Int. J. Mol. Sci. 2017, 18, 1215
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.6.17. Synthesis of 1-(2-(1-(m-(1H-Tetrazol-5-Yl)Benzyl)-1H-Pyrrole-3-Carboxamido)Ethyl)
Guanidinium 2,2,2-Trifluoroacetate 17
From 17b (20 mg, 0.025 mmol) and TES (0.004 mL, 0.025 mmol) in TFA–DCM 95:5 (0.75 mL),
following the general procedure D (5 h) and after purification by semi-preparative HPLC (10–60%
ACN, 45 min), then lyophilization, final product 17 (7.89 mg, 68%) was obtained as a white solidwith
1
9
7
1
9% purity. Data for 17: H NMR (600 MHz, CD OD)
δ
7.95 (d, 1H, J = 7.8 Hz, Ar’), 7.90 (s, 1H, Ar’),
3
.57 (t, 1H, J = 7.8 Hz, Ar’), 7.43 (d, 1H, J = 7.8 Hz, Ar’), 7.41 (app dd, 1H, J = 2.4, 1.8 Hz, Ar), 6.85 (dd,
H, J = 3.0, 2.4 Hz, Ar), 6.56 (dd, 1H, J = 3.0, 1.8 Hz, Ar), 5.26 (s, 2H, CH Ar’), 3.47 (t, 2H, J = 6.0 Hz,
CH ), 3.36 (t, 2H, J = 6.0 Hz, CH ); C NMR (100 MHz, CD OD)
40.8 (C Ar’), 131.5 (CH), 131.1 (CH), 127.7 (CH), 127.2 (CH), 126.3 (C Ar’), 125.4 (CH), 123.7 (CH),
20.5 (C Ar), 109.4 (CH Ar), 54.0 (CH Ar’), 42.4 (CH ), 39.5 (CH ); ESI-MS m/z found for C H N O:
54.53 [M + H] ; RP-HPLC gradient separation from 10% to 100% acetonitrile at 30 min, flow rate:
mL/min, t = 17.7 min.
2
13
δ
168.6 (C=O), 159.0 (2
×
C=NH),
2
2
3
1
1
3
1
2
2
2
16 19
9
+
R
3
.6.18. Synthesis of N-[2-(2,3-Di-Tert-Butoxycarbonyl)Guanidinoethyl]-1-(p-Tert-Butoxycarbonyl
Methyl)Benzyl-1H-Pyrrole-3-Carboxamide 18b
From 1H-pyrrole 21 (168 mg, 0.66 mmol), NaH 60% (39.8 mg, 1.66 mmol) in DMF (6.6 mL), and
a solution of 18a, (189 mg, 0.66 mmol) in DMF (6.6 mL), following the general procedure A (2 h) and
after chromatographic purification (50–100% AcOEt-Et O), 18b (87.6 mg, 22%) was obtained as a white
2
1
solid). Data for 18b: H NMR (400 MHz, CDCl )
δ 11.49 (s, 1H, NH), 8.78 (s, 1H, NH), 7.46 (s, 1H, NH),
3
7
.31 (s, 1H, Ar), 7.22 (d, 2H, J = 8.0 Hz, Ar’), 7.07 (d, 2H, J = 8.0 Hz, Ar’), 6.57 (d, 2H, J = 2.0 Hz, Ar), 5.02
(
s, 2H, CH Ar), 3.67–3.71 (m, 2 H, CH ), 3.56 (br s, 2H, CH ), 3.50 (s, 2H, CH CO t-Bu), 1.51 (s, 9H, 3×
2
2
2
2
2
CH t-Bu),1.49 (s, 9H, 3× CH t-Bu), 1.43 (s, 9H, 3× CH t-Bu).
3
3
3
3
.6.19. Synthesis of 1-(2-(1-(p-(Carboxymethyl)Benzyl)-1H-Pyrrole-3-Carboxamido)Ethyl)
Guanidinium 2,2,2-Trifluoroacetate 18
From 18b (50 mg, 0.083 mmol) and TES (0.01 mL, 0.083 mmol) in TFA–DCM 95:5 (2.50 mL),
following the general procedure D (5 h) and after purification by semi-preparative HPLC (10–60%
ACN, 45 min), then lyophilization, final product 18 (23.2 mg, 61%) was obtained as a white
1
solidwith 98% purity. Data for 18
1
6
:
H NMR (600 MHz, CD OD)
δ
7.33 (app dd, 1H, J = 2.4,
6.78 (dd, 1H, J = 3.0, 2.4 Hz, Ar)
.52 (dd, 1H, J = 3.0, 1.8 Hz, Ar), 5.11 (s, 2H, CH Ar’), 3.59 (s, 2H, CH CO H), 3.46 (t, 2H, J = 6.0 Hz,
3
.8 Hz, Ar), 7.27 (d, 2H, J = 8.1 Hz, Ar’)
,
7.17 (d, 2H, J = 8.1 Hz, Ar’)
,
,
2
2
2
+
CH ), 3.35 (t, 2H, J = 6.0 Hz, CH ); ESI-MS m/z found for C H N O : 344.66 [M + H] ; RP-HPLC
2
2
17 21
5
3
gradient separation from 10% to 100% acetonitrile at 30 min, flow rate: 1 mL/min, t = 16.6 min.
R
3
.6.20. Synthesis of N-[2-(2,3-Di-Tert-Butoxycarbonyl)Guanidinoethyl]-1-(P-Methoxycarbonyl)
Benzyl-1H-Pyrrole-3-Carboxamide 19b
From 1H-pyrrole 21 (109 mg, 0.43 mmol), NaH 60% (25.8 mg, 0.65 mmol) in DMF (4.3 mL), and
a solution of 19a, (98.5 mg, 0.43 mmol) in DMF (4.3 mL), following the general procedure A (2 h)
and after chromatographic purification (50–100% AcOEt-Et O), 19b (103 mg, 44%) was obtained as
2
1
a white solid. Data for 19b: H NMR (400 MHz, CDCl )
δ 11.49 (s, 1H, NH), 8.73 (s, 1H, NH), 7.98
3
(d, 2H, J = 8.2 Hz, Ar’), 7.49 (s, 1H, NH), 7.31 (t, 1H, J = 1.8 Hz, Ar), 7.15 (d, 2H, J = 8.2 Hz, Ar’),
6
2
3
.56–6.60 (m, 2 H, Ar), 5.10 (s, 2H, CH Ar), 3.90 (s, 3H, OCH ), 3.67–3.71 (m, 2H, CH ), 3.55–3.57 (m,
2
3
2
H, CH ), 1.50 (s, 9 H, 3
×
CH t-Bu), 1.49 (s, 9H, 3
×
CH t-Bu); ESI-MS m/z found for C H N O :
3 27 37 5 7
2
3
+
44.60 [(M–2
×
Boc) + H] ; RP-HPLC gradient separation from 5% to 100% acetonitrile at 30 min, flow
rate: 1 mL/min, t = 25.7 min.
R