4
254
T. Mizuno et al.
PAPER
From the viewpoint of practical and solvent-free produc- 1,3-Dimethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one (DMPU,
1
d)
tion of DMI (1a) and DMPU (1d), the present method is
very significant in terms of the use of easily available and
inexpensive carbon monoxide and oxygen and mild reac-
tion conditions (0.1 MPa, 20 °C).
Compound 1d was purified by short-column chromatography (sili-
1
6
ca gel, EtOAc–MeOH, 1:1) to give an oil; yield: 1.20 g (94%). For
the identification of 1d, IR, NMR and MS spectra of 1d were com-
pared with those of commercially available DMPU (1d).
IR (neat): 2933, 2860, 1635, 1523, 1446, 1402, 1317, 1252, 1216
–
1
Melting points were determined on a Mettler FP 5 instrument and
were uncorrected. FT-IR spectra were recorded on a Jasco FT/IR-
cm .
1
H NMR (300 MHz, CDCl ): d = 1.97 (quintet, J = 6.0 Hz, 2 H,
1
13
3
4
100 instrument. H and C NMR spectra were obtained on a Jeol
CH ), 2.92 (s, 6 H, 2 CH ), 3.24 (t, J = 6.0 Hz, 4 H, 2 CH ).
2
3
2
JNM-AL300 (300 MHz, 75 MHz) instrument relative to TMS. Both
LR-MS and HRMS were measured on a Jeol JMS-600 spectrome-
1
3
C NMR (75 MHz, CDCl ): d = 22.1, 35.5, 47.8, 156.7.
3
ter. Amines 2a–k, base (Et N, 1-methylpyrrolidine), Se (99.9%),
+
3
MS (EI, 70 eV): m/z (%) = 128 (100) [M ], 127 (29), 99 (37), 70
(31), 57 (28).
and THF were used as purchased. CO (99.9%) and O (99.9%) were
2
also used.
1
,3-Diethyl-3,4,5,6-tetrahydropyrimidin-2(1H)-one (1e)
1
,3-Dimethylimidazolidin-2-one (DMI, 1a) by Stoichiometric
Compound 1c was purified by short-column chromatography (silica
gel, EtOAc–MeOH, 1:1) to give an oil; yield: 1.24 g (80%).
Reaction; Typical Procedure
22
To a 100-mL flask, N,N¢-dimethylethylenediamine (2a, 3.2 mL, 30
mmol) and metallic Se (790 mg, 10 mmol) were added under argon.
Ambient pressure of CO was charged and vigorously stirred under
CO from a balloon (0.1 MPa) at 20 °C for 2 h. Then, the soln
changed from black to transparent and colorless. CO was purged
–
1
IR (neat): 2970, 2932, 2870, 1631, 1509, 1451, 1292, 1213 cm .
1H NMR (300 MHz, CDCl
1.94 (quintet, J = 5.9 Hz, 2 H, CH
): d = 1.09 (t, J = 7.0 Hz, 6 H, 2 CH
),
),
3
3
), 3.23 (t, J = 5.9 Hz, 4 H, 2 CH
2
2
3.37 (q, J = 7.0 Hz, 4 H, 2 CH
).
2
and O (0.1 MPa) was charged at 20 °C. The mixture was stirred un-
13
2
C NMR (75 MHz, CDCl ): d = 12.8, 22.4, 42.5, 44.9, 155.4.
3
der O from a balloon (0.1 MPa) at 20 °C for an additional 1 h. The
2
+
MS (EI, 70 eV): m/z (%) = 156 (59) [M ], 141 (100), 113 (36), 70
resulting soln was diluted with MTBE (100 mL) and metallic Se
was recovered by filtration. After evaporation of the solvent and pu-
rification by short-column chromatography (silica gel, EtOAc–
MeOH, 1:1), 1,3-dimethylimidazolidin-2-one, DMI (1a) was ob-
tained as an oil;16 yield: 1.03 g (90%). For the identification of 1a,
IR, NMR and MS spectra of 1a were compared with those of com-
mercially available DMI (1a).
(
41).
HRMS (EI, 70 eV): m/z calcd for C H ON : 156.1263; found:
156.1222.
8
16
2
1,1¢-Carbonyldipyrrolidine (1f)
Compound 1f was purified by short-column chromatography (silica
gel, EtOAc–MeOH, 1:1) to give an oil; yield: 1.69 g (100%).
1
9
–
1
IR (neat): 2940, 2865, 1698, 1507, 1444, 1397, 1291, 1249 cm .
–
1
1
IR (neat): 2966, 2871, 1631, 1412, 1339 cm .
H NMR (300 MHz, CDCl ): d = 2.79 (s, 6 H, 2 CH ), 3.27 (s, 4 H,
3
3
1
2
CH2).
H NMR (300 MHz, CDCl ): d = 1.80–1.85 (m, 8 H, 4 CH ), 3.35–
3 2
1
3
3.39 (m, 8 H, 4 CH2).
C NMR (75 MHz, CDCl ): d = 31.3, 44.9, 161.9.
3
1
3
+
C NMR (75 MHz, CDCl ): d = 25.5, 47.9, 161.4.
MS (EI, 70 eV): m/z (%) = 114 (100) [M ], 113 (70), 85 (20), 72
16), 58 (22), 56 (34).
3
+
(
MS (EI, 70 eV): m/z (%) = 168 (68) [M ], 98 (70), 70 (100), 55 (63).
HRMS (EI, 70 eV): m/z calcd for C H ON : 168.1263; found:
9
16
2
1
,3-Diethylimidazolidin-2-one (1b)
1
68.1236.
Compound 1b was purified by short-column chromatography (sili-
ca gel, EtOAc–MeOH, 1:1) to give an oil; yield: 1.37 g (96%).
1
6
1
,1¢-Carbonyldipiperidine (1g)
–
1
IR (neat): 2975, 2934, 2873, 1689, 1496, 1452, 1265 cm .
Compound 1g was purified by short-column chromatography (sili-
ca gel, EtOAc) to give an oil; yield: 1.96 g (100%).
1
9
1
H NMR (300 MHz, CDCl ): d = 1.10 (t, J = 7.2 Hz, 6 H, 2 CH ),
3
3
–
1
3
.24 (q, J = 7.2 Hz, 4 H, 2 CH ), 3.28 (s, 4 H, 2 CH ).
IR (neat): 2932, 2851, 1645, 1415, 1370, 1250, 1212 cm .
2
2
1
3
1
C NMR (75 MHz, CDCl ): d = 12.7, 38.7, 42.1, 161.0.
H NMR (300 MHz, CDCl ): d = 1.53–1.56 (m, 12 H, 6 CH ), 3.16–
3
3
2
+
3.18 (m, 8 H, 4 CH ).
2
1
MS (EI, 70 eV): m/z (%) = 142 (54) [M ], 127 (100), 99 (19), 56
(
3
39).
C NMR (75 MHz, CDCl ): d = 24.7, 25.7, 47.9, 164.8.
3
+
HRMS (EI, 70 eV): m/z calcd for C H ON : 142.1106; found:
MS (EI, 70 eV): m/z (%) = 196 (30) [M ], 112 (19), 84 (100), 69
(21).
7
14
2
1
42.1067.
HRMS (EI, 70 eV): m/z calcd for C H ON : 196.1576; found:
1
1
20
2
1
,3-Diisopropylimidazolidin-2-one (1c)
1
96.1537.
Compound 1c was purified by short-column chromatography (silica
gel, EtOAc–MeOH, 1:1) to give an oil; yield: 1.00 g (59%).
1
6
4
,4¢-Carbonyldimorpholine (1h)
–
1
IR (neat): 2971, 1677, 1489, 1434, 1271, 1224 cm .
Compound 1h was purified by short-column chromatography (sili-
1
ca gel, EtOAc–MeOH, 1:1); yield: 1.70 g (85%); mp 142.2 °C
H NMR (300 MHz, CDCl ): d = 1.10 (d, J = 6.8 Hz, 12 H, 4 CH ),
3
3
2
3
(
Lit. 141–142 °C).
3
.22 (s, 4 H, 2 CH ), 4.14 (septet, J = 6.8 Hz, 2 H, 2 CH).
2
–
1
1
3
IR (KBr): 2974, 2857, 1647, 1414, 1263, 1236 cm .
C NMR (75 MHz, CDCl ): d = 19.4, 37.2, 43.3, 160.1.
3
1
+
H NMR (300 MHz, DMSO-d ): d = 3.12 (t, J = 4.6 Hz, 8 H, 4
MS (EI, 70 eV): m/z (%) = 170 (20) [M ], 155 (100), 113 (38).
6
CH ), 3.54 (t, J = 4.6 Hz, 8 H, 4 CH ).
2
2
HRMS (EI, 70 eV): m/z calcd for C H ON : 170.1419; found:
1
9
18
2
1
3
C NMR (75 MHz, DMSO-d ): d = 46.8, 65.8, 163.0.
70.1392.
6
Synthesis 2010, No. 24, 4251–4255 © Thieme Stuttgart · New York