Synthesis of 2-[3-Alkoxy-4-(hydroxy, alkoxy, acyloxy)phenyl]-5-methyl-1H- benzimidazoles

Article abstract of DOI:10.1134/S1070428011050071

From substituted benzaldehydes of the vanillin series and 4-methyl-1,2-phenylene diaminein the presence of sodium hydrogen sulfi te in DMF medium at 80°C new functionally substituted 2-[3-alkoxy-4-(hydroxy, alkoxy, acyloxy)phenyl]-5-methyl-1H-benzimidazol

Full text of DOI:10.1134/S1070428011050071

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2011, Vol. 47, No. 5, pp. 694−701. © Pleiades Publishing, Ltd., 2011.
Original Russian Text © E.A. Dikusar, V.I. Potkin, 2011, published in Zhurnal Organicheskoi Khimii, 2011, Vol. 47, No. 5, pp. 692−698.
Synthesis
of 2-[3-Alkoxy-4-(hydroxy, alkoxy, acyloxy)phenyl]-
5-methyl-1H-benzimidazoles
E. A. Dikusar and V. I. Potkin
Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus,
Minsk, 220072 Belarus
e-mail: dikusar@ifoch.bas-net.by
Received July 22, 2010
Abstract—From substituted benzaldehydes of the vanillin series and 4-methyl-1,2-phenylene diaminein the
presence of sodium hydrogen sulfite in DMF medium at 80°C new functionally substituted 2-[3-alkoxy-4-(hydroxy,
alkoxy, acyloxy)phenyl]-5-methyl-1H-benzimidazoles were obtained in preparative yields.
DOI: 10.1134/S1070428011050071
We formerly reported on the synthesis of 2-[3-alkoxy-
4-(hydroxy, alkoxy, acyloxy)phenyl]-1H-benzimidazoles,
derivatives of benzaldehydes of the vanillin series [1].
Functionally substituted 1H-benzimidazoles exhibit high
antiviral, antimicrobial, and antitumor activities thus
stimulating the studies on their synthesis [2–7].
regioisomers: 2-aryl-5-methyl- and 2-aryl-6-methyl-1H-
benzimidazoles. The synthesized compounds IIIa–IIIu,
IVa–IVl, Va–Vc, VI, VIIa, VIIb according to the data
of 1H NMR and GC-MS formed exclusively as 2-aryl-5-
CHO
H2N
The target of this investigation was the synthesis of
+
R
functionally substituted 2-[3-alkoxy-4-(hydroxy, alkoxy
,
H2N
Me
acyloxy)phenyl]-5-methyl-1H-benzimidazoles IIIa–IIIu,
IVa–IVl, Va–Vc, VI, VIIa, VIIb that were obtained by
the oxidative condensation of substituted benzaldehydes
and aldehydes of the vanillin series I with 4-methyl-1,2-
phenylenediamine (II) in the presence of a mild and selec-
tive oxidant, sodium hydrogen sulfite in DMF medium at
80°C, at the stoichiometric ratio of the reagents (5 mmol
of I, 5 mmol of II, and 1.67 mmol of NaHSO3) and the
reaction time 1 h. The yields of target azoles IIIa–IIIu,
IVa–IVl, Va–Vc, VI, VIIa, VIIb reached 73–87%.
R'
I
II
NH
N
NaHSO3
R'
Me
DMF,
R
_NaHS, _3H2O
IIIа_IIIw, IVа_IVl, Vа_Vc
III, R = R’ = H (a); R = H, R' = MeO (b); R = 3-HO,
R' = MeO (c); R = 3-MeO, R' = HO (d), MeO (e), AcO
(f), EtC(O)O (g), PrC(O)O (h), i-PrC(O)O (i), BuC(O)O
(j), i-BuC(O)O (k), Me(CH2)8C(O)O (l), Me(CH2)16C(O)
O (m), H2C=C(Me)C(O)O (n), PhCH(Me)CH2C(O)O
(o), BzO (p), 2,4-Cl2C6H3C(O)O (q), 3-O2NC6H4C(O)
O (r), 1-AdC(O)O (s), MeOC(O)O (t), EtOC(O)O (u);
IV, R = 3-EtO, R' = HO (a), MeO (b),AcO (c), EtC(O)O
(d), PrC(O)O (e), i-PrC(O)O (f), BuC(O)O (g), i-BuC(O)
O (h), 4-MeC6H4C(O)O (i), 1-AdC(O)O (j), MeOC(O)
O (k), EtOC(O)O (l); V, R = R' = 2-HO (a), AcO (b),
EtC(O)O (c).
Obtained compounds IIIa–IIIu, IVa–IVl, Va–Vc, VI,
VIIa, VIIb are yellow or orange crystalline substances,
their composition was confirmed by elemental analysis
and GC-MS method, and the structure, by 1H NMR, IR,
and UV spectra.
Unlike the 2-[3-alkoxy-4-(hydroxy, alkoxy, acyloxy)
phenyl]-1H-benzimidazoles [1] the methyl derivatives
obtained in the present study may exist in the form of two
694

SYNTHESIS OF 2-[3-ALKOXY-4-(HYDROXY, ALKOXY, ACYLOXY)PHENYL]...
695
Vanillin and vanillal esters I were obtained by proce-
dures [11–14]. The used 4-methyl-1,2-phenylenediamine
(II) was of “pure for analysis” grade of 98% purity, mp
87–88°C, sodium hydrogen sulfite was of “pure” grade,
of 97% purity.
(CH2)2
O
O
O
O
R
R
Ht
Ht
2-[3-Alkoxy-4-(hydroxy, alkoxy, acyloxy)-phenyl]-
5-methyl-1H-benzimidazoles IIIa–IIIu, IVa–IVl, Va–
Vc, VI, VIIa, VIIb. A mixture of 5 mmol of substituted
benzaldehyde I, 5 mmol of 1-methyl-3,4-phenylenedi-
amine (II), 1.67 mmol of sodium hydrogen sulfite, and
2 ml of DMF was stirred for 1 h at 80°C. On cooling
the mixture was diluted with 20 ml of methanol (to
prevent too fast coagulation of the precipitate), the solu-
tion obtained was added dropwise to 200 ml of water
at vigorous stirring in the course of 30–45 min. In the
synthesis of compounds VI, VIIa, VIIb per 5 mmol of
initial dialdehyde I was taken a double quantity of the
other ingredients. The formed fine crystalline precipitate
was filtered off, washed with water, and dried in air at
20–23°C over 5–7 days.
Ht
Ht
VI
VIIа, VIIb
NH
N
Ht =
; R = MеO (a), EtO (b).
Me
methyl-1H-benzimidazoles of the purity 95±1%.
In order to confirm the assumed for the synthesized
azoles IIIa–IIIu, IVa–IVl, Va–Vc, VI, VIIa, VIIb the
2-aryl-5-methyl-configuration we carried out quantum-
chemical calculations of the enthalpy of formation (Hf)
of 2-aryl-5-methyl- IIIe, IIIo, IVd, IVf and of their iso-
mers 2-aryl-6-methyl-1H-benzimidazoles VIIIe, VIIIo,
IXd, IXf. The quantum-chemical calculations were
performed on the level of semiempirical approximation
MNDO PM3 [8, 9] using GAMESS program [10] with
the complete optimization of all bond distances, bond and
dihedral angles. The values Hf for 5-methyl derivatives
were –55.43 (IIIe), –19.50 (IIIo), –65.92 (IVd), –70.18
(IVf) kcal mol−1; for 6-methyl isomers they were –54.58
(VIIIe), –18.64 (VIIIo), –65.40 (IXd), –70.00 (IXf) kcal
mol−1. These results show that 2-aryl-5-methyl-1H-
benzimidazoles by 0.18–0.86 kcal mol−1 (MNDO PM3)
are thermodynamically more stable than their 6-methyl
isomers. Therefore under the conditions of the dynamic
equilibrium the formation of 5-methylazoles is favored.
5-Methyl-2-phenyl-1H-benzimidazole (IIIa). Yield
85%, yellow crystals, mp 84–85°C. IR spectrum, ν, cm–1:
3085, 3055, 3033 (CHarom.); 2952, 2923, 2835 (CHaliph);
1627 (C=N); 1611, 1500, 1474, 1454, 1436 (C=Carom);
845, 790, 760, 740 (CHarom). UV spectrum, λmax, nm
(log ε): 210 (4.18), 244 (3.95), 308 (4.18), 320 (3.90).
1H NMR spectrum, δ, ppm: 2.44 s (3H, Me), 6.80–8.04 m
(9H, NH, CHarom). Mass spectrum: m/z 208 [M]+. Found,
%: C 80.44; H 5.56; N 13.09. C14H12N2. Calculated, %:
C 80.74; H 5.81; N 13.45. M 208.26.
5-Methyl-2-(4-methoxyphenyl)-1H-benzimidazole
(IIIb). Yield 88%, yellow crystals, mp 67–68°C. IR
spectrum, ν, cm–1: 3085, 3033, 3005 (CHarom); 2970,
2923, 2855 (CHaliph); 1627 (C=N); 1600, 1512, 1453
(C=Carom); 1296, 1255, 1179, 1034, 966 (C–O); 860, 801
(CHarom). UV spectrum, λmax, nm (log ε): 211 (4.15), 246
(3.95), 308 (4.20), 319 (3.90). 1H NMR spectrum, δ, ppm:
2.44 s (3H, Me), 3.84 s (3H, MeO), 6.82–8.24 m (8H,
NH, CHarom). Mass spectrum: m/z 238 [M]+. Found, %:
C 75.93; H 6.12; N 11.42. C15H14N2O. Calculated, %:
C 75.61; H 5.92; N 11.76. M 238.28.
EXPERIMENTAL
IR spectra were recorded from compounds in pellets
with KBr on an IR Fourier spectrophotometer Nicolet
Protege-460, UV spectra from 1 × 10–4 M solutions of
compounds in methanol, on a spectrophotometer Specord
1
UV Vis. H NMR spectra were registered on a spec-
trometer Tesla BS-587A (100 MHz) from 5%-solutions
in DMSO-d6 or chloroform-d, internal reference TMS.
Mass spectra were obtained on an instrument Hewlett
Packard 5890/5972 in the electron impact mode at the
energy of ionizing electrons 70 eV; capillary column
HP-5MS 30 m × 0.25 mm, phase 0.25 μm, vaporizer
temperature 250°C. Elemental analysis was carried out
on a CHNOS-analyzer Elementar Vario EL-III, measure-
ment error 0.1%.
2-(3-Hydroxy-4-methoxyphenyl)-5-methyl-1H-
benzimidazole (IIIc). Yield 86%, yellow crystals, mp
107–108°C. IR spectrum, ν, cm–1: 3374 (OH); 3067,
3030, 3004 (CHarom); 2962, 2929, 2854, 2839 (CHaliph);
1614, 1591, 1510, 1441 (C=Carom); 1275, 1216, 1177,
1031, 1025 (C–O); 870, 805, 763 (CHarom). UV spec-
trum, λmax, nm (log ε): 213 (4.40), 244 (3.78), 313 (4.08),
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DIKUSAR, POTKIN
696
325 (3.70). 1H NMR spectrum, δ, ppm: 2.44 s (3H, Me),
3.84 s (3H, MeO), 5.60 s (1H, OH), 6.60–7.94 m (7H,
NH and CHarom). Mass spectrum: m/z 254 [M]+. Found,
%: C 71.20; H 5.68; N 10.86. C15H14N2O2. Calculated,
%: C 70.85; H 5.55; N 11.02. M 254.28.
243 (3.78), 313 (4.08), 324 (3.78). 1H NMR spectrum, δ,
ppm: 1.16 t (3H, Me), 2.44 s (3H, Me), 2.56 q (2H, CH2),
3.91 s (3H, MeO), 6.82–8.00 m (7H, NH, CHarom). Mass
spectrum: m/z 310 [M]+. Found, %: C 69.94; H 6.03;
N 8.65. C18H18N2O3. Calculated, %: C 69.66; H 5.85;
N 9.03. M 310.45.
2-(4-Hydroxy-3-methoxyphenyl)-5-methyl-1H-
benzimidazole (IIId). Yield 82%, yellow crystals,
mp 80–81°C. IR spectrum, ν, cm–1: 3400 (OH); 3060,
3032, 3004 (CHarom); 2960, 2928, 2852 (CHaliph); 1624
(C=N); 1602, 1512, 1501, 1495, 1460, 1434 (C=Carom);
1274, 1213, 1154, 1124, 1032 (C–O); 870, 816, 744
(CHarom). UV spectrum, λmax, nm (log ε): 214 (4.38),
342 (3.78), 314 (4.08), 324 (3.70). 1H NMR spectrum, δ,
ppm: 2.44 s (3H, Me), 3.75 s (3H, MeO), 5.50 s (1H, OH),
6.62–7.95 m (7H, NH, CHarom). Mass spectrum: m/z 254
[M]+. Found, %: C 71.08; H 5.79; N 10.80. C15H14N2O2.
Calculated, %: C 70.85; H 5.55; N 11.02. M 254.28.
2-(4-Butyryloxy-3-methoxyphenyl)-5-methyl-
1H-benzimidazole (IIIh). Yield 80%, yellow crys-
tals, mp 38–39°C. IR spectrum, ν, cm–1: 3063, 3004
(CHarom); 2964, 2938, 2874, 2850 (CHaliph); 1762
(C=O); 1624 (C=N); 1604, 1596, 1501, 1457, 1432
(C=Carom); 1267, 1240, 1203, 1128, 1095, 1032 (C–O);
871, 832, 804, 760 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 243 (4.36), 314 (4.08), 324 (3.78).
1H NMR spectrum, δ, ppm: 1.03 t (3H, Me), 1.77 m
(2H, MeCH2), 2.44 s (3H, Me), 2.55 t [2H, CH2C(O)],
3.91 s (3H, MeO), 6.80–8.00 m (7H, NH, CHarom). Mass
spectrum: m/z 324 [M]+. Found, %: C 70.87; H 6.44;
N 8.25. C19H20N2O3. Calculated, %: C 70.35; H 6.21;
N 8.64. M 324.37.
2-(3,4-Dimethoxyphenyl)-5-methyl-1H-benzimid-
azole (IIIe). Yield 80%, yellow crystals, mp 91–92°C.
IR spectrum, ν, cm–1: 3060, 3003 (CHarom); 2960, 2934,
2926, 2850 (CHaliph); 1624 (C=N); 1605, 1592, 1504,
1455, 1437 (C=Carom); 1264, 1233, 1176, 1138, 1023
(C–O); 860, 810, 765, 746 (CHarom). UV spectrum,
λmax, nm (log ε): 215 (4.34), 342 (3.78), 314 (4.08), 325
2-(4-Isobutyryloxy-3-methoxyphenyl)-5-methyl-
1H-benzimidazole (IIIi). Yield 84%, yellow crystals,
mp 69–70°C. IR spectrum, ν, cm–1: 3066, 3004 (CHarom);
2974, 2938, 2877, 2845 (CHaliph); 1760 (C=O); 1624
(C=N); 1604, 1592, 1504, 1463, 1430 (C=Carom); 1270,
1242, 1202, 1126, 1093, 1032 (C–O); 867, 815, 783, 765
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38), 243
(3.78), 313 (4.08), 324 (3.78). 1H NMR spectrum, δ, ppm:
1.38 d (6H, Me2C), 2.43 s (3H, Me), 2.90 m (1H, CH),
3.91 s (3H, MeO), 6.76–8.02 m (7H, NH, CHarom). Mass
spectrum: m/z 324 [M]+. Found, %: C 70.62; H 6.19;
N 8.28. C19H20N2O3. Calculated, %: C 70.35; H 6.21;
N 8.64. M 324.37.
1
(3.78). H NMR spectrum, δ, ppm: 2.44 s (3H, Me),
3.89 s (3H, 3-MeO), 3.92 s (3H, 4-MeO), 6.80–7.80 m
(7H, NH, CHarom). Mass spectrum: m/z 268 [M]+. Found,
%: C 72.02; H 6.21; N 10.12. C16H16N2O2. Calculated,
%: C 71.62; H 6.01; N 10.44. M 268.31.
2-(4-Acetoxy-3-methoxyphenyl)-5-methyl-1H-
benzimidazole (IIIf). Yield 87%, yellow crystals, mp
94–95°C. IR spectrum, ν, cm–1: 3071, 3009 (CHarom);
2962, 2938, 2922, 2856 (CHaliph); 1765 (C=O); 1625
(C=N); 1605, 1509, 1463, 1431 (C=Carom); 1277, 1214,
1196, 1174, 1122, 1032, 1011 (C–O); 862, 831, 804
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.36),
345 (3.78), 313 (4.04), 326 (3.78). 1H NMR spectrum, δ,
ppm: 2.28 s (3H, Me), 2.44 s (3H, Me), 3.92 s (3H, MeO),
6.80–8.00 m (7H, NH, CHarom). Mass spectrum: m/z 296
[M]+. Found, %: C 69.32; H 5.58; N 9.03. C17H16N2O3.
Calculated, %: C 68.91; H 5.44; N 9.45. M 296.33.
2-(4-Valeroyloxy-3-methoxyphenyl)-5-methyl-1H-
benzimidazole (IIIj). Yield 73%, yellow crystals, mp
83–84°C. IR spectrum, ν, cm–1: 3060, 3005 (CHarom);
2957, 2933, 2871 (CHaliph); 1762 (C=O); 1624 (C=N);
1604, 1593, 1501, 1463, 1432 (C=Carom); 1267, 1231,
1171, 1127, 1096, 1031 (C–O); 868, 784, 762 (CHarom).
UV spectrum, λmax, nm (log ε): 213 (4.40), 244 (3.78),
313 (4.08), 324 (3.78). 1H NMR spectrum, δ, ppm: 0.96 t
(3H, Me), 1.12–1.94 m [4H, (CH2)2], 2.43 s (3H, Me),
2.56 t [2H, CH2C(O)], 3.92 s (3H, MeO), 6.80–8.04 m
(7H, NH, CHarom). Mass spectrum: m/z 338 [M]+. Found,
%: C 71.35; H 6.71; N 7.90. C20H22N2O3. Calculated, %:
C 70.99; H 6.55; N 8.28. M 324.40.
5-Methyl-2-(3-methoxy-4-propionyloxyphenyl)-
1H-benzimidazole (IIIg). Yield 86%, yellow crystals,
mp 75–76°C. IR spectrum, ν, cm–1: 3062, 3004 (CHarom);
2978, 2940, 2926, 2884, 2850 (CHaliph); 1764 (C=O);
1624 (C=N); 1606, 1501, 1460, 1432 (C=Carom); 1267,
12043, 1176, 1130, 1075, 1032 (C–O); 884, 860, 830,
760 (CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38),
2-(4-Isovaleroyloxy-3-methoxyphenyl)-5-methyl-
1H-benzimidazole (IIIk). Yield 74%, yellow crystals,
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SYNTHESIS OF 2-[3-ALKOXY-4-(HYDROXY, ALKOXY, ACYLOXY)PHENYL]...
697
mp 77–78°C. IR spectrum, ν, cm–1: 3062, 3004 (CHarom);
2976, 2938, 2876, 2842 (CHaliph); 1759 (C=O); 1624
(C=N); 1604, 1593, 1504, 1463, 1430 (C=Carom); 1268,
1246, 1170, 1126, 1090, 1033 (C–O); 867, 814, 765, 740
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38),
NH, CHarom). Mass spectrum: m/z 322 [M]+. Found, %:
C 71.23; H 5.75; N 8.24. C19H18N2O3. Calculated, %:
C 70.79; H 5.63; N 8.69. M 322.36.
5-Methyl-2-[3-methoxy-4-(3-phenylbutyryloxy)]-
1H-benzimidazole (IIIo). Yield 86%, yellow crystals,
mp 73–74°C. IR spectrum, ν, cm–1: 3090, 3060, 3030,
3003 (CHarom); 2962, 2925, 2890, 2870, 2854 (CHaliph);
1758 (C=O); 1624 (C=N); 1604, 1500, 1452, 1432
(C=Carom); 1266, 1233, 1201, 1082, 1032 (C–O); 880,
840, 765, 745, 702 (CHarom). UV spectrum, λmax, nm
(log ε): 211 (4.48), 244 (3.85), 314 (4.15), 326 (3.85).
1H NMR spectrum, δ, ppm: 1.45 d (3H, Me), 2.46 s (3H,
Me), 2.94 d (2H, CH2), 3.42 q (1H, CH), 3.93 s (3H, MeO),
6.80–8.00 m (12H, NH, CHarom). Mass spectrum: m/z 400
[M]+. Found, %: C 75.32; H 6.19; N 6.74. C25H24N2O3.
Calculated, %: C 74.98; H 6.04; N 7.00. M 400.47.
1
243 (3.78), 313 (4.08), 324 (3.78). H NMR spectrum,
δ, ppm: 1.14 d (6H, Me2C), 1.45–2.90 m (3H, CH, CH2),
2.43 s (3H, Me), 3.92 s (3H, MeO), 6.83–8.00 m (7H,
NH, CHarom). Mass spectrum: m/z 338 [M]+. Found, %:
C 71.24; H 6.59; N 8.01. C20H22N2O3. Calculated, %:
C 70.99; H 6.55; N 8.28. M 324.40.
2-(4-Caprinoyloxy-3-methoxyphenyl)-5-methyl-
1H-benzimidazole (IIIl). Yield 79%, yellow crystals,
mp 41–42°C. IR spectrum, ν, cm–1: 3060, 3005 (CHarom);
2954, 2927, 2855 (CHaliph); 1764 (C=O); 1624 (C=N);
1605, 1503, 1456, 1432 (C=Carom); 1270, 1232, 1202, 1175,
1106, 1034 (C–O); 885, 860, 840, 765, 745 (CHarom). UV
spectrum, λmax, nm (log ε): 213 (4.38), 244 (3.78), 312
2-(4-Benzoyloxy-3-methoxyphenyl)-5-methyl-1H-
benzimidazole (IIIp). Yield 87%, yellow crystals, mp
106–107°C. IR spectrum, ν, cm–1: 3090, 3062, 3040,
3006 (CHarom); 2964, 2933, 2852 (CHaliph); 1744 (C=O);
1625 (C=N); 1501, 1452, 1429 (C=Carom); 1264, 1202,
1174, 1058, 1025 (C–O); 874, 818, 801, 760, 744, 706
(CHarom). UV spectrum, λmax, nm (log ε): 208 (4.48), 245
(4.26), 316 (4.20), 326 (3.90). 1H NMR spectrum, δ, ppm:
2.46 s (3H, Me), 3.94 s (3H, MeO), 6.90–8.20 m (12H,
NH, CHarom). Mass spectrum: m/z 358 [M]+. Found, %:
C 74.10; H 5.28; N 7.43. C22H18N2O3. Calculated, %:
C 73.73; H 5.06; N 7.82. M 358.39.
1
(4.08), 324 (3.70). H NMR spectrum, δ, ppm: 0.93 t
(3H, Me), 1.35 m [12H, (CH2)6], 1.84 m (2H, MeCH2),
2.44 s (3H, Me), 2.60 t [2H, CH2C(O)], 3.92 s (3H,
MeO), 6.80–8.08 m (7H, NH, CHarom). Mass spectrum:
m/z 408 [M]+. Found, %: C 73.90; H 8.11; N 6.43.
C25H32N2O3. Calculated, %: C 73.50; H 7.90; N 6.86.
M 408.53.
5-Methyl-2-(3-methoxy-4-stearoyloxyphenyl)-1H-
benzimidazole (IIIm). Yield 84%, yellow crystals, mp
37–38°C. IR spectrum, ν, cm–1: 3060, 3004 (CHarom);
2964, 2918, 2850 (CHaliph); 1765 (C=O); 1624 (C=N);
1603, 1503, 1466, 1433 (C=Carom); 1268, 1240, 1202,
1174, 1031 (C–O); 870, 835, 760 (CHarom). UV spectrum,
2-[4-(2,4-Dichlorobenzoyloxy)-3-methoxyphenyl]-
5-methyl-1H-benzimidazole (IIIq). Yield 81%, yellow
crystals, mp 96–97°C. IR spectrum, ν, cm–1: 3090, 3070,
3007 (CHarom); 2960, 2928, 2852 (CHaliph); 1754 (C=O);
1625 (C=N); 1606, 1586, 1500, 1464, 1432 (C=Carom);
1266, 1234, 1201, 1173, 1124, 1085, 1032 (C–O); 873,
824, 760, 744 (CHarom). UV spectrum, λmax, nm (log ε):
λ
max, nm (log ε): 213 (4.38), 245 (3.78), 312 (4.08), 324
1
(3.70). H NMR spectrum, δ, ppm: 0.91 t (3H, Me),
1.10–2.14 m [30H, (CH2)15], 2.44 s (3H, Me), 2.68 t
[2H, CH2C(O)], 3.92 s (3H, MeO), 6.80–8.10 m (7H,
NH, CHarom). Mass spectrum: m/z 520 [M]+. Found, %:
C 76.52; H 9.35; N 5.03. C33H48N2O3. Calculated, %:
C 76.11; H 9.29; N 5.38. M 520.75.
1
220 (4.62), 244 (4.38), 310 (4.20). H NMR spectrum,
δ, ppm: 2.46 s (3H, Me), 3.94 s (3H, MeO), 6.90–8.16 m
(10H, NH, CHarom). Mass spectrum: m/z 427 [M]+. Found,
%: C 62.30; H 3.99; Cl 16.12; N 6.05. C22H16Cl2N2O3.
Calculated, %: C 61.84; H 3.77; Cl 16.59; N 6.56.
M 427.28.
2-(4-Methacryloyloxy-3-methoxyphenyl)-5-
methyl-1H-benzimidazole (IIIn). Yield 82%, yellow
crystals, mp 83–84°C. IR spectrum, ν, cm–1: 3080, 3060,
3030, 3004 (CHarom); 2966, 2924, 2854 (CHaliph); 1738
(C=O); 1636 (C=C); 1624 (C=N); 1604, 1501, 1454,
1431 (C=Carom); 1267, 1204, 1175, 1032 (C–O); 880, 822,
760 (CHarom). UV spectrum, λmax, nm (log ε): 213 (4.41),
5-Methyl-2-[3-methoxy-4-(3-nitrobenzoyloxy)
phenyl]-1H-benzimidazole (IIIr). Yield 85%, yellow
crystals, mp 119–120°C. IR spectrum, ν, cm–1: 3084,
3070, 3010 (CHarom); 2976, 2922, 2857 (CHaliph); 1747
(C=O); 1627 (C=N); 1616, 1607, 1508, 1478, 1464,
1440 (C=Carom); 1532, 1350 (NO2); 1290, 1253, 1202,
1127, 1057, 1032 (C–O); 862, 806, 716 (CHarom). UV
1
244 (3.85), 313 (4.15), 324 (3.78). H NMR spectrum,
δ, ppm: 2.10 s (3H, Me), 2.44 s (3H, Me), 3.92 s (3H,
MeO), 5.81 s and 6.42 s (2H, C=CH2), 6.82–8.00 m (7H,
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spectrum, λmax, nm (log ε): 215 (4.56), 244 (4.26), 310
(4.20). H NMR spectrum, δ, ppm: 2.46 s (3H, Me),
3.94 s (3H, MeO), 6.90–8.40 m (11H, NH, CHarom). Mass
spectrum: m/z 403 [M]+. Found, %: C 65.89; H 4.61;
N 10.02. C22H17N3O5. Calculated, %: C 65.50; H 4.25;
N 10.42. M 403.39.
3040, 3002 (CHarom); 2977, 2923, 2854 (CHaliph); 1628
(C=N); 1600, 1513, 1472, 1454, 1395 (C=Carom); 1275,
1233, 1209, 1125, 1040 (C–O); 870, 820, 801, 740
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38), 244
(3.78), 314 (4.08), 325 (3.70). 1H NMR spectrum, δ, ppm:
1.26 t (3H, Me), 2.44 s (3H, Me), 4.04 q (2H, CH2O),
6.12 br.s (1H, OH), 6.60–7.98 m (7H, NH, CHarom).
Mass spectrum: m/z 268 [M]+. Found, %: C 71.94; H 6.14;
N 9.99. C16H16N2O2. Calculated, %: C 71.62; H 6.01;
N 10.44. M 268.31.
1
2-[4-(1-Adamantylcarbonyloxy)-3-methoxyphen-
yl]5-methyl-1H-benzimidazole (IIIs). Yield 80%, yellow
crystals, mp 144–145°C. IR spectrum, ν, cm–1: 3076,
3045, 3030, 3004 (CHarom); 2934, 2907, 2852 (CHaliph);
1753 (C=O); 1625 (C=N); 1607, 1508, 1453 (C=Carom);
1277, 1263, 1221, 1199, 1177, 1121, 1051, 1043 (C–O);
870, 845, 799, 752, 736 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 244 (3.78), 312 (4.08), 324 (3.70).
1H NMR spectrum, δ, ppm: 1.67–2.40 m (15H, Ad),
2.44 s (3H, Me), 3.92 s (3H, MeO), 6.75–8.04 m (7H,
NH, CHarom). Mass spectrum: m/z 416 [M]+. Found, %:
C 75.21; H 6.88; N 6.29. C26H28N2O3. Calculated, %:
C 74.97; H 6.78; N 6.73. M 416.51.
5-Methyl-2-(4-methoxy-3-ethoxyphenyl)-1H-
benzimidazole (IVb). Yield 79%, yellow crystals,
mp 69–70°C. IR spectrum, ν, cm–1: 3060, 3030, 3002
(CHarom); 2986, 2928, 2840 (CHaliph); 1624 (C=N); 1604,
1501, 1475, 1450, 1392 (C=Carom); 1270, 1138, 1028
(C–O); 878, 811, 766 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.40), 244 (3.78), 314 (4.08), 324 (3.70).
1H NMR spectrum, δ, ppm: 1.27 t (3H, Me), 2.44 s (3H,
Me), 3.82 s (3H, MeO), 3.88 q (2H, CH2O), 6.45–7.85 m
(7H, NH, CHarom). Mass spectrum: m/z 282 [M]+. Found,
%: C 72.76; H 6.67; N 9.61. C17H18N2O2. Calculated, %:
C 72.32; H 6.43; N 9.92. M 282.34.
5-Methyl-2-(3-methoxy-4-methoxycarbonyl-
oxyphenyl)-1H-benzimidazole (IIIt). Yield 73%,
yellow crystals, mp 83–84°C. IR spectrum, ν, cm–1:
3060, 3004 (CHarom); 2954, 2936, 2846 (CHaliph); 1768
(C=O); 1624 (C=N); 1604, 1502, 1454, 1438 (C=Carom);
1260, 1204, 1176, 1124, 1032 (C–O); 862, 830, 804
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38),
243 (3.78), 313 (4.08), 324 (3.78). 1H NMR spectrum, δ,
ppm: 2.44 s (3H, Me), 3.92 (3H, 3-MeO), 3.96 s [3H,
4-MeOC(O)O], 6.80–8.00 m (7H, NH, CHarom). Mass
spectrum: m/z 312 [M]+. Found, %: C 65.62; H 5.31;
N 8.90. C17H16N2O4. Calculated, %: C 65.38; H 5.16;
N 8.97. M 312.32.
2-(4-Acetoxy-3-ethoxyphenyl)-5-methyl-1H-
benzimidazole (IVc). Yield 86%, yellow crystals,
mp 92–93°C. IR spectrum, ν, cm–1: 3060, 3031, 3002
(CHarom); 2979, 2924, 2900, 2865 (CHaliph); 1768 (C=O);
1624 (C=N); 1605, 1510, 1473, 1452, 1394 (C=Carom);
1276, 1213, 1189, 1123, 1040 (C–O); 870, 830, 802,
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.38),
1
344 (3.78), 314 (4.08), 326 (3.78). H NMR spectrum,
δ, ppm: 1.26 t (3H, Me), 2.32 s (3H, Me), 2.44 s (3H,
Me), 3.94 q (2H, CH2O), 7.00–7.98 m (7H, NH, CHarom).
Mass spectrum: m/z 310 [M]+. Found, %: C 69.93; H 6.04;
N 8.87. C18H18N2O3. Calculated, %: C 69.66; H 5.85;
N 9.03. M 310.45.
5-Methyl-2-(3-methoxy-4-ethoxycarbonyloxy-
phenyl)-1H-benzimidazole (IIIu). Yield 74%, yellow
crystals, mp 88–89°C. IR spectrum, ν, cm–1: 3060, 3004
(CHarom); 2968, 2934, 2874, 2852 (CHaliph); 1764 (C=O);
1624 (C=N); 1606, 1503, 1464, 1432 (C=Carom); 1244,
1203, 1177, 1122, 1096, 1053, 1030 (C–O); 860, 834,
804, 775, 744 (CHarom). UV spectrum, λmax, nm (log ε):
213 (4.38), 244 (3.78), 314 (4.08), 324 (3.78). 1H NMR
spectrum, δ, ppm: 1.45 t (3H, Me), 2.44 s (3H, Me),
3.92 s (3H, MeO), 4.18 q (2H, CH2), 6.84–8.00 m (7H,
NH, CHarom). Mass spectrum: m/z 326 [M]+. Found, %:
C 66.71; H 5.65; N 8.19. C18H18N2O4. Calculated, %:
C 66.25; H 5.56; N 8.58. M 326.35.
5-Methyl-2-(4-propionyloxy-3-ethoxyphenyl)-
1H-benzimidazole (IVd). Yield 80%, yellow crystals,
mp 54–55°C. IR spectrum, ν, cm–1: 3063, 3025, 3004
(CHarom); 2980, 2942, 2898, 2852 (CHaliph); 1764
(C=O); 1624 (C=N); 1604, 1501, 1474, 1450, 1430,
1392 (C=Carom); 1268, 1175, 1124, 1076, 1044 (C–O);
835, 812, 760, 744 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 343 (3.78), 314 (4.08), 325 (3.78).
1H NMR spectrum, δ, ppm: 1.32 t [3H, MeCH2C(O)],
1.36 t (3H, MeCH2O), 2.44 s (3H, Me), 2.60 q [2H,
CH2C(O)], 4.14 q (2H, CH2O), 7.02–7.90 m (7H, NH,
CHarom). Mass spectrum: m/z 324 [M]+. Found, %:
C 70.72; H 6.28; N 8.10. C19H20N2O3. Calculated, %:
2-(4-Hydroxy-3-ethoxyphenyl)-5-methyl-1H-
benzimidazole (IVa). Yield 77%, yellow crystals, mp
100–101°C. IR spectrum, ν, cm–1: 3400 (OH); 3062,
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SYNTHESIS OF 2-[3-ALKOXY-4-(HYDROXY, ALKOXY, ACYLOXY)PHENYL]...
699
C 70.35; H 6.21; N 8.64. M 324.37.
1392 (C=Carom); 1264, 1181, 1151, 1092, 1036 (C–O);
866, 832, 766, 746 (CHarom). UV spectrum, λmax, nm
(log ε): 214 (4.38), 344 (3.78), 314 (4.11), 324 (3.78).
1H NMR spectrum, δ, ppm: 1.12 d (6H, Me2C), 1.42 t
(3H, Me), 1.38–2.90 m (3H, CH, CH2), 2.44 s (3H, Me),
4.14 q (2H, CH2O), 7.04–8.02 m (7H, NH, CHarom). Mass
spectrum: m/z 352 [M]+. Found, %: C 71.95; H 6.92;
N 7.50. C21H24N2O3. Calculated, %: C 71.57; H 6.86;
N 7.95. M 352.43.
2-(4-Butyryloxy-3-ethoxyphenyl)-5-methyl-1H-
benzimidazole (IVe). Yield 86%, yellow crystals, mp
58–59°C. IR spectrum, ν, cm–1: 3065, 3045, 3004
(CHarom); 2970, 2934, 2878, 2852 (CHaliph); 1753 (C=O);
1625 (C=N); 1605, 1592, 1504,1475, 1441, 1400, 1392
(C=Carom); 1270, 1245, 1190, 1134, 1108, 1042 (C–O);
871, 822, 790, 760, 742 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 242 (3.78), 313 (4.08), 324 (3.78).
1H NMR spectrum, δ, ppm: 1.02 t [3H, MeCH2C(O)],
1.38 t (3H, MeCH2O), 1.72 m (2H, MeCH2CH2), 2.44 s
(3H, Me), 2.52 t [2H, CH2C(O)], 4.16 q (2H, CH2O),
7.04–8.00 m (7H, NH, CHarom). Mass spectrum: m/z 338
[M]+. Found, %: C 71.23; H 6.67; N 8.02. C20H22N2O3.
Calculated, %: C 70.99; H 6.55; N 8.28. M 338.40.
5-Methyl-2-[4-(4-toluoyloxy)-3-ethoxyphenyl]-
1H-benzimidazole (IVi). Yield 87%, yellow crystals,
mp 94–95°C. IR spectrum, ν, cm–1: 3092, 3060, 3043,
3005 (CHarom); 2976, 2923, 2902, 2880, 2852 (CHaliph);
1742 (C=O); 1626 (C=N); 1608, 1504, 1475, 1446, 1392
(C=Carom); 1263, 1196, 1178, 1122, 1064, 1041, 1020 (C–
O); 873, 840, 830, 814, 760, 742 (CHarom). UV spectrum,
λmax, nm (log ε): 212 (4.48), 242 (4.26), 314 (4.20), 325
(3.90). 1H NMR spectrum, δ, ppm: 1.44 t (3H, MeCH2),
2.45 s (3H, MeC6H4), 2.49 s (3H, MeC6H4CO2), 4.18 q
(2H, CH2O), 6.98–8.25 m (11H, NH, CHarom). Mass
spectrum: m/z 386 [M]+. Found, %: C 74.87; H 5.98;
N 7.05. C24H22N2O3. Calculated, %: C 74.59; H 5.74;
N 7.25. M 386.44.
2-(4-Isobutyryloxy-3-ethoxyphenyl)-5-methyl-
1H-benzimidazole (IVf). Yield 82%, yellow crystals,
mp 52–53°C. IR spectrum, ν, cm–1: 3064, 3030, 3005
(CHarom); 2970, 2933, 2877, 2854 (CHaliph); 1763
(C=O); 1625 (C=N); 1604, 1592, 1502, 1470, 1447,
1392 (C=Carom); 1269, 1180, 1124, 1092, 1040 (C–O);
866, 810, 762, 742 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 343 (3.78), 314 (4.08), 324 (3.78).
1H NMR spectrum, δ, ppm: 1.34 d (6H, Me2C), 1.42 t
(3H, Me), 2.44 s (3H, Me), 2.85 m (1H, CH), 4.18 q
(2H, CH2O), 7.02–8.02 m (7H, NH, CHarom). Mass
spectrum: m/z 338 [M]+. Found, %: C 71.19; H 6.66;
N 7.91. C20H22N2O3. Calculated, %: C 70.99; H 6.55;
N 8.28. M 338.40.
2-[4-(1-Adamantylcarbonyloxy)-3-ethoxyphenyl]-
5-methyl-1H-benzimidazole (IVj). Yield 84%, yellow
crystals, mp 118–119°C. IR spectrum, ν, cm–1: 3076, 3042,
3004 (CHarom); 2977, 2930, 2906, 2851 (CHaliph); 1754
(C=O); 1625 (C=N); 1607, 1506, 1452 (C=Carom); 1278,
1265, 1217, 1191, 1180, 1123, 1043 (C–O); 870, 848,
804, 752, 735 (CHarom). UV spectrum, λmax, nm (log ε):
214 (4.38), 244 (3.78), 312 (4.08), 324 (3.78). 1H NMR
spectrum, δ, ppm: 1.26 t (3H, Me), 1.66–2.40 m (15H,
Ad), 2.44 s (3H, Me), 4.14 q (2H, CH2O), 6.74–8.04 m
(7H, NH, CHarom). Mass spectrum: m/z 430 [M]+. Found,
%: C 75.68; H 7.21; N 6.10. C27H30N2O3. Calculated, %:
C 75.32; H 7.02; N 6.51. M 430.54.
2-(4-Valeroyloxy-3-ethoxyphenyl)-5-methyl-1H-
benzimidazole (IVg). Yield 81%, yellow crystals,
mp 43–44°C. IR spectrum, ν, cm–1: 3052, 3030, 3004
(CHarom); 2956, 2922, 2901, 2974, 2862 (CHaliph); 1766
(C=O); 1625 (C=N); 1605, 1596, 1504, 1486, 1458,
1392 (C=Carom); 1256, 1232, 1192, 1132, 1096, 1034
(C–O); 894, 870, 832, 760, 754 (CHarom). UV spectrum,
λmax, nm (log ε): 214 (4.38), 244 (3.78), 312 (4.08), 324
5-Methyl-2-(4-methoxycarbonyloxy-3-
ethoxyphenyl)-1H-benzimidazole (IVk). Yield 73%,
yellow crystals, mp 63–64°C. IR spectrum, ν, cm–1:
3060, 3030, 3004 (CHarom); 2982, 2956, 2932, 2901,
2854 (CHaliph); 1770 (C=O); 1626 (C=N); 1606, 1502,
1475, 1444, 1394 (C=Carom); 1272, 1200, 1123, 1055,
1034 (C–O); 874, 832, 820, 774, 740 (CHarom). UV
spectrum, λmax, nm (log ε): 213 (4.38), 242 (3.78),
314 (4.08), 324 (3.78). 1H NMR spectrum, δ, ppm: 1.27 t
(3H, Me), 2.44 s (3H, Me), 3.96 s (3H, MeO), 4.16 q
(2H, CH2O), 7.00–7.98 m (7H, NH, CHarom). Mass
spectrum: m/z 326 [M]+. Found, %: C 66.72; H 5.70;
1
(3.70). H NMR spectrum, δ, ppm: 0.94–1.50 m (6H,
2Me), 1.54–2.20 m [4H, (2CH2)2], 2.44 s (3H, Me), 2.54
t [2H, CH2C(O)], 4.16 q (2H, CH2O), 7.04–8.00 m (7H,
NH, CHarom). Mass spectrum: m/z 352 [M]+. Found, %:
C 71.89; H 7.00; N 7.58. C21H24N2O3. Calculated, %:
C 71.57; H 6.86; N 7.95. M 352.43.
2-(4-Isovaleroyloxy-3-ethoxyphenyl)-5-methyl-
1H-benzimidazole (IVh). Yield 79%, yellow crystals,
mp 42–43°C. IR spectrum, ν, cm–1: 3063, 3030, 3004
(CHarom); 2962, 2933, 2900, 2875, 2850 (CHaliph); 1762
(C=O); 1625 (C=N); 1605, 1502, 1474, 1448, 1432,
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N 8.69. C18H18N2O4. Calculated, %: C 66.25; H 5.56;
N .58. M 326.35.
CHarom). Mass spectrum: m/z 352 [M]+. Found, %:
C 68.71; H 5.96; N 7.52. C20H20N2O4. Calculated, %:
C 68.17; H 5.72; N 7.95. M 352.38.
5-Methyl-2-(3-ethoxy-4-ethoxycarbonyloxy-
phenyl)-1H-benzimidazole (IVl). Yield 78%, yellow
crystals, mp 57–58°C. IR spectrum, ν, cm–1: 3060, 3030,
3003 (CHarom); 2978, 2932, 2900, 2854 (CHaliph); 1765
(C=O); 1626 (C=N); 1606, 1502, 1474, 1447, 1432, 1394
(C=Carom); 1255, 1194, 1124, 1092, 1040 (C–O); 867,
830, 809, 760, 743 (CHarom). UV spectrum, λmax, nm
(log ε): 213 (4.38), 244 (3.78), 314 (4.08), 324 (3.70).
1H NMR spectrum, δ, ppm: 1.20–1.74 m (6H, 2Me),
2.44 s (3H, Me), 4.00–4.56 m (4H, 2CH2O), 7.00–7.98 m
(7H, NH, CHarom). Mass spectrum: m/z 340 [M]+. Found,
%: C 67.24; H 6.18; N 7.78. C19H20N2O4. Calculated, %:
C 67.05; H 5.92; N 8.23. M 340.37.
2,2'-Biphenyl-4,4'-diylbis-1H-benzimidazole (VI).
Yield 79%, orange crystals, mp 218–219°C. IR spectrum,
ν, cm–1: 3060, 3028 (CHarom); 2921, 2888, 2856
(CHaliph); 2625 (C=N); 1602, 1593, 1500, 1444, 1403,
1377 (C=Carom); 877, 860, 824, 800, 737 (CHarom). UV
spectrum, λmax, nm (log ε): 207 (4.60), 266 (4.00), 328
1
(4.43). H NMR spectrum, δ, ppm: 2.45 s (6H, Me),
6.70–8.20 m (14H, NH, CHarom). Mass spectrum: m/z 412
[M]+. Found, %: C 81.79; H 5.13; N 13.10. C28H20N4.
Calculated, %: C 81.53; H 4.89; N 13.58. M 412.49.
Bis[4-(5-methyl-1H-benzimidazol-2-yl)-2-me-
thoxyphenyl]succinate (VIIa). Yield 82%, yellow
crystals, mp 149–150°C. IR spectrum, ν, cm–1: 3070,
3006 (CHarom); 2960, 2923, 2856 (CHaliph); 1763 (C=O);
1625 (C=N); 1605, 1507, 1463, 1420 (C=Carom); 1273,
1233, 1201, 1124, 1031 (C–O); 883, 800, 730 (CHarom).
UV spectrum, λmax, nm (log ε): 213 (4.66), 244 (3.95),
313 (4.34), 324 (4.00). 1H NMR spectrum, δ, ppm: 2.44 s
(6H, 2Me), 3.06 s [4H, (CH2)2], 3.91 s (6H, 2MeO), 6.80–
8.00 m (14H, 2NH, CHarom). Mass spectrum: m/z 590
[M]+. Found, %: C 69.59; H 5.36; N 9.11. C34H30N4O6.
Calculated, %: C 69.14; H 5.12; N 9.49. M 590.63.
2-(2,4-Dihydroxyphenyl)-5-methyl-1H-benzimid-
azole (Va). Yield 80%, orange crystals, mp 114–115°C.
IR spectrum, ν, cm–1: 3356 (OH); 3066, 3028
(CHarom); 2955, 2920, 2856 (CHaliph); 1612, 1512, 459
(C=Carom); 1245, 1196, 1166, 1122 (C–O); 845, 801,
746 (CHarom). UV spectrum, λmax, nm (log ε): 214
(4.40), 245 (4.08), 285 (4.00), 293 (3.95), 320 (4.11),
1
334 (4.08), 366 (3.90). H NMR spectrum, δ, ppm:
2.45 s (3H, Me), 6.80–8.10 m (7H, NH, CHarom). Mass
spectrum: m/z 240 [M]+. Found, %: C 70.41; H 5.14;
N 11.28. C14H12N2O2. Calculated, %: C 69.99; H 5.03;
N 11.66. M 240.27.
Bis[4-(5-methyl-1H-benzimidazol-2-yl)-2-ethoxy-
phenyl]succinate (VIIb). Yield 80%, yellow crystals, mp
133–134°C. IR spectrum, ν, cm–1: 3062, 3037 (CHarom);
2978, 2924, 2897, 2865 (CHaliph); 1763 (C=O); 1626
(C=N); 1606, 1506, 1474, 1449, 1429, 1395 (C=Carom);
1267, 1233, 1192, 1121, 1039 (C–O); 870, 830, 801
(CHarom). UV spectrum, λmax, nm (log ε): 213 (4.66), 245
(4.00), 313 (4.34), 324 (4.00). 1H NMR spectrum, δ, ppm:
1.26 t (6H, Me), 2.44 s (6H, 2Me), 3.06 s [4H, (CH2)2],
3.94 q (4H, 2CH2O), 6.80–8.10 m (16H, 2NH, CHarom).
Mass spectrum: m/z 618 [M]+. Found, %: C 70.12; H 5.13;
N 8.77. C36H34N4O6. Calculated, %: C 69.89; H 5.54;
N 9.06. M 618.68.
2-(2,4-Diacetoxyphenyl)-5-methyl-1H-benzimid-
azole (Vb). Yield 74%, orange crystals, mp 177–178°C.
IR spectrum, ν, cm–1: 3072, 3035 (CHarom); 2962, 2938,
2922, 2855 (CHaliph); 1755 (C=O); 1619, 1505, 1449
(C=Carom); 1224, 1149, 1107, 1032, 1015 (C–O); 848,
803 (CHarom). UV spectrum, λmax, nm (log ε): 213
1
(4.40), 345 (3.85), 312 (4.15), 326 (3.78). H NMR
spectrum, δ, ppm: 2.26 s (3H, Me), 2.29 s (3H, Me),
2.44 s (3H, Me), 6.70–8.00 m (7H, NH, CHarom). Mass
spectrum: m/z 324 [M]+. Found, %: C 66.98; H 5.17;
N 8.20. C18H16N2O4. Calculated, %: C 66.66; H 4.97;
N 8.64. M 324.33.
2-[2,4-Bis(propionyloxy)phenyl]-5-methyl-1H-
benzimidazole (Vc). Yield 75%, orange crystals, mp
96–97°C. IR spectrum, ν, cm–1: 3077, 3032 (CHarom);
2977, 2923, 2853 (CHaliph); 1761 (C=O); 1620, 1514,
1460 (C=Carom); 1261, 1146, 1130, 1075 (C–O); 805
(CHarom). UV spectrum, λmax, nm (log ε): 214 (4.40),
344 (3.85), 312 (4.15), 328 (3.90). H NMR spec-
trum, δ, ppm: 0.90–1.20 m (6H, 2Me), 2.04–2.30 m
(4H, 2CH2), 2.44 s (3H, Me), 6.72–8.04 m (7H, NH,
REFERENCES
1. Dikusar, E.A. and Potkin, V.I., Zh. Org. Khim., 2010,
vol. 46, p. 273.
2. Xiangming, Han, Huiqiang, Ma, and Yulu Wang, Zh. Org.
Khim., 2008, vol. 44, p. 872.
3. Migawa, M.T., Giradet, J.L., Walker, J.A., Koszalka, G.W.,
Chamberlain, S.D., Drach, J.C., and Townsend, L.B.,
J. Med. Chem., 1998, vol. 41, p. 1242.
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SYNTHESIS OF 2-[3-ALKOXY-4-(HYDROXY, ALKOXY, ACYLOXY)PHENYL]...
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