Parallel Solution Phase Synthesis and Preliminary Biological Activity of a 5′-Substituted Cytidine Analog Library

Article abstract of DOI:10.1021/acscombsci.9b00072

A 109-membered library of 5′-substituted cytidine analogs was synthesized, via funding through the NIH Roadmap Initiative and the Pilot Scale Library (PSL) Program. Reaction core compounds contained -NH₂ (2) and -COOH (44 and 93) groups that were coupled to a diversity of reactants in a parallel, solution phase format to produce the target library. The assorted reactants included -NH₂, -CHO, -SO₂Cl, and -COOH functional groups, and condensation with the intermediate core materials 2 and 44 followed by acidic hydrolysis produced 3-91 in good yields and high purity. Linkage of the amino terminus of d-phenylalanine methyl ester to the free 5′-COOH of 44 and NaOH treatment led to core library -COOH precursor 93. In a libraries from libraries approach, compound 93 served as the vital building block for our unique library of dipeptidyl cytidine analogs 94-114 through amide coupling of the -COOH group with numerous commercial amines followed by acidic deprotection. Initial screening of the complete final library through the MLPCN program revealed a modest number of hits over diverse biological processes. These hits might be considered as starting points for hit-to-lead optimization and development studies.

Full text of DOI:10.1021/acscombsci.9b00072

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Article
Parallel Solution Phase Synthesis and Preliminary Biological
Activity of a 5’-Substituted Cytidine Analog Library
Omar MOUKHA-CHAFIQ, Robert C. Reynolds, Jacob C. Wilson, and Timothy S. Snowden
ACS Comb. Sci., Just Accepted Manuscript • DOI: 10.1021/acscombsci.9b00072 • Publication Date (Web): 31 Jul 2019
Downloaded from pubs.acs.org on August 7, 2019
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Parallel Solution Phase Synthesis and
Preliminary Biological Activity of a 5’-
Substituted Cytidine Analog Library
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Omar Moukha-Chafiq1*, Robert C. Reynolds2*, Jacob C. Wilson3, and Timothy S. Snowden3
1Chemistry Department, Drug Discovery Division, Southern Research, 2000 Ninth Avenue
South, Birmingham, Alabama 35205, United States.
2Department of Medicine, Division of Hematology and Oncology, University of Alabama at
Birmingham, NP 2540 J, 1720 2nd Avenue South, Birmingham, AL 35294-3300, USA
3Department of Chemistry and Biochemistry, The University of Alabama, 250 Hackberry Lane,
Tuscaloosa, AL 35487-0336, USA
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ABSTRACT: A 109-membered library of 5’-substituted cytidine analogs was synthesized, via
funding through the NIH Roadmap Initiative and the Pilot Scale Library (PSL) Program. Reaction
core compounds contained -NH2 (2) and -COOH (44 and 93) groups that were coupled to a
diversity of reactants in a parallel, solution phase format to produce the target library. The assorted
reactants included -NH2, -CHO, -SO2Cl, and –COOH functional groups, and condensation with
the intermediate core materials 2 and 44 followed by acidic hydrolysis, produced 3-91 in good
yields and high purity. Linkage of the amino terminus of D-phenylalanine methyl ester to the free
5’-COOH of 44 and NaOH treatment led to core library –COOH precursor 93. In a libraries from
libraries approach, compound 93 served as the vital building block for our unique library of
dipeptidyl cytidine analogs 94-114 through amide coupling of the –COOH group with numerous
commercial amines followed by acidic deprotection. Initial screening of the complete final library
through the MLPCN program revealed a modest number of hits over diverse biological processes.
These hits might be considered as starting points for hit-to-lead optimization and development
studies.
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NH2
N
NH2
N
H
N
H2N
N
O
N
O
2 steps
R
O
O
2
HO
3-43
O
OH
O
NH2
N
NH2
N
NH2
N
NH2
N
O
H
H
HO2C
N
HO
2 steps
O
O
N
O
O
O
O
O
O
R
N
O
N
O
2 steps
N
O
N
O
2 steps
R
Ph
Ph
OH
OH
O
44
O
O
O
HO
94-114
OH
45-91
93
KEYWORDS: cytidine nucleoside analogs, solution phase, diversity libraries, biological
activities.
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INTRODUCTION
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Nucleosides are fundamental biological components that interact with a significant portion of the
human proteome, including peptide ligases, tRNA synthetases, polymerases, kinases, reductases,
motor proteins, membrane receptors, and structural proteins. With advances in both high
throughput chemical synthesis and screening, these key building blocks are increasingly relevant
today, and they are finding utility in the discipline of chemical biology as well as modern drug
discovery. As privileged and biologically relevant scaffolds, nucleosides continue to be useful as
probes for novel and essential nucleoside-dependent processes. In fact, over the past few decades,
new nucleoside-based agents have been discovered that are active for viral infections, cancers,
cardiovascular disorders, pain, etc. A number of drugs have resulted from targeting nucleoside
metabolism, including potent antiviral and anticancer drugs.1-3 As with many drug classes,
however, the increasing resistance of pathogens and cancers to current nucleoside-based drugs, the
severe side effects sometimes produced by nucleoside antimetabolites, and the plethora of new
nucleoside-dependent targets resulting from genetic sequencing highlight the continued need for
new and unique nucleoside diversity sets relevant to this fundamental slice of the proteome. Such
diverse nucleoside-based libraries will be potentially useful not only as probes for new chemical
biology approaches to assess fundamental pathways and the role of target proteins in metabolism,
growth, and drug resistance, but may also serve as a reservoir for new drug leads. Nucleosides are
relatively low molecular weight compounds that can serve as superb starting components for
diversity-oriented synthesis to prepare interesting and highly diversified small molecules with
various groups having unique and varied spatial orientation for probing biological diversity space.
In spite of their rich history and utility, however, nucleoside analogs are not commonly present in
research or commercial chemical libraries.
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Advancements in high-throughput chemistry have rarely been applied to nucleoside synthesis but
may allow rapid preparation of diverse and biologically relevant libraries featuring this privileged
scaffold. Thus, the goal of our PSL grant was to prepare novel and diverse nucleosides not only
for our own use, but also as a public resource for access via government-sponsored chemical
libraries and screening programs. It is notable that standard nucleosides can be promiscuous toxins
via phosphorylation of the 5’-hydroxyl group and entry into numerous crucial metabolic pathways.
As such, the perception that nucleoside drugs are generally nonselective and potently toxic through
cross reactivity through multifarious DNA and RNA pathways has led to the stigma associated
with this class. In sharp contrast, however, there are abundant cases of relatively discriminating
nucleosides, both simple and complex, that exhibit specific biological activities.5,6 The naturally
occurring nucleoside antibiotics, are one such example. As a class, they show widely varying and
compelling activities against numerous specific targets such as the protein synthesis machinery,
glycosyltransferases, and methyltransferases as well as many other critical protein targets.4-7 Of
particular interest are the 5’-substituted peptidyl nucleoside analogs containing a diversity of
amino acids and amino sugars, leading to the vigorous research to isolate and prepare new amino
acid and perptide-substituted nucleosides.7-11 Herein, we report the preparation of a focused set of
cytidine compounds inspired by the broad class of natural peptidyl nucleosides6,12,13 including
capuramycin, the polyoxins (tunicamycin and nikkomycin), the muramycins and the
mureidomycins.
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EXPERIMENTAL DESIGN AND DISCUSSION
We recently described the preparation and testing of a variety of adenosine and uridine analogs
that demonstrated diverse biological activities in early MLPCN assays.14 We now report the
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synthesis of a cytidine analog library derived from intermediates 2 (-NH2 reactant) and 44 and 93
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(-COOH reactants) (Schemes 1 & 2) using solution phase, parallel chemistry.
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Our goal was to target variations around the 5’-position to mimic structures represented by the
natural nucleoside antibiotics that demonstrate a variety of interesting activities. This task was
accomplished through robust coupling chemistry either utilizing 5’-aminocytidine (2) or the 4’-
COOH analog of the nucleoside to produce amines (via reductive amination), amides (peptide
coupling), or sulfonamides (via diverse commercial R-SO2Cl reagents). In a libraries-from-
libraries approach, D-phenylalanine was randomly chosen to be coupled to 44 to give the chiral
amino acid intermediate. Further coupling through the free D-Phe carboxylic acid yielded a
diverse array of amide-linked analogs potentially relevant to the natural nucleoside antibiotics,
since the more complex natural products oftentimes contain chiral linkages (amino acids,
carbohydrates, etc.) that are considered critical for biological uptake and targeting. It was essential
to demonstrate that our new library was unique in order to obtain PSL funding. Hence, we first
selected a commercial set of -CHO, -NH2, -COOH, and –SO2Cl containing reactants that were
obtainable in satisfactory amounts and at an acceptable cost to drive downstream synthesis and
diversity. This set was further filtered by eye for diversity and desired reactivity to work in the
designed coupling reactions and provide the expected diversity of nucleoside products. Finally,
the 3D representations were further assessed using Tanimoto structural similarity relative to the
current MLSCN library set at that time. Tanimoto similarity is one measure to determine similarity
between compounds and compound sets using compound fingerprints. The score ranges from 0
to 1 with 0 (no similarity) and 1 (100% similarity). A Tanimoto value of 0.7 to 1.0 suggests that
two molecules are highly similar to identical. Every proposed structure was compared with the
total MLSCN library (as of the year 2010 - 197,873 discrete molecules). Only 9.3% of our total
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proposed set had a Tanimoto value greater than 0.7, indicating that the new materials were
significantly divergent from the MLSCN library available in 2010. Furthermore, 36% of the new
nucleosides had Tanimoto values below 0.5, indicating significant diversity relative to the current
MLSCN library.
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5’-Amino and 5’-carboxylic nucleosides are common staring points to prepare diverse nucleosides
for screening.12-20 Consequently, the nucleoside 2 and nucleosides 44 and 93 were chosen as three
diversification reagents for robust reductive aminations, sulfonation reactions or amidations in
order to synthesize our unique cytidine-based library as depicted in Schemes 1-3.
Scheme 1: Synthesis of Analogs 3-43
NH2
NH2
NH2
NH2
N
N
N
N
N
O
HO
N
O
N
O
N3
H2N
N
O
TsO
iii)
i)
ii)
O
O
O
O
O
O
O
O
O
O
O
O
1
1b
(82%)
2
1a
(72%)
(74%)
iv) and v)
NH2
N
NH2
N
NH2
N
H
N
H
N
H
N
O
R
N
O
N
O
N
R
R
S
O
O
O
O
O
O
HO
OH
HO
35-43
(65-78%)
HO
OH
OH
3-29
30-34
(71-75%)
(67-85%)
o
Reagents and conditions: i) TsCl, pyridine; ii): NaN3, DMF, 50 C. iii): NH4OOCH, Pd-C
o
10%, MeOH. iv) aldehyde derivative MeOH, 0-40 C, NaBH4; sulfonyl chloride derivative,
DMF, Cs2CO3 or carboxylic acid derivative, HATU, DIEA, CH3CN; v) 50% HCO2H, 70 oC.
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Scheme 2: Synthesis of Analogs 45-91
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NH2
NH2
N
NH2
N
N
N
O
HO
N
O
R
O
O
O
N
O
HO
i)
ii), iii)
O
O
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O
O
HO
OH
O
O
45-91
(66-82%)
44
(86%)
1
Reagents and conditions: i) cat. TEMPO, BAIB, NaHCO3, MeCN:H2O, r.t.;
ii): R = amine derivative, HATU, DIEA, CH3CN.; iii) 50% HCO2H, 70 oC.
Scheme 3: Synthesis of Analogs 94-114
NH2
N
NH2
N
NH2
N
NH2
N
O
H
H
H
MeO2C
i)
HO2C
N
N
N
O
O
O
O
N
O
N
O
N
O
N
O
HO
R
O
O
iii)
ii)
O
O
Ph
Ph
Ph
HO
O
O
OH
O
O
O
O
94-114
92
(88%)
93
(75%)
44
(65-73%)
Reagents and conditions: i): Methyl (R)-2-amino-3-phenylpropanoate, HATU, DIEA, MeCN. r.t.; ii): 1N
NaOH, dioxane, r.t.; iii): a: R = amine derivatives, HATU, DIEA, MeCN, r.t.; b: 50% HCO2H, 70 oC, 2 h.
5’-Amino-5’deoxycytidine (2) was prepared from 1 in three steps via a reported procedure and
was identical in all respects to the reported material.20 Reductive amination is efficient and easily
adaptable to parallel chemistry, and we utilized this approach to couple pure compound 2 with a
variety of diverse, commercially available -CHO containing reagents. Coupling was accomplished
in MeOH over molecular sieves to drive intermediate imine formation through water removal; the
drying reagent was critical for higher yields. A Radleys 12-place carousel reaction station was
used for parallel production of the libraries. Chemistry was carried out at room temperature unless
o
indicated as certain reactions with poorly soluble aldehydes required warming to 40 C for 10
minutes. The aldimine intermediates were treated in situ by careful addition of solid NaBH4. After
30 minutes, the reaction was adsorbed onto silica gel without further workup and dried followed
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by automated flash chromatography purification. Acid catalyzed removal of the acetonide
protecting group in 50% formic acid yielded the final compounds 3-29 (Scheme 1) in 67-85%
yields.
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Target compounds are presented in Charts 1-3.
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Chart 1: Structures of Analogs 3-43
NH2
N
5
6
7
8
H
N
O
N
R
O
9
HO
OH
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Compound
Compound
Compound
R
R
R
S
S
N
Me
NC
Me
17
3
N
31
O
N
O
N
N
S
O
O
O
S
O
S
O
O
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4
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Ac
O
N
O
S
OiPr
5
MeHNO2S
Cl
OMe
Cl
O
O
O
6
S
O
S
O
O
CN
CN
O
OMe
Cl
7
NH2
O
F3C
Me
N
HO
O
8
Cl
NH2
S
O
N
N
N
CH2
9
Br
BnO
N
NHCHO
OBn
N
N
OMe
O
Me
O
O
N
N
O
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11
12
13
14
15
16
O
N
H
H
Cl
O
MeN
N
Me
OMe
NH2
O
S
N
S
O
Me2N
Me
N
O
H
Me
MeO
HO
N
O
MeHN
O
O
HO
H2C
42
43
O
N
O
S
O
O
NH2
O
MeO
O
HC
Me
O
F
N
NHCHO
Cl
O
S
O
S
Me
S
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Chart 2: Structures of Analogs 45-91
NH2
N
5
6
7
8
N
O
R
O
9
O
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HO
OH
Compound
Compound
Compound
R
R
R
N
N
MeO
PhO
H
N
O
45
77
H
N
N
N
61
N
H
N
O
N
H
Pr
O
H
N
N
N
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47
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49
50
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78
79
80
81
82
83
84
85
86
87
88
89
90
91
NH
62
63
64
65
66
67
68
69
70
71
72
73
74
S
O
O
N
Me
N
F
N
N
NH
NH
N
N
O
N
Me
N
N
N
NH
N
MeO
MeO
F
NH
S
N
N
N
N
MeO
H
Me
F3C
N
N
N
Me
N
Cl
NH
N
N
CF3
H
N
OMe
N
OH
OH
Me
Me
Me
N
F3C
Me
O
Me
N
MeO
MeO
N
Me
NH
OCHO
NH
OH
O
MeO
Me
N
N
H2NOC
O
Me
N
O
Me
N
H
N
F3C
N
N
H
H
O
O
O
N
OCHO
NH
N
Me2N
Me
N
N
H
Me
HN
F3C
N
N
N
N
N
HO
Me
Me
HN
H
O
NH
N
F
N
N
OHCO
Me
O
Me
HO
MeS
O
H
Me
Me
N
N
N
N
H
O
O
O
OH
HO
N
N
N
N
75
76
NH
H
F
F
H
N
Me
N
N
Me
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Chart 3: Structures of Analogs 94-114
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6
7
8
NH2
N
H
O
N
O
N
O
R
O
9
Ph
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HO
OH
R
R
Compound
Compound
94
H2NOC
105
OH
N
N
H
F3C
95
S
N
106
107
108
109
110
111
112
113
Me
H
Me
N
N
N
O
96
H
F
F
OMe
OMe
O
N
H
97
N
N
N
OMe
MeO
O
HN
N
H
98
N
O
N
N
O
O
N
N
99
N
F3C
O
H
O
O
N
N
O
100
101
102
103
104
N
H
Me2N
O
N
O
Me
N
N
H
N
O
N
S
N
N
H
N
O
N
N
OMe
Me
MeO
MeO
N
114
HO
N
OMe
N
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A 24-position MiniBlock XT vessel was employed to prepare our library members 30-43 (Chart
1), 45-91 (Chart 2) and 94-114 (Chart 3) in solution phase. A Tecan liquid handling system was
used for dispensation, retraction, and aspiration with a compatible 17 × 110 mm test tube carousel
and a Genevac evaporation system. In this format, five sulfonyl chlorides were reacted with 2 to
prepare the sulfonylamide cytidine analogs 30-34 (Scheme 1) using the solvent DMF and CsCl
(base) for coupling. The isopropylidene blocking groups were removed as described above.
HATU (1 equiv) was used for amide coupling of 2 with nine -COOH compounds catalyzed by
DIEA (1.5 equiv) in acetonitrile (three hours) to prepare amide-linked compounds 35-43 in 65-
78% yields (Scheme 1) after acid mediated deprotection.. These conditions with intermediate 44
gave amides 45-91 in 66-82% yields (Scheme 2). Compound 44 was prepared by reported methods
using catalytic amounts of TEMPO and BAI in acetonitrile-water (1:1).12a
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Compound 44 was coupled to the free amino group of D-phenylalanine-COOMe 92 (Scheme 3)
in 88% yield. Hydrolysis with 1N NaOH in dioxane at 25 oC gave the -COOH intermediate 93 in
o
75% yield. Deprotection with 50% formic acid at 70 C afforded a high yield of nucleoside 94.
Target 93 was designed from a “libraries from libraries” standpoint, and produced a site of further
diversity expansion through another amide coupling with diverse amines to produce targets 95-
114 (Scheme 2). Coupling of 93 with 20 diverse amines and HATU/DIEA produced the desired
targets in 65-73% yield and high purity after acid catalyzed removal of the isopropylidene
protecting group and purification.
1
Analysis of all products involved H NMR, HPLC, and mass analysis. Purity ranged from 90-
100%, and the average purity was 97%. Comparison of the NMR spectra of crude 93 as its
carboxylate salt with spectra of the corresponding crude epi-93 carboxylate salt -prepared by amide
coupling of 44 with methyl (S)-2-amino-3-phenylpropanate to form epi-92, purification, then
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saponification using 1N LiOH in dioxane - established that the hydrolysis of 92 to 93 proceeds
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without epimerization.22
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BIOLOGICAL EVALUATION
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All biological screening was performed via government grants and contracts to external and
independent academic laboratories through the MLPCN program, and all results can be readily
accessed by a specific assay name in PubChem Assay or through the compound database via
www.ncbi.nlm.nih.gov/pcsubstance (search term Robert Reynolds). Certain nucleosides (see
Table 1) afforded a variety of modest activities in the primary screens.
Table 1: Selected Results from PubChem Bioactivity Analysis
Compound
Assay Title in PubChem
Biological results
54, 59, 65, 97, 101, “High-Throughput-Screening (HTS) to 26%, 52%, 26% 45%,
103, 107 and 112
identify inhibitors against Sialic Acid 17%, 47%, 45% and 23%,
Acetyl Esterase (SIAE)”
respectively at 9.6 µM
28
“Discovery of small molecule inhibitors
of the oncogenic and cytokinetic protein
MgcRacGAP.”
34% inhibition at 40 µM
35
39
42
“HTS to identify agonists of the mouse 5-
hydroxytryptamine (serotonin) receptor
2A (HTR2A)”
29% inhibition at 7.6 µM
10% inhibition at 12.2 µM
43% inhibition at 9.9 µM
“HTS to identify inhibitors of
phospholipase
gamma1).”
C
isozymes (PLC-
“Small Molecule Inhibitors of FGF22-
Mediated Excitatory Synaptogenesis &
Epilepsy Measured in Biochemical
System Using RT-PCR.”
54
“HTS to identify positive allosteric
modulators (PAMs) of the human
cholinergic receptor, muscarinic 4
(CHRM4).”
20% activation at 3 µM
59 and 85
“THS to identify modulators of
interaction between CendR and NRP-1.”
“Counterscreen for inhibitors of 5-
40% inhibition at 25 µM
43% inhibition at 4.4 µM
65
meCpG-binding domain protein
(MBD2).”
2
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57 and 71
“DENV2 CPE-Based HTS Measured in 70% and 87 inhibition,
Cell-Based
and
Microorganism
respectively, at 9.99 µM
Combination System”
80
90
“HTS to identify D3 Dopamine Receptor
Antagonist.”
40% inhibition at 2.3 µM
“HTS to identify inhibitors of the
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interaction
of
nucleotide-binding
oligomerization domain containing 2
(NOD2) and the receptor-interacting
serine-threonine kinase 2 (RIPK2).”
“HTS to identify inhibitors of protein
arginine methyltransferase 1 (PRMT1).”
28% inhibition at 5 µM
21% inhibition at 2.8 µM
102
For example: 5’-carboxamide nucleoside analogs 54, 59 and 65, and di-peptidyl compounds 97,
103, 107 and 112 showed modest, lead-like inhibitory activity against Sialic Acid Acetyl Esterase
(SIAE) (Table 1). This enzyme could serve as a target for the pharmacological induction of
immune activation to empower B cells that are specific for weak epitopes and to enhance T cell
memory responses.
It has been shown that excitatory and inhibitory synapses can be organized in the brain by two
fibroblast growth factor (FGF) family members, FGF22 (excitatory) and FGF7 (inhibitory). .
Remarkably, FGF22-deficient mice are resistant to epileptic seizures, and FGF7-deficient mice are
prone to them.22 These results indicate that the identification of small molecules that inhibit
FGF22-mediated excitatory synapse formation or those that can activate FGF7-mediated
inhibitory synapse formation may lead to new treatment approaches for epilepsy. Analog 42
showed modest inhibition (43%) against FGF22 at 9.9 µM (Table 1) and may be used as a lead for
developing potent FGF inhibitors due to its unique structure.
In addition, protein arginine methyltransferase 1 (PRMT1) activity has been linked with a number
of human health conditions including cardiovascular disease, cancer, infectious disorders and
autoimmune conditions.23 Di-peptidyl analog 102 showed modest activity against PRMT1 with
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21% inhibition at 2.8 µM (Table 1) and may warrant further investigation as this structure is unique
from other reported inhibitors.23
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CONCLUSION
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Preparation and initial screening of a unique library of 109 cytidine-based compounds is reported.
Application of newer higher throughput equipment and technologies were utilized in the
preparation of this small-sized diversity set. Targets were sent to the MLPCN for screening, and
early assay results showed modest activities against the targets SIAE, FGF, and PRMT1. The
PRMT1 hit, while only modestly active, is unique relative to reported PRMT1 inhibitors, and we
are currently preparing more material as well as analogs for confirmation of activity in advanced
assays. All assay data and protocols can be viewed by visiting PubChem Substance.
ASSOCIATED CONTENT
Supporting Information detailing the general experimental procedures and analytical data for the
libraries is available free of charge on the ACS Publications website at DOI:.
General Experimental Section
Page S3
General Procedures & Analytical Data for Compounds 3-29
General Procedures & Analytical Data for Compounds 30-34 & 35-43
Procedure & Analytical Data for Compound 44
Pages S3-S8
Pages S8-S11
Page S11
General Procedures & Analytical Data for Compounds 45-91
Pages S11-S19
General Procedure & Analytical Data for Compounds 92, epi-92, and 93 Pages S19-S20
General Procedures & Analytical Data for Compounds 94-114
References
Pages S20-S24
Page S24
NMR Spectra of Representative Products Pages
Comparative NMR Epimerization Study Pages
S25-S51
S52-S54
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AUTHOR INFORMATION
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Corresponding Author
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*Omar Moukha-Chafiq: omoukha-chafiq@southernresearch.org
*Robert C. Reynolds: rcr12lkt@uab.edu
ORCID
Omar Moukha-Chafiq: 0000-0002-4906-1643
Robert C. Reynolds: 0000-0001-9413-2247
Jacob C. Wilson: 0000-0001-9777-9898
Timothy S. Snowden: 0000-0002-6838-1220
Notes
The authors have no financial conflicts.
Author Contributions
The manuscript was written through contributions of all authors. All authors have given approval
to the final version of the manuscript. All authors contributed equally.
Funding Sources
This investigation was supported by NIH grant No. 1P41 GM086163-01 (entitled: Pilot-Scale
Libraries Based on Nucleoside Templates for the ML Initiative, Robert C. Reynolds, P.I.).
ACKNOWLEDGMENT
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We appreciate the input of James M. Riordan, Jackie Truss, Mark Richardson and David Poon of
the Molecular and Spectroscopy Section of Southern Research Institute for analytical support. The
reported work was sustained by NIH grant No. 1P41 GM086163-01 (entitled: Pilot-Scale Libraries
Based on Nucleoside Templates for the ML Initiative, Robert C. Reynolds, P.I.). Dr. Robert C.
Reynolds would like to thank Drs. Boris Pasche and Ravi Bhatia for support of this research project
via start-up funds provided through the Division of Hematology and Oncology at the University
of Alabama at Birmingham.
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ABBREVIATIONS
PSL, Pilot Scale Library; NIH, National Institutes of Health USA; tRNA, transfer ribonucleic
acid; MLPCN, Molecular Libraries Probe Production Centers Network; DNA , deoxyribonucleic
acid; MLSCN, Molecular Libraries Screening Centers Network; DMF, N,N-dimethylformamide;
HATU, [(2-(7-Aza-1H-benzotriazole-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate];
DIEA, N,N-diisoproplyethylamine; TEMPO, 2,2,6,6-tetramethyl-1-piperidinyloxyl; BAIB,
[bis(acetoxy)iodo]benzene; NMR, nuclear magnetic resonance; HPLC, high performance liquid
chromatography; FGF, fibroblast growth factor; PRMT1, Protein arginine methyltransferase 1;
SIAE, Sialic Acid Acetyl Esterase; TLC, thin layer chromatography; TMS, tetramethylsilane.
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TOC
NH2
N
NH2
N
H
N
H2N
N
O
N
O
2 steps
R
O
O
2
HO
3-43
O
OH
O
NH2
N
NH2
N
NH2
N
NH2
N
O
H
H
HO2C
N
O
O
N
O
O
HO
2 steps
O
O
O
O
R
N
O
N
O
2 steps
N
O
N
O
2 steps
R
Ph
Ph
OH
OH
O
44
O
O
O
HO
94-114
OH
45-91
93
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