426
L. A. Reznichenko et al.
TABLE 2. Yields and Characteristics of Nitro Compounds XIX – XXIII and XXV
IR spectrum*: nmax, cm – 1
UV spectrum (in
Compound
Empirical formula
M.p., °C
M+
ethanol): lmax
,
Yield, %
R
R¢
NH2
CO
NH
OH
nm (log e)
XIX
XX
C7H12N4O2
119 – 120**
172 – 174
113 – 115
94 – 96
184
198
240
268
296
323
1610
1660
1660
1650
1620
1650
3350, 3450
374(4.01)
92
60
85
78
67
84
CH3
CH3
H
C8H14N4O2
3260, 3400, 3445
3210, 3300, 3320
3200, 3320, 3420
3200, 3320, 3380
3200, 3320, 3420
CH3
XXI
XXII
XXIII
XXV
374(3.98)
373(3.95)
372(3.94)
C3H7
C2H5
i-C3H7
C4H9
i-C3H7
C11H20N4O2 × HCl
C13H24N4O2
C15H28N4O2
C17H33N5O
i-C4H9
C5H11
i-C4H9
97 – 98
124 – 125
*
Compound XIX measured in nujol mull; other compounds, in KBr disks.
In [7] compound XIX was obtained in the form of an oil.
**
respect to the initial acids I – VI. Methyl esters VII and VIII
were obtained from acids I and V as described in [8].
2-Hydroxyethylamides of 1-alkyl(1,2-dialkyl)-4-nitro-
imidazolyl-5-carboxylic acids (IX – XIV). M e t h o d A .
To 1-methyl-4-nitroimidazolyl-5-carboxylic acid chloroan-
hydride (Ia), prepared from 3.4 g (0.02 mole) of acid I and
dissolved in 50 ml of anhydrous benzene, was added
dropwise with stirring and cooling 7.3 g (0.06 mole) of
aminoethanol. The mixture was stirred for 2 h at 20 – 22°C
and allowed to stand for 10 – 12 h. Then benzene and resid-
ual aminoethanol were distilled off in vacuum, the residue
was washed with diluted hydrochloric acid, and the precipi-
tate was filtered, washed with water, and dried to obtain 3.3 g
(76%) of compound IX. A similar procedure was used to ob-
tain compounds XI – XIV.
aminoethanol was stirred for 30 min at 50 – 55°C, boiled for
2 h, and cooled. The precipitate was separated by filtration,
washed with benzene and water, and dried to obtain 3.9 g of
compound X.
M e t h o d C . A mixture of 1.85 g (0.01 mole) of ester
VII and 1.5 ml (0.02 mole) of aminoethanol in 20 ml of
methanol was boiled for 4 h, cooled, and poured into water.
The precipitate was separated by filtration, washed with wa-
ter, and dried to obtain 1.9 g (89%) of compound IX. A mix-
ture of this product with compound IX obtained by method A
showed no depression in the melting temperature. The IR
spectra of these substances were identical as well.
The same method was used to obtain amide XIII (yield,
85%) from ester VIII; the product was also identical to the
substance synthesized by method A.
M e t h o d B . A mixture of 5.5 g (0.022 mole) of techni-
cal-purity chloroanhydride IIa and 3.3 ml (0.05 mole) of
The general properties of compounds IX – XIV are as
follows: pale-yellow crystalline substances, insoluble in wa-
ter and soluble in organic solvents; do not form hydrochlor-
ides and picrates. Prior to analyses, these substances were
additionally purified by recrystallization from methanol.
2-Chloroethylamides of 1-alkyl(1,2-dialkyl)-4-nitro-
imidazolyl-5-carboxylic acids (XV – XVIII). To a suspen-
sion of 0.01 mole of the initial compound (IX, X, XII, XIII)
in 30 – 40 ml of anhydrous benzene were added dropwise
0.05 mole of thionyl chloride and 2 drops of DMF. The mix-
ture was stirred for 4 h at 65 – 70°C and cooled. The precipi-
tate was separated by filtration, washed with benzene, and
dried to obtain the target compound (XV – XVIII). The prod-
ucts appear as pale-yellow crystalline substances soluble in
organic solvents and insoluble in water; do not form hydro-
chlorides and picrates. Prior to analyses, these substances
were additionally purified by crystallization from methanol
(XV, XVIII), dioxane (XVI), and aqueous acetone (XVII).
2-Hydroxyethylamides of 1-alkyl(1,2-dialkyl)-4-ami-
noimidazolyl-5-carboxylic acids (XIX – XXIII). A solu-
tion of 0.02 mole of the initial compound (IX – XIV) in
130 – 150 ml of methanol was hydrogenated in the presence
of 1.0 – 1.5 g of a 5% carbon-supported palladium oxide cat-
alyst until hydrogen absorption ceased (1.5 – 2 h). Then the
catalyst was separated by filtration and washed with metha-
TABLE 3. Parameters of the 1H NMR Spectra of Compounds
IX – XI, XIII, XV – XVIII, and XX
Compound
IX
Chemical shift d, ppm*
3.68 (s, 3H, N–CH), 4.70 (t, 1H, J 6 Hz, O-H), 7.79 (s,
1H, 2-H), 888 (t, 1H, J 6 Hz, N–H)
X
2.38 (s, 3H, C–CH3), 3.4 (m, 4H, CH2-CH2), 3.64 (s, 3H,
N–CH3)
XI
4.65 (bs, 1H, O–H), 8.82 (bs, 1H, N–H)
0.85 (d, 6H, J 7 Hz, C2-CH(CH3)2), 1,3 (d, 6H, J 7 Hz,
CH(CH3)2), 4.05 (d, 2H, J 6 Hz, CH2-CH)
XIII
XV
3.7 (m, 7H, N–CH3 + CH2CH2), 7.81 (s, 1H, C2-H), 9.18
(bs, 1H, N–H)
XVI
2.42 (s, 3H, C–CH3), 3.59 (s, 3H, N–CH3)
XVII
1.0 (m, 7H, C–C3H7), 3.78 (m, 4H, N–CH2CH2), 4.11 (t,
2H, J 6 Hz, N–CH2), 13.0 (bs, 1H, N–H)
XVIII
XX
0.85 (d, 6H, J 6 Hz, C-(CH3)2)
2.42 (s, 3H, C–CH3), 3.86 (s, 3H, N–CH3), 3.6 (m, 4H,
CH2CH2), 7.3 (bs, 1H, NH or OH), 5.1 (bs, 2H, NH2)
*
1H NMR spectra of samples dissolved in DMSO-d6 (IX, X, XX),
DMF-d7 (XI, XV), CDCl3 (XII, XIII, XVII, XVIII), CF3COOD
(XVI).