4-Phosphorylated 1,2-disubstituted imidazoles

Article abstract of DOI:10.1002/hc.20584

4-Selenophosphoryl-1,2-disubstituted imidazoles have been obtained by thermal decomposition of methyl 5-(diamidoselenophosphoryl)- imidazolium chlorides. The position of selenophosphoryl group in the imidazole ring was proved by ¹H, ¹³C NMR spectroscopy, and X-ray analysis. Previously unknown diamido- and dichloro(imidazol-4-yl)- phosphoniteswere synthesized, and differences in their reactivity compared to analogous 5-phosphorylated imidazoles are shown.

Full text of DOI:10.1002/hc.20584

Heteroatom Chemistry
Volume 21, Number 3, 2010
4-Phosphorylated 1,2-Disubstituted
Imidazoles
A. N. Huryeva, A. P. Marchenko, G. N. Koidan, A. A. Yurchenko,
E. V. Zarudnitskii, A. M. Pinchuk, and A. N. Kostyuk
Institute of Organic Chemistry, National Academy of Sciences of Ukraine, Murmanskaya Str. 5,
Kiev-94, 02094, Ukraine
Received 3 December 2009; revised 1 February 2010
it was found that the reaction of 2-methylthio-1-
ABSTRACT: 4-Selenophosphoryl-1,2-disubstituted
methylimidazole (2-phenyl-1-methylimidazole) with
imidazoles have been obtained by thermal de-
phosphorus trichloride resulted in formation of a
composition of methyl 5-(diamidoselenophosphoryl)-
mixture of tris(imidazolyl)phosphines. At the last
imidazolium chlorides. The position of selenophos-
stage of the phosphorylation, the substitution pro-
phoryl group in the imidazole ring was proved by
ceeded both at the fourth and the fifth positions of
1H, 13C NMR spectroscopy, and X-ray analysis. Previ-
the imidazole ring.
ously unknown diamido- and dichloro(imidazol-4-yl)-
Regioselectivity of the electrophilic substitution
phosphonites were synthesized, and differences in their
reactions of 1,2-disubstituted imidazoles is obvi-
reactivity compared to analogous 5-phosphorylated
ously determined by greater electronic density on
ꢀ
C
imidazoles are shown.
2010 Wiley Periodicals, Inc.
the C(5) atom, preventing direct introduction of elec-
trophilic reagents at the fourth position. From this
point of view, 4-phosphorylated 1,2-disubstituted
imidazoles bearing the unoccupied fifth position are
of theoretical interest. There are a few compounds
of such type. Among them (1-alkyl-2-aryl-5-
methylthioimidazol-4-yl)triphenylphosphonium
salts are known to be obtained by cyclization of the
corresponding phosphonium derivatives, bearing
an imidoyl chloride group in a side chain. [3].
4-P(V)-Phosphorylated derivatives of imidazole
were prepared via cross-cycloaddition between two
different isocyanides, with one of them bearing a
phosphonate group [4]. In the recent review on
direct phosphonylation on aromatic azaheterocyles,
some 4-phosphorylated imidazoles with different
substitution patterns are presented [5]. Notewor-
thy, those corresponding trivalent phosphorus
derivatives are currently unknown.
Heteroatom Chem 21:103–118, 2010; Published online
in Wiley InterScience (www.interscience.wiley.com). DOI
10.1002/hc.20584
INTRODUCTION
In electrophilic substitution reactions, reactivity
of 1,2-disubstituted imidazoles strongly depends
on the electronic nature of the substituent at
the second position. For instance, 1-methyl-2-
dimethylaminoimidazole reacts readily with acylat-
ing, formylating reagents, sulfenyl chlorides, adds
isocyanates, enters into Mannich reaction afford-
ing exclusively 5-substituted imidazole derivatives
[1]. The reactions with PCl3 and AlkLi take the
same course [2]. Namely, earlier we have reported
that 1-methyl-2(R)-disubstituted imidazoles (R =
NMe2, SMe, Ph) reacted with excess of PCl3 in pyri-
dine to give 5-dihalophosphine derivatives. Also,
RESULTS AND DISCUSSION
Correspondence to: A. N. Kostyuk; e-mail: kostyuk@enamine
.net.
2010 Wiley Periodicals, Inc.
In the present study, we report on the synthesis
of 4-phosphorylated 1,2-disubstituted imidazoles
103
c
ꢀ

104 Huryeva et al.
C2Cl6/ Et3N,
H2O;
or Se
N
N
N
X
4 Me2NH
R
P(NMe2)2
R
R
P(NMe2)2
PCl2
N
N
N
- 2 Me2NH.HCl
Me
Me
Me
1
2 a–d
3 a–d, 4 a–d
R=NMe2 (a); i-Pr (b);
Ph (c); SMe (d)
3: X=O
4: X=Se
SCHEME 1
starting from available 5-phosphorylated deriva-
tives [2]. synthetic method was developed
less high-melting crystalline compounds, soluble in
water, and relatively stable in air. Their structures
A
1
based on peculiarities of imidazolium salts’ ther-
mal decomposition. For instance, 4(5)-nitro-1,2,3-
trimethylimidazolium iodide on heating above
melting point decomposes, affording 4-nitro-1,2-
dimethylimidazole in 67% yield and evolving methyl
iodide [6].
We suggested that thermal decomposition of 1,3-
dimethyl-2-R-5-phosphorylimidazolium salts would
also mainly lead to 4-phosphorylated imidazoles
because like the NO2-group, an electron-accepting
phosphoryl group should have a greater effect on
the lone electron pair of N(1). Toward this end,
(imidazol-5-yl)diamidophosphonites 2a–d were syn-
thesized [2] and then by standard oxidative proce-
dures were transformed into the corresponding 5-
phosphorylated derivatives 3a–d, 4a–d (Scheme 1).
It was found that diamidophosphonates 3a–d,
4a–d are alkylated with methyl chloride at 75◦C to
give imidazolium chlorides 5, 6 (Scheme 2) as color-
are consistent with 31P, H, and 13C NMR spectral
data. Methyl groups at nitrogen atoms of the imida-
zole ring are not equivalent and exhibit two singlets
in 1H and 13C NMR spectra.
The resonance form “B” probably contributes
markedly to the structure of imidazolium salts 5a–d,
6a–d, so that the carbon atom at the second position
should be prone to nucleophilic attack [7]. Indeed,
compounds 5b,c reacted with moist silver oxide
to afford C-phosphorylated ethylene-1,2-diamines
7b,c, whereas in the case of imidazolium chloride 5a
imidazolone 8 was obtained (Scheme 2). The struc-
ture of compounds 7b,c and 8 was confirmed by 31P,
1H, and 13C NMR spectroscopy, elemental analysis,
and mass-spectrum. Analogous transformations on
the reaction with hydroxide ions are known for im-
idazolium salts in heterocyclic series. For instance,
substituted ortho-phenylenediamines were obtained
by alkaline hydrolysis of benzimidazolium salts
Me
Me
OH
Me
Cl
Cl
N+
.
N
N
+
N
+
Ag2O H2O
X
X
O
X
CH3Cl
P(NMe2)2
R
P(NMe2)2
P(NMe2)2
R
R
R
P(NMe2)2
N
N
N
N
5 a–c
Me
Me
B
Me
Me
A
3 a–d, 4 a–d
5 a–d, 6 a–d
4–8: R=NMe2 (a); i-Pr (b);
Ph (c); SMe (d)
3, 5: X=O;
Me
N
R
H
4, 6: X=Se
O
Me
N
Me
P(NMe2)2
O
N
O
R
7 b,c
P(NMe2)2
N
Me
HO
Me
N
R=NMe2
O
P(NMe2)2
O
N
– Me2NH
Me
8
SCHEME 2
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 105
Se
Me
P(NMe2)2
N
Cl
N+
N
Se
Se
CH3 Cl
R
P(NMe2)2
+
4 a–c
R
P(NMe2)2
N
R
N
N
~30
Me
Me
6 a–d
Me
4 a–d
Me
9 a–c >70%
R=NMe2 (a); i-Pr (b); Ph (c); SMe (d);
N
Se
P(NMe2)2
S
N
R=SMe
Me
10
SCHEME 3
[8], whereas κaκ 1,3-dialkyl-2-benzthioimidazolium
salts on treatment with aqueous K2CO3 solution
transformed into 1,3-dialkyl-1,3-dihydroimidazo-
lones [9]. Tetraalkylimidazolium-2-amidinate re-
acted with water via a ring opening to give ketoami-
dine [10].
We found that imidazolium chlorides 6a–c on
heating above melting point (200–220◦C) in vacuo
(12 Torr) decompose, evolving methyl chloride to
afford a mixture of (imidazolyl)selenophosphonates
9a–c (δ 31P 68 ppm) and 4a–c (δ 31P 62 ppm) in a
ratio ≈ 2: 1 as evidenced by 31P NMR (Scheme 3). As
expected, 4-phosphorylated imidazoles 9a–c exhibit-
ing chemical shifts in 31P NMR downfield formed
predominantly. Thermal decomposition of com-
pound 6d was under kinetic control and resulted in
imidazol-2-thione 10 [11].
served at δ 7.40–7.65 ppm. The signals of N(1)-Me
are observed at δ 2.50–2.90 ppm and in comparison
to those of selenophosphonates 4a–c shifted upfield
probably due to greater remoteness of (Me2N)2P(Se)-
group. In 13C NMR spectrum of compounds 9a–c, the
C(4)-P atom exhibits a doublet at δ 131.3–135.7 ppm
(with coupling constant JC-P 157 Hz). Whereas, it
is typical of compound 4a–c that the C(5)-P atom
exhibits a doublet at δ 120.0–124.2 ppm (with JC-P
143 Hz). Thus, the values of chemical shifts of C(4)
and C(5) atoms could be considered for the determi-
nation of the position of phosphorous atom in the
imidazole ring which has been already reported ear-
lier [2].
The structure of selenophosphonates 9a–c was
finally proved by X-ray analysis for 9a (Fig. 1).
In the above-mentioned transformations, attack
of chloride anion on the C(2) atom is unlikely due to
low stability of forming α-chloralkyl amine.
5-, 4-Isomers 4a–c and 9a–c were separated by
chromatography on silica gel (for 4a and 9a), crys-
tallization from pentane (for 4b, c and 9b, c), and
by the so-called “salt” method (for 4a and 9a). The
salt method is based on disparity in basicity of 4-
and 5-phosphorylated 1,2-disubstituted imidazoles.
So, if the amount of picric acid calculated according
to integral ratio of 4a and 9a in a 31P NMR spectrum
is added, picrate of (imidazol-5-yl)phosphonate 4a
which has higher basicity will precipitate first. Such
salts are not soluble in organic solvents (diethyl
ether, benzene, pentane, hexane) and could be eas-
ily separated from (imidazol-4-yl)phosphonate 9a,
which in the base state remains in solution. The salt
method is general in nature and, for example, com-
pound 9a was retrieved from mixture with 90% yield.
The structure of selenophosphonates 9a–c was
FIGURE 1 X-ray crystal structure of compound 9a. Selected
bond lengths and angles for 9a P1 Se1 2.1026(5), C2 P1
1.7790(19) N4 P1 1.6466(16), N5 P1 1.6791(17), C1 N3
˚
1.394(3), C6 N1 1.462(3) A; N4 P1 N5 105.10(8) N4 P1 C2
1
1
confirmed by H and 13C NMR spectroscopy. In H
107.87(9) N5 P1 C2 103.62(9) N4 P1 Se1 112.72(6) N5 P1
Se1 115.40(6) C2 P1 Se1 111.43(6)◦.
NMR spectrum, the C(5)-H proton signals are ob-
Heteroatom Chemistry DOI 10.1002/hc

106 Huryeva et al.
was confirmed by 31P, 1H, and 13C NMR spec-
troscopy (Scheme 5). In addition, treatment of
14a with dimethylamine followed by oxidation
with selenium afforded the starting selenophos-
phonate 9a. It should be noted that in 31P NMR
spectrum signals of compounds 14a–c are down-
field (δ 146–147 ppm) compared with signals of
(imidazol-5-yl)dichlorophosphines observed at
δ 121–127 ppm [2]. Dichlorophosphines 14b,c
are viscous liquids distillable in vacuo with slight
decomposition. Dichlorophosphine 14a decom-
posed during distillation by 60–70% unlike isomeric
(imidazol-5-yl)dichlorophosphine [2]. Obviously,
low thermal stability of compound 14a is caused by
reactivity of the unoccupied fifth position of the im-
idazole ring activated by the dimethylaminogroup
at the second position.
Cl
Cl
Me
Me
N+
N+
(Me2N)3P
Se
P(NMe2)2
i-Pr
P(NMe2)2
i-Pr
N
16oC, 15 h
N
Me
Me
6b
11
SCHEME 4
It is of special synthetic interest to prepare 1,2-
disubstituted (imidazol-4-yl)phosphines, including
such key compounds in organophosphorus chem-
istry as dihalophosphines.
(Hexalkyl)triamidophosphites are commonly
used for reduction of the selenophosphoryl group
[12,13]. It was shown that on treatment with (hexam-
ethyl)triamidophosphite imidazolium salt 6b could
be readily reduced, giving salt 11 (Scheme 4).
Unfortunately, triamidophosphites are unsuit-
able for the reduction of compounds 9a–c owing to
reaction equilibrium. For this purpose, highly nucle-
ophilic bis(hexalkyltriamidophosphazo)dimethyl-
amidophosphite 12 was used successfully [14]. The
reduction with metallic sodium in boiling toluene
appeared to be even more convenient and simple
method [15] (Scheme 5).
We have found that heating (45◦C) of
dichlorophosphine 14a in pyridine in the pres-
ence of triethylamine and PCl3 resulted in com-
1
pound 15a, exhibiting a broad singlet at δ 31P-{ H}
25.1 ppm (Scheme 6). Without PCl3 tar formation
is observed. The presence of doublet of doublets at
3
δ 115.0 and 135.6 ppm with coupling constant JP-P
317 Hz might be attributed to formation of a trace
amount of 4,5-bis(dichlorophosphino)-1-methyl-2-
dimethylaminoimidazole. Heating (125◦C) of 14b in
pyridine for 9 days or in benzene solution in the
presence of pyridine for 20 days resulted in analo-
gous compound 15b (δ 31P NMR 23.4 ppm).
Amidophosphonites 13a–c are colorless crys-
talline compounds sensitive to air moisture and oxy-
gen, easily distillable in vacuo without decomposi-
tion. In 31P NMR spectrum, they exhibit a singlet at
1,4-Dichloro-1,4-diphosphinine 15a is a yellow
high-melting solid, which is sensitive to air mois-
1
1
ture and oxygen. Its structure was confirmed by H
δ 86.0–88.0 ppm. In H NMR spectrum, the C(5)-H
and 13C NMR spectroscopy as well as by chemical
transformations. Thus, compound 15a reacted with
dimethylamine to give amide 16a, which was oxi-
dized with selenium, sulfur under mild conditions
to give [1,4]diphosphinino-4,8-diselenide 17a or sul-
fide 18, respectively. Diphosphinino-4,8-diselenide
17b was prepared similarly without isolation of com-
pounds 15b and 16b. Diphosphinino-4,8-diamines
16a,b were obtained in analytically pure state by
reduction of selenides 17a,b with metallic sodium
in benzene. In 31P NMR spectrum, compounds
16a,b exhibited two signals of different intensity
at δ 15.0 and 17.0 ppm, whereas their selenides
proton signals are observed at δ 6.55–6.76 ppm. In
13C NMR spectrum, doublets at δ 137.4–141.4 ppm
(JC-P 22 Hz) and δ 123.1–127.4 ppm (JC-P 31 Hz)
were assigned to the C(4)-P and the C(5)-H atoms,
respectively.
Amidophosphonites
13a–c
reacted
with
phosphorus trichloride to give (imidazol-4-
yl)dichlorophosphines
14a–c
that
structure
Se
P(NMe2)
PCl3
PCl2
N
P(NMe2)
N
N
1
17a,b exhibited a singlet at δ 31P-{ H} 25.4 ppm.
12
R
1
R
R
N
In H NMR spectrum, the absence of imidazolium
N
N
or Na/toluene,
reflux, 2 h
Me
13 a–c
ring proton signals corroborate the proposed struc-
ture of 1,4-dihydro-1,4-diphosphinine-1,4-diamine-
1,4-diselenide for compounds 17a,b. Doubling of the
alkyl group matched with these compounds existing
as the mixture of two isomers (E and Z) in 3:1 ra-
tio that was also detected by HPLC-MS, both iso-
mers gave molecular ion. For compound 17a, both
Me
Me
9 a–c
14 a–c
R=NMe2 (a); i-Pr (b); Ph (c)
12- [(Et2N)3P=N]2PNMe2
SCHEME 5
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 107
NMe2
Me
Cl
P
Me
PCl2
[PCl3]
P
N
N
N
N
N
N
N
i. Me2NH
R
R
R
R
R
Py
N
N
N
P
P
Me
Me
Me
Cl
NMe2
14 a,b
15 a,b
16 a,b
PCl2
N
Na /
toluene
ii. Se or S8
PCl2
Me2N
N
Me
X
Me2N
Me
R=NMe2 (a), i-Pr (b)
17: X=Se
18: X=S
P
P
N
N
R
R
N
N
NMe2
Me
X
17 a,b (E, Z)
18 a (E)
SCHEME 6
isomers were separated by chromatography on sil-
with t-BuLi, but the reaction proceeds very slowly
(Scheme 7). Thus, after 8 h stirring with t-BuLi at
−80◦C, an electrophile was added affording a mix-
ture containing, as evidenced by 31P NMR, the start-
ing phosphonite 13a (62%), compound 19 (a) or
21 (b). In case (a), P N bond cleavage furnished
phosphonite 20 as well. It should be noted that use
of 2 equiv of t-BuLi resulted in total consumption of
the starting phosphonite 13a. At the same time, yield
of compound 19 decreased at expense of formation
of 20, reaching 1:1 ratio.
1
ica gel and characterized by H and 13C NMR spec-
troscopy. We also managed to isolate the major iso-
mer (E) partially by crystallization from acetonitrile.
As we failed to carry out X-ray analysis of (E)-
17a crystal, we analyzed sulfide (E)-18a the closest
analogue of (E)-17a. The X-ray data of compound
(E)-18a indicated (Fig. 2) that sulfur atoms are in
trans-orientation. Thus, oxidizing reaction 16 → 17,
18 resulted in the mixture (3:1) of two isomers
(E and Z) which are different in sulfur (selenium)
atoms location toward the plane of 1,4-dihydro-1,4-
diphosphinine circle.
Amidophosphonites 19, 20, and 21 were trans-
formed into the corresponding selenoic derivatives
22, 23, and 24, which were isolated in individ-
ual state by chromatography on silica gel or by
(Imidazol-4-yl)amidophosphonites 13a–c unlike
5-phosphorylated analogous 2a–c undergo lithiation
Se
P(NMe2)R'
SiMe3
P(NMe2)R'
Na /
toluene
N
ii:Me3SiCl
N
Se
19
Me2N
Me2N
SiMe3
P(NMe2)2
i. t-BuLi
N
N
a
22
N
Me
Me
22, 23
19, 20
Me2N
N
Se
THF
–80oC
P(NMe2)2
P(NMe2)2
Me
N
N
N
N
13a
Se
ii:(Me2N)2PCl
b
Se
19, 22: R'= NMe2;
20, 23: R'= t-Bu;
a: 1.57 mol equivalent of t-BuLi;
Me2N
P(NMe2)2
Me2N
P(NMe2)2
Me
21
Me
b: 1.1 mol equivalent of t-BuLi
24
SCHEME 7
Heteroatom Chemistry DOI 10.1002/hc

108 Huryeva et al.
stitute of the Organic Chemistry National Academy
of Sciences of Ukraine.
Crystallographic measurements were performed
at 173(1)K on a Bruker Smart Apex II diffractometer
operating in the ω and ϕ scans mode. The structure
was solved by direct methods refined by full-matrix
least-squares technique in anisotropic approxima-
tion for non-hydrogen atoms using SHELXS97 and
SHELXL97 [16a,b] program packages. Hydrogen
atoms were located from Fourier synthesis and re-
fined isotropically.
X-ray crystal data for 9a: crystal system, or-
thorhombic; space group Fdd2; unit cell dimensions:
˚
a = 24.5254(8), b = 24.6691(6), c = 10.0515(2) A,
FIGURE 2 X-ray crystal structure of compound 18a. Se-
lecꢁted bond lengths and angles for 18a: P1 C1 1.781(3), P1
3
−3
˚
V = 6081.4(3) A , Z = 16, dc = 1.408 g·cm , μ =
2.564 mm−1; F(000) = 2656; crystal size ca. 0.36 ×
0.44 × 0.48 mm. 22,908 reflections were collected,
3160 unique reflections (2838 reflections with I ≥
2σ(I), Rmerg = 0.0357) were used in refinement; Mo
˚
C2 1.789(3), P1 N3 1.650(3), P1 S1 1.9301(11) A; C2 C1
P1 130.3(2), C1 P1 C2ꢁ 100.42(12), C1 C2 P1ꢁ 129.2(2)◦.
The atoms labeled with (‘) are generated symmetry operation
−x + 1, −y + 1, −.
˚
Kα radiation (λ = 0.71078 A). Convergence was ob-
tained at R1 = 0.0264 and wR2 = 0.0383, for all re-
flection and R1 = 0.0206 and wR2 = 0.0372, GOF =
0.979 for observed 242 parameters. In compound 9a,
P1 atom has a slightly distorted tetrahedral coordi-
nation. The distances P1–N4 and P1–N5 are unequiv-
alent, and sum of bond angles around N4 and N5
atoms is 357.55◦ (18) and 339.94◦ (18), respectively,
because of conjugation of the LP-N4 atoms with d
orbitals of phosphorus atom. The sum of bond an-
gles around N3 atom is 337.53◦ (20). The geometry
of imidazole cycle is normal for such systems.
crystallization (24). Selenide 22 was reduced to ami-
dophosphonite 19 with metallic sodium.
CONCLUSION
A facile synthetic route to 4-phosphorylated imi-
dazoles starting from available 5-diamidoseleno-
phosphoryl 1,2-disubstituted imidazoles has been
developed. Previously unknown (imidazol-4-
yl)diamido- and dihalogen phosphines have been
obtained. The higher reactivity of 4-phosphorylated
imidazoles compared with 5-phosphorylated imida-
zoles was observed.
X-ray-crystal data for 18a: crystal system, mon-
oclinic, space group, P21/c; a = 9.0851(9), b =
◦
˚
12.0381(11), c = 10.7717(10) A, β = 96.721 (4), V =
1169.98(19) A , Z = 2, dc = 1.307 g·cm−3, μ =
3
˚
EXPERIMENTAL
General
0.384 mm−1, F(000) = 488, crystal size ca. 0.1 ×
0.14 × 0.3 mm. 8195 reflections were collected, 2316
unique reflections, (1452 reflections with I ≥ 2σ(I),
Rmerg = 0.0494) were used in the refinement; Mo
All procedures with air and moisture sensitive com-
pounds were performed under an atmosphere of dry
argon in flame-dried glassware. Solvents were puri-
fied and dried by standard methods. Melting points
were determined with an electrothermal capillary
˚
Kα radiation (λ = 0.71078 A). Convergence was ob-
tained at R1 = 0.0941 and wR2 = 0.1144, for all
reflection and R1 = 0.0482 and wR2 = 0.0953,
GOF = 1.022 for observed 175 parameters. The six-
membered P2C4 central cycle in 18a is planar due to
1
melting point apparatus and were uncorrected. H
˚
spectra were recorded on a Bruker Avance DRX
500 (500.13 MHz) or Varian VXR-300 (299.94 MHz)
spectrometer. 13C NMR spectra were recorded on a
Bruker Avance DRX 500 (125.75 MHz) spectrom-
eter. 31P NMR spectra were recorded on a Var-
ian VXR-300 (121.42 MHz) spectrometer. Chemical
shifts (δ) are reported in ppm downfield relative to
centrosymmetric arrangement. The bond lengths (A)
in this heterocyclic system are close to correspond-
ing ones the related system [16c], both P C bonds
in the cycle practically equivalent within standard
error.
Crystallographic data (excluding structure fac-
tors) for the structures reported in this paper have
been deposited with the Cambridge Crystallographic
Data Centre as supplementary publication no. CCDC
748955 (9a), and CCDC 748956 (18a) and can be
obtained free of charge on application to CCDC, 12,
1
internal TMS (for H, 13C) and external 85% H3PO4
(for 31P). Chromatography was performed on sil-
ica gel Gerudan SI60. Elemental analyses were per-
formed at the Microanalytical laboratory of the In-
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 109
Union Road, Cambridge CB2 1EZ, UK; fax: +44 1223
336033; or deposit@ccdc.cam.ac.uk.
2.6 g (87%), colorless liquid; bp 123–128◦C/5 ×
1
10−2 Torr. H NMR (500 MHz, C6D6): δ = 1.27 (d,
J = 7.0 Hz, 6H, CH(CH3)2), 2.57 (d, J = 9.0 Hz, 12H,
NCH3), 2.70 (m, 1H, CH), 3.10 (s, 3H, NCH3), 7.23 (s,
1H, 4-H). 13C NMR (125 MHz, C6D6): δ = 21.5, 26.3,
30.1 (d, 3 JCP = 6.3 Hz), 40.8 (d, 2 JCP = 16.3 Hz), 128.8
(d, 1 JCP = 7.5 Hz), 133.9 (d, 2 JCP = 6.3 Hz), 155.9 (d,
3 JCP = 5.0 Hz). 31P NMR (121 MHz, C6D6): δ = 83.4.
Anal. Calcd for C11H23N4P: C, 54.53; N, 23.12; P,
12.78. Found: C, 54.65; N, 23.03; P, 12.50.
2-Isopropyl-1-methyl-1H-imidazol-5-yl-
phosphonous Dichloride (1b)
Phosphorus trichloride (7.0 g, 50 mmol) was cooled
at −10 to −30◦C and a solution of 2-isopropyl-1-
methyl-1(H)-imidazole (2.5 g, 20 mmol) in pyridine
(10 mL) was added. The reaction mixture was heated
at 100◦C for 15 h. Pyridine was removed in vacuo, the
residue was treated with warm Et2O (2 × 30 mL),
insoluble precipitate was filtered, and washed with
Et2O (30 mL). The filtrate was concentrated in vacuo;
and the oily residue was distilled (bp 110–115◦C/5 ×
10−2 Torr) to give 1b (3.9 g, 70%) pale yellow solid;
mp 41–44◦C.
N,N,Nꢁ,Nꢁ-Tetramethyl-P-(1-methyl-2-phenyl-1H-
imidazol-5-yl)-phosphonous Diamide (2c). Follow-
ing the typical procedure for 2a using 1c; yield:
6.9 g (93%), pale yellow liquid; bp 180–184◦C/5 ×
1
10−2 Torr. H NMR (500 MHz, C6D6): δ = 2.55 (d,
12H, J = 9.5 Hz, NCH3), 3.20 (s, 3H, NCH3), 7.09–
7.11 (m, 2H, 3,5-H-Ph), 7.17 (t, 1H, J = 7.5 Hz, 4-H-
Ph), 7.41 (d, 1H, J = 2.5 Hz, 4-H pyr), 7.63 (d, 2H,
J = 7.5 Hz, 2,6-H-Ph). 13C NMR (125 MHz, C6D6):
1H NMR (500 MHz, C6D6): δ = 1.11 (d, J =
6.5 Hz, 6H, CH(CH3)2), 2.62–2.70 (m, 1H, CH), 3.41
(s, 3H, NCH3), 7.39 (s, 1H, 4-H). 13C NMR (125 MHz,
3
3
2
C6D6): δ = 20.9, 21.0, 26.1, 31.5 (d, JCP = 2.5 Hz),
δ = 33.60 (d, JCP = 7.5 Hz), 41.8 (d, JCP = 2.5 Hz),
1
2
1
127.1 (d, JCP = 77.0 Hz), 140.7 (d, JCP = 56.6 Hz),
129.0, 129.2, 130.0, 132.3 (d, JCP = 5.0 Hz), 132.4,
3
2
3
162.3 (d, JCP = 5.0 Hz). 31P NMR (121 MHz, C6D6):
136.2 (d, JCP = 6.3 Hz), 151.9 (d, JCP = 5.0 Hz).
31P NMR (121 MHz, C6D6): δ = 81.9. Anal. Calcd for
C14H21N4P: C, 60.85; N, 20.28; P, 11.21. Found; C,
60.62; N, 19.95; P, 11.07.
δ = 125.6. Anal. Calcd for C7H11Cl2N2P: C, 37.36; N,
12.45; P, 13.76. Found: C, 37.10; N, 12.72; P, 13.11.
Compounds 1a,c,d were prepared as described
in [2].
N,N,Nꢁ,Nꢁ -Tetramethyl-P-[1-methyl-2-(methyl-
thio)-1H-imidazol-5-yl]-phosphonous Diamide (2d).
Following the typical procedure for 2a using 1d;
yield: 8.9 g (96%), yellow liquid; bp 133–136◦C/5 ×
Typical Procedure for 2a–d by the Example of 2a
P-[2-(Dimethylamino)-1-methyl-1H-imidazol-5-
yl]-N,N,Nꢁ,Nꢁ-tetramethyl-phosphonous diamide (2a).
To a solution of compound 1a (19.6 g, 0.087 mol)
in Et2O (100 mL) at −30◦C to −10◦C dimethylamine
(17.0 g, 0.4 mol) in Et2O (20 mL) was added drop-
wise over 20 min. The reaction mixture was allowed
to warm to r. t., and stirring was continued for fur-
ther 30 min at 20◦C. The precipitate was filtered and
washed with Et2O (2 × 30 mL), the filtrate was con-
centrated in vacuo, and the oily residue was distilled
(bp 137–143◦C/5 × 10−2 Torr) to give 2a (20.1 g, 96%)
as pale yellow liquid.
1
10−2 Torr. H NMR (500 MHz, C6D6): δ = 2.50 (s,
3H, SCH3), 2.54 (d, 12H, J = 9.6 Hz, NCH3), 3.18 (s,
3H, NCH3), 7.33 (d, 1H, J = 2.4 Hz, 4-H). 13C NMR
3
(125 MHz, C6D6): δ = 15.34, 30.9 (d, JCP = 5.0 Hz),
2
1
40.75 (d, JCP = 16.3 Hz), 131.3 (d, JCP = 5.0 Hz),
135.5 (d, 2 JCP = 7.5 Hz [4]), 146.3 (d, 3 JCP = 5.0 Hz).
31P NMR (121 MHz, C6D6): δ = 82.2. Anal. Calcd for
C9H19N4PS: C, 43.89; N, 22.75; P, 12.57. Found: C,
43.57; N, 22.61; P, 12.35.
Typical Procedure for 3a–d by Oxidation of 2d
1H NMR (500 MHz, C6D6): δ = 2.68 (s, 6H,
NCH3), 2.70 (d, J = 2.0 Hz, 12H, NCH3), 3.24 (s,
3H, NCH3), 7.23 (s, 1H, 4-H). 13C NMR (125 MHz,
N,N,Nꢁ,Nꢁ -Tetramethyl-P-[1-methyl-2-(methyl-
thio)-1H-imidazol-5-yl]-phosphonic diamide (3d). A
solution of 2d (3.44 g, 14 mmol) in CH2Cl2 (20 mL)
was cooled to 0–5◦C, and a solution of hex-
achloroethane (3.22 g, 14 mmol) in CH2Cl2 (15 mL)
was added. After stirring for 30 min, a solution of
Et3N (2.83 g, 28 mmol) in CH2Cl2 (15 mL) was
added. The reaction mixture was recooled to 0–
5◦C, and degassed water (0.2 mL) was added. In
10–15 min, CH2Cl2 was removed in vacuo. The
residue was treated with warm Et2O (50 mL), insol-
uble precipitate was filtered and washed with Et2O
3
2
C6D6): δ = 30.4 (d, JCP = 6.0 Hz), 40.8 (d, JCP
=
1
16.3 Hz), 42.8, 126.6 (d, JCP = 10.0 Hz), 132.0 (d,
2 JCP = 6.3 Hz), 156.6 (d, JCP = 6.3 Hz). 31P NMR
3
(91 MHz, C6D6): δ = 83.2. Anal. Calcd for C10H22N5P:
C, 49.37; H, 9.11; N, 28.79; P, 12.73. Found: C, 49.05;
N 28.47; P, 12.33.
P-(2-Isopropyl-1-methyl-1H-imidazol-5-yl)-N,N,
Nꢁ,Nꢁ-tetramethylphosphonous Diamide (2b). Fol-
lowing the typical procedure for 2a using 1b; yield:
Heteroatom Chemistry DOI 10.1002/hc

110 Huryeva et al.
(2 × 20 mL), and the filtrate was concentrated to
20 mL. The solid precipitating on cooling was filtered
and washed with Et2O (10 mL) to give 3d (3.10 g,
85%) colorless solid; mp. 90–91◦C.
Typical Procedure for 4a–d by Selenoxidation of
2a
P-[2-(Dimethylamino)-1-methyl-1H-imidazol-5-
yl]-N,N,Nꢁ,Nꢁ-tetramethylphosphonoselenoic diamide
(4a). To a solution of 2a (5.35 g, 22 mmol) in
benzene (20 mL), selenium (1.86 g, 24 mmol) was
added portionwise. The reaction mixture was stirred
at 20◦C for 1 h. Selenium excess was filtered and
washed with benzene (2 × 5 mL). The filtrate was
concentrated in vacuo; the residue recrystallized
from pentane (60 mL) to give 4a (6.45 g, 91%) yellow
solid; mp 57–58◦C.
1H NMR (500 MHz, CDCl3): δ = 2.66 (s, 3H,
SCH3), 2.85 (d, 12H, J = 10.0 Hz, NCH3), 3.73 (s, 3H,
NCH3), 7.25 (s, 1H, 4-H). 13C NMR (125 MHz, CDCl3):
δ = 15.1, 32.2, 36.2 (d, 3 JCP = 4.0 Hz), 123.4 (d, 1 JCP
=
185.0 Hz), 137.6 (d, 2 JCP = 16.3 Hz), 149.4 (d, 3 JCP
=
12.8 Hz). 31P NMR (121 MHz, CDCl3): δ = 18.7. Anal.
Calcd for C9H19N4OPS: C, 41.21; N, 21.36; P, 11.81.
Found: C, 41.03; N, 21.65; P, 11.57.
1H NMR (500 MHz, CDCl3): δ = 2.70 (d, 12H,
J = 12.0 Hz, NCH3), 2.82 (s, 6H, NCH3), 3.65 (s, 3H,
NCH3), 7.06 (s, 1H, 4-H). 13C NMR (125 MHz, CDCl3):
P-[2-(Dimethylamino)-1-methyl-1H-imidazol-5-
yl]-N,N,Nꢁ,Nꢁ-tetramethylphosphonic Diamide (3a).
Following the typical procedure for 3d using 2a;
yield: 3.6 g (68%), colorless solid; mp 72–74◦C (Et2O).
1H NMR (500 MHz, CDCl3): δ = 2.85 (d, 12H,
J = 9.5 Hz, NCH3), 2.70 (s, 6H, NCH3), 3.53 (s, 3H,
NCH3), 6.92 (s, 1H, 4-H). 13C NMR (125 MHz, CDCl3):
δ = 32.5, 37.5 (d, 3 JCP = 2.5 Hz), 42.4, 119.6 (d, 1 JCP
=
142.4 Hz), 134.8 (d, 2 JCP = 12.5 Hz), 158.2 (d, 3 JCP
=
13.8 Hz). 31P NMR (121 MHz, CDCl3): δ = 61.4. Anal.
Calcd for C10H22N5PSe: C, 37.27; N, 21.73; P, 9.61.
Found: C, 37.11; N, 21.48; P, 9.36.
δ = 31.9, 36.3 (d, 3 JCP = 3.8 Hz), 42.4, 119.0 (d, 1 JCP
=
188.6 Hz), 134.9 (d, 2 JCP = 15.1 Hz), 157.7 (d, 3 JCP
=
13.8 Hz). 31P NMR (121 MHz, CDCl3): δ = 20.3. Anal.
Calcd for C10H22N5OP: C 46.32; N, 27.01; P, 11.95.
Found: C 46.18; N, 26.85; P, 11.77.
P-(2-Isopropyl-1-Methyl-1H-Imidazol-5-yl)-N,N,
Nꢁ,Nꢁ-Tetramethylphosphonoselenoic Diamide (4b).
Following the typical procedure for 4a using 2b, the
crude product was distilled (bp 165◦C/5 × 10−2 Torr)
and crystallized from Et2O; yield: 8.8 g (85%), yellow
solid; mp 82–83◦C.
P-(2-Isopropyl-1-methyl-1H-imidazol-5-yl)-N,N,
Nꢁ,Nꢁ-tetramethylphosphonic Diamide (3b). Follow-
ing the typical procedure for 3d using 2b; yield:
1H NMR (500 MHz, CDCl3): δ = 1.31 (d, 6H, J =
7.0 Hz, CH(CH3)2), 2.69 (d, 12H, J = 12.0 Hz, NCH3),
2.98–3.08 (m, 1H, CH), 3.79 (s, 3H, NCH3), 7.18
(s, 1H, 4-H). 13C NMR (125 MHz, CDCl3): δ = 21.0,
1
5.9 g (91%), colorless solid; mp 77–79◦C (Et2O). H
NMR (500 MHz, CDCl3); δ = 1.34 (d, 6H, J = 6.6 Hz,
CH(CH3)2), 2.69 (d, 12H, J = 9.6 Hz, NCH3), 3.00–
3.10 (m, 1H, CH), 3.78 (s, 3H, NCH3), 7.19 (s, 1H,
4-H). 13C NMR (125 MHz, CDCl3): δ = 20.9, 25.9,
3
1
26.81, 31.9, 37.5 (d, JCP = 3.8 Hz), 122.0 (d, JCP
145.0 Hz), 136.2 (d, 2 JCP = 13.0 Hz), 158.8 (d, 3 JCP
=
=
10.0 Hz, C-2). 31P NMR (121 MHz, CDCl3): δ = 62.0.
Anal. Calcd for C11H23N4PSe: C, 41.13; N, 17.44; P,
9.64. Found: C, 41.06; N, 17.65; P, 9.80.
3
1
31.4, 36.1 (d, JCP = 3.8 Hz), 121.1 (d, JCP
186.1 Hz), 136.3 (d, 2 JCP = 17.6 Hz), 158.0 (d, 3 JCP
=
=
12.8 Hz). 31P NMR (121 MHz, CDCl3): δ = 23.6. Anal.
Calcd for C11H23N4OP: C, 51.15; N, 21.69; P, 11.99.
Found: C, 50.93; N, 21.56; P, 11.85.
N,N,Nꢁ,Nꢁ-Tetramethyl-P-[1-methyl-2-phenyl-1H-
imidazol-5-yl]-phosphonoselenoic Diamide (4c).
Following the typical procedure for 4a using 2c;
yield: 8.0 g (90%), yellow solid; mp 110–111◦C
(Et2O).
N,N,Nꢁ,Nꢁ-Tetramethyl-P-(1-methyl-2-phenyl-1H-
imidazol-5-yl)-phosphonic Diamide (3c). Following
the typical procedure for 3d using 2c, the crude
product was distilled (bp 120–130◦C/5 × 10−2 Torr)
and crystallized from Et2O; yield: 3.0 g (92%), color-
1H NMR (500 MHz, CDCl3): δ = 2.62 (d, 12H,
J = 12.5 Hz, NCH3); 3.77 (s, 3H, NCH3); 7.33 (m,
3H, 2ꢁ,4ꢁ,6ꢁ-H), 7.48 (dd, 2H, J = 1.5, 8.0 Hz, 3ꢁ,5ꢁ-
H). 13C NMR (125 MHz, CDCl3): δ = 34.3, 37.6 (d,
1
less solid; mp 82–84◦C. H NMR (500 MHz, CDCl3):
δ = 2.74 (d, 12H, J = 10.0 Hz, NCH3); 3.89 (s, 3H,
NCH3); 7.36 (s, 1H, 4-H), 7.45–7.50 (m, 3H, 2ꢁ,4ꢁ,6ꢁ-
H), 7.60–7.63 (m, 2H, 3ꢁ,5ꢁ-H). 13C NMR (125 MHz,
1
3 JCP = 3.8 Hz), 123.9 (d, JCP = 143.0 Hz), 128.6,
129.2, 129.4, 129.8, 137.24 (d, 2 JCP = 11.0 Hz), 153.3
(d, 2 JCP = 11.0 Hz). 31P NMR (121 MHz, CDCl3): δ =
61.1. Anal. Calcd for C14H21N4PSe: C, 47.33; N, 15.77;
P, 8.72. Found: C, 47.15; N, 15.83; P, 8.56.
3
CDCl3): δ = 33.8, 36.3 (d, JCP = 5.0 Hz), 123.2 (d,
1 JCP = 183.6 Hz), 128.5, 129.0, 129.2, 129.9, 137.5
2
3
(d, JCP = 16.3 Hz), 152.7 (d, JCP = 12.8 Hz). 31P
NMR (121 MHz, CDCl3): δ = 23.5. Anal. Calcd for
C14H21N4OP: C, 57.52; N, 19.17; P, 10.60. Found: C,
57.37; N, 19.05; P, 10.45.
N,N,Nꢁ,Nꢁ -Tetramethyl-P-[1-methyl-2-(methyl-
thio)-1H-imidazol-5-yl]-phosphonoselenoic Diamide
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 111
(4d). Following the typical procedure for 4a us-
ing 2d; yield: 6.9 g (96%), yellow solid; mp 95–96◦C
(pentane).
3.66–3.80 (m, 1H, CH), 3.99 (s, 3H, NCH3), 4.17 (s,
3H, NCH3), 8.91 (s, 1H, 4-H). 13C NMR (125 MHz,
CDCl3): δ = 18.3, 25.1, 34.5, 35.9, 36.5, 124.8 (d,
1 JCP = 177.3 Hz), 131.6 (d, 2 JCP = 19.0 Hz), 153.0 (d,
3 JCP = 6.3 Hz). 31P NMR (121 MHz, CDCl3): δ = 14.4.
Anal. Calcd for C12H26N4OPCl: C, 46.68; N, 18.14, P,
10.03. Found: C, 46.50; N, 18.35, P, 10.22.
1H NMR (500 MHz, CDCl3): δ = 2.67 (s, 3H,
SCH3), 2.71 (d, 12H, J = 12.5 Hz, NCH3), 3.75 (s, 3H,
NCH3), 7.29 (s, 1H, 4-H). 13C NMR (125 MHz, CDCl3):
δ = 15.2, 32.7, 37.5 (d, 3 JCP = 4.0 Hz), 124.2 (d, 1 JCP
=
143.4 Hz), 137.4 (d, 2 JCP = 12.8 Hz), 150.5 (d, 3 JCP
=
11.3 Hz). 31P NMR (121 MHz, CDCl3): δ = 60.2. Anal.
Calcd for C9H19N4PSSe: C, 33.23; N, 17.22; P, 9.52.
Found: C, 33.12; N, 17.30; P, 9.35.
4(5)-[Bis(dimethylamino)phosphinyl]-1,3-dime-
thyl-2-phenyl-1H-imidazolium Chloride (5c). Fol-
lowing the typical procedure for 6b using 3c; yield:
2.5 g, (90%), colorless solid; mp 185–187◦C (dec.).
1H NMR (500 MHz, CDCl3): δ = 2.52 (d, 12H,
J = 10.0 Hz, NCH3); 3.59 (s, 3H, NCH3); 3.71 (s, 3H,
NCH3), 7.38–7.48 (m, 5H, Ph-H), 8.68 (s, 1H, 4-H).
Typical Procedure for 5a–d, 6a–d by Alkylation
of 4b
4(5)-[Bis(dimethylamino)phosphoroselenoyl]-2-
isopropyl-1,3-dimethyl-1H-imidazolium chloride
(6b). A solution of compound 4b (8.0 g, 25 mmol)
in MeCl (7.7 g, 150 mmol) was heated at 70–75◦C for
6 days in a sealed tube. MeCl excess was removed,
the solid residue was treated with Et2O and filtered
and dried in vacuo to give 6b (9.0 g, 91%) colorless
solid; mp 214–215◦C (dec.).
13C NMR (125 MHz, CDCl3): δ = 35.2, 36.1 (d, 3 JCP
=
4.0 Hz), 36.4, 120.3, 125.5 (d, 1 JCP = 177.3 Hz), 129.8,
130.2, 131.2 (d, 2 JCP = 10.0 Hz), 132.9, 148.2 (d, 3 JCP
=
6.3 Hz). 31P NMR (121 MHz, CDCl3): δ = 15.2. Anal.
Calcd for C15H24N4OPCl: C, 52.56; N, 16.34; P, 9.04.
Found: C, 52.37; N, 16.22; P, 9.25.
4(5)-[Bis(dimethylamino)phosphinyl]-1,3-dime-
thyl-2-(methylthio)-1H-imidazolium Chloride (5d).
Following the typical procedure for 6b using 3d;
yield: 2.7 g (76%), colorless solid; mp 174–175◦C
(dec.).
1H NMR (500 MHz, CDCl3): δ = 1.46 (d, 6H,
J = 7.5 Hz, CH(CH3)2), 2.58 (d, 12H, J = 12.0 Hz,
NCH3), 3.53–3.56 (m, 1H, CH), 3.84 (s, 3H, NCH3),
3.98 (s, 3H, NCH3), 8.50 (s, 1H, 4-H). 13C NMR
(125 MHz, CDCl3): δ = 18.5, 25.4, 36.9, 34.6, 37.6 (d,
1H NMR (500 MHz, CDCl3): δ = 2.66 (s, 3H,
SCH3), 2.73 (d, 12H, J = 10.0 Hz, NCH3), 4.10 (s,
3H, NCH3), 4.24 (s, 3H, NCH3), 8.99 (s, 1H, 4-H).
13C NMR (125 MHz, CDCl3): δ = 17.9, 35.8, 36.2 (d,
3 JCP = 5.0 Hz), 37.2, 127.8 (d, 1 JCP = 175.0 Hz), 132.9
1
3 JCP = 3.8 Hz), 126.5 (d, JCP = 136.0 Hz), 130.6 (d,
2 JCP = 16.3 Hz), 153.6. 31P NMR (121 MHz, CDCl3):
δ = 55.0. Anal. Calcd for C12H26N4PSeCl: C, 38.77; N,
15.07; P, 8.33. Found: C, 38.43; N, 14.77; P, 8.18.
2
3
(d, JCP = 19.0 Hz), 145.1 (d, JCP = 7.5 Hz). 31P
NMR (121 MHz, CDCl3): δ = 14.6. Anal. Calcd for
C10H22N4OPSCl: C, 38.40; N, 17.91; P, 9.90. Found:
C, 38.23; N, 17.70; P, 9.76.
4(5)-[Bis(dimethylamino)phosphinyl]-2-(dime-
thylamino)-1,3-dimethyl-1H-imidazolium Chloride
(5a). Following the typical procedure for 6b using
3a; yield: 1.2 g (86%), colorless solid; mp 162–165◦C
(dec.).
4(5)-[Bis(dimethylamino)phosphinoselenoyl]-2-
(dimethylamino)-1,3-dimethyl-1H-imidazolium Chlo-
ride (6a). Following the typical procedure for 6b
using 4a; yield: 5.8 g (86%), colorless solid; mp 218–
220◦C (dec.).
1H NMR (500 MHz, CDCl3): δ = 2.70 (d, 12H,
J = 10.2 Hz, NCH3), 3.13 (s, 6H, NCH3), 3.75 (s, 3H,
NCH3), 3.96 (s, 3H, NCH3), 8.19 (d, J = 2.7 Hz, 1H, 4-
H). 13C NMR (125 MHz, CDCl3): δ = 33.8, 35.5, 35.9
(d, JCP = 5.0 Hz), 40.9, 121.1 (d, JCP = 135.0 Hz),
128.3 (d, 2 JCP = 18.0 Hz), 149.6 (d, 3 JCP = 9.0 Hz, C-2).
31P NMR (121 MHz, CDCl3): δ = 15.7. Anal. Calcd for
C11H25N5OPCl: C, 42.65; N, 22.61; P, 10.00. Found:
C, 42.46; N, 22.34; P, 9.85.
1H NMR (500 MHz, CDCl3): δ = 2.70 (d, 12H,
J = 10.2 Hz, NCH3), 3.13 (s, 6H, NCH3), 3.75 (s, 3H,
NCH3), 3.96 (s, 3H, NCH3), 8.19 (d, J = 2.7 Hz, 1H, 4-
H). 13C NMR (125 MHz, CDCl3): δ = 33.8, 35.5, 35.9
3
1
3
1
(d, JCP = 5.0 Hz), 40.9, 121.1 (d, JCP = 135.0 Hz),
128.3 (d, 2 JCP = 18.0 Hz), 149.6 (d, 3 JCP = 9.0 Hz). 31
P
4(5)-[Bis(dimethylamino)phosphoryl]-2-isopro-
pyl-1,3-dimethyl-1H-imidazolium Chloride (5b).
Following the typical procedure for 6b using 3b;
yield: 6.4 g (96%), colorless solid; mp 118–122◦C
(dec.).
NMR (121 MHz, CDCl3): δ = 57.0. Anal. Calcd for
C11H25N5PSeCl: C, 35.45; N, 18.79; P, 8.31. Found: C,
35.62; N, 18.95; P, 8.16.
4(5)-[Bis(dimethylamino)phosphoroselenoyl]-
1,3-dimethyl-2-phenyl-1H-imidazolium Chloride (6c).
Following the typical procedure for 6b using 4c;
1H NMR (500 MHz, CDCl3): δ = 1.46 (d, 6H, J =
7.5 Hz, CH(CH3)2), 2.69 (d, 12H, J = 12.0 Hz, NCH3),
Heteroatom Chemistry DOI 10.1002/hc

112 Huryeva et al.
yield: 2.3 g (95%), colorless solid; mp 193–194◦C
(dec.).
1H NMR (500 MHz, CDCl3): δ = 2.31 (d, 6H, J =
12.6 Hz, NMe), 2.35 (d, 6H, J = 9.0 Hz, NMe), 2.97
(s, 3H, J = 4.5 Hz, NHMe), 3.13 (s, 3H, NMe), 4.95–
5.10 (m, 1H, NH), 6.40–6.46 (dd, 1H, J1 = 6.0; J2 =
13.5 Hz, CH), 7.26–7.29 (m, 3H, H-Ph), 7.58 (d, 2H,
1H NMR (500 MHz, CDCl3): δ = 2.86 (d, 12H,
J = 12.0 Hz, NCH3); 3.80 (s, 3H, NCH3); 3.93 (s,
3H, NCH3), 7.59–7.67 (m, 3H, 2ꢁ,4ꢁ,6ꢁ-H), 7.76–7.79
(m, 2H, 3ꢁ,5ꢁ-H), 8.43 (d, J = 2.4 Hz, 1H). 13C NMR
1
J = 6.6 Hz, H-Ph). H NMR (500 MHz, CD3OD):
3
(125 MHz, CDCl3): δ = 35.0, 36.8, 37.8 (d, JCP
=
δ = 2.06 (d, 6H, J = 10.0 Hz, NMe), 2.49 (d, 6H, J =
10.0 Hz, NMe), 2.99 (s, 3H, NMe), 3.11 (s, 3H, NMe),
6.44 (d, 1H, J = 6.0 Hz, CH), 7.31–7.38 (m, 3H, H-
Ph), 7.50–7.53 (m, 2H, H-Ph). 13C NMR (125 MHz,
1
4.0 Hz), 120.3, 127.2 (d, JCP = 136.0 Hz), 129.9,
130.2 (d, 2 JCP = 16.3 Hz), 130.4, 133.0, 148.8 (d, 3 JCP
=
7.5 Hz). 31P NMR (121 MHz, CDCl3): δ = 56.0. Anal.
Calcd for C15H24N4PSeCl: C, 44.40; N, 13.81; P, 7.63.
Found: C, 44.72; N, 13.55; P, 7.34.
2
CDCl3): δ = 34.4, 35.3, 35.6 (d, JCP = 4.0 Hz), 35.8
2
1
(d, JCP = 4.0 Hz), 99.9 (d, JCP = 205.0 Hz), 127.4,
129.5, 136.7, 148.1 (d, JCP = 31.4 Hz), 173.0. 13C
2
2
4(5)-[Bis(dimethylamino)phosphinoselenoyl]-
1,3-dimethyl-2-(methylthio)-1H-imidazolium Chlo-
ride (6d). Following the typical procedure for 6b
using 4d; yield: 1.2 g (95%), colorless solid; mp
182–183◦C (dec.).
NMR (125 MHz, CD3OD): δ = 34.5, 35.8 (d, JCP
=
2
4.0 Hz), 36.1, 36.2 (d, JCP = 4.0 Hz), 97.9 (d,
1 JCP = 211.3 Hz), 127.9, 128.5, 130.5, 138.5, 150.0 (d,
2 JCP = 34.0 Hz), 175.8. 31P NMR (121 MHz, CDCl3):
δ = 28.20; 31P (121 MHz, CD3OD): δ = 32.0. MS (EI,
70eV): m/z (%) = 280 (94) [M + H]+. Anal. Calcd for
C15H25N4O2P: C, 55.54; N, 17.27; P, 9.55. Found: C,
55.27; N, 17.05; P, 9.33.
1H NMR (500 MHz, CDCl3): δ = 2.76 (s, 3H,
SCH3), 2.88 (d, 12H, J = 12.6 Hz, NCH3), 4.13 (s,
3H, NCH3), 7.29 (s, 1H, 4-H). 13C NMR (125 MHz,
3
CDCl3): δ = 16.8, 33.3, 34.7, 37.0 (d, JCP = 4.0 Hz),
120.3 (d, 1 JCP = 145.0 Hz), 126.6 (d, 2 JCP = 19.0 Hz),
166.2 (d, 3 JCP = 6.3 Hz). 31P NMR (121 MHz, CDCl3):
δ = 55.6. Anal. Calcd for C10H22N4PSSeCl: C, 31.96;
N, 14.91; P, 8.24. Found: C, 31.63; N, 14.65; P, 8.06.
P-(2,3-Dihydro-1,3-dimethyl-2-oxo-1H-imidazol-
4-yl)-N,N,Nꢁ,Nꢁ-tetramethyl-phosphonic
Diamide (8)
A solution of compound 5a (2.50 g, 6.2 mmol) in
MeOH (10 mL) was added to moist AgOH (1.55 g,
12.4 mmol) in MeOH (20 mL). The suspension was
stirred at 16◦C for 15 h. The precipitate was filtered
and washed with MeOH (2 × 10 mL), the filtrate
was concentrated in vacuo at 60◦C. The residue was
treated with warm Et2O (40 mL), impurities were
filtered, the filtrate was concentrated in vacuo to
10 mL, and the solid precipitated on cooling was
filtered to give 8 (1.50 g, 98%) colorless solid; mp.
134–136◦C.
Typical Procedure for 7b,c by an Example of 7b
P-[2-(dimethylamino)-1-isobutyrylvinyl]-N,N,Nꢁ,
Nꢁ-tetramethylphosphonic diamide (7b). A solution
of compound 5b (2.6 g, 8.3 mmol) in MeOH (20 mL)
was added to moist AgOH (1.1 g, 8.8 mmol) in MeOH
(20 mL). The suspension was stirred at 20◦C for
60 min. MeOH was removed in vacuo at 20◦C. The
solid residue was recrystallized from benzene to give
7b (1.8 g, 75%) pale brown solid; mp 176–178◦C.
1H NMR (500 MHz, CDCl3): δ = 0.89 (d, 3H, J =
6.5 Hz, CHMe2), 0.96 (d, 3H, J = 7.0 Hz, CHMe2),
2.48 (d, 6H, J = 7.0 Hz, PNMe), 2.50 (d, 6H, J =
9.0 Hz, PNMe), 2.81 (d, 3H, J = 4.5 Hz, NHMe),
2.87 (s, 3H, NMe), 2.88 (m, 1H, CHMe), 4.43 (br s,
1H, NH), 6.58 (dd, 1H, J1 = 6.0 Hz, J2 = 13.5 Hz, CH).
13C NMR (125 MHz, CDCl3): δ = 19.6, 20.6, 36.1 (d,
2 JCP = 4.0 Hz), 36.2 (d, 2 JCP = 4.0 Hz), 30.5, 33.6, 34.1,
1H NMR (500 MHz, CDCl3); δ = 2.45 (d, 12H,
J = 12.6 Hz, NCH3), 3.10 (s, 3H, NCH3), 3.17 (s,
3H, NCH3), 6.39 (s, 1H, 4H). 13C NMR (125 MHz,
3
CDCl3): δ = 29.3, 30.6, 36.2 (d, JCP = 3.8 Hz), 112.8
1
2
(d, JCP = 194.0 Hz), 121.0 (d, JCP = 19.0 Hz, C-4),
154.4 (d, JCP = 9.0 Hz, C-2). 31P NMR (121 MHz,
3
CDCl3): δ = 18.2. MS (EI, 70eV): m/z (%) = 247
(91) [M + H]+. Anal. Calcd for C9H19N4O2P: C,
43.90; N, 22.75; P, 12.58. Found: C, 43.63; N, 22.46;
P, 12.35.
1
2
100.1 (d, JCP = 83.0 Hz), 148.0 (d, JCP = 34.0 Hz),
180.0. 31P NMR (121 MHz, CDCl3): δ = 28.5; 31P
(121 MHz, CH3OH): δ = 32.7. HPLC-MS: 290 (95%).
Anal. Calcd for C12H27N4O2P: C, 49.64; N, 19.30; P,
10.67. Found: C, 49.75; N, 19.08; P, 10.86.
Typical Procedure for 9a–c by Thermal
Decomposition of 6b
N-[2-[Bis(dimethylamino)phosphoryl]-2-(me-
thylamino)vinyl]-N-methylbenzamide (7c). Follow-
ing the typical procedure for 7b using 5d; yield: 2.5 g
(95%), yellow solid; mp 195–196◦C (benzene).
P-(2-Isopropyl-1-methyl-1H-imidazol-4-yl)-N,N,
Nꢁ,Nꢁ-tetramethylphosphonoselenoic Diamide (9b).
Compound 6b (24 mmol) was heated at 210–220◦C
under water-jet pump pressure until gas stopped
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 113
to evolve. The residue was distilled (bp 160–180◦C/
5 × 10−2 Torr). The distillate was recrystallized from
pentane (30 mL) to give 9b (3.5 g, 47%), pale brown
solid; mp 80–81◦C.
P-(1,3-Dimethyl-2-thioxo-2,3-dihydro-1H-
imidazol-4-yl)-N,N,Nꢁ,Nꢁ-tetramethylphos-
phonoselenoic Diamide (10)
Following the typical procedure for 9b using 6d;
yield: 6.6 g (97%), bp 200–205◦C/5 × 10−2 Torr; yel-
low solid, mp 167–168◦C.
1H NMR (500 MHz, CDCl3): δ = 1.31 (d, 6H, J =
6.6 Hz, CH(CH3)2), 2.65 (d, 12H, J = 13.2 Hz, NCH3),
2.91–3.04 (m, 1H, CH), 3.60 (s, 3H, NCH3), 7.62
(s, 1H, 5-H). 13C NMR (125 MHz, CDCl3): δ = 21.2,
1H NMR (500 MHz, CDCl3): δ = 2.70 (d, 12H,
J = 12.6 Hz, NCH3), 3.64 (s, 3H, NCH3), 3.78 (s,
4
2
26.3, 32.8, 37.2 (d, JCP = 2.5 Hz), 133.2 (d, JCP
40.24 Hz), 133.9 (d, 1 JCP = 157.2 Hz), 155.3 (d, 3 JCP
=
=
3H, NCH3), 7.15 (d, J = 3.3 Hz, 1H, 4-H). 13C NMR
3
(125 MHz, CDCl3): δ = 34.4, 35.4, 37.6 (d, JCP
=
=
17.6 Hz). 31P NMR (121 MHz, CDCl3): δ = 67.7. Anal.
Calcd for C11H23N4PSe: C, 41.13; N, 17.44; P, 9.64.
Found: C, 40.85; N, 17.30; P, 9.44.
1
2
3.8 Hz), 121.8 (d, JCP = 140.0 Hz), 127.0 (d, JCP
20.1 Hz), 167.2 (d, 3 JCP = 5.0 Hz). 31P NMR (121 MHz,
CDCl3): δ = 60.9. Anal. Calcd for C9H19N4PSSe: C,
33.23; N, 17.22; P, 9.52. Found: C, 33.56; N, 16.87; P,
9.90.
P-[2-(Dimethylamino)-1-methyl-1H-imidazol-4-
yl]- N,N,Nꢁ,Nꢁ-tetramethyl-phosphonoselenoic Di-
amide (9a). The mixture of 2a and 9a (6.6 g,
20 mmol) prepared by thermal decomposition of 6a
(8.0 g, 21 mmol) following the typical procedure de-
scribed for 9b was dissolved in CH2Cl2 (30 mL), then
cooled to −80◦C and a solution of picric acid (1.5 g,
7 mmol) in CH2Cl2 (25 mL) was added dropwise.
The reaction mixture was allowed to warm to 20◦C
and stirred for another 15–20 min. The solvent was
removed in vacuo; the oily residue was treated with
hot pentane (4 × 30 mL). Impurities were collected,
the solution was concentrated, the residue distilled
in vacuo (bp 150–155◦C/5 × 10−2 Torr) to give 9a
(3.91 g, 86%) yellow solid; mp. 41–42◦C.
4(5)-[Bis(dimethylamino)phosphino]-2-
isopropyl-1,3-dimethyl-1H-imidazolium
Chloride (11)
To compound 6c (3.9 g, 10 mmol) in THF (20 mL)
hexamethyltriamidophosphite (Me2N)3P (1.96 g,
12 mmol) was added. The reaction mixture was
stirred at 16◦C for 15 h. The precipitate was filtered
and washed with THF (2 × 10 mL) and dried in
vacuo to give 11 (2.85 g, 92%) colourless solid; mp
130–145◦C.
1H NMR (500 MHz, C6D6): δ = 1.12 (d, 6H, J =
7.2 Hz, CH(CH3)2), 2.46 (d, 12H, J = 10.0 Hz, NCH3),
3.51 (s, 3H, NCH3), 3.52 (m, 1H, CH(CH3)2), 3.86 (s,
3H, NCH3), 7.28 (s, 1H, 4(5)-H). 13C NMR (125 MHz,
1H NMR (500 MHz, CDCl3): δ = 2.65 (d, 12H,
J= 13.2 Hz, NCH3), 2.77 (s, 6H, NCH3), 3.50 (s, 3H,
NCH3), 7.51 (s, 1H, 5-H). 13C NMR (125 MHz, CDCl3):
3
C6D6): δ = 18.6, 25.1, 33.7 (d, JCP = 6.3 Hz), 36.0,
36.7, 41.1 (d, 2 JCP = 17.6 Hz), 127.7 (d, 2 JCP = 7.5 Hz),
133.5 (d, 1 JCP = 11.3 Hz), 151.8. 31P NMR (121 MHz,
CDCl3): δ = 76.8. Anal. Calcd for C12H26N4PCl: C,
49.23; N, 19.14; P, 10.58. Found: C, 49.41; N, 18.84;
P, 10.75.
δ = 32.5, 37.2 (d, 4 JCP = 4.0 Hz), 42.7, 131.2 (d, 2 JCP
=
39.0 Hz), 131.4 (d, 1 JCP = 157.2 Hz), 155.2 (d, 3 JCP
=
20.1 Hz). 31P NMR (121 MHz, CDCl3): δ = 68.4. Anal.
Calcd for C10H22N5PSe: C, 37.27; N, 21.73; P, 9.61.
Found: C, 37.10; N, 21.52; P, 9.35.
N,N-Dimethyl-Nꢁ,Nꢁꢁ-bis[tris(diethylamino)-
phosphinidene]phosphorous Triamide (12)
N,N,Nꢁ,Nꢁ-Tetramethyl-P-(1-methyl-2-phenyl-1H-
imidazol-4-yl)phosphonoselenoic Diamide (9c). Fol-
lowing the typical procedure for 9b using 6c; yield:
600 mg (61%), bp 132–140◦C/5 × 10−2 Torr; pale yel-
low solid, mp 90–91◦C.
A solution of hexamethylphosphorimidic triamide
(Et2N)3PNH (37.2 g, 14.2 mmol) in benzene
(15 mL) was cooled to 0–5◦C and added drop-
wise to dichloroamidophosphite Me2NPCl2 (6.0 g,
41.1 mmol) in benzene (40 mL) at 0–5◦C over 60 min.
Benzene was removed in vacuo, the residue was
dissolved in liquid ammonia (70 mL), and metallic
sodium (1.75 g, 7.6 mmol) was added portionwise till
the solution turned stable blue. Liquid ammonia ex-
cess was removed; the oily residue was treated with
pentane (75 mL). Insoluble precipitate was filtered
and washed with pentane (2 × 30 mL). The filtrate
was concentrated in vacuo; the residue was distilled
1H NMR (500 MHz, CDCl3): δ = 2.70 (d, 12H, J =
13.2 Hz, NCH3); 3.73 (s, 3H, NCH3); 7.43–7.50 (m,
3H, 2ꢁ,4ꢁ,6ꢁ-H), 7.58–7.63 (m, 2H, 3ꢁ,5ꢁ-H), 7.83 (br.
s 1H, 5-H). 13C NMR (125 MHz, CDCl3): δ = 34.7,
4
37.3 (d, JCP = 3.8 Hz), 128.6, 129.0, 129.3, 129.9,
135.0 (d, 2 JCP = 36.5 Hz), 136.7 (d, 1 JCP = 156.0 Hz),
3
150.0 (d, JCP = 18.9 Hz). 31P NMR (121 MHz,
CDCl3): δ = 67.3. Anal. Calcd for C14H21N4PSe: C,
47.33; N, 15.77; P, 8.72. Found: C, 47.05; N, 15.62;
P, 8.97.
Heteroatom Chemistry DOI 10.1002/hc

114 Huryeva et al.
N,N,Nꢁ,Nꢁ-Tetramethyl-P-(1-methyl-2-phenyl-1H-
imidazol-4-yl)phosphonous Diamide (13c). Follow-
ing method B for 13a using 9c; yield: 700 mg, (90%),
pale yellow liquid; bp 165–170◦C/5 × 10−2 Torr.
1H NMR (500 MHz, C6D6); δ = 2.90 (d, 12H, J =
9.3 Hz, NCH3); 2.96 (s, 3H, NCH3); 6.76 (d, 1H, J =
1.8 Hz, 5-H), 7.10–7.19 (m, 3H, 2ꢁ,4ꢁ,6ꢁ-H), 7.61 (d,
2H, J = 6.6 Hz, 3ꢁ,5ꢁ-H). 13C NMR (125 MHz, CDCl3):
δ = 33.7, 41.8 (d, 2 JCP = 16.3 Hz), 127.4, 128.0, 128.3,
(bp 190–200◦C/5 × 10−2 Torr) to give 12 (13.8 g, 57%)
colorless liquid.
1H NMR (500 MHz, C6D6): δ = 1.11 (t, 36H, J =
7.2 Hz, CH3); 2.86 (d, 6H, J = 7.8 Hz, CH3), 3.07–
3.29 (m, 24H, CH2). 13C NMR (125 MHz, C6D6):
2
δ = 14.0, 36.6 (d, JCP = 10.0 Hz), 39.4. 31P NMR
(121 MHz, C6D6): δ = 15.43 (d, JP-N-P = 75.3 Hz),
97.45 (t, JP-N-P = 75.3 Hz). Anal. Calcd for C26H66N9P3:
C, 52.24; N, 21.09; P, 15.54. Found: C, 52.67; N, 21.04;
P, 15.32.
128.6, 131.6, 141.4 (d, 1 JCP = 21.4 Hz), 149.0 (d, 3 JCP
=
9.0 Hz). 31P NMR (121 MHz, CDCl3): δ = 87.0. Anal.
Calcd for C14H21N4P: C, 60.85; N, 20.28; P, 11.21.
Found: C, 61.08; N, 20.15; P, 10.95.
Typical Procedure for 13a–c by Reduction of 9a
P-[2-(Dimethylamino)-1-methyl-1H-imidazol-4-
yl]-N,N,Nꢁ,Nꢁ-tetramethyl-phosphonous
Diamide
Typical Procedure for 14a–c by the Example of
(13a). Method A. A solution of compound 9a (1.6 g,
5 mmol) and 12 (3.3 g, 5.5 mmol) in benzene (5 mL)
was stirred for 10–15 min. Benzene was removed in
vacuo, the oily residue was distilled (112–120◦C/5 ×
10−2 Torr) affording 13a (1.14 g, 94%), colorless
solid; mp. 55–56◦C.
14a
[2-(Dimethylamino)-1-methyl-1H-imidazol-4-yl]-
phosphonous dichloride (14a). A solution of
compound 13a (730 mg, 3 mmol) in phosphorus
trichloride (8.0 g, 58 mmol) was stirred at 20◦C for
10 min. Phosphorus trichloride excess was removed
in vacuo. The residue was distilled (120–140◦C/5 ×
10−2 Torr) to give 14a (260 mg, 39%), pale yellow
solid; mp 42–44◦C.
Method B. To a sodium suspension (410 mg,
18 mmol) in toluene (30 mL) a solution of 9a (4.2 g,
13 mmol) in toluene (10 mL) was added. The re-
action mixture was heated with stirring at 120◦C for
1.5 h in a sealed flask. Toluene was removed in vacuo;
the residue was treated with hot pentane (30 mL).
The precipitate was filtered out and washed with
pentane (2 × 20 mL). The filtrate was concentrated in
vacuo, and the residue was distilled (112–116◦C/5 ×
10−2 Torr) to give 13a (3.06 g, 97%).
1H NMR (500 MHz, C6D6): δ = 2.39 (s, 6H,
NCH3), 2.60 (s, 3H, NCH3), 6.66 (s, 1H, 5-H). 13C
NMR (125 MHz, C6D6): δ = 31.8, 42.0, 126.1 (d,
1
2 JCP = 40.2 Hz), 135.9 (d, JCP = 39.0 Hz), 155.8
3
(d, JCP = 12.75 Hz). 31P NMR (121 MHz, C6D6):
δ = 146.7. Anal. Calcd for C6H10Cl2N3P: C, 31.88; N,
18.59; P, 13.70. Found: C, 31.65; N, 18.27; P, 13.55.
1H NMR (500 MHz, C6D6): δ = 2.52 (s, 6H,
NCH3), 2.75 (s, 3H, NCH3), 2.91 (d, J = 9.0 Hz,
12H, NCH3), 6.55 (d, J = 1.5 Hz, 1H, 5-H). 13C
NMR (125 MHz, C6D6): δ = 31.2, 41.7, 42.8, 123.1 (d,
(2-Isopropyl-1-methyl-1H-imidazol-4-yl)phospho-
nous Dichloride (14b). Following the typical pro-
cedure for 14a using 13b; yield: 820 mg (96%),
colorless solid; 116–120◦C/5 × 10−2 Torr, mp
24–26◦C.
1
2 JCP = 30.2 Hz), 137.4 (d, JCP = 22.6 Hz), 154.7 (d,
3 JCP = 10.0 Hz). 31P NMR (121 MHz, CDCl3): δ = 88.2.
Anal. Calcd for C10H22N5P: C, 49.37; N, 28.79; P,
12.73. Found: C, 49.25; N, 28.60; P, 12.43.
1H NMR (500 MHz, C6D6): δ = 1.09 (d, 6H, J =
7.2 Hz, CH(CH3)2), 2.45 (m, 1H, CH), 3.76 (s, 3H,
NCH3), 6.97 (d, 1H, J = 3.3 Hz, 5-H). 13C NMR
P-(2-Isopropyl-1-methyl-1H-imidazol-4-yl)-N,N,
Nꢁ,Nꢁ-tetramethylphosphonous Diamide (13b). Fol-
lowing method B for 13a using 9b; yield: 2.6 g
(93%), colorless liquid; bp 110–115◦C/5 × 10−2 Torr.
1H NMR (500 MHz, C6D6): δ = 1.22 (d, 6H, J =
7.0 Hz, CH(CH3)2), 2.74 (s, 3H, NCH3), 2.87 (d, 12H,
J = 10.0 Hz, NCH3), 2.46–2.58 (m, 1H, CH), 6.62 (d,
1H, J = 1.0 Hz, 5-H). 13C NMR (125 MHz, C6D6): δ =
(125 MHz, C6D6): δ = 21.0, 26.1, 32.0, 128.3 (d, 2 JCP
=
=
1
3
34.0 Hz), 138.3 (d, JCP = 36.5 Hz), 156.1 (d, JCP
13.8 Hz). 31P (121 MHz, C6D6): δ = 147.5. Anal. Calcd
for C7H11Cl2N2P: C, 37.36; N, 12.45; P, 13.76. Found:
C, 37.54; N, 12.15; P, 14.00.
(1-Methyl-2-phenyl-1H-imidazol-4-yl)phosphonous
Dichloride (14c). Following the typical procedure
for 14a using 13c; yield: 300 mg, (53%), pale yellow
liquid; bp 160–165◦C/5 × 10−2 Torr.
21.5, 26.1, 31.3, 36.6 (d, 4 JCP = 4.0 Hz), 41.7 (d, 2 JCP
=
=
2
1
15.0 Hz), 125.2 (d, JCP = 31.4 Hz), 139.6 (d, JCP
23.0 Hz), 153.9 (d, 3 JCP = 9.0 Hz). 31P NMR (121 MHz,
C6D6): δ = 87.7. Anal. Calcd for C11H23N4P: C, 54.53;
N, 23.12; P, 12.78. Found: C, 54.23; N, 23.45;
P, 12.67.
1H NMR (500 MHz, C6D6): δ = 2.76 (s, 3H,
NCH3); 6.92 (s, 1H, 5-H), 7.09–7.20 (m, 3H,
2ꢁ,4ꢁ,6ꢁ-H), 7.37–7.44 (m, 2H, 3ꢁ,5ꢁ-H). 13C NMR
(125 MHz, C6D6): δ = 34.0, 128.5, 128.7, 129.2, 129.5
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 115
2
1
4.0 Hz), 139.3 (t, J = 7.0 Hz), 157.8 (t, J = 9.0 Hz).
31P NMR (121 MHz, C6D6): δ = 15.6. Anal. Calcd for
C16H30N8P2: C, 48.48; N, 28.27; P, 15.63. Found: C,
48.48; N, 28.27; P, 15.63.
(d, JCP = 33.0 Hz), 129.8, 140.0 (d, JCP = 37.7 Hz),
150.5 (d, 3 JCP = 13.8 Hz). 31P NMR (121 MHz, C6D6):
δ = 146.2. Anal. Calcd for C10H9Cl2N2P: C, 46.36; N,
10.81; P, 11.96. Found: C, 46.70; N, 11.07; P, 11.55.
2,6-Diisopropyl-1,5,N,N,Nꢁ,Nꢁ-hexamethyl-1H,
5H-1,3,5,7-tetraaza-4,8-diphospha-s-indacene-
4,8-diamine(16b)
4,8-Dichloro-1,5,N,N,Nꢁ,Nꢁ-hexamethyl-1,4,5,8-
tetrahydro-1,3,5,7-tetraaza-4,8-diphospha-s-
indacene-2,6-diamine (15a)
Following method B for 16a using 17b, the crude
product was crystallized from Et2O; yield: 130 mg
(96%), yellow solid; mp 236–238◦C.
To a solution of compound 13a (2.61 g, 11.5 mmol)
in phosphorus trichloride (1.6 g, 11.6 mmol), a solu-
tion of Et3N (1.42 g, 14 mmol) in pyridine (15 mL)
was added. The reaction mixture was heated at
45◦C for 4 days. Pyridine and phosphorus trichlo-
ride excess were removed in vacuo, the residue was
treated with hot benzene (25 mL), insoluble precipi-
tate was filtered and the filtrate was concentrated in
vacuo. The solid residue was treated with warm Et2O
(30 mL), and insoluble products were removed. The
solid precipitated on cooling was filtered and dried
to give 15a (1.59 g, 73%), yellow solid; mp 190–191◦C
(dec.).
1H NMR (500 MHz, C6D6): δ = 1.24 (d, 6H,
J = 7.0 Hz, CH(CH3)2), 1.29 (d, 6H, J = 6.5 Hz,
CH(CH3)2), 2.49 (d, 12H, J = 9.0 Hz, NCH3), 2.56–
2.62 (m, 2H, CH), 3.90 (s, 6H, NCH3). 13C NMR
3
(125 MHz, C6D6): δ = 21.5 (d, JCP = 22.6 Hz); 26.5;
1
31.5 (m); 40.5 (m); 133.3 (t, JCP = 4.0 Hz); 141.4
1
3
(t, JCP = 7.5 Hz); 158.0 (t, JCP = 10.0 Hz). 31P
NMR (121 MHz, C6D6): δ = 15.1. Anal. Calcd for
C18H32N6P2: C, 54.81; N, 21.31; P, 15.71. Found: C,
54.55; N, 21.16; P, 15.43.
1H NMR (500 MHz, C6D6): δ = 2.41 (s, 12H,
NCH3), 3.07 (s, 6H, NCH3). 13C NMR (125 MHz,
1,5,N,N,Nꢁ,Nꢁ,Nꢁꢁ,Nꢁꢁ,Nꢁꢁꢁ,Nꢁꢁꢁ-Decamethyl-4,8-dis-
elenoxo-1,4,5,8-tetrahydro-1,3,5,7-tetraaza-4 λ5,8
λ5-diphospha-s-indacene-2,4,6,8-tetraamine(17a)
3
C6D6): δ = 31.2, 41.8, 129.7, 137.4, 159.0 (t, JCP
=
12.8 Hz). 31P NMR (121 MHz, C6D6): δ = 25.8. Anal.
Calcd for C12H18Cl2N6P2: C, 38.01; N, 22.16; P, 16.34.
Found: C, 37.66; N, 21.82; P, 16.57.
Method A. To a solution of 13a (1.13 g, 5 mmol) in
phosphorus trichloride (1.86 g, 13.5 mmol), a solu-
tion of Et3N (940 mg, 9 mmol) in pyridine (0.5 mL)
was added. The reaction mixture was heated at 45◦C
for 4 days. The excess of pyridine and phospho-
rus trichloride was removed in vacuo, the residue
was dissolved in benzene (6 mL), the solution was
cooled at −20 to −30◦C, and dimethylamine (2.0 mL,
28 mmol) was added. The reaction mixture was
allowed to warm to 20◦C and stirred for another
30 min. Insoluble precipitate was filtered out and
was washed with benzene (2 × 5 mL); the filtrate
was concentrated in vacuo. The residue was treated
with warm Et2O (3 × 40 mL), the solid (450 mg) pre-
cipitated on cooling was collected, and the filtrate
was concentrated in vacuo. The residue was treated
with hot pentane (2 × 40 mL), insoluble products
were collected, the pentane was removed in vacuo,
and the solid residue (260 mg) was dried. The solids
were combined (710 mg) and dissolved in pyridine
(6 mL). Selenium (160 mg, 2 mmol) was added, and
the reaction mixture was heated at 90◦C for 20 min.
The pyridine was removed in vacuo, the residue
was treated with warm Et2O (2 × 40 mL), insolu-
ble products were collected, and Et2O was removed
in vacuo. The residue was crystallized from ace-
tonitrile (15 mL). The solid precipitated on cooling
was collected by filtration to give (E)-17a (190 mg,
1,5,N,N,Nꢁ,Nꢁ,Nꢁꢁ,Nꢁꢁ,Nꢁꢁꢁ,Nꢁꢁꢁ-Decamethyl-1H,5H-
1,3,5,7-tetraaza-4,8-diphospha-s-indacene-
2,4,6,8-tetraamine (16a)
Method A. A solution of 15a (1.5 g, 4 mmol) in ben-
zene (5 mL) was cooled to 0–5◦C, and dimethylamine
(800 mg, 18 mmol) in benzene (10 mL) was added
dropwise. The reaction mixture was stirred at 0–5◦C
to 20◦C and then heated at 60◦C for 5–10 min in
a sealed flask. The precipitate was filtered out and
was washed with benzene (5 mL); the filtrate was
concentrated in vacuo. The residue was dissolved in
benzene (8 mL) on reflux. In 4 h, the solid precip-
itated on cooling to −7◦C was filtered and dried to
give 16a (510 mg, 32%) yellow solid; mp 240–242◦C.
Method B. To a sodium (330 mg, 14 mmol) sus-
pension in benzene (20 mL) compound (E) 17a
(550 mg, 1 mmol) was added. The reaction mixture
was heated on stirring at 125◦C for 2.5 h in a sealed
tube. Insoluble precipitate was filtered and washed
with benzene (2 × 10 mL). The filtrate was concen-
trated in vacuo to give 16a (370 mg, 98%).
1H NMR (500 MHz, C6D6): δ = 2.54 (br d, 12H,
J = 9.0 Hz, NCH3), 2.57 (s, 12H, NCH3), 3.56 (s,
6H, NCH3). 13C NMR (125 MHz, CDCl3): δ = 31.3 (t,
J = 4.0 Hz), 40.2 (t, J = 6.3 Hz), 42.5, 130.9 (t, J =
Heteroatom Chemistry DOI 10.1002/hc

116 Huryeva et al.
13.4%). The filtrate was concentrated in vacuo, and
the residue was purified by chromatography on silica
gel (EtOAc–hexane, 19:1) affording (E)-17a (340 mg,
24.0%) yellow solid; mp 280–282◦C; Rf = 0.70 and
(Z)-17a (150 mg, 10.6%) orange oil; Rf = 0.26.
1H NMR (500 MHz, CDCl3): δ = 2.77 (d, 12H,
J = 12.6 Hz, NCH3), 2.88 (s, 12H, NCH3), 3.75 (s,
6H, NCH3). 13C NMR (125 MHz, CDCl3): δ = 32.6,
37.4, 42.4, 122.7 (dd,JC1P = 26.4; JC2P = 118.2 Hz),
a mixture of isomers) precipitated on cooling was
filtered. The second crystallization from acetonitrile
(4 mL) afforded (E)-17b (0.2 g, 20%) orange solid;
mp 263–265◦C.
1H NMR (500 MHz, CDCl3): δ = 1.37 (d, 6H,
J = 6.5 Hz, CH(CH3)2), 1.39 (d, 6H, J = 7.0 Hz,
CH(CH3)2), 2.63 (d, 12H, J = 12.6 Hz, NCH3),
3.04–3.10 (m, 2H, CH), 3.90 (s, 6H, NCH3). 13C
NMR (125 MHz, CDCl3): δ = 21.1, 26.7, 32.1, 37.2,
125.2 (dd, J1C-P = 28.0; J2C-P = 117.0 Hz), 138.0
(dd, J1C-P = 13.0; J2C-P = 137.0 Hz), 160.8 (m). 31P
NMR (121 MHz, CDCl3): δ = 22.0. Anal. Calcd for
C18H32N6P2Se2: C, 39.14; N, 15.21; P, 11.22. Found:
C, 38.84; N, 14.85; P, 11.00.
136.1 (dd, JC1P = 11.3; JC2P = 137.0 Hz), 159.4 (m). 31
P
NMR (121 MHz, CDCl3): δ = 21.1. Anal. Calcd for
C16H30N8P2Se2: C, 34.67; N, 20.21; P, 11.18. Found:
C, 34.93; N, 20.45; P, 10.88.
(Z)-17a. 1H NMR (500 MHz, CDCl3): δ = 2.79 (d,
12H, J = 13.0 Hz, NCH3), 2.87 (s, 12H, NCH3), 3.73
(s, 6H, NCH3). 13C NMR (125 MHz, CDCl3): δ = 37.3,
37.4, 42.4, 122.0 (dd, J1 CP = 26.0; J2 CP = 119.5 Hz),
136.0 (dd, J1 CP = 12.6; J2 CP = 135.8 Hz), 159.2 (m).
31P NMR (121 MHz, CDCl3): δ = 21.4. MS (EI, 70eV):
m/z (%) = 555 (64), 555 (29.5) [M + H]+.
1,5,N,N,Nꢁ,Nꢁ,Nꢁꢁ,Nꢁꢁ,Nꢁꢁꢁ,Nꢁꢁꢁ-Decamethyl-4,8-
dithioxo-1,4,5,8-tetrahydro-1,3,5,7-tetraaza-4
λ5,8λ5-diphospha-s-indacene-2,4,6,8-tetraamine
(18a)
To a solution of compound 16a (400 mg, 1 mmol)
in pyridine (3 mL) powdered sulfur (65 mg, 2 mmol)
was added. The reaction mixture was stirred at 25◦C
for 10–15 min. Pyridine was removed in vacuo; the
residue was dissolved in acetone and refined with ac-
tivated charcoal. The filtrate was concentrated, and
the residue recrystallized from acetonitrile (15 mL)
to give 18a (0.39 g, 85%) yellow solid; mp 280–283◦C.
1H NMR (500 MHz, CDCl3): δ = 2.73 (d, 12H,
J = 12.6 Hz, NCH3), 2.87 (s, 12H, NCH3), 3.73 (s,
6H, NCH3). 13C NMR (125 MHz, CDCl3): δ = 32.5,
36.7, 42.4, 124.4 (dd, J1C-P = 29.0; J2C-P = 128.3 Hz),
137.0 (dd, J1C-P = 13.0; J2C-P = 148.0 Hz), 159.3 (m).
31P NMR (121 MHz, CDCl3): δ = 31.9. Anal. Calcd for
C16H30N8P2S2: C, 41.73; N, 24.33; P, 13.45. Found: C,
42.05; N, 24.02; P, 13.64.
Method B. A mixture of compound (E)-16a
(430 mg, 1.1 mmol) and selenium (170 mg,
2.2 mmol) in benzene (3 mL) was refluxed for 5–
10 min. Selenium excess was filtered, the filtrate was
concentrated in vacuo, and the residue was recrys-
tallized from acetonitrile (15 mL) to give (E)-17a
(0.5 g, 90%), mp. 280–282◦C.
2,6-Diisopropyl-1,5,N,N,Nꢁ,Nꢁ-hexamethyl-4,8-
diselenoxo-1,4,5,8-tetrahydro-1,3,5,7-tetraaza-
4λ5,8λ5-diphospha-s-indacene-4,8-diamine(17b)
A solution of 14b (1.3 g, 5.8 mmol) in a mixture of
benzene (10 mL) and toluene (1 mL) was heated at
125◦C for 20 days in a sealed tube. The solvents were
removed in vacuo to dryness, the residue was dis-
solved in benzene (20 mL), the solution was cooled
to −30◦C, and dimethylamine (2.5 mL, 35.5 mmol)
was added dropwise. The reaction mixture was al-
lowed to warm to 20◦C and stirred for another 1 h.
Excess of benzene and dimethylamine was removed
in vacuo, the residue was treated with Et2O (20 mL),
insoluble precipitate was filtered, washed with Et2O
(3 × 10 mL), and the filtrated product was concen-
trated in vacuo. The residue was dissolved in pyri-
dine (3 mL), selenium (460 mg) was added, and the
reaction mixture was heated at 90◦C for 30 min. Pyri-
dine was removed in vacuo, the residue was treated
with CH2Cl2 (10 mL). Insoluble products were fil-
tered and washed with CH2Cl2 (5 mL), the filtrate
was concentrated in vacuo, and the residue recrys-
tallized from benzene (5 mL). The solid (0. 64 g, 40%,
P-[2-(Dimethylamino)-1-methyl-5-(trimethyl-
silyl)-1H-imidazol-4-yl]-N,N,Nꢁ,Nꢁꢁ-
tetramethylphosphonous Diamide (19)
Following the typical procedure for 12a using 22,
heating at 125◦C for 3h; yield: 430 mg (98%), color-
less solid; bp 110–113◦C /5 × 10−2 Torr.
1H NMR (500 MHz, C6D6): δ = 0.38 (s, 9H,
SiCH3), 2.54 (s, 6H, NCH3), 2.95 (d, 6H, J = 9.6 Hz,
NCH3), 3.09 (s, 3H, NCH3). 13C NMR (125 MHz,
C6D6): δ = 1.3 (d, JSi-P = 54.0 Hz), 32.5, 42.0 (d,
2
3 JCP = 15.0 Hz), 42.8, 131.7 (d, JCP = 54.0 Hz),
1
3
149.6 (d, JCP = 2.5 Hz), 156.4 (d, JCP = 5.0 Hz).
31P NMR (121 MHz, C6D6): δ = 81.9. Anal. Calcd for
C13H30N5PSi: C, 49.49; N, 22.20; P, 9.82. Found: C,
49.37; N, 22.45; P, 9.47.
Heteroatom Chemistry DOI 10.1002/hc

4-Phosphorylated 1,2-Disubstituted Imidazoles 117
pentane) (5.0 mL, 8.5 mmol) was added dropwise
at −90◦C over 5 min. After stirring at −80◦C for
8 h, the reaction mixture was recooled to −90◦C and
solution of bis(tetramethylamino)chlorophosphine
(1.3 g, 8.2 mmol) in pentane (10 mL) was added
dropwise over 10 min, at that the solution became
clear. The reaction mixture was allowed to warm to
20◦C, and stirring was continued for further 12 h.
The mixture was recooled to −20◦C, and dimethy-
lamine (5.5 mL) was added. In 10–15 min, the
solvents were removed in vacuo to dryness. The
residue was treated with benzene (40 mL), insoluble
products were filtered, the filtrate concentrated in
vacuo, then the residue was distilled twice (bp 110–
120◦C/5 × 10−2 Torr). To a solution of the distillate
(1.61 g, 57%) in pyridine (15 mL), selenium (0.37 g,
4.7 mmol) was added and the mixture was stirred at
20◦C for 30 min. Selenium excess was filtered and
washed with pyridine (10 mL); the filtrate concen-
trated in vacuo. The residue was recrystallized from
pentane to give 24 (1.8 g, 42%) reddish-brown solid;
mp 135–137◦C.
P-[2-(Dimethylamino)-1-methyl-5-(trimethyl-
silyl)-1H-imidazol-4-yl]-N,N,Nꢁ,Nꢁ-
tetramethylphosphonoselenoic Diamide (22)
To a solution of compound 12a (2.0 g, 8.2 mmol)
in THF (45 mL), t-BuLi (1.7 H solution in pen-
tane) (8.2 mL, 14 mmol) was added dropwise at
−90◦C over 5 min. The reaction mixture was stirred
at −80◦C for 8 h and was recooled to −90◦C, and
Me3SiCl (1.92 g, 17.7 mmol) was added. The reac-
tion mixture was allowed to warm to 20◦C, and stir-
ring was continued for further 12 h, at that the solu-
tion became clear. The solution was concentrated to
15 mL and was cooled to −20◦C, and dimethylamine
(9 mL) was added. In 10–15 min, the solvents were
removed in vacuo leaving the residue that was dis-
tilled (bp 125–130◦C/5 × 10−2 Torr). To a solution
of the distillate (1.76 g) in pyridine (15 mL), sele-
nium (0.65 g, 8.2 mmol) was added and the mixture
was stirred at 20◦C for 30 min. Selenium excess was
filtered and washed with pyridine (10 mL); the fil-
trate concentrated in vacuo. The residue (a mixture
of 22 and 23) was refined by chromatography on
silica gel (EtOAc–hexane, 1:1) to give phosphonate
22 (730 mg, 22%) pale yellow solid; Rf = 0.51; mp
116–117◦C and phosphinate 23 (770 mg, 23%) or-
ange solid; Rf = 0.82; mp 95–96◦C.
1H NMR (500 MHz, CDCl3): δ = 2.73 (br s, 6H,
NMe), 3.66 (s, 3H, NMe), 2.78 (d, 24H, J = 10.0 Hz,
NCH3). 13C NMR (125 MHz, CDCl3): δ = 33.6, 38.7,
3
38.8 (d, JCP = 5.0 Hz), 42.4, 126.2 (dd, J1CP
=
5.0; J2CP = 149.7 Hz, C-5), 139.7 (dd, J1CP = 12.8;
1H NMR (500 MHz, CDCl3): δ = 0.45 (s, 9H,
SiCH3), 2.69 (d, 12H, J = 12.0 Hz, NMe), 2.74 (s,
6H, NMe), 3.50 (s, 3H, NMe). 13C NMR (125 MHz,
CDCl3): δ = 1.07, 33.89, 38.20 (d, 3 JCP = 4.0 Hz), 42.7,
J2CP = 149.7 Hz, C-4), 156.7 (dd, J1 = 15.0; J2CP
=
CP
22.6 Hz, C-2). 31P NMR (121 MHz, CDCl3): δ = 62.7
(1 JPP = 2.0 Hz); 66.53 (1 JPP = 2.0 Hz). Anal. Calcd for
C14H33N7P2Se2: C, 32.38; N, 18.88; P, 11.93. Found:
C, 32.65; N, 19.06; P, 11.71.
2
1
135.6 (d, JCP = 4.0 Hz), 141.9 (d, JCP = 161.0 Hz),
156.0 (d, 3 JCP = 20.1 Hz). 31P NMR (121 MHz, CDCl3):
δ = 70.9. Anal. Calcd for C13H30N5PSeSi: C, 39.59; N,
17.76; P, 7.85. Found: C, 39.33; N, 17.52; P, 8.10.
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1H NMR (500 MHz, CDCl3): δ = 0.45 (s, 9H, SiCH3),
1.45 (d, 9H, J = 12.6 Hz, C(CH3)), 2.73 (s, 6H, NCH3),
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