6844
R. P. Sellers et al. / Bioorg. Med. Chem. 18 (2010) 6822–6856
(0.397 mmols, 1.0 equiv) of linear pentapeptide, 0.543 mL (8 equiv)
of DIPEA, 67.0 mg (0.21 mmols, 0.7 equiv) of TBTU, 80.0 mg
(0.21 mmols, 0.7 equiv) HATU, and 62.5 mg (0.21 mmols, 0.7 equiv)
of DEPBT. The crude reaction was purified by reverse phase-HPLC to
yield the macrocycle (42.3 mg, 16.2% yield).
(4.41 mmols, 1.1 equiv) of amine MeO-Lys(CBz)-NH2, 1000 mg
(4.01 mmols, 1.0 equiv) of acid HO-Leu-NHBoc, 2.8 mL (4 equiv)
of DIPEA, and 1545 mg (4.8 mmols, 1.2 equiv) of TBTU. The crude
reaction was purified by column chromatography (silica gel,
EtOAc/Hex) to yield the dipeptide (1182 mg, 97% yield).
Rf: 0.65 (EtOAc/Hex 1:1).
1H NMR (400 MHz, CD3OD): d 0.6–1.0 (m, 8H), 1.2 (m, 11H),
1.4–1.6 (m, 3H), 1.7–1.8 (m, 4H), 2.0 (m, 1H), 3.4 (m, 3H), 4.1 (s,
1H NMR (200 MHz, CDCl3): d 1.0–1.2 (d, 6H), 1.6 (s, 9H), 1.7–2.2
aH), 4.2 (s,
aH), 4.5 (s,
aH), 5.2 (m, 2H), 7.0–7.2 (m, 22H).
(m, 9H), 3.3 (m, 2H), 3.7 (s, 3H), 4.3 (dd,
2H), 7.5 (d, 5H).
aH), 4.6 (dd, aH), 5.3 (s,
12.11.11. Macrocycle Phe-N-Me-
Macrocycle Phe-N-Me- -Phe-
utilizing 20 mg (0.08 mmols, 1.0 equiv) of macrocycle Phe-N-Me-
-Phe- -Val-Cha-Ser(Bzl).The compound was dissolved in 0.8 mL
EtOH (0.1 M) and was hydrogenated using a catalytic amount of
Pd/C and excess H2 for 24 h. The reaction was filtered over Celite
D
-Phe-
D-Val-Cha-Ser
D
D-Val-Cha-Ser was synthesized
12.12.6. Dipeptide HO-Lys(CBz)-Leu-NHBoc
Dipeptide HO-Lys(CBz)-Leu-NHBoc was synthesized following
the ‘General acid deprotection’. This dipeptide was taken on to
the next reaction without further purification or characterization
(1089 mg, 95% yield).
D
D
and afforded 18 mg (93% yield) of pure macrocycle Phe-N-Me-D-
Phe-D-Val-Cha-Ser.
12.12.7. Pentapeptide MeO-
Pentapeptide MeO- -Tyr-Leu-Val-Lys(CBz)-Leu-NHBoc was syn-
thesized following the ‘General peptide synthesis’ procedure. Utiliz-
ing 1021 mg (2.5 mmols, 1.1 equiv) of amine MeO- -Tyr-Leu-Val-
NH2, 1089 mg (2.3 mmols, 1.0 equiv) of acid HO-Lys(CBz)-Leu-
NHBoc, 1.6 mL (4 equiv) of DIPEA, and 826 mg (2.76 mmols,
1.2 equiv) of DEPBT. The crude reaction was purified by column
chromatography (silica gel, EtOAc/Hex) to yield the pentapeptide
(192 mg, 20% yield).
D-Tyr-Leu-Val-Lys(CBz)-Leu-NHBoc
1H NMR (400 MHz, CD3OD): d 0.7–0.9 (m, 8H), 1.2 (m, 11H),
D
1.4–1.6 (m, 3H), 1.7–1.8 (m, 4H), 2.0 (m, 1H), 3.4 (m, 3H), 4.2–4.3
(s,
a
H), 4.2 (s,
aH), 4.5 (s, aH), 5.2 (m, 2H), 7.2–7.4 (m, 14H).
D
LCMS: m/z called for C36H49N5O6 (M+1) = 648.4, found 648.3.
12.12. Synthesis of compounds 23 and 24
12.12.1. Dipeptide MeO-
Dipeptide MeO- -Tyr-Leu-NHBoc was synthesized following
the ‘General peptide synthesis’ procedure. Utilizing 1026.9 mg
(4.43 mmols, 1.1 equiv) of amine MeO- -Tyr-NH2, 1000.9 mg
D-Tyr-Leu-NHBoc
D
Rf: 0.6 (EtOAc/Hex 3:1).
1H NMR (500 MHz, CD3OD): d 0.8–1.0 (m, 18H), 1.3 (m, 2H), 1.5
(s, 9H), 1.6–1.8 (m,6H), 2.0–2.2 (m, 6H), 2.9 (m, 2H), 3.1 (m, 4H),
D
(4.01 mmols, 1.0 equiv) of acid HO-Leu-NHBoc, 2.8 mL (4 equiv)
of DIPEA, and 1440 mg (4.81 mmols, 1.2 equiv) of DEPBT. The
crude reaction was purified by column chromatography (silica
gel, EtOAc/Hex) to yield the dipeptide (1526 mg, 93% yield).
Rf: 0.65 (EtOAc/Hex 1:1).
3.7 (s, 3H), 4.2 (m, 2
aH), 4.4 (m, 2aH), 4.6 (m, aH), 5.0 (s, 2H),
6.7–7.0 (d, 4H), 7.4 (d, 5H), 7.8 (m, 2H), 8.0–8.2 (m, 4H).
12.12.8. Macrocycle
protected)
D-Tyr-Leu-Val-Lys(CBz)-Leu (Cyclized
1H NMR (200 MHz, CDCl3): d 0.9–1.0 (d, 6H), 1.4 (s, 9H), 1.6 (br,
1H), 2.0 (s, 2H), 3.0 (m, 2H), 3.7 (s, 3H), 4.1 (dd,
aH), 4.8 (dd, aH),
Macrocycle
D-Tyr-Leu-Val-Lys(CBz)-Leu was synthesized fol-
5.0 (s, 1H), 6.6–6.8 (d, 2H), 7.0 (d, 2H), 7.2 (s, 2H).
lowing the ‘Macrocyclization procedure’. Utilizing 169 mg
(0.22 mmols, 1.0 equiv) of linear pentapeptide, 0.3 mL (8 equiv) of
DIPEA, 35 mg (0.11 mmols, 0.5 equiv) of TBTU, 42 mg (0.11 mmols,
0.5 equiv) HATU, and 33 mg (0.11 mmols, 0.5 equiv) of DEPBT. The
crude reaction was purified by reverse phase-HPLC to yield the
macrocycle (30 mg, 18% yield).
12.12.2. Dipeptide MeO-D-Tyr-Leu-NH2
Dipeptide MeO- -Tyr-Leu-NH2 was synthesized following the
D
‘General amine deprotection’. This dipeptide was taken on to the
next reaction without further purification or characterization
(1153 mg, 100% yield).
Rf: 0.6 (EtOAc/Hex 1:0).
1H NMR (500 MHz, CD3OD): d 0.8–1.0 (m, 18H), 1.2–1.4 (m, 4H),
12.12.3. Tripeptide MeO-
Tripeptide MeO- -Tyr-Leu-Val-NHBoc was synthesized follow-
ing the ‘General peptide synthesis’ procedure. Utilizing 1153 mg
(3.73 mmols, 1.1 equiv) of amine MeO- -Tyr-Leu-NH2, 750 mg
D-Tyr-Leu-Val-NHBoc
1.5–1.8 (m, 8H), 2.6 (m,
aH), 3.1 (m, 4H), 3.2 (m, 2H), 4.1 (m, 2aH),
D
4.3 (m, 2 H), 4.5 (m, H), 5.1 (s, 2H), 6.7 (dd, 2H), 7.0 (dd, 2H), 7.2–
a
a
7.4 (d, 5H), 7.5 (d, 1H), 7.7 (d, 1H), 8.1 (d, 1H), 8.3 (d, 1H), 8.5 (d,
1H), 8.7 (d, 1H).
D
(3.4 mmols, 1.0 equiv) of acid HO-Val-NHBoc, 2.4 mL (4 equiv) of
DIPEA, and 1240 mg (4.07 mmols, 1.2 equiv) of DEPBT. The crude
reaction was purified by column chromatography (silica gel,
EtOAc/Hex) to yield the tripeptide (1754 mg, 73% yield).
Rf: 0.65 (EtOAc/Hex, 3:1).
LCMS: m/z calcd for C34H52N6O5 (M+1) = 750.4, found 752.
12.12.9. Removal of Cbz group
12.12.9.1. Macrocycle
D-Tyr-Leu-Val-Lys-Leu. Macrocyclic pen-
1H NMR (200 MHz, CD3OD): d 0.8–0.9 (m, 12H), 1.4 (s, 9H), 1.9
(br, 1H), 2.0 (s, 2H), 2.8 (m, 1H), 3.0 (m, 2H), 3.7 (s, 3H), 3.8 (dd,
tapeptide -Tyr-Leu-Val-Lys(CBz)-Leu was further deprotected to
D
remove Cbz protecting group of the lysine residue. The compound
was synthesized by utilizing 16 mg (0.021 mmols, 1.0 equiv) of
cyclic pentapeptide, 5.0 mL of Ethanol, 8.0 mg 10% wt palladium
on carbon. The crude reaction was purified by reverse phase-HPLC
aH), 4.4 (dd,
aH), 4.6 (dd, 2aH), 5.0 (s, 1H), 6.6–6.8 (d, 2H), 7.0
(d, 2H).
to yield the deprotected macrocycle
(5.0 mg, 38% yield).
D-Tyr-Leu-Val-Lys-Leu
12.12.4. Tripeptide MeO-
D-Tyr-Leu-Val-NH2
Tripeptide MeO- -Tyr-Leu-Val-NH2 was synthesized following
D
Rf: 0.5 (DCM/MeOH 98:2).
the ‘General amine deprotection’. This dipeptide was taken on to
the next reaction without further purification or characterization
(1021 mg, 100% yield).
1H NMR (500 MHz, CD3OD): d 0.8–1.0 (m, 18H), 1.2–1.4 (m, 4H),
1.5–1.8 (m, 8H), 2.0 (m, 2H), 2.6 (m, H), 3.0 (m, 4H), 3.2 (m, 2H),
a
4.1 (m, 2 H), 4.3 (m, 2 H), 4.5 (m, aH), 6.7 (dd, 2H), 7.0 (dd, 2H),
a
a
7.5 (d, 1H), 7.7 (d, 1H), 8.1 (d, 1H), 8.3 (d, 1H), 8.5 (d, 1H), 8.7 (d,
1H).
12.12.5. Dipeptide MeO-Lys(CBz)-Leu-NHBoc
Dipeptide MeO-Lys(CBz)-Leu-NHBoc was synthesized following
the ‘General peptide synthesis’ procedure. Utilizing 1459 mg
LCMS: m/z calcd for C34H52N6O5 (M+1) = 617.