Synthesis and properties of 2-(diorganylphosphorylhydroxymethyl)-1-organylimidazoles

Article abstract of DOI:10.1023/A:1014855309771

1-Organyl-2-formylimidazoles and -benzimidazoles react with diorganylphosphine oxides under mild conditions (room temperature, dioxane, 1 h) to give in practically quantitative yields 2-(diorganylphosphorylhydroxymethyl)-1-organylimidazoles - highly react

Full text of DOI:10.1023/A:1014855309771

Chemistry of Heterocyclic Compounds, Vol. 38, No. 1, 2002
SYNTHESIS AND PROPERTIES
OF 2-(DIORGANYLPHOSPHORYL-
HYDROXYMETHYL)-
1-ORGANYLIMIDAZOLES*
N. K. Gusarova, S. N. Arbuzova, A. M. Reutskaya, N. I. Ivanova, L. V. Baikalova,
L. M. Sinegovskaya, N. N. Chipanina, A. V. Afonin, and I. A. Zyryanova
1-Organyl-2-formylimidazoles and -benzimidazoles react with diorganylphosphine oxides under mild
conditions (room temperature, dioxane,
1 h) to give in practically quantitative yields
2-(diorganylphosphorylhydroxymethyl)-1-organylimidazoles – highly reactive synthons and polydentate
ligands for the design of metal complex catalysts.
Keywords: diorganylphosphine oxides, 2-(diorganylphosphorylhydroxymethyl)-1-organylimidazoles,
1-organyl-2-formylbenzimidazoles, 1-organyl-2-formylimidazoles, camphorsulfonic acid, phosphorylation,
sulfonates, complexes.
Aldehydes of the azole series, available recently [1] are highly reactive intermediates for the preparation
of synthetic analogs of natural materials, and also potential ligands in the synthesis of metal complexes [2]. One
real route for the further broadening of the synthetic potential of these aldehydes may be their reactions with
secondary phosphine oxides. The latter react with formaldehyde [3], aliphatic [4] and aromatic aldehydes [4-7],
chloral [5, 6], cyclohexane and cyclohexene aldehydes [6] in the presence of bases (EtONa–ethanol [3, 4],
KOH–DMSO [3], NaOH–dioxane [6] systems) and also in the absence of catalysts [5-7].
The object of the present study was to synthesize new functionally substituted chiral azoles containing
hydroxyl and phosphoryl groups, from 1-organyl-2-formylimidazoles and -benzimidazoles and to study the
properties of these reactive compounds as potential materials for the solution of fundamental questions of
coordination chemistry.
It was found that 1-organyl-2-formylimidazoles and -benzimidazoles readily react with
diorganylphosphine oxides under mild conditions (room temperature, dioxane, 1 h) to give, in practically
quantitative yield, 2-(diorganylphosphorylhydroxymethyl)-1-organylimidazoles 1a-j, the structures of which
were studied by 1H NMR spectroscopy.
_______
* Presented to Academician of the Russian Academy of Sciences M. G. Voronkov on his 80th birthday.
__________________________________________________________________________________________
A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, Irkutsk
664033, Russia; e-mail: admin@irioch.irk.ru. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1,
71-77, January, 2002. Original article submitted May 30, 2001.
0009-3122/02/3801-0065$27.00©2002 Plenum Publishing Corporation
65

3
R3
R
R4
R5
O
H
R4
N
O
N
H
P
P
+
2
R5
C
2
R
CH
OH
N
R
N
O
R1
R1
1a–j
1 a R1 = Me, R2 = R3 = H, R4 = R5 = Ph; b R1 = Et, R2 = R3 = H, R4 = R5 = Ph; c R1 = Vin, R2 = R3 = H, R4 = R5 = Ph;
d R1 = Et, R2 = R3 = H, R4 = R5 = PhCH2CH2; e R1 = Me, R2 = R3 = H, R4 = Et, R5 = Ph; f R1 = Et, R2 = R3 = H, R4 = Et, R5 = Ph;
g R1 = Vin, R2 = R3 = H, R4 = Et, R5 = Ph; h R1 = Et, R2+R3 = (CH)4, R4 = R5 = Ph; i R1 = Vin, R2+R3 = (CH)4, R4 = R5 = Ph;
j R1 = Et, R2+R3 = (CH)4, R4 = Et, R5 = Ph
All the compounds synthesized contain an asymmetric carbon atom and some (1e-g, j) also have an
asymmetric phosphorus atom. The presence of a chiral carbon atom and a prochiral phosphorus atom in the phosphine
oxide 1d led to non-equivalence of all the methylene protons of two phenylethyl units [8] which appear in the
1H NMR spectrum in the 2.03-2.98 ppm region as five complex multiplets with intensity ratio 1:2:2:1:2.
H"
Ph
H'
a
H"
a
C
C
O
N
a
H'
H"
a
P
.
C
b
CH
OH
N
Et
H"
C
b
H'
Ph
b
H'
b
1d
Use of the 2M COSY method, 31P decoupling, and analysis of the 1M 2M cross section (1H, 13C) of the
HSQC spectrum [9] permitted the identification of each of the signals of the mentioned methylene protons in
phosphine oxide 1d (δ, ppm): O=PCHa' 2.03; O=PCHa" 2.21; PhCHa' 2.40; PhCHa" 2.75; O=PCHb' 2.21;
O=PCHb" 2.40, PhCHb' 2.98; PhCHb" 2.98.
Phosphine oxides 1e-g,j, which have two chiral centers, are formed as two diastereomers. Most of the
1
31
signals are splitted in both the H and P NMR spectra of these compounds. The differences in the integrated
intensities of the signals of the two diastereomers of molecules 1e-g,j indicate a considerable preponderance of
one of them, i.e., the reaction of the aldehydes studied with unsymmetrical secondary phosphine oxides has a
diastereodirecting character. In these diastereomers the difference in the chemical shifts of the protons of the
O=PCH2 unit is 0.15-0.25 ppm, while the signal of the methyne proton (OCHP=O) of the predominant
diastereomer lies to weaker field. In the 31P NMR spectrum the signal of this diastereomer is also to weaker field.
Compounds 1a-d,h,i can serve as predecessors for optically active ligands. The reaction of
2-(diphenylphosphorylhydroxymethyl)-1-ethylimidazole (1b) with optically active (+)-camphorsulfonic acid (2),
which occurs at room temperature to give a practically quantitative yield of the corresponding sulfonate 3 (as a
pair of diastereomers), is the first step in realistic route to the separation of the racemate into enantiomers [10].
Me
Me
Me
Me
H
+
O
Ph
Ph
N
P
+
1b
CH
OH
N
Et
–
CH2SO3
CH2SO3H
O
O
2
3
66

31
Only one signal is present in the P NMR spectrum of the diastereomeric mixture of compound 3 and
the 1H NMR spectrum does not show doubling of many of the characteristic signals (e.g., the OCHP=O proton
and the protons of the CH2SO3 group). However doubling of the proton signals of the imidazole ring in the
1H NMR spectrum of compound 3 indicates the presence of two isomers, while the presence of two independent
(spin independent) pairs of these protons was demonstrated by the 1H–1H NMR COSY method.
Since phosphine oxides are also capable of forming salts with acids [11, 12], while the values of the
relative basicities (shift of the phenol bands on forming the associates) for tertiary phosphine oxides [13] and
1-organylimidazoles [14] are similar (∆νOH in the 430-530 cm-1 region), we synthesized the model compounds
4a,b to confirm the structure of sulfonate 3.
Me
Me
H
+
N
N
2
+
R
R
N
Et
N
Et
–
CH2SO3
O
4a,b
4a R = H, b R = HOCH2
Comparative analysis of the IR spectra of sulfonates 3 and 4a,b shows that the center of protonation in
the reaction of compound 1b with the acid 2 is the "pyridine" nitrogen atom . Thus the expected intense band at
~3000 cm-1 with a complex structure, characteristic of the νNH+ vibrations, is present in the spectra of the salts
4a,b and sulfonate 3. The spectra of the salts 4a,b contain the band corresponding to stretching vibrations of the
imidazole ring at 1545 and 1527 cm-1, shifted (by 35 and 23 cm-1 respectively) to higher frequencies in
comparison with the analogous vibrations in 1-ethyl- and 1-ethyl-2-hydroxymethylimidazole starting materials.
The band of stretching vibrations of the imidazole ring in sulfonate 3 is found at 1520 cm-1, whereas it appears
at 1509 cm-1 in the initial heterocycle 1b, i.e., in this case protonation of the imidazole ring has led to an
increase in the frequency of the stretching vibrations of the ring.
In the spectrum of the initial solid imidazole 1b a broad band at 2600 cm-1corresponds to the stretching
vibrations of the OH group, which is involved in intermolecular OH···N bonds. The phosphoryl group remains
free and has νP=O at 1195 cm-1, which is characteristic of tertiary phosphine oxides containing aryl substituent
[13]. In compound 3 this band appears at 1204 cm-1 which shows that it also is free.
Using imidazoles 1c,e as examples, it was shown that compounds 1a-j may be used in the synthesis of
metal complexes. Imidazoles 1c,e react readily with zinc and cadmium dichlorides in ethanol to give 1:1
complexes (from elemental analysis data) in high yield. The structures of these complexes are being
investigated.
Thus reactions of aldehydes of the azole series with available diorganylphosphine oxides [15] is a
valuable method for the synthesis of new functionally substituted derivatives of imidazole which have promise
for the synthesis of amphiphilic ligands (including optically active ones), extractants for precious and rare
metals, antipyrenes, and intermediates for the synthesis of biologically active materials.
EXPERIMENTAL
1H and 31P NMR spectra were recorded on a Bruker DPX (400 MHz) spectrometer in CDCl3 solution
with HMDS as internal standard and 85% H3PO4 as external standard. IR spectra were recorded with a Bruker
IFS 25 apparatus as KBr disks or microlayers.
67

General Method for the Preparation of 2-(Diorganylphosporylhydroxymethyl)-1-
organylimidazoles (1a-j). Mixture of 1-organyl-2-formylimidazole (3 mmol), and diorganylphosphine oxide
(3 mmol) in dioxane (2 ml) was stirred at room temperature for 1 h, here the crystalline product was formed.
The solvent was removed in vacuum, and the residue was washed with ether and dried.
2-(Diphenylphosphorylhydroxymethyl)-1-methylimidazole (1a). Yield 99%; mp 156-158°C
(hexane). 1H NMR spectrum, δ, ppm, J (Hz): 3.71 (3H, s, CH3); 5.64 (1H, d, 2JHP = 5.2, CHP); 6.81 (1H, s); 6.83
(1H, s, H-4 and H-5); 7.43-7.82 (10H, m, Ph). 31P NMR spectrum: 31.8. IR spectrum, ν, cm-1: 2600 (OH); 3175,
3066 (CH of phenyl and imidazole ring); 2957, 2889 (C–H); 1589, 1520, 1486 (C=C, C=N of phenyl and
imidazole rings); 1178 (P=O); 1055 (δC–O–H). Found, %: C 65.48; H 5.53; N 8.79; P 9.65. C17H17N2O2P.
Calculated, %: C 65.38; H 5.49; N 8.97; P 9.92.
2-(Diphenylphosphorylhydroxymethyl)-1-ethylimidazole (1b). Yield 99%; mp 138-140°C (hexane).
3
2
1H NMR spectrum, δ, ppm, J (Hz): 1.31 (3H, t, J = 7.3, CH3); 4.11 (2H, m , CH2); 5.70 (1H, d, JHP = 4.9,
CHP); 6.70 (1H, s); 6.83 (1H, s) (2H, H-4, H-5); 7.32-7.85 (10H, m. Ph). 31P NMR spectrum: 34.2. IR spectrum,
ν, cm-1: 2620 (OH); 3100, 3050, 3010 (CH of phenyl and imidazole ring); 2970, 2940 (C–H); 1590, 1490 (C=C,
C=N of phenyl and imidazole rings); 1195 (P=O); 1050 (δC–O–H). Found, %: C 66.07; H 6.01; N 8.56; P 9.25.
C18H19N2O2P. Calculated, %: C 66.25; H 5.87; N 8.58; P 9.49.
1
2-(Diphenylphosphorylhydroxymethyl)-1-vinylimidazole (1c). Yield 96%; mp 146-148°C. H NMR
spectrum, δ, pp, J (Hz): 4.85 (1H, dd, 2J = 1.3, 3J = 8.8, =CH2-cis); 5.16 (1H, dd, 2J = 1.3, 3J = 15.6, =CH-trans);
2
3
5.70 (1H, d, JHP = 6.0, CHP); 6.84 (1H, d, J = 0.8, H-5); 7.17 (1H, s, H-4); 7.42 (1H, dd, =CH); 7.36-7.90
(10H, m, Ph). 31P NMR spectrum: 30.2. IR spectrum, ν, cm-1: 2620 (OH); 3100, 3052, 3010, 2970 (=CH2, CH of
phenyl and imidazole ring); 1645 (C=C, vinyl); 1589, 1528, 1486 (C=C, C=N of phenyl and imidazole ring);
1202 (P=O); 1035 (δC–O–H). Found, %: C 66.49; H 5.32; N 5.89; P 9.42. C18H17N2O2P. Calculated, %: C 66.66;
H 5.28; N 8.54; P 9.55.
2-[Bis(2-phenylethyl)phosphorylhydroxymethyl]-1-ethylpyrimidine (1d). Yield 98%, (oil). 1H NMR
3
spectrum, δ, ppm, J (Hz): 1.42 (1H, t, J = 7.3, CH3); 2.03 (1H, m), 2.21 (2H, m), 2.40 (2H, m), 2.75 (1H, m),
2.98 (2H, m) ((CH2CH2Ph)2); 4.13 (2H, m, CH2N); 5.08 (1H, d, 2JHP = 7.7, CHP); 6.94 (1H, d, 3J54 = 1.4, H-5);
6.98 (1H, d, J45 = 1.4, H-4); 7.07-7.28 (10 H, m, Ph). 31P NMR spectrum: 54.7. IR spectrum, ν, cm-1:
3
3100 (OH); 3080, 3065, 3020 (C–H of phenyl and imidazole ring); 2960, 2920, 2840 (C–H); 1600, 1580, 1498
(C=C, C=N, of phenyl and imidazole ring); 1157 (P=O); 1045 (δC–O–H). Found, %: C 68.96; H 6.95; N 7.80;
P 7.21. C22H27N2O2P. Calculated, %: C 69.09; H 7.12; N 8.10; P 7.32.
2-[Ethyl(phenyl)phosphorylhydroxymethyl]-1-methylimidazole (1e). Mixture of two diastereomers
1
(ratio 2:1). Yield 99%; mp 157-159°C (hexane). First diastereomer, H NMR spectrum, δ, ppm, J (Hz): 1.00
3
3
2
(3H, dt, J = 7.6, JHP = 17.0, CH3CH2P); 2.28 (2H, m, CH2P); 3.32 (1H, s, CH3N); 5.42 (1H, d, JHP = 7.2,
CHP); 6.94 (1H, d, J54 = 1.4, H-5); 7.11 (1H, d, J45 = 1.4, H-4); 7.48-7.51 (5H, m, Ph); 31P NMR spectrum:
3
3
1
3
3
48.3. Second diastereomer, H NMR spectrum, δ, ppm, J (Hz): 1.01 (3H, dt, J = 7.6, JHP = 17.2, CH3CH2P);
2.15 (2H, m, CH2P); 3.33 (1H, s, CH3N); 5.33 (1H, d, 3JHP = 7.8, CHP); 6.88 (1H, d, 3J54 = 1.3, H-5); 7.09 (1H,
d, J45 = 1.3, H-4); 7.48-7.51 (5H, m, Ph). 31P NMR spectrum: 48.2. IR spectrum, ν, cm-1: 2600 (OH); 3100,
3
3030 (C–H of phenyl and imidazole ring); 2970, 2930, 2870 (C–H); 1580, 1480 (C=C, C=N of phenyl and
imidazole ring); 1435 (δCH , P–Ph, ν imidazole ring); 1275 (δC–H); 1180 (P=O); 1160, 1105 (δC–H); 1050 (δC–O–H).
3
1070, 930, 780, 755, 735, 700, 550, 490 (δC–H). Found, %: C 58.94; H 6.46; N 10.12; P 11.83. C13H17N2O2P.
Calculated, %: C 59.09; H 6.48; N 10.62; P 11.72.
2-[Ethyl(phenyl)phosphorylhydroxymethyl]-1-ethylimidazole (1f). Mixture of two diastereomers
1
(ratio 2.3:1). Yield 97%; mp 194-195°C (hexane). First diastereomer: H NMR spectrum, δ, ppm, J (Hz): 1.03
3
3
3
(3H, dt, J = 7.7, JHP2 = 17.3, CH3CH2P); 1.40 (3H, t, J = 7.3, CH3CH2N); 2.13 (2H, m, CH2P); 4.12 (2H, m,
3
CH2N); 5.29 (1H, d, JHP = 5.8, CHP); 6.87 (1H, d, J = 1.3, H-5); 6.93 (1H, d, H-4); 7.41-7.95 (5H, m, Ph);
1
3
31P NMR spectrum: 47.9. Second diastereomer: H NMR spectrum, δ, ppm, J (Hz): 1.01 (3H, dt, J = 7.7,
3JHP = 17.1, CH3CH2P); 1.40 (3H, t, 3J = 7.3, CH3CH2N); 2.40 (2H, m, CH2P); 4.11 (2H, m, CH2N); 5.25 (1H, d,
68

3
3
31
2JHP = 6.5, CHP); 6.99 (1H, d, J54 = 1.3, H-5); 7.08 (1H, d, J45 = 1.3, H-4); 7.41-7.95 (5H, m, Ph); P NMR
spectrum: 47.7. IR spectrum, ν, cm-1: 2630 (OH); 3120, 3095 (C–H of phenyl and imidazole ring); 2970, 2940,
2870 (C–H); 1580, 1490 (C=C, C=N of phenyl, imidazole ring); 1180 (P=O); 1045 (δC–O–H). Found, %: C 60.53;
H 7.11; N 10.07; P 11.30. C14H19N2O2P. Calculated, %: C 60.42; H 6.88; N 10.07; P 11.13.
2-[Ethyl(phenyl)phosphorylhydroxymethyl]-1-vinylimidazole (1g). Mixture of two diastereomers
1
(1.4:1). Yield 96%; mp 192-196°C (hexane). First diastereomer: H NMR spectrum (CDCl3/CD3OD), δ, ppm,
J (Hz): 1.03 (3H, dt, 3J = 7.6, 3JHP = 17.2 , CH3); 2.25 (2H, m, CH2); 4.78 (1H, dd, 2J = 1.7, 3J = 8.8, =CH2 cis);
2
3
2
3
5.28 (1H, dd, J = 1.7, J = 15.7, =CH2 trans); 5.53 (1H d, JHP = 5.8, CHP); 7.02 (1H, d, J = 1.4, H-5); 7.30
31
1
(1H, dd, =CH); 7.45-7.80 (6H m, H-4, Ph); P NMR spectrum: 48.4. Second diastereomer: H NMR spectrum,
3
3
2
3
δ, ppm, J (Hz): 0.99 (3H, dt, J = 7.6, JHP = 17.2, CH3); 2.10 (2H, m, CH2); 4.85 (1H, dd, J = 1.6, J = 8.8,
2
3
2
3
=CH2 cis); 5.32 (1H, dd, J = 1.6, J = 15.7, =CH2 trans); 5.42 (1H, d, JHP = 7.4, CHP); 6.96 (1H, d, J = 1.2,
H-5); 7.39 (1H, dd, =CH); 7.45-7.80 (6H, m, 4-H, Ph); 31P NMR spectrum: 48.1. IR spectrum, ν, cm-1: 2650
(OH); 3050, 3100 (CH2, C–H of phenyl and imidazole ring); 2965, 2870 (C–H); 1645 (C=C vinyl); 1590, 1490
(C=C, C=N of phenyl and imidazole ring); 1185 (P=O); 1045 (δC–O–H). Found, %: C 60.76; H 6,13; N 10.30;
P 11.74. C14H17N2O2P. Calculated, %: C 60.86; H 6.20; N 10.14; P 11.21.
2-(Diphenylphosphorylhydroxymethyl)-1-ethylbenzimidazole (1h). Yield 98%; mp 142-143°C
1
3
(hexane). H NMR spectrum, δ, ppm, J (Hz): 1.41 (3H, t, J = 7.2, CH3); 4.44 (2H, m CH2); 5.85 (1H, d,
3JHP = 6.6, CHP); 7.19-7.49 (10H, m, Ph); 7.68 (2H, m, Harom); 7.90 (2H, m, Harom). 31P NMR spectrum: 31.1.
IR spectrum, ν, cm-1: 3000 (OH); 3057 (C–H of phenyl, benzimidazole ring); 2936, 2861 (C–H); 1613, 1591,
1487 (C=C, C=N of phenyl, benzimidazole ring); 1202 (P=O); 1067 (δC–O–H). Found, %: C 70.56; H 5.73;
N 7.44; P 8.22. C22H21N2O2P. Calculated, %: C 70.20; H 5.62; N 7.44; P 8.23.
2-(Diphenylphosphorylhydroxymethyl)-1-vinylbenzimidazole (1i). Yield 97%; mp 178-180°C (hexane).
1H NMR spectrum, δ, ppm, J (Hz): 5.25 (1H, dd, 2J = 1.0, 3J = 8.8, =CH2 cis); 5.52 (1H, dd, 2J = 1.3, 3J = 15.6,
2
=CH2 trans); 5.84 (1H, d, JHP = 7.2, CHP); 7.25 (1H, dd, =CH); 7.36-7.63 (10 H, m, Ph); 7.90 (2H, m, Harom).
31P NMR spectrum: 31.3. IR spectrum, ν, cm-1: 3180 (OH); 3086, 3053 (CH2, CH, phenyl, benzimidazole ring);
1643 (C=C vinyl); 1607, 1590, 1518, 1457 (C=C, C=N phenyl, benzimidazole ring); 1190 (P=O); 1051 (δC–O–H).
Found, %: C 70.49; H 4.99; N 7.32; P 8.23. C22H19N2O2P. Calculated, %: C 70.58; H 5.12; N 7.48; P 8.27.
2-[Ethyl(phenyl)phosphorylhydroxymethyl-1-ethylbenzimidazole (1j). Mixture of two diastereomers
(2:1). Yield 96%; mp 129-132°C (hexane). First diastereomer: 1H NMR spectrum, δ, ppm, J (Hz): 1.09 (3H, dt,
3J = 7.7, JHP = 17.4, CH3CH2P); 1.35 (3H, t, J = 7.2, CH3CH2N); 2.35 (2H, m CH2P); 4.35 (2H, m, CH2N);
3
3
5.46 (1H, d, JHP = 7.0, CHP); 7.15-7.28 (9H, m, Ph, Harom); 31P NMR spectrum: 47.1. Second diastereomer:
2
1H NMR spectrum, δ, ppm, J (Hz): 0.98 (3H, dt, J = 7.9, JHP = 17.2, CH3CH2P); 1.33 (3H, t, J = 7.3,
3
3
3
2
CH3CH2N); 2.16 (2H, m CH2P); 4.28 (2H, m, CH2N); 5.41 (1H, d, JHP = 7.9, CHP); 7.15-7.28 (9H, m, Ph,
Harom). 31P NMR spectrum: 45.8. IR spectrum, ν, cm-1: 2700 (OH); 3070, 3010 (CH2, CH, phenyl, benzimidazole
ring); 2970, 2930 (C–H); 1605, 1480 (C=C, C=N phenyl, benzimidazole ring); 1190 (P=O); 1055 (δC–O–H).
Found, %: C 65.62; H 6.53; N 8.56; P 9.38. C18H21N2O2P. Calculated, %: C 65.84; H 6.45; N 8.53; P 9.43.
Synthesis of Sulfonate 3. Mixture of imidazole 1b (0.29 g, 0.9 mmol) and camphorsulfonic acid 2
(0.21 g, 0.9 mmol) in THF (6 ml) was stirred at room temperature for 0.5 h. The precipitate was filtered off,
washed with ether, and dried to give sulfonate 3 (0.49 g, 99%) as a mixture of diastereomers (ratio 1:1);
184-186°C (hexane), [α]
mp
D = 15.058° (c = 10, CH3OH). 1H NMR spectrum, δ, ppm, J (Hz): 0.79 (3H, s), 1.05
3
3
(3H, s) (2 CH3); 1.37 (t, J = 7.3), 1.37 (t, J = 7.3) (3H, CH3CH2 of 2 diastereomers); 1.35 (1H, m), 1.61 (1H,
3
m), 1.84 (1H, d, J = 18.2), 1.97 (1H, m), 2.02 (1H, m), 2.29 (1H, m), 2.58 (1H, m) (cyclohexane ring); 2.69
(1H, d, 2J = 14.7), 3.14 (1H, d) (CH2S); 4.42 (2H, m, CH2N); 6.52 (1H, d, 2JHP = 9.0, CHP); 7.01 (d, 3J54 = 1.9),
3
3
3
7.02 (d, J54 = 1.9) (1H, H-5 of two diastereomers); 7.28 (d, J45 = 1.9), 7.31 (d, 1H, J45 = 1.9) (H-4 of two
diastereomers); 7.44-7.94 (10H, m, Ph). IR spectrum, ν, cm-1: ~3000 (NH+); 1737 (C=O); 1590, 1520, 1470
(C=C, C=N of imidazole and phenyl rings); 1163, 1144 (νas S=O); 1040 (νs S=O); 1204 (P=O). Found, %: C 59.35;
H 6.53; N 4.81; P 5.57; S 5.53. C28H35N2O6PS. Calculated, %: C 60.20; H 6.32; N 5.01; P 5.54; S 5.74.
69

Synthesis of Sulfonate 4a. Mixture of 1-ethylimidazole (0.14 g, 1.5 mmol) and camphorsulfonic acid 2
(0.34 g, 1.5 mmol) in THF (6 ml) was stirred at room temperature for 0.5 h. The solvent was evaporated in
vacuum, the residue was washed with ether and dried to give sulfonate 4a (0.46 g, 95% yield); mp 50-56°C
(pentane). IR spectrum, ν, cm-1: ~3000 (NH+); 1741, 1731 (C=O); 1576, 1545, 1471 (C=C, C=N of imidazole
and phenyl rings); 1189, 1172 (νas S=O); 1042 (νs S=O). Found, %: C 54.79; H 7.34; N 8.56; S 9.68. C25H24N2O4S.
Calculated, %: C 54.86; H 7.37; N 8.53; S 9.76.
Synthesis of Sulfonate 4b. Mixture of 1-ethyl-2-hydroxymethylimidazole (0.19 g, 1.5 mmol) and
camphorsulfonic acid 2 (0.34 g, 1.5 mmol) in THF (6 ml) was stirred at room temperature for 0.5 h. The solvent
was evaporated in vacuum, the residue washed with ether, and dried to give sulfonate 4b (0.52 g, 98%);
mp 94-98°C (pentane). IR spectrum, ν, cm-1: 3290 (OH); ~3000 (NH+); 1742, 1732 (C=O); 1602, 1527, 1456
(C=C, C=N of imidazole and phenyl rings); 1189, 1172 (νas S=O); 1042 (νs S=O). Found, %: C 53.39; H 7.28;
N 7.81, S 8.96. C16H26N2O5S. Calculated, %: C 53.61; H 7.31; N 7.82; S 8.95.
Synthesis of Zinc Chloride Complex with Ligand 1c. Equimolar amounts of imidazole 1c and ZnCl2
in ethanol were stirred for 15 h at 60°C. The product was precipitated with ether, filtered, and dried. Yield 74%;
mp 160°C (dec). IR spectrum, ν, cm-1; 1483, 1442 (C=C, C=N of imidazole and phenyl ring); 1140 (P=O).
Found, %: C 47.15; H 3.97, Cl 15.22; N 6.35; P 6.73. C18H17Cl2N2O2PZn. Calculated, %: C 46.94; H 3.72;
Cl 15.39; N 6.08; P 6.72.
Synthesis of Cadmium Complex with Ligand 1e was carried out analogously with imidazole 1e and
CdCl2. Yield 59%; mp 160°C (dec). IR spectrum, ν, cm-1: 1490, 1440 (C=C, C=N of imidazole and phenyl ring);
1150 (P=O). Found, %: C 35.03; H 4.17, Cl 15.76; N 6.57; P 6.85. C13H17CdCl2N2O2P. Calculated, %: C 34.89;
H 3.83; Cl 15.84; N 6.26; P 6.92.
REFERENCES
1.
2.
3.
L. V. Baikalova, E. S. Domnina, N. N. Chipanina, A. V. Afonin, and A. M. Shulunova, Izv. Akad. Nauk.
Ser. Khim., 971 (1999).
L. V. Baikalova, E. S. Domnina, T. V. Kashik, G.A.Gavrilova, V. A Kukhareva, A. V. Afonin, and
T. N. Mamaseva, Zh. Obshch. Khim., 68, 842 (1998).
I. I. Patsanovskii, E. A. Ishmaeva, E. N. Sundukova, A. N. Yarkevich, and E. N. Tsvetkov, Zh. Obshch.
Khim., 56, 567 (1986).
4.
5.
R. C. Miller, C. D. Miller, W. Rogers, and L.A. Hamilton, J. Amer. Chem. Soc., 79, 424 (1957).
V. S. Abramov, N. I. D'yakonova, and V. D. Efimova, Zh. Obshch. Khim., 39, 1971 (1969).
H.-J. Kleiner, Lieb. Ann. Chem., 751 (1974).
6.
7.
M. I. Kabachnik and E. N. Tsvetkov, Izv. Akad. Nauk SSSR. Ser. Khim., 1227 (1963).
G. Hunter, Introduction to NMR spectroscopy [Russian translation], Mir, Moscow (1984).
T. Parella, Magn. Res. Chem., 36, 467 (1998).
8.
9.
10.
11.
V. M. Potapov, Stereochemistry [in Russian], Khimiya, Moscow, 2, 50 (1988).
J. Drabowicz, P. Lyzwa, J. Omelanczuk, K. M. Pietruiewicz, and M. Mikolajczyk, Tetrahedron:
Asymmetry, 10, 2757 (1999).
12.
13.
14.
15.
D. Purdela and R. Vylchanu, Chemistry of Organic Compounds of Phosphorus [in Russian], Khimiya,
Moscow (1972).
L. Bellamy, Advances in the IR spectra of Complex Molecules. Infrared Spectra of Complex Molecules.
[Russian translation], Mir, Moscow (1971).
N. N. Chipanina, Yu. L. Frolov, N. A. Kazakova, E. S. Domnina, G. G. Skvortsova, and
M. G. Voronkov, Doklady Akad. Nauk, 216, 31 (1974).
N. K. Gusarova, S. F. Malysheva, S. N. Arbuzova, and B. A. Trofimov, Izv. Akad. Nauk. Ser. Khim.,
1695 (1998).
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