J. O. Rich et al. / Bioorg. Med. Chem. Lett. 19 (2009) 3059–3062
3061
Table 1
Table 2
Cyclic bislactone analogs of dihydroxymethylzearalenone
Cyclic bislactam analogs of dihydroxymethylzearalenone
Compound ID
Diol
Yield (%)
72
Compound ID Diol
Yield (%)
46
OH
3
NH2
HO
15
16
17
18
19
H2N
H2N
H2N
OH
OH
4
5
6
7
70
70
65
45
HO
HO
HO
HO
23
57
74
83
NH2
NH2
OH
N
O
O
OH
H2N
H2N
NH2
O
NH2
HO
O
8
9
40
44
48
O
OH
HO
HO
O
OH
OH
biocatalytic strategy is applicable to a wide variety of pharmaceu-
tical compounds with complex structures that may be difficult to
approach using conventional synthetic methods, thus allowing
expansion into otherwise inaccessible chemical space.
10
11
20
HO
OH
OH
Acknowledgments
OH
We thank Dr. M. Muzzio, Dr. S. Hu, and L. Fischer for help with
HPLC purification and analysis.
12a
13
48
55
OH
References and notes
OH
OH
1. Urry, W. H.; Wehrmeister, E. B.; Hodge, E. B.; Hidy, P. H. Tetrahedron Lett. 1966,
7, 3109.
2. Agatsuma, T.; Takahashi, A.; Kabuto, C.; Nozoe, S. Chem. Pharm. Bull. 1993, 41,
373.
3. Nair, M. S. R.; Carey, S. T. Tetrahedron Lett. 1980, 21, 2011.
4. Dombrowski, A.; Jenkins, R.; Raghoobar, S.; Bills, G.; Polishook, J.; Pelaez, F.;
Burgess, B.; Zhao, A.; Huang, L.; Zhang, Y.; Goetz, M. J. Antibiot. 1999, 52, 1077.
5. Zhao, A.; Lee, S. H.; Mojena, M.; Jenkins, R. G.; Patrick, D. R.; Huber, H. E.; Goetz,
M. A.; Hensens, O. D.; Zink, D. L.; Vilella, D.; Dombrowski, A.; Lingham, R. B.;
Huang, L. J. Antibiot. 1999, 52, 1086.
OH
HO
HO
14a
90
6. (a) Khmelnitsky, Y. L.; Michels, P. C.; Dordick, J. S.; Clark, D. S. Generation of
solution-phase libraries of organic molecules by combinatorial biocatalysis. In
Molecular Diversity and Combinatorial Chemistry; Chaiken, I. M., Janda, K. D.,
Eds.; American Chemical Society: Washington, DC, 1996; pp 144–157; (b)
Michels, P. C.; Khmelnitsky, Yu. L.; Dordick, J. S.; Clark, D. S. Trends Biotechnol.
1998, 16, 210; (c) Rich, J. O.; Michels, P. C.; Khmelnitsky, Yu. L. Curr. Opin. Chem.
Biol. 2002, 6, 161.
7. (a) Bjorkling, F.; Godtfredsen, S. E.; Kirk, O. J. Chem. Soc., Chem. Commun. 1990,
19, 1301; (b) Carboni-Oerlemans, C.; de Maria, P. D.; Tuin, B.; Bargeman, G.; van
der Meer, A.; van Gemert, R. J. Biotechnol. 2006, 126, 140.
a
Esterification occurred at the primary hydroxyls.
Chirazyme L-9 (0.5 g) and anhydrous sodium sulfate (6 g) were
added to initiate the reaction, and reaction mixture was incubated
at 60 °C under shaking at 250 rpm. After 72 h incubation, the reac-
tion was terminated by removing the enzyme by filtration. The fil-
trate was dried under vacuum and the reaction products were
isolated and purified by preparative HPLC.9c
Structures of synthesized cyclic bislactams and corresponding
reaction yields are shown in Table 2. In most cases, the correspond-
ing amide (either mono- or di-) derivatives were also generated by
amidation of one or both carboxylic groups in 2 with correspond-
ing diamines, with yields ranging approximately from 10 to 25%.
Structures of all purified bislactams were confirmed by NMR.10
All compounds in Tables 1 and 2 (3-19) were evaluated as
inhibitors of Lck activity. None of these compounds showed Lck
inhibitory activity at 10 lM suggesting that the presence of the
14-membered macrocyclic lactone is critically important for inhi-
bition of the kinase activity.
In summary, a combinatorial chemoenzymatic strategy was ap-
plied to generate a diverse set of dihydroxymethylzearalenone
analogs with modified ring structure. The reaction cascade was ini-
tiated with a unique enzyme-catalyzed oxidative ring opening
reaction of the parent compound, resulting in generation of new
reactive sites on the molecule amenable to further derivatization
via a combination of chemical and enzymatic steps. This general
8. LC/MS analysis was performed on an Applied Biosystems MDS SCIEX API 2000
system operated in ESI positive mode. Chromatography was accomplished
using a Luna C8 (Phenomenex) column (50 Â 2 mm, 5
lm) with the mobile
phase initially composed of 80% water and 20% acetonitrile (both containing
0.4% acetic acid) at a flow rate of 1.0 mL/min. After an initial isocratic hold for
0.5 min, concentration of acetonitrile was increased linearly to 100% in 3 min,
followed by isocratic hold for 0.5 min.
9. (a) Purifications were performed on
a
Shimadzu LC8A preparative HPLC
m) with the
system. Columbus C18 (Phenomenex) column (21 Â 60 mm, 5
l
mobile phase initially composed of 67% water and 33% acetonitrile at a flow
rate of 20 mL/min. After an initial isocratic hold for 16 min, concentration of
acetonitrile was increased linearly to 100% in 3 min, followed by isocratic hold
for 4 min.; (b) SymmetryPrep C8 (Waters) column (40 Â 200 mm, 7
lm), with
the mobile phase initially composed of 60% water and 40% acetonitrile at a flow
rate of 40 mL/min, with linear gradient to 100% acetonitrile over 30 min,
followed by isocratic hold for 3 min, with UV detection at 230 nm.; (c) Zorbax
RX-C8 (Agilent) column (21 Â 250 mm, 7
lm), with the mobile phase initially
composed of 80% water and 20% acetonitrile (both containing 0.1%
trifluoroacetic acid) at a flow rate of 15 mL/min, with linear gradient to 100%
acetonitrile over 40 min, followed by isocratic hold for 3 min, with UV
detection at 230 nm.
10. All compounds were fully characterized by 1D and where necessary by 2D
NMR analysis. The compounds showed expected NMR spectra. Data for
representative compounds are listed here. Compound 5: 1H NMR 500 MHz
(CD3OD–CDCl3, 1:1) d 7.06 (1H, d, J = 15.5 Hz), 6.46 (1H, d, J = 2.5 Hz), 6.37 (1H,
d, J = 2.5 Hz), 5.93 (1H, dt, J = 15.5, 8.0 Hz), 5.16 (1H, m), 4.16 (4H, m), 3.87 (3H,
s), 3.31 (1H, m), 3.24 (1H, dd, 15.5, 7.5 Hz), 2.37 (2H, m), 1.77 (2H, m), 1.66 (6H,