Arkivoc 2017, iii, 63-72
Baranov, V.V. et al.
Experimental Section
General. All reagents were purchased from commercial sources and used without treatment, unless
1
13
otherwise indicated. The product were purified by recrystallization. H and C NMR spectra were
recorded on a Bruker AM-300 spectrometer (300,13 and 75,13 MHz, respectively) in DMSO-d with TMS as
6
internal standard. MS and ESI were recorded using Kratos MS-30 and Bruker MicrOTOF II mass
spectrometers respectively. Elemental analyses were performed on a Perkin Elmer 2400 Elemental CHN
analyzer and Euro EA elemental Analyzer.
N-[2-(5-Oxo-3a,6a-diphenyl-2-thioxotetrahydro-2H-imidazo[4,5-d]oxazol-6(6aH)-yl)ethyl]acetamide
(1d).
AcOH (3.00 ml) was added to a solution of the imidazolone 5a (1.35 g, 4 mmol) and KSCN (0.44 g, 4.5 mmol) in
MeCN (17 ml) at r.t., and the mixture was refluxed for 1h. The mixture was allowed to cool to r.t. and kept for
1
2
4 h to give a precipitate 1d. Colorless crystals (0.68 g, 27%), mp 250-252 °C. H-NMR (300 MHz, DMSO-d
6
): δ
1
.74 (s, 3 H, Ac), 2.76 – 2.90 (m, 1 H, CH
2
), 3.08 – 3.29 (m, 2 H, CH
2
), 3.30 – 3.44 (m, 1 H, CH
2
), 6.89 – 7.10 (m, 4
13
H, Ph), 7.11 – 7.22 (m, 6 H, Ph), 7.82 (t, 1 H, J 5.1 Hz, NH), 9.02 (s, 1 H, NH), 11.52 (s, 1 H, NH). C-NMR (75
MHz, DMSO-d ): δ 22.58 (Me), 37.40, 40.47 (CH ), 83.51 (C-O), 106.66 (C-N) 126.82, 126.87, 127.92, 128.25,
28.95, 129.34, 132.12, 134.58 (Ph), 157.98, 169.18 (C=O), 187.16 (C=S). HRMS (EI): m/z calcd for
6
2
1
C
+
20 20
H N
4
O S+H : 397.1329; found: 397.1321.
3
General procedure for the synthesis of N-[2-(5-hydroxy-2-oxo-4,5-diphenyl-2,5-dihydro-1H-imidazol-1-yl)-
ethyl]acetamide (5a) and N-[3-(5-hydroxy-2-oxo-4,5-diphenyl-2,5-dihydro-1H-imidazol-1-yl)propyl]acet-
amide (5b). 63% aq. HNO
mmol) in MeCN (25 ml). The reaction was monitored by the dissolution of the precipitated 7 and by the
change in color of the solution. The mixture was then extracted with 1:1 CHCl /H O, the CHCl layer was
evaporated (for 5b), and the product 5a was crystallized from CHCl
3
(5ml) was added dropwise to a suspension of the appropriate imidazolinone 7a,b (4
3
2
3
3
.
N-[2-(5-Hydroxy-2-oxo-4,5-diphenyl-2,5-dihydro-1H-imidazol-1-yl)ethyl]acetamide (5a). White solid (0.86 g,
1
2
3
6
3
4%), mp 275-276 °C. H-NMR (300 MHz, DMSO-d
6
3
): δ 1.72 (s, 3 H, Ac), 2.82 (dt, 1 H, J 13.7 Hz, J 6.7 Hz, CH
2
),
2
.00 – 3.13 (m, 2 H, CH
2
), 3.27 (dt, 1 H, J 13.7 Hz, J 7.2 Hz, CH
2
), 7.30 – 7.48 (m, 7 H, Ph), 7.53 – 7.58 (m, 1 H,
3
13
Ph), 7.74 (t, 1 H, J 5.6 Hz, NH), 7.82 (s, 1 H, OH), 7.07 – 8.05 (m, 2 H, Ph). C-NMR (75 MHz, DMSO-d
6
): δ 22.51
), 92.88 (C-OH), 125.21, 128.57, 128.76, 128.90, 129.01, 129.66, 133.45, 136.80 (Ph),
63.81, 169.50 (C=O), 186.34 (C=N). MS: m/z (%) 337 (40), 323 (2), 305 (3), 278 (90), 265 (16), 253 (12), 237
: C: 67.64; H:
(
1
(
Me), 38.22, 38.47 (CH
2
11), 209 (54), 194 (65), 180 (68), 166 (28), 131 (6), 104 (45), 85 (100). Anal. calcd for C19
19
H N
O
3 3
5
.68; N: 12.46; found: C: 67.67; H: 5.66; N: 12.42.
N-[3-(5-Hydroxy-2-oxo-4,5-diphenyl-2,5-dihydro-1H-imidazol-1-yl)propyl]acetamide (5b). Yellowish solid
1
(
CH
1.00 g, 71%), mp 85-87 °C. H-NMR (300 MHz, DMSO-d
6
): δ 1.30 – 1.46 (m, 1 H, CH
), 2.88 – 2.98 (m, 2 H, CH ), 3.14 – 3.26 (m, 1 H, CH
m, 7 H, Ph), 7.51 – 7.58 (m, 1 H, Ph), 7.75 – 7.85 (m, 2 H, NH+OH), 7.82 (1H, s, OH), 7.98 - 8.04 (m, 2 H, Ph).
2
), 1.47 – 1.60 (m, 1 H,
2
), 1.76 (s, 3 H, Ac), 2.76 – 2.87 (m, 1 H, CH
2
2
2
), 7.33 – 7.48
(
1
3
C-NMR (75 MHz, DMSO-d
6
): δ 22.59 (Me), 28.54, 36.47, 37.10 (CH ), 92.99 (C-OH), 125.20, 128.73, 128.83,
2
1
C
28.96, 129.09, 129.73, 133.47, 137.13 (Ph), 163.78, 169.17 (C=O), 186.26 (C=N). HRMS (EI): m/z calcd for
+
20 21
H N
3
O
3
+H : 352.1656; found: 352.1649.
General procedure for the synthesis of N-[2-(2-oxo-4,5-diphenyl-2,3-dihydro-1H-imidazol-1-yl)ethyl]-
acetamide (7a) and N-[3-(2-oxo-4,5-diphenyl-2,3-dihydro-1H-imidazol-1-yl)propyl]acetamide (7b): To a
mixture of corresponding N-(aminoalkyl)acetamide (9a,b) (30 mmol) and paraformaldehyde (1.28 g, 40 mmol),
MeOH (50 mL) was added. The reaction mixture was stirred at room temperature for 24 h and was then
evaporated to dryness. The obtained mixture was dissolved in MeOH (50 mL), and 2-(hydroxyimino)-1,2-
diphenylethanone (10) (6.36 g, 30 mmol) was added. The reaction mixture was refluxed for 3 h. After that, it
was evaporated to dryness. The obtained mixture was added CHCl
3
(20 mL), a solution of Ac O (6.4 mL, 62.5
2
mmol) in CHCl (10 mL) was added dropwise over 30 min with cooling on an ice bath. The reaction mixture
3
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