JOURNAL OF CHEMICAL RESEARCH 2008 471
2 hours, anhydrous methanol (2 ml) was added and after 24 hours
at room temperature the reaction mixture was extracted with EtOAc
(3 u 20 ml). The combined organic extracts were washed with water
and dried over MgSO4, The solvent was removed using a rotary
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Table 2 Crystal data and structure refinement for 3b
Empirical formula
Formula weight
C20H27N3O4
372.94
Temperature, K
120(2)
0.71073
Wavelength, Å
1
the compound 6, as an oil Yield: 70%. H NMR (300 MHz, CDCl3)
Crystal system, space group
Unit cell dimensions
Monoclinic, P21/c
a = 24.9660(8)Å
b = 9.4872(2) Å,
E = 105.6980(10)d°
c = 16.7156(6) Å
3811.5(2) Å3
G: 7.36–7.26 (5H, m, Ph), 5.12 (2H, s, CH2Ph), 4.91(br) + 5.00(br)
[1H, H2], 4.08 (1H, m, H6eq), 3.73 (3H, s, CH3), 3.01 (1H, m, H6ax),
2.26–1.20 (6H, m, H3ax, H3eq, H4ax, H4eq, H5ax, H5eq) ppm. 13C NMR
(75 MHz, CDCl3) G: 172.3, 156.7, 136.8, 128.7, 128.2, 128.0, 67.5,
54.6, 52.4, 42.1, 26.9, 24.9, 20.9 ppm. Found: C, 64.8; H, 7.1; N, 4.9.
C15H19NO4 requires C, 65.0; H, 6.9; N, 5.05%.
Volume
Z
Density (calculated)
Absorption coefficient
F(000)
Crystal size
Theta range for data collection
Index ranges
4
1.300 Mg/m3
0.091 mm-1
1596
0.58ꢀuꢀ0.12ꢀuꢀ0.10 mm
3.06 to 27.48 deg.
–32< = h < = 21;
–12< = k < = 12;
–21< = l < = 21
39958
Crystallography
The sample was recrystallised from EtOH. Data were obtained at
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KappaCCDareadetectordiffractometeroftheEPSRCcrystallographic
service, based at the University of Southampton. Data collection
was carried out under the control of the program COLLECT30 and
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COLLECT30 and DENZO programs.31 Correction for absorption,
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applied using the program SADABS.32 The progam ORTEP-3 for
Windows33 was used in the preparation of the Figure and SHELXL-
9734 and PLATON27 in the calculation of molecular geometry. The
structure was solved by direct methods using SHELXS-9735 and
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Reflections collected
Independent reflections
Reflections observed (>2V)
Refinement method
8679 [R(int) = 0.0977]
4691
Full-matrix least-squares on F2
8679/0/494
Data/restraints/parameters
Goodness-of-fit on F2
Final R indices [I>2V(I)]
R indices (all data)
1.008
R1 = 0.0717 wR2 = 0.1556
R1 = 0.1477 wR2 = 0.1899
0.864 and –0.628 e. Å-3
Largest diff. peak and hole
,5ꢑꢀȞmax 1710 (CONH), 1680 (COM) cm-1. Found: C, 69.1; H, 8.1; N,
12.6. Calc. for C19H27N3O2: C, 69.3; H, 8.3; N, 12.75%.
1,3-Dicyclohexyl-1-(pyridine-3-carbonyl)-urea: (3d): (65%), m.p.
1
171.5°C. H NMR (500 MHz, CDCl3) G: 8.81 (1H, s, H2), 8.69 (d,
Jꢀ ꢀ ꢌꢃꢅꢀ +]ꢂꢀ ꢋ+ꢂꢀ +6), 7.91 (1H, d, Jꢀ ꢀ ꢍꢃꢅꢀ +]ꢂꢀ +4), 7.37 (1H, dd,
Jꢀ ꢀꢍꢃꢅꢀ+]ꢀDQGꢀꢌꢃꢅꢀ+]ꢂꢀ+5), 6.33 (1H, s, NH), 4.14 (1H, m, NCH),
3.48 (1H, m, NHCH), 0.8–2 (20H, m, cyclohexyl) ppm. 13C NMR
(100 MHz, CDCl3) G: 167.9, 153.6, 150.8, 147.5, 134.8, 133.1, 123.3,
56.9, 49.9, 33.9, 32.3, 30.8, 26.1, 25.6, 25.2, 25.1, 24.9, 24.6 ppm.
,5ꢑꢀȞmax 1695 (CONH), 1655 (CON) cm-1. Found: C, 69.1; H, 8.3;
N, 12.6 C19H27N3O2 requires C, 69.3; H, 8.3; N, 12.75%.
1,3-Dicyclohexyl-1-(pyridine-4-carbonyl)-urea
(3e):
(70%),
m.p.161.5°C. 1H NMR (500 MHz, CDCl3) G: 8.68 (2H, d, Jꢀ ꢀꢄꢃꢅꢂꢀ+5
and H6), 7.40 (2H, d, Jꢀ ꢀꢄꢃꢅꢂꢀ+2 and H3), 6.33 (1H, s, NH), 4.02 (1H,
m, NCH), 3.48 (1H, m, 1NHCH), 0.8–2.0 (20H, m, cyclohexyl) ppm.
13 C NMR (100 MHz, CDCl3) G: 168.6, 153.5, 150.1, 144.7, 120.9,
57.4, 50.0, 34.1, 32.3, 30.8, 26.3, 25.8, 25.4, 25.3, 25.1, 24.7 ppm.
,5ꢑꢀȞmax 1698 (CONH) and 1677 (CON) cm-1. Found: C, 69.2; H, 8.1;
N, 12.7 C19H27N3O2 requires C, 69.3; H, 8.3; N, 12.75%.
1,3-Dicyclohexyl-1-(pyrazinecarbonyl)-urea
(3f):
(68%),
m.p.164.5°C. 1H NMR (400 MHz, CDCl3) G: 8.99 (1H, d, Jꢀ ꢀꢋꢃꢄꢀ+]ꢂꢀ
H3), 8.65 (1H, d, Jꢀ ꢀꢐꢃꢎꢀ+]ꢂꢀ+6), 8.51 (1H, dd, Jꢀ ꢀꢐꢃꢎꢀ+]ꢀDQGꢀꢋꢃꢄꢀ+]ꢂꢀ
H5), 5.94 (1H, s, NH), 4.22 (1H, m, NCH), 3.56 (1H, m, NHCH),1.0–
2.0 (20H, m, cyclohexyl) ppm. 13C NMR (100 MHz, CDCl3)
G: 166.7, 154.2, 149.6, 146.6, 145.4, 143.2, 57.2, 50.6, 33.1, 31.4,
ꢐꢄꢃꢍꢂꢀꢐꢄꢃꢅꢂꢀꢐꢌꢃꢒꢂꢀꢐꢌꢃꢏꢀSSPꢃꢀ,5ꢑꢀȞmax 1702 (CONH), 1650 (CON) cm-1.
Found: C, 65.3; H, 8.0; N, 16.8. C18H26N4O2 requires C, 65.4; H, 7.9;
N, 16.9%.
N-(Benzyloxycarbonyl)-DL-pipecolic acid (5): A solution of benzyl
chloroformate (0.84 ml, 6 mmol) in THF (20 ml) was slowly added
to a solution of DL-pipecolic acid 4 (516 mg, 4 mmol) in 10% NaOH
(20 ml) at 0°C. After the addition of the reagent was complete, the
mixture was allowed to warm to room temperature, and kept for
2 hours. The reaction mixture was washed with Et2O (20 ml), and
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extracted with EtOAc (3ꢀuꢀ50 ml). The combined organic extracts
were washed with water, and dried over MgSO4. The solvent was
removed using a rotary evaporator to give the desired product as a
colourless solid (84%), m.p. 110°C. 1H NMR (300 MHz, CDCl3)
G: 8.13 (1H, s, OH), 7.36–7.26 (5H, m, Ph), 5.16 (2H, s, CH2Ph),
5.00(br) + 4.91(br) [1H, H2], 4.09 (1H, m, H6eq), 3.03 (1H, m, H6ax),
2.30–1.25 (6H, m, H3ax, H3eq, H4ax, H4eq, H5ax, H5eq) ppm. 13C NMR
(75 MHz, CDCl3) G: 177.4, 156.9, 136.7, 128.7, 128.2, 128.0, 67.7,
54.6, 42.1, 26.9, 24.8, 20.8 ppm. Found: C, 64.0; H, 6.5; N, 5.5.
C14H17NO4 requires C, 63.9; H, 6.5; N, 5.3%.
Fig. 2 Chains of molecules of 3b. (a) molecule 1, generated by
N6–H6---O5ii (b) molecule 2, generated by N106–H106---O105i:
symmetry operations: i = –1 – x, 1/2 + y, –1/2 – z; ii = –x, 1/2 +
y, –1/2 – z.
Methyl N-(benzyloxycarbonyl)-DL-pipecolate (6): DCC (177 mg,
0.86 mmol) and HOBt (catalytic amount) were added to a stirred
solution of 5 (205 mg, 0.78 mmol) in dry CH2Cl2 (20 ml). After