2
t
further purification. PyBOP (484 mg, 0.93 mmol) was added
to a solution of the free acid (300 mg, 0.62 mmol) and glycine
methyl ester hydrochloride (117 mg, 0.93 mmol) in 20 mL of
DMF at 0 ◦C, and the pH of the solution adjusted to 7–8 with
DIPEA. The mixture was stirred overnight at room temperature.
The solvent was evaporated and the remaining brown oil was
purified by column chromatography with ethyl acetate–toluene
(3 : 1) as the eluant to yield product 11 (280 mg, 89%) as a
colourless powder. mmax(KBr)/cm−1 3281, 3089, 3033, 2986, 2953,
2875, 2110, 1752, 1668, 1642, 1407, 1382, 1277, 1229, 1217, 1155,
(s, 1H, 9a-H), 4.88 (d, JBn = 11.1 Hz, 1H, Ph-CH2 ), 4.84 (d,
proR
2
3J3-H,2
= 7.5 Hz, 1H, 3-H), 4.69 (d, JBn = 11.1 Hz, 1H,
-H
Ph-CH2 ), 4.65 (d, 3J6-H,7-H = 10.8 Hz, 1H, 6-H), 4.23 (d, 3J9-H,8-H
=
h
2.3 Hz, 1H, 9-H), 4.06 (dd, J8-H,7-H = 8.8 Hz,3J8-H,9-H = 2.3 Hz,
1H, 8-H), 3.80 (dd, 3J7-H,8-H = 8.8 Hz,3J7-H,6-H = 10.8 Hz, 1H, 7-H),
3
3.47 (dd, JaGly–H = 17.0 Hz,3JaGly-H
= 5.4 Hz, 1H, Gly-Ht),
2
t
,N-H
3.41 (dd, 2J2
= 11.4 Hz, 3J2
= 7.5 Hz, 1H,
proR
proS
2
proR
-H,2
-H
-H,3-H
2proR-H), 3.39 (dd, JaGly-H = 17.0 Hz,3JaGly-H
= 4.5 Hz, 1H,
h
,N-H
Gly-Hh), 2.94 (d,2J2
-H = 11.4 Hz, 1H, 2proS-H), 1.41 (s, 3H,
proS
proR
-H,2
t
h
isopr.-CH3 ), 1.38 (s, 3H, isopr.-CH3 ); dC(150 MHz, DMSO[d6])
170.6 (aGly-CO), 168.2 (3-CO), 165.2 (5), 138.1, 128.33, 127.7,
127.6 (Ar), 108.5 (isopr.quat.), 81.8 (8), 80.2 (9), 74.8 (CH2-Ph),
70.2 (7), 66.6 (3), 61.5 (6), 60.8 (9a), 43.1 (aGly), 32.0 (2), 26.3
(isopr.-CH3 ), 26.0 (isopr.-CH3 ); HRMS (ESI) Calcd for M−:
490.1391; found: 490.1389.
3
1082; dH(500 MHz, DMSO[d6]) 8.33 (t, JGly-NH,aGly-H = 5.8 Hz,
1H, Gly-NH), 7.42–7.27 (m, 5H, Ph), 5.26 (s, 1H, 9a-H), 4.90 (d,
2JBn = 11.2 Hz, 1H, Ph-CH2 ), 4.79 (d, 3J3-H,2
= 7.4 Hz, 1H,
t
proR
-H
2
h
3
t
h
3-H), 4.69 (d, JBn = 11.2 Hz, 1H, Ph-CH2 ), 4.57 (d, J6-H,7-H
=
3
11.0 Hz, 1H, 6-H), 4.25 (d, J9-H,8-H = 2.3 Hz, 1H, 9-H), 4.04
3
(dd, J8-H,7-H = 8.8 Hz,3J8-H,9-H = 2.3 Hz, 1H, 8-H), 3.90–3.78 (m,
N3-Hexapeptide-OMe 14. Compound 13 (110 mg,
0.20 mmol), 12 (97.0 mg, 0.20 mmol) and PyBOP (160 mg,
0.31 mmol) were dissolved in DMF (15 mL) at 0 ◦C, and the pH
of the solution was adjusted to 7–8 with DIPEA. The mixture
was stirred overnight at room temperature. The solvent was
evaporated and the remaining yellow oil was purified by column
chromatography with DCM–MeOH (25 : 1) as the eluant to yield
product 14 as a colourless powder (105 mg, 54%); dH(600 MHz,
DMSO[d6]) d = 8.31–8.25 (m, 2H, Gly-NHA, Gly-NHB), 7.82 (d,
3
3
2H, Gly-H), 3.81 (dd, J7-H,6-H = 11.0 Hz, J7-H,8-H = 8.8 Hz, 1H,
7-H), 3.62 (s, 3H, OCH3), 3.44 (dd, 2J2
= 11.5 Hz,
proR
proS
-H,2
-H
proS
proR
proR
3J2
= 7.4 Hz, 1H, 2proR-H), 2.90 (d,2J2
=
-H,3-H
-H,2
-H
11.5 Hz, 1H, 2proS-H), 1.43 (s, 3H, isopr.-CH3 ), 1.38 (s, 3H,
t
h
isopr.-CH3 ); dC(125 MHz, DMSO[d6]) 170.28, 170.07, 165.27
(5, 3-CO, aGly-CO), 138.07, 128.33, 127.75, 127.70 (Ar), 108.66
(isopr.quat.), 82.20 (8), 80.44 (9), 75.03 (CH2-Ph), 70.37 (7), 66.60
(3), 61.53 (6), 61.15 (9a), 51.64 (OCH3), 40.59 (aGly), 32.06 (2),
t
h
26.58 (isopr.-CH3 ), 26.24 (isopr.-CH3 ); HRMS (ESI) Calcd
for M + Na+: 528.1523; found: 528.1529.
3J6
= 8.8 Hz, 1H, 6B-NH), 7.40–7.28 (m, 10H, ArA, ArB),
B
B
-NH,6 -H
5.43 (s, 1H, 9aB-H), 5.28 (s, 1H, 9aA-H), 4.99–4.97 (m, 1H, 6B-H),
(3aS,4S,4aS,7R,9R,9aS)-Methyl [(9-amino-4-benzyloxy-2,2-
dimethyl-8-oxo-octahydro-1,3-dioxa-5-thia-7a-azacyclopenta[f ]-
azulene-7-carbonyl)amino]acetate (12). Compound 11 (120 mg,
0.240 mmol) was dissolved in MeOH (15 mL) and treated with
Pd/C (25.0 mg) under an H2 atmosphere. The suspension was
stirred vigorously for 7 h. The reaction mixture was filtered
through Celite and the solvent was removed to give product 12
as a colourless solid (110 mg, 97%). dH(600 MHz, DMSO[d6])
4.90 (d, 2JBn = 11.0 Hz, 1H, Ph-CH2B,t), 4.89 (d, 2JBn = 11.1 Hz,
1H, Ph-CH2A,t), 4.78–4.73 (m, 2H, 3B-H, 3A-H), 4.71 (d, JBn
=
2
11.0 Hz, 1H, Ph-CH2B,h), 4.69 (d, 2JBn = 11.1 Hz, 1H, Ph-CH2A,h),
3
A
A
3
A
A
4.55 (d, J6
= 10.9 Hz, 1H, 6A-H), 4.24 (d, J9
=
-H,7 -H
-H,8 -H
2.4 Hz, 1H, 9A-H), 4.20 (d, J9
= 2.4 Hz, 1H, 9B-H), 4.04
3
B
B
-H,8 -H
(dd, 3J8
-H = 8.8 Hz, 3J8
-H = 2.4 Hz, 1H, 8A-H), 4.04 (dd,
A
A
A
A
-H,7
3J8
= 8.8 Hz, J8
-H,9 = 2.4 Hz, 1H, 8B-H), 3.87–3.71
B
B
3
B
B
–H,7 -H
-H,9 -H
(m, 5H, aGlyA-H, aGlyB-H, 7A-H), 3.71–3.61 (m, 1H, 7B-H), 3.60 (s,
3H, OCH3), 3.45 (dd,2J2
= 11.4 Hz, 3J2
=
3
proR,A
proS,A
proR,A
A
8.28 (t, JGly-NH,aGly-H = 5.9 Hz, 1H, Gly-NH), 7.40–7.27 (m, 5H,
-H,2
-H
-H/3 -H
7.46 Hz, 1H, 2proR,A-H), 3.59 (dd,2J2
= 11.2 Hz,
proS,A proR,A
-H,2 -H
2
t
proR,B
proS,B
Ar), 5.26 (s, 1H, 9a-H), 4.90 (d, JBn = 11.2 Hz, 1H, Ph-CH2 ),
-H,2
-H
3J2
= 7.3 Hz, 1H, 2proR,B-H), 3.00 (d,2J2
=
3
proR
2
proR,B
B
4.78 (d, J3-H,2
= 7.5 Hz, 1H, 3-H), 4.69 (d, JBn = 11.2 Hz,
H
-H/3 -H
11.4 Hz, 1H, 2proS,A-H), 2.86 (d,2J2
= 11.2 Hz, 1H,
h
3
proS,B
proR,B
1H, Ph-CH2 ), 4.18 (d, J9-H,8-H = 2.4 Hz, 1H, 9-H), 3.91 (dd,
3J8-H,7-H = 9.0 Hz,3J8-H,9-H = 2.4 Hz, 1H, 8-H), 3.86–3.77 (m, 3H,
-H,2
-H
2proS,B-H), 1.43 (s, 3H, isopr.-CH3A,t), 1.38 (s, 3H, isopr.-CH3A,h),
1.35 (s, 3H, isopr.-CH3B,t), 1.32 (s, 3H, isopr.-CH3B,h); dC(150 MHz,
DMSO[d6]) 170.11 (aGly-COB), 169.66 (3-COB), 169.35 (3-COA),
168.10 (aGly-COA), 166.61 (5B), 165.41 (5A), 138.22, 138.07, 128.30,
3
Gly-H, 6-H), 3.61 (s, 3H, OCH3), 3.51 (dd, J7-H,6-H = 10.6 Hz,
3J7-H,8-H = 9.0 Hz, 1H, 7-H), 3.44 (dd, J2
= 11.3 Hz,
2
proR
proS
-H,2
proS
-H
3J2 -H,3-H = 7.5 Hz, 1H, 2proR-H), 2.86 (d,2J2
-H = 11.3 Hz,
proR
proR
-H,2
1H, 2proS-H), 1.67 (brs, 2H, NH2), 1.40 (s, 3H, isopr.-CH3 ), 1.34
127.72, 127.62, (Ar), 108.64 (isopr.quat.,A), 127.62 (isopr.quat.,B),
t
(s, 3H, isopr.-CH3 ); dC(150 MHz, DMSO[d6]) 170.10 (aGly-CO),
82.67, 82.26 (8A, 8B), 80.73 (9A), 80.43 (9B), 74.97, (Ph-CH2
,
h
A
Ph-CH2 ), 70.79 (7B), 70.38 (7A), 66.84 (3A), 66.58 (3B), 61.57
(6A), 61.21 (9aA), 61.11 (9aB), 52.08 (6B), 51.60 (OCH3), 40.55,
40.06 (aGly,A, aGly,B), 32.22 (2A), 32.04 (2B), 26.71 (isopr.-CH3B,t),
26.58 (isopr.-CH3A,t), 26.30 (isopr.-CH3B,h), 26.23 (isopr.-CH3A,h);
HRMS (ESI) Calcd for M + Na+: 975.2987; found 975.2976.
B
169.91 (3-CO), 169.52 (5), 138.27, 128.30, 127.61 (Ar), 107.74
(isopr.quat.), 82.33 (8), 80.77 (9), 74.86 (CH2-Ph), 73.37 (7), 66.50
(3), 61.03 (9a), 53.92 (6), 51.62 (OCH3), 40.59 (aGly), 32.01 (2),
t
h
26.87 (isopr.-CH3 ), 26.28 (isopr.-CH3 ); HRMS (ESI) Calcd
for M + H+: 480.1799; found 480.1795.
(3aS,4S,4aS,7R,9R,9aS)-Lithium [(9-azido-4-benzyloxy-2,2-
dimethyl-8-oxo-octahydro-1,3-dioxa-5-thia-7a-azacyclopenta[f ]-
azulene-7-carbonyl)amino]acetate·lithium chloride (13). A solution
of 11 (120 mg, 0.24 mmol) in MeOH–THF (1 : 1) (15 mL) was
treated with 1 N LiOH (0.48 mL, 0.48 mmol) for 4 h at room
temperature, and the solution then neutralised with 1 N HCl.
The solvent was removed and the desired product 13 (130 mg,
quant.) was used without further purification. dH(600 MHz,
DMSO[d6]) 7.63 (brs, 1H, Gly-NH), 7.39–7.28 (m, 5H, Ph), 5.32
H2N-Hexapeptide-OMe 15. Compound 14 (50.0 mg,
53.0 lmol) was dissolved in MeOH (7.00 mL) and treated with
Pd(OH)2 (5.0 mg) under H2 atmosphere. The suspension was
stirred for 20 h at room temperature, filtered through Celite and
the solvent was removed to give a yellow crude product, which
was purified by column chromatography (MeOH–DCM = 1 :
15). The desired product 15 (29.0 mg, 60%) was obtained as a
colourless solid; dH(600 MHz, DMSO[d6]) 8.28 (t, 3JGly
=
A
A
-NH,Gly -H
3
B
B
6.1 Hz, 1H, Gly-NHA), 8.26 (t, JGly
= 6.1 Hz, 1H,
-NH,Gly -H
This journal is
The Royal Society of Chemistry 2006
Org. Biomol. Chem., 2006, 4, 4491–4496 | 4495
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