Total Synthesis of Gallinamide A
FULL PAPER
purified by column chromatography (eluent: 2:1 v/v EtOAc/Hexane) to
(d, 1H, J=8.0 Hz, NH), 6.22 (d, 1H, J=8.0 Hz, NH), 5.16 (dd, 1H, J=
9.2, 4.0 Hz, CH), 5.03 (s, 1H, CH), 4.72 (m, 1H, CH), 4.61 (q, 1H, J=
f
afford 21 as a colorless oil (192 mg, 94%). R =0.2 (1:1 v/v EtOAc/
2
D
5
1
Hexane); ½aꢀ = +53 (c=0.3, MeOH); H NMR (500 MHz, CD
3
OD)
6.4 Hz, CH), 4.43 (m, 1H, CH), 3.87 (s, 3H, CH
10.4 Hz, CH), 2.31 (s, 6H, 2ꢂCH ), 1.90–1.52 (m, 8H, 3ꢂCH
1.49 (d, 3H, J=6.4 Hz, CH ), 1.30 (d, 3H, J=6.8 Hz, CH ), 1.16 (m, 1H,
CH), 1.00–0.85 ppm (m, 18H, 6ꢂCH ); C NMR (100 MHz, CDCl ) d=
3
), 2.94 (d, 1H, J=
d=7.39 (d, 1H, J=15.5 Hz, CH), 6.96 (dd, 1H, J 15.5, 5.0, CH), 5.20 (s,
3
2
, 2ꢂCH),
1
3
1
H, CH), 4.68–4.61 (m, 2H, 2ꢂCH), 4.13 (dd, 1H, J=9.8, 5.5 Hz, CH),
.93 (s, 3H, OCH ), 1.70 (m, 1H, CH), 1.62–1.45 (m, 14H, 4ꢂCH , CH ),
.30 (d, 1H, J=3.5 Hz, CH ); C NMR
/CD OD) d=181.1, 172.8, 170.2, 164.6, 156.1,
3
3
1
3
3
3
2
3
3
1
3
), 0.95 ppm (m, 6H, 2ꢂCH
3
180.8, 171.2, 170.7, 170.6, 169.8, 164.3, 148.3, 122.5, 93.1, 72.6, 72.6, 58.9,
55.8, 51.6, 46.3, 41.8, 41.0, 41.0, 33.6, 25.3, 24.9, 24.6, 23.3, 23.1, 22.1, 21.6,
20.1, 17.2, 15.9, 10.6 ppm; IR (thin film) n˜ =3287, 2958, 2927, 2917, 2876,
3
(
100 MHz, 5:1 v/v CDCl
3
3
1
1
1
48.7, 122.0, 92.7, 79.9, 58.8, 55.8, 52.8, 45.9, 41.6, 28.1, 24.6, 22.8, 21.6,
ꢁ1
9.4, 16.9 ppm; IR (thin film) n˜ =3302, 2975, 2934, 1670, 1625, 1528,
1728, 1652, 1628, 1550, 1460, 1378, 1351, 1328 cm . HRMS (ESI): m/z
ꢁ
1
+
+
454, 1356, 1328 cm ; MS (ESI) m/z (%): 460 (100) [M+Na] ; HRMS
53 4 7
calcd for C31H N O [M+H] : 593.3909; found: 593.3904.
+
(
ESI): m/z calcd for
C
22
H
35
N
3
O
6
Na [M+Na] : 460.2418; found:
Me N-l-allo-Ile-Hic-Leu-Apa-pyAla-OMe (5a): Amino ester 6b was con-
2
4
60.2423.
N-l-Leu-Apa-pyAla-OMe (7): Boc-protected fragment 21
181 mg, 0.41 mmol), was dissolved in 1:1 v/v TFA/DCM (5 mL). The re-
densed with fragment 7 (18.0 mg, 39.9 mmol) according to the general
procedure. The product was purified by preparative reverse phase HPLC
(gradient: 0–60% MeCN over 40 min) to afford 18b as the trifluoroace-
TFA·H
(
2
action was stirred for 5 min before the reaction was concentrated in
vacuo. The residue was purified by preparative reverse phase HPLC (gra-
dient: 0–60% MeCN over 40 min) to afford 7 as an amorphous white
tate salt as a white amorphous solid (28.3 mg, quant). R
t
=21.2 min (gra-
2
5
dient: 0–100% MeCN over 30 min); ½aꢀ
=ꢁ101 (c=0.06, MeOH);
D
1
3
H NMR (400 MHz, CDCl ) d=7.38 (dd, 1H, J=15.6, 1.2 Hz, CH),
solid (183 mg, 98%).
R
t
=16.4 min (gradient: 0–100% MeCN over
6.97–6.93 (m, 2H, CH, NH), 6.45 (d, 1H, J=8.0 Hz, NH), 5.11 (dd, 1H,
J=9.6, 4.0 Hz, CH), 5.03 (s, 1H, CH), 4.71 (m, 1H, CH), 4.60 (q, 1H, J=
2
5
1
3
0 min); m.p.=176–1788C; ½aꢀ = +31.2 (c=0.4, CHCl
3
); H NMR
OD) d=7.41 (dd, 1H, J=15.4, 1.6 Hz, CH), 6.98 (dd,
H, J=15.6, 4.8 Hz, CH), 5.20 (s, 1H, CH), 4.71 (m, 1H, CH), 4.64 (q,
H, J=6.7 Hz, CH), 3.92 (s, 1H, OCH ), 3.87 (m, 1H, CH), 1.90–1.70
), 1.46 (d, 3H, J=6.4 Hz, CH ), 1.35 (d, 3H, J=7.2 Hz,
), 1.07–0.99 ppm (m, 6H, 2ꢂCH3); C NMR (100 MHz, CD OD)
D
6
.4, CH), 4.47 (m, 1H, CH), 3.86 (s, 3H, CH
NH), 2.95 (s, 6H, 2ꢂCH ), 2.03 (m, 1H, CH), 1.84 (m, 1H, CHH), 1.73–
, CHH), 1.54–1.48 (m, 1H, CH), 1.48 (d, 3H, J=
), 1.30 (d, 3H, J=6.8 Hz, CH ), 1.26–1.17 (m, 1H, CH), 1.15
3
), 3.81 (d, 1H, J=8.8 Hz,
(
400 MHz, CD
3
1
1
3
1
6
.57 (m, 5H, 2ꢂCH
.8 Hz, CH
2
3
(
m, 3H, CH, CH
2
3
3
3
1
3
1
3
3 3
(d, 3H, J=6.8 Hz, CH ), 0.98–0.89 ppm (m, 15H, 5ꢂCH ); C NMR
CH
3
3
(
1
100 MHz, CDCl
22.6, 93.1, 74.9, 72.1, 58.9, 55.9, 52.0, 46.4, 41.5, 40.6, 40.6, 34.2, 25.4,
24.8, 24.8, 23.1, 21.9, 21.4, 20.0, 17.2, 15.2, 11.0 ppm; IR (thin film) n˜ =
3
) d=181.0, 171.3, 170.0, 169.3, 166.1, 164.3, 148.0,
d=183.0, 171.7, 170.1, 165.6, 149.4, 123.1, 93.7, 59.8, 57.0, 53.1, 47.6, 41.9,
2
1
3
3
5.5, 23.2, 21.8, 19.9, 17.4 ppm; IR (thin film) n˜ =3294, 3080, 2960, 1720,
ꢁ
1
660, 1618, 1553, 1512, 1457, 1372, 1344, 1332 cm ; MS (ESI) m/z (%):
ꢁ1
+
+
3313, 2960, 2873, 1728, 1654, 1627, 1546, 1455, 1353, 1328 cm ; MS (ESI)
m/z (%): 593 (100) [M+H] ; Trifluoroacetate salt 18b (7.5 mg,
38 (100) [M+H] ; HRMS (ESI): m/z calcd for C17
28 3 4
H N O : [M+H] ,
+
38.2074; found: 338.2076.
1
0.6 mmol) was converted to the free base according to the general proce-
General Procedure for fragment condensation with HATU: Imide frag-
ment 7 (18 mg, 40 mmol), amino ester fragment 6 (20 mg, 52 mmol) and
HATU (20 mg, 52 mmol) were dissolved in DMF (0.4 mL) before NMM
2
5
dure to afford 5a as a white amorphous solid (5.1 mg, 81%). ½aꢀ =ꢁ108
D
1
(
c=0.06, MeOH); H NMR (400 MHz, CDCl
3
) d=7.42 (dd, 1H, J=15.4,
1
.2 Hz, CH), 6.97 (dd, 1H, J=15.4, 5.2 Hz, CH), 6.39 (d, 1H, J=8.0 Hz,
NH), 6.18 (d, 1H, J=8.0 Hz, NH), 5.15 (dd, 1H, J=9.2, 4.0 Hz, CH),
.03 (s, 1H, CH), 4.72 (m, 1H, CH), 4.61 (q, 1H, J=6.4 Hz, CH), 4.43
m, 1H, CH), 3.87 (s, 3H, CH ), 2.91 (d, 1H, J=10.4 Hz, CH), 2.32 (s,
), 1.88–1.52 (m, 8H, 3ꢂCH , 2ꢂCH), 1.49 (d, 3H, J=6.8 Hz,
), 1.30 (d, 3H, J=6.8 Hz, CH ), 1.07 (m, 1H, CH), 0.99–0.88 ppm (m,
); C NMR (100 MHz, CDCl ) d=180.8, 171.2, 170.7, 170.6,
(
15 mL, 137 mmol) was added and the reaction was stirred for 2 h. The re-
action was subsequently diluted with 0.1% aqueous TFA and purified by
preparative reverse phase HPLC (gradient: 0–60% MeCN over 60 min).
5
(
3
General Procedure for neutralization of trifluoroacetate salts: The tri-
fluoroacetate salts of depsipeptides 18a–d (7.5 mg, 10 mmol) were dis-
6
H, 2ꢂCH
3
2
CH
3
3
solved in 9:1 v/v H
3 mmol) was added and the mixture was extracted into 3:1 v/v CHCl
iPrOH (3ꢂ10 mL). The combined extracts were dried (MgSO ) and con-
2
O/MeCN (1 mL), 0.05m aqueous NaOH (250 mL,
13
1
1
4
8H, 6ꢂCH
3
3
1
3
/
69.8, 164.3, 148.3, 122.5, 93.2, 73.1, 72.6, 58.9, 55.8, 51.6, 46.3, 41.6, 41.0,
1.0, 34.2, 26.5, 24.9, 24.6, 23.3, 23.2, 22.1, 21.6, 20.1, 17.3, 15.4, 11.4 ppm;
4
centrated in vacuo to an oil which was purified by preparative reverse
phase HPLC (gradient: 0–80% MeCN over 40 min; eluent A: water,
eluent B: MeCN).
IR (thin film) n˜ =3294, 2959, 2933, 2873, 1727, 1651, 1627, 1546, 1454,
ꢁ1
+
1
5
349, 1325 cm . HRMS (ESI): m/z calcd for C31
93.3909; found: 593.3913.
H
53
N
4
O
7
[M+H] :
Gallinamide A (2): Amino ester 6a was condensed with fragment 7
2
Me N-d-Ile-Hic-Leu-Apa-pyAla-OMe (5b): Amino ester 6c was con-
densed with fragment 7 (18.0 mg, 39.9 mmol) according to the general
(
17.0 mg, 37.7 mmol) according to the general procedure. The product
was purified by preparative reverse phase HPLC (gradient: 0–60%
MeCN over 40 min) to afford the trifluoroacetate salt of gallinamide A
procedure. The product was purified by preparative reverse phase HPLC
(
gradient: 0–60% MeCN over 40 min) to afford 18c as the trifluoroace-
1
0
8a as a white amorphous solid (24.4 mg, 92%). R
–100% MeCN over 30 min); ½aꢀ ꢁ47 (c=0.06, MeOH); H NMR
t
=19.8 min (gradient:
tate salt as a white amorphous solid (28.2 mg, quant). R =21.5 min (gra-
t
2
5
1
25
D
dient: 0–100% MeCN over 30 min); ½aꢀ =ꢁ97 (c=0.06, MeOH);
D
1
(
600 MHz, CDCl
3
) d=7.38 (dd, 1H, J=15.6, 1.2 Hz, CH), 7.21 (br d,
H NMR (400 MHz, CDCl ) d=7.36 (dd, 1H, J=15.6, 1.2 Hz, CH), 6.97
3
1
H, J=6.6 Hz, NH), 6.94 (dd, 1H, J=15.6, 4.8 Hz, CH), 6.26 (br d, 1H,
(m, 1H, NH), 6.94 (dd, 1H, J=15.4, 4.8 Hz, CH), 6.42 (d, 1H, J=7.6 Hz,
NH), 5.07 (dd, 1H, J=9.6, 4.0 Hz, CH), 5.03 (s, 1H, CH), 4.68 (m, 1H,
CH), 4.60 (q, 1H, J=6.8, CH), 4.48 (m, 1H, CH), 4.04 (d, 1H, J=6.4 Hz,
NH), 3.86 (s, 3H, CH ), 2.96 (s, 6H, 2ꢂCH ), 2.04 (m, 1H, CH), 1.86–
J=6.6 Hz, NH), 5.15 (dd, 1H, J=9.6, 4.8 Hz, CH), 5.04 (s, 1H, CH), 4.69
m, 1H, CH), 4.60 (q, 1H, J=6.6, CH), 4.44 (m, 1H, CH), 3.87 (s, 3H,
CH ), 3.81 (d, 1H, J=6.0 Hz, NH), 2.95 (s, 6H, 2ꢂCH ), 2.03 (m, 1H,
CH), 1.84 (m, 1H, CHH), 1.72–1.59 (m, 6H, CH , CHH, CHH, 2ꢂCH),
.48 (d, 3H, J=6.6 Hz, CH ), 1.38 (m, 1H, CH), 1.30 (d, 3H, J=6.6 Hz,
CH ), 1.07 (d, 3H, J=7.2 Hz, CH ), 1.00–0.91 ppm (m, 15H, 5ꢂCH );
C NMR (150 MHz, CDCl ) d=180.8, 171.1, 169.8, 169.3, 165.5, 164.1,
(
3
3
3
3
2
2 3
1.58 (m, 7H, 3ꢂCH , CH), 1.48 (d, 3H, J=6.8 Hz, CH ), 1.39 (m, 1H,
1
3
3 3
CH), 1.30 (d, 3H, J=6.8 Hz, CH ), 1.01–0.91 ppm (m, 18H, 6ꢂCH );
1
3
3
3
3
3
C NMR (100 MHz, CDCl ) d=181.0, 171.4, 170.0, 169.5, 167.4, 164.3,
1
3
3
148.1, 122.6, 93.1, 75.0, 69.9, 58.9, 55.9, 51.9, 46.4, 41.3, 40.6, 40.6, 34.2,
26.5, 24.9, 24.6, 23.1, 21.9, 21.4, 20.0, 17.2, 15.6, 11.2 ppm; IR (thin film)
1
5
2
1
62.0 (q, J=30 Hz), 147.9, 122.5, 116.3 (q, J=285 Hz), 92.9, 75.2, 71.6,
8.8, 55.7, 52.0, 46.2, 41.7, 40.8, 40.5, 34.0, 26.4, 24.7, 24.5, 22.8, 22.8, 21.8,
1.4, 19.9, 17.1, 14.8, 11.3 ppm; IR (thin film) n˜ =2962, 2928, 2874, 1725,
ꢁ
1
n˜ =3289, 2960, 2935, 2871, 1726, 1651, 1627, 1549, 1456, 1353, 1329 cm
;
+
MS (ESI) m/z (%): 593 (100) [M+H] ; Trifluoroacetate salt 18c
(15.0 mg, 21.2 mmol) was converted to the free base according to the gen-
eral procedure to afford 5b as a white amorphous solid (9.0 mg, 71%).
ꢁ1
671, 1624, 1546, 1458, 1326, 1292, 1181, 1133, 1057, 978 cm ; MS (ESI)
+
m/z (%): 593 (100) [M+H] ; Trifluoroacetate salt 18a (7.5 mg,
0.6 mmol) was converted to the free base according to the general proce-
dure to afford gallinamide A 2 as a white amorphous solid (5.4 mg,
2
5
1
1
½aꢀ =ꢁ67 (c=0.06, MeOH); H NMR (400 MHz, CDCl ) d=7.41 (dd,
D
3
1H, J=15.6, 1.6 Hz, CH), 6.97 (dd, 1H, J=15.6, 4.8 Hz, CH), 6.53 (d,
1H, J=8.4 Hz, NH), 6.25 (d, 1H, J=8.0 Hz, NH), 5.17 (dd, 1H, J=9.2,
4.0 Hz, CH), 5.03 (s, 1H, CH), 4.72 (m, 1H, CH), 4.61 (q, 1H, J=6.8 Hz,
2
D
5
1
8
7
6%). ½aꢀ =ꢁ56 (c=0.06, MeOH); H NMR (400 MHz, CDCl
3
) d=
.41 (d, 1H, J=15.6 Hz, CH), 6.97 (dd, 1H, J=15.6, 5.2 Hz, CH), 6.44
Chem. Eur. J. 2011, 17, 13544 – 13552
ꢁ 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
13551