ1): 3375 (w), 3263 (m),
3166 (s), 1612 (s), 1528 (s), 1495 (w), 1452 (w), 1411 (w), 1366 (m),
1280 (m), 1006 (m), 750 (m), 699 (m, C]Se). 1H NMR (CDCl3, ppm):
7.31–7.25 (m, 3H, ArH), 6.24–6.22 (m, 2H, ArH), 4.14 (s, 3H, NCH3),
3.46 (t, J¼9.6 Hz, 2H, NCH2), 2.97 (t, J¼9.6 Hz, 2H, PhCH2). 13C NMR
(CDCl3, ppm): 207.1 (C]Se), 135.1, 128.9, 127.5, 126.8, 126.0, 37.25,
33.7, 31.0. 77Se NMR (CD3CN, ppm): 607.7. MS (ESþ, m/z), 265
[MþNa]þ. Accurate mass measurement [CIþ(NH3), m/z]: 239.0425
[MþH]þ, calculated mass for C10H14N2Se: 239.0422 (76Se).
3
3J(H,H)¼8.2 Hz, 2H, ArH), 7.06 (d, J(H,H)¼8.2 Hz, 2H, ArH), 2.59 (t,
3J(H,H)¼7.2 Hz, 2H, CH2), 1.60–1.56 (m, 3J(H,H)¼7.2 Hz, 2H, CH2), 1.25–
1.18 (m, 14H, CH2), 0.85 (t, 3J(H,H)¼7.2 Hz, 3H, CH3). 13C NMR (CDCl3,
1
ppm): 167.3 (d, J(P,C)¼24.9 Hz, P–C), 145.4, 135.7, 134.8, 131.9 (d,
3
2J(P,C)¼13.5 Hz), 131.6, 130.8, 128.4 (d, J(P,C)¼13.5 Hz), 124.1, 35.6,
32.0, 31.3, 29.7, 29.5, 29.4, 29.3, 22.8, 14.2. 31P NMR (CDCl3, ppm):
30.2 (s, J(P,Se)¼702 Hz). 77Se NMR (CDCl3, ppm): ꢀ83.7 (d,
J(P,Se)¼702 Hz). MS (ESꢀ, m/z), 525 [MꢀH]þ.
3.4.13. 1-Phenethyl-1-(propionyloxy)selenourea (4h)
Slightly yellow powder in an yield of 91% based on WR from
method B and 98% yield from method C; mp 110–112 ꢁC. Elemental
analysis: Found C, 47.91; H, 5.17; N, 9.13. C12H16N2O2Se requires C,
48.17; H, 5.39; N, 9.36. IR (KBr, nmax/cmꢀ1): 3327 (m), 3205 (w),1715
(s), 1598 (s), 1372 (s), 1256 (s), 1196 (s), 994 (m), 899 (m), 769 (m),
705 (m), 656 (m, C]Se). 1H NMR (CDCl3, ppm): 10.47 (d,
3.4.9. N0-(4-Bromobenzyl)carbamidoyl(phenyl)-
phosphinodiselenoic acid (3c)
Orange solid (220 mg) in 47% yield from method B; mp 135–
137 ꢁC. Elemental analysis: Found C, 34.71; H, 3.30; N, 5.75.
C14H16BrN2PSe2 requires C, 34.95; H, 3.35; N, 5.82. IR (KBr, nmax
/

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G. Hua et al. / Tetrahedron 65 (2009) 6074–6082
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J(H,H)¼7.2 Hz, 2H, ArH); 8.24 (d, J(H,H)¼7.2 Hz, 1H, ArH), 7.26 (d,
J(H,H)¼7.2 Hz, 2H, ArH), 4.62 (t, J(H,H)¼7.9 Hz, 2H, ArCH2), 4.15 (q,
J(H,H)¼6.9 Hz, 2H, OCH2), 3.06 (t, J(H,H)¼7.9 Hz, 2H, NCH2), 1.30 (t,
J(H,H)¼6.9 Hz, 3H, CH3), 0.07 (s, 2H, NH2). 13C NMR (CDCl3, ppm):
186.7 (C]Se), 154.7 (C]O), 138.5 (ArC), 129.1 (ArC), 128.6 (ArC),
126.6 (ArC), 64.2 (OCH2), 54.2 (NCH2), 34.9 (ArCH2), 14.1 (CH3). 77Se
NMR (CDCl3, ppm): 382.1. MS (ESþ, m/z), 323 [MþNa]þ.
13. (a) Hua, G.; Li, Y.; Slawin, A. M. Z.; Woollins, J. D. Eur. J. Inorg. Chem. 2007, 891–
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Acknowledgements
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16. Hua, G.; Li, Y.; Slawin, A. M. Z.; Woollins, J. D. Angew. Chem., Int. Ed. 2008, 47,
2857–2859.
The authors are thankful to the University of St. Andrews and
the Engineering and Physical Science Research Council (EPSRC,
U.K.) for financial support.
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