B.L. Oliveira et al. / Journal of Organometallic Chemistry 696 (2011) 1057e1065
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0
L3Boc (30 mg, 0.076 mmol) was dissolved in a mixture of TFA
(2 ml) and CH2Cl2 (1:1) and stirred at room temperature for 3 h.
L3 was obtained as colorless oil after purification by RP-HPLC.
Yield: 73.9% (23 mg, 0.056 mmol, calcd. for C14H29N7$TFA). 1H
NMR (D2O): d(ppm) 6.01 (s, pz, 1H), 4.38 (t, CH2, 2H), 3.53 (t, CH2,
2H), 3.51 (m, CH2, 2H), 3.38 (m, CH2, 2H), 3.27 (m, CH2, 2H), 3.03
2.19 (m, CHf2, 1H), 2.17 (m, CH2f , 1H). 13C NMR (CD3OD):
d(ppm) 197.3
(C^O), 196.7 (C^O), 195.5 (C^O), 164.9 (q, CF3COOꢁ), 158.5 (C]N),
156.5 (pz), 147.1 (pz), 118.0 (q, CF3COOꢁ), 110.5 (pz), 65.7, 63.9, 55.4,
49.7, 44.9, 39.9, 25.2, 18.0 (CH3pz), 13.6 (CH3pz). ESI-MS (þ) (m/z):
552.2 [M]þ, calcd. for C16H27N7O3Re ¼ 552.1. Retention time
(analytical RP-HPLC, 220 nm): 19.0 min.
(m, CH2, 2H), 2.65 (s, CeNHeCH3, 3H), 2.15 (s, CH3pz, 3H), 2.08 (s,
CH3pz, 3H), 1.79 (m, CH2, 2H). 13C NMR (D2O):
d(ppm) 165.3 (q,
4.2.2.2. fac-[Re(CO)3(k3-L2)] (2). Starting from 17 mg (0.041 mmol)
of L2$TFA, a colorless oil formulated as 2 was obtained (15 mg,
CF3COOꢁ), 162.6 (C]N), 155.7 (pz), 148.4 (pz), 115.6 (q, CF3COOꢁ),
106.1 (pz), 51.4, 50.6, 49.2, 42.0, 37.3, 33.3, 26.6, 22.4, 11.0
(CH3pz), 9.3 (CH3pz). ESI-MS (þ) (m/z): 296.1 [M þ H]þ; calcd for
C14H29N7 ¼ 295.2. Retention time (analytical RP-HPLC, 220 nm):
15.0 min.
53.7%, calcd. for C16H27N7O4Re$TFA). 1H NMR (D2O):
d(ppm) 6.03
0
(s, pz(4), 1H), 5.07 (br s, NH, 1H), 4.28 (dd, CHa, 1H), 4.06 (m, CHa ,
0
1H), 3.64 (m, NH, 1H), 3.49 (m, CHg, 1H), 3.35e3.23 (m, CHg þ CHb,
0
2H), 3.20 (m, CHe þ CHe, 2H), 3.07 (m, CHd, 1H), 2.73 (m,
0
0
0
CHd þ CHc, 2H), 2.60 (m, CHb2 , 1H), 2.38 (m, CHc , 1H), 2.27 (s,
0
4.2.1.4. 1-(3-((2-aminoethyl)(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)
amino)propyl)-3-nitro-guanidine (L4) and methyl 3-((2-aminoethyl)
(2-(3,5-dimethyl-1H-pyrazol-1-yl)ethyl)amino)propylcarbamimido-
CH3pz, 3H), 2.15 (s, CH3pz, 3H), 2.10 (m, CHf2, 1H), 1.91 (m, CH2f ,
1H). 13C NMR (D2O):
d(ppm) 193.8 (C^O), 193.2 (C^O), 192.0
(C^O), 162.0 (q, CF3COOꢁ), 158.0 (C]N), 152.9 (pz), 143.5 (pz),
115.0 (q, CF3COOꢁ), 107.0 (pz), 63.6, 61.0, 52.4, 46.3, 41.4, 37.7, 23.4,
14.5 (CH3pz), 10.0 (CH3pz). ESI-MS (þ) (m/z): 567.9 [M]þ, calcd. for
thioate (L5). To
a stirred solution of pzC3NH2NH-Boc (80
mg, 0.235 mmol) in anhydrous EtOH were added NEt3 (145 mg,
1.41 mmol) and 2-methyl-1-nitro-2-thiopseudourea (95 mg,
0.706 mmol) prepared as described in supplementary material. The
reaction temperature was then raised to 40 ꢀC, and stirring
continued overnight under nitrogen. The solvent was evaporated
under reduced pressure, and the crude residue was purified by
a silica-gel column (CH2Cl2 to MeOH), giving L4Boc (55 mg,
0.128 mmol, 54.9%) and L5Boc (22 mg, 0.053 mmol, 22.7%) as pure
compounds. Boc-deprotection of L4Boc (35 mg, 0.082 mmol) and
L5Boc (20 mg, 0.048 mmol) with TFA, followed by RP-HPLC puri-
fication gave L4 (30 mg, 0.068 mmol, 83.0%, calcd. for
C13H26N8O2$TFA) and L5 (16 mg, 0.037 mmol, 78.1%, calcd. for
C14H29N7S$TFA), respectively.
C16H27N7O4Re
220 nm): 19.1 min.
¼
368.1. Retention time (analytical RP-HPLC,
4.2.2.3. fac-[Re(CO)3(k3-L3)] (3). Starting from 30 mg (0.073 mmol)
of L3$TFA, a colorless oil formulated as 3 was obtained (35 mg,
70.5%, calcd. for C17H29N7O3Re$TFA). 1H NMR (D2O):
d(ppm) 6.01 (s,
0
pz(4), 1H), 5.06 (br s, NH, 1H), 4.32 (dd, CHa, 1H), 4.02 (0m, CHa , 1H),
3.63 (m, NH, 1H), 3.50 (m, CHg, 1H), 3.39e3.26 (m, CHg 0 þ CHb, 2H),
0
3.18 (m, CHe þ CHe, 2H), 3.02 (m, CHd, 1H), 2.71 (m, CHd þ CHc, 2H),
0
0
2.66 (s, CeNHeCH3, 3H), 2.57 (m, CHb2 , 1H), 2.36 (m, CHc , 1H), 2.26
0
(s, CH3pz, 3H), 2.16 (s, CH3pz, 3H), 2.06 (m, CHf2, 1H), 1.87 (m, CH2f ,
1H). 13C NMR (D2O):
d(ppm) 193.7 (C^O), 193.3 (C^O), 192.0
L4: IR (KBr, cmꢁ1): 1711m, 1314w (NO2), 1213m, 1123m, 837w,
(C^O),162.4 (q, CF3COOꢁ), 161.9 (C]N),155.7 (pz),152.9 (pz),115.3
(q, CF3COOꢁ), 107.0 (pz), 63.7, 61.1, 52.5, 46.4, 41.4, 37.7, 26.7, 23.6,
14.5 (CH3pz), 10.1 (CH3pz). ESI-MS (þ) (m/z): 566.0 [M]þ, calcd. for
800w and 723w. 1H NMR (D2O):
d(ppm) 6.03 (s, pz, 1H), 4.42 (t,
CH2, 2H), 3.56 (t, CH2, 2H), 3.46 (m, CH2, 2H), 3.32 (m, CH2, 2H),
3.18 (t, CH2, 2H), 3.09 (m, CH2, 2H), 2.17 (s, CH3pz, 3H), 2.10 (s,
C17H29N7O3Re
220 nm): 19.2 min.
¼
566.1. Retention time (analytical RP-HPLC,
CH3pz, 3H), 1.84 (m, CH2, 2H). 13C NMR (D2O):
d(ppm) 162.9 (q,
CF3COOꢁ), 158.3 (C]N), 147.9 (pz), 144.2 (pz), 115.4 (q,
CF3COOꢁ), 106.7 (pz), 50.6, 49.1, 41.6, 37.1, 33.0, 22.3, 22.0, 10.4
(CH3pz), 9.3 (CH3pz). ESI-MS (þ) (m/z): 327.0 [M þ H]þ; calcd
for C13H26N8O2 ¼ 326.2. Retention time (analytical RP-HPLC,
220 nm): 16.2 min.
4.2.2.4. fac-[Re(CO)3(k3-L4)] (4). Starting from 20 mg (0.045 mmol)
of L4$TFA, a colorless oil formulated as 4 was obtained (25 mg,
78.2%, calcd. for C16H26N8O5Re$TFA). 1H NMR (CD3OD):
d(ppm)
5.99 (s, pz(4), 1H), 0 5.35 (br s, NH, 1H), 4.32e4.23 (dd, CHa, 1H),
4.07e4.00 (m, CHa , 1H), 3.63 (m, NH, 1H), 3.48 (m, CHg, 1H),
L5: IR (KBr, cmꢁ1): 1703m, 1208m, 1127m, 839w and 801w. 1H
0
0
NMR (D2O):
d
(ppm) 5.85 (s, pz, 1H), 3.99 (t, CH2, 2H), 3.07 (t, CH2,
3.36e3.20 (m, CHg þ CHb,02H), 3.20e3.10 (m, CHe þ0 CHe, 2H), 3.00
2H), 2.92 (m, CH2, 2H), 2.86 (m, CH2, 2H), 2.76 (m, CH2, 2H), 2.48 (m,
CH2, 2H), 2.44 (s, SCH3, 3H), 2.13 (s, CH3pz, 3H), 2.07 (s, CH3pz, 3H),
(m, 0CHd, 1H), 2.67 (m, CHd þ CHc, 2H), 2.54 (m, CHb2 , 1H), 2.32 (m,
CHc , 1H), 2.22 (s, CH3pz, 3H), 2.11 (s, CH3pz, 3H), 2.10 (m, CHf2, 1H),
0
1.58 (m, CH2, 2H). 13C NMR (D2O):
d(ppm) 168.2 (C]N), 147.9 (pz),
1.90 (m, CHf2, 1H). 13C NMR (CD3OD):
d
(ppm) 196.7 (C^O), 196.2
141.0 (pz), 104.9 (pz), 51.5, 49.8, 49.6, 44.9, 40.8, 36.0, 23.5, 12.5, 11.4
(CH3pz), 9.4 (CH3pz). ESI-MS (þ) (m/z): 313.21 [M þ H]þ; calcd for
C14H28N6S ¼ 312.21. Retention time (analytical RP-HPLC, 220 nm):
11.4 min.
(C^O), 195.0 (C^O), 161.4 (C]N), 155.9 (pz), 145.5 (pz), 110.1 (pz),
66.9, 64.0, 55.5, w49.0 (overlapped with CD3OD solvent peak),
44.4, 40.8, 26.0, 17.5, 13.1. ESI-MS (þ) (m/z): 597.0 [M]þ, calcd. for
C26H26N8O5Re
¼
597.1. Retention time (analytical RP-HPLC,
220 nm): 19.9 min.
4.2.2. General procedure for the preparation of fac-[Re(CO)3(k3-L)]
(1, L ¼ L1; 2, L ¼ L2; 3, L ¼ L3; 4, L ¼ L4; and 5, L ¼ L5)
[Re(CO)3(H2O)3]Br reacted with equimolar amounts of L1eL5 in
refluxing MeOH for 18 h. The solvent was removed under vacuum,
and the resulting residue dissolved in water and purified by
preparative RP-HPLC.
4.2.2.5. fac-[Re(CO)3(k3-L5)] (5). Starting from 13 mg (0.030 mmol)
of L5$TFA, a colorless oil formulated as 5 was obtained (35 mg,
73.3%, calcd. for C17H28N6O3ReS$TFA). 1H NMR (D2O):
d(ppm) 6.04
0
(s, pz(4), 1H), 5.03 (br s, NH, 1H), 4.39 (dd, CHa, 1H), 4.07 (m, CHa ,
0
1H), 3.78 (m, NH, 1H), 3.054 (m, CHg, 1H), 3.48e3.28 (m, CHg þ CHb,
2H), 3.28e3.19 (m, CHe þ CHe, 2H), 3.03 (m, CHd, 1H), 2.74 (m,
0
0
0
4.2.2.1. fac-[Re(CO)3(k3-L1)] (1). Starting from 18 mg (0.035 mmol)
of L1$2TFA, a colorless oil formulated as 1 was obtained (22 mg,
CHd þ CHc, 2H), 2.59 (m, CH2b , 1H), 2.45 (s, SCH3, 3H), 2.37 (m, CHc ,
1H), 2.27 (s, CH3pz, 3H), 2.15 (s, CH3pz, 3H), 2.14 (m, CHf2, 1H), 1.97
0
80.6%, calcd. for C16H27N7O3Re$2TFA). 1H NMR (CD3OD):
d
(ppm) 6.21
(m, CHf2, 1H). 13C NMR (D2O):
d
(ppm) 191.7 (C^O), 191.2 (C^O),
0
(s, pz(4),1H), 5.57 (br s, NH,1H), 4.50 (dd, CHa,1H), 4.22 (m, CHa ,1H),
189.9 (C^O), 161.9 (C]N), 150.9 (pz), 141.4 (pz), 105.0 (pz), 61.4,
58.9, 50.3, 44.3, 39.4, 38.4, 21.4, 12.5, 10.4, 8.02. ESI-MS (þ) (m/z):
583.0 [M]þ, calcd. for C17H28N6O3SRe ¼ 581.1. Retention time
(analytical RP-HPLC, 220 nm): 19.6 min.
0
4.10 (m, NH, 1H), 3.71 (m, CHg,1H), 3.47 (m, CHg þ CHb, 2H), 3.20 (m,
0
0
CHe0 þ CHe, 2H), 3.14 (m, CHd, 1H), 2.84 (m, CHd þ CHc, 2H), 2.69 (m,
0
CHb2 , 1H), 2.55 (m, CHc , 1H), 2.44 (s, CH3pz, 3H), 2.36 (s, CH3pz, 3H),