Synthesis of 7-trifluoromethyl-7-deazapurine ribonucleoside analogs and their monophosphate prodrugs

Article abstract of DOI:10.1080/15257770.2019.1674333

Novel 7-trifluoromethyl-7-deazapurine ribonucleoside analogs (13a-c) and their Protides (15a-c) were successfully synthesized from ribolactol or 1-α-bromo-ribose derivatives using Silyl-Hilbert-Johnson or nucleobase-anion substitution reactions followed by key aromatic trifluoromethyl substitution. Newly prepared compounds were evaluated against a panel of RNA viruses, including HCV, Ebola or Zika viruses.

Full text of DOI:10.1080/15257770.2019.1674333

Nucleosides, Nucleotides and Nucleic Acids
ISSN: 1525-7770 (Print) 1532-2335 (Online) Journal homepage: https://www.tandfonline.com/loi/lncn20
Synthesis of 7-trifluoromethyl-7-deazapurine
ribonucleoside analogs and their monophosphate
prodrugs
Jong Hyun Cho, Leda C. Bassit, Franck Amblard & Raymond F. Schinazi
To cite this article: Jong Hyun Cho, Leda C. Bassit, Franck Amblard & Raymond F.
Schinazi (2019): Synthesis of 7-trifluoromethyl-7-deazapurine ribonucleoside analogs
and their monophosphate prodrugs, Nucleosides, Nucleotides and Nucleic Acids, DOI:
10.1080/15257770.2019.1674333
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NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
https://doi.org/10.1080/15257770.2019.1674333
Synthesis of 7-trifluoromethyl-7-deazapurine
ribonucleoside analogs and their monophosphate
prodrugs
Jong Hyun Choa, Leda C. Bassitb, Franck Amblardb, and
Raymond F. Schinazib
b
aDepartment of Medicinal Biotechnology, Dong-A University, Busan, South Korea; Department
of Pediatics, Emory University, Atlanta, GA, USA
ABSTRACT
ARTICLE HISTORY
Received 29 August 2019
Accepted 26 September 2019
Novel 7-trifluoromethyl-7-deazapurine ribonucleoside analogs
(13a-c) and their Protides (15a-c) were successfully synthe-
sized from ribolactol or 1-a-bromo-ribose derivatives using
Silyl-Hilbert-Johnson or nucleobase-anion substitution reac-
tions followed by key aromatic trifluoromethyl substitution.
Newly prepared compounds were evaluated against a panel
of RNA viruses, including HCV, Ebola or Zika viruses.
KEYWORDS
7-trifluoromethyl-7-deaza-
purine ribonucleoside;
protides; Silyl-Hilbert-
Johnson; RNA viruses
1. Introduction
Nucleoside analogs played a pivotal role in the development of antiviral
and anti-cancer agents. Since the discovery by William Prussoff in 1962[1]
of idoxuridine, the first antiviral drug approved for the treatment of herpes
virus, more than 25 nucleoside derivatives have been approved to treat
human infectious diseases. 7-Deazapurine nucleoside derivatives are an
extremely interesting class of analogs due to their innate biological activ-
ity.[2] Over the past 50 years, more than twenty 7-deazapurine derivatives
have been discovered from terrestrial and marine sources.[3] Among them,
naturally occurring tubercidin (1a),[4] toyocamycin (1b),[5] and sangivamy-
cin (1c)[6] display a broad spectrum of activity and have driven extensive
SAR studies towards the development of new antiviral and anticancer
agents. Thus, 7-deazaadenosine derivatives of 6-hetaryl-7-deazapurine (2a)
and 7-fluoro-7-deazapurine ribonucleosides (2b-c)[7] as well as 7-hetaryl-
7-dazaapurine ribonucleoside (3a)[8] displayed potent cytostatic activity
in multiple cancer cell lines. Recently, a series of 6-substituted 7-furyl or
ethynyl-7-deazapurine ribonucleoside analogs (3b-c)[9] showed significant
cytostatic, antimicrobial and promising anti-HCV activity. Furthermore,
CONTACT Raymond F. Schinazi
rschina@emory.edu
Department of Pediatics, Emory University, Atlanta,
GA, USA.
Color versions of one or more of the figures in the article can be found online at www.tandfonline.com/lncn.
ß 2019 Taylor & Francis Group, LLC

2
J. H. CHO ET AL.
Figure 1. Biologically relevant 7-deazapurine nucleoside analogs.
7-fluoro-7-deazapurine ribonucleoside (4a)[10] showed improved anti-cancer
activity and reduced cytotoxicity when compared with its parent tubercidin
(1a). 7-Fluoro-7-deazapurine-20-C-methyl and 20-deoxy-20-fluoro-20-C-methyl
ribonucleosides (4b)[11] and (4c)[12] were highly potent inhibitors of HCV rep-
lication. Interestingly, 7-deazapurine-20-C-methylribonucleoside (5a) has been
reported to inhibit both HCV[13] and Zika virus replication.[14] Additionally,
7-deazapurine-20-C-ethynylribonucleoside (5b, NITD008) potentially inhibited
dengue and Zika viruses.[15] Furthermore, 7-vinyl-7-deazapurine-20-deoxy-20-
fluoro-20-C-methyl ribonucleoside (5c) exhibited promising anti-HCV activity
as well as weak anti-HIV activity.[16] The 1,2,4-oxadiazole-7-deazapurine-20-C-
methylribonucleoside (5d) showed high antiviral potency against HCV replica-
tion cells.[17] 7-Deazaneplanocin A analog (6) exhibited potent antiviral activity
against cowpox and vaccinia viruses.[18]
If a large variety of groups has been introduced at the 7-position of
7-deazapurine nucleosides (Figure 1), the effect of a CF3 group at this pos-
ition remains underexplored. Herein, we wish to report the synthesis and
antiviral evaluation of novel ribo, b-20-methyl- or a-20-fluoro-b-20-methyl-
D-ribofuranoses 7-deazapurine derivatives with a trifluoromethyl group at
the 7-position using a key aromatic trifluoromethyl substitution (Figure 2).
2. Results and discussion
6-Chloro-7-iodo-7-deazapurine (8), prepared from commercially available
6-chloro-7-deazapurine (7) by treatment with N-iodosuccinimide (NIS) in

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
3
Figure 2. Target 7-trifluoromethyl-7-deazapurine analogs.
DMF,[19] was reacted with 1-a-/b-O-acetyl-2,3,5-tri-O-benzoyl-D-ribose
(9a) and 1-a-/b-O-benzoyl-2,3,5-tri-O-benzoyl-20-C-methyl-D-ribose (9b)
under classical Vorbru€ggen glycosylation conditions[20–22] to give b- 6-
chloro-7-iodo-7-deazapurine ribonucleosides 10a and 10b. Next, aromatic
trifluoromethylation reaction[23,24] of compound 10a and 10b was carried
out by treatment with methyl fluorosulfonyldifuoroacetate (MFSDA) and
CuI in a mixture hexamethylphosphoramide (HMPA) and N,N-dimethyl-
formamide (DMF) to give 7-trifluoromethyl-7-deazapurine nucleoside
derivatives 11a and 11b in 90–93% yield.[25] Subsequent treatment with
a saturated solution of ammonia in MeOH gave 7-trifluoromethyl-7-deaza-
purine nucleosides 12a and 12b in good yields. Finally, since the mono-
phosphorylation of a nucleoside analog[26] can be the limiting step to the
formation of the active triphosphate form, nucleosides 12a and 12b were
converted into their corresponding phosphoramidate prodrug 14a and 14b
by reaction with chlorophosphoramidate derivative 13 in presence of
t-BuMgCl.[27] Prodrugs 14a and 14b were obtained as 1/1 Rp/Sp-mixtures,
1
as determined by H-NMR and 31P-NMR. It is noteworthy that when
N-methylimidazole (NMI) was employed instead of t-BuMgCl, prodrugs
14a and 14b were obtained in poor yields due to incomplete reactions and
formation of 30,50-bis-phosphoramidate by-products (Scheme 1).
20-C-Me,20-F nucleoside analog 12c and its phosphoramidate prodrug
14c were prepared according to the chemistry described in Scheme 2.
1-a-Bromo-3,5-di-O-benzoyl-20-deoxy-20-fluoro-20-C-methylribose (9c), syn-
thesized from commercially available 3,5-di-O-benzoyl-20-deoxy-20-fluoro-
20-C-methyl ribolactone (15),[28,29] was coupled with 7-deaza purine 8
in presence of KOH and tris-[2-(2-methoxyethoxy)]ethylamine (TDA-1)[30]
to give 3,5-di-O-benzoyl-20-deoxy-20-fluoro-20-C-methyl-6-chloro-7-iodo-
7-deazapurine ribonucleoside (10c) in 68% yield. Subsequent reaction
with MFSDA and CuI in a mixture of DMF and HMPA afforded 3,5-
di-O-benzoyl-20-deoxy-20-fluoro-20-C-methyl-6-chloro-7-tri-fluoromethyl-
7-deazapurine ribonucleoside (11c) in 97% yield. Finally, treatment
of 11c with a saturated solution of ammonia in MeOH provided 20-
deoxy-20-fluoro-20-C-methyl-7-trifluoromethyl-7-deazapurine ribonucleoside

4
J. H. CHO ET AL.
Scheme 1. Synthesis of compound 12a-b and 14a-b.
Reagents and reaction conditions: (a) NIS, DMF, rt, 12h; (b) BSA, TMSOTf, 0 ꢀC ! 80 ꢀC, 12h for
10a; 8h for 10b; (c) FSO2CF2CO2Me, CuI, HMPA, DMF, 70 ꢀC, 12h; (d) sat. NH3/MeOH, 90 ꢀC, 12h,
steel bomb; (e) 13, t-BuMgCl, THF, ꢁ78 ꢀC ! rt, 8h for 14a; 12h for 14b.
Scheme 2. Synthesis of compound 12c and 14c.
Reagents and reaction conditions: (a) i. LiAl(t-BuO)3H, THF, ꢁ20 ꢀC, 4 h: ii. AcCl, DMAP, Et3N,
CH2Cl2, 0 ꢀC, 3 h; (b) 33% HBr in AcOH, CH2Cl2, 0 ꢀC then rt 4 h; (c) TDA-1, KOH, 4 Å MS, CH3CN,
rt, 2 h; (d) FSO2CF2CO2Me, CuI, HMPA, DMF, 70 ꢀC, 12 h; (e) sat. NH3/MeOH, 90 ꢀC, 12 h, steel
bomb; (e) 13, t-BuMgCl, THF, ꢁ78 ꢀC, 6 h.
(12c) in 85% yield. Phosphoramidate prodrug 14c was prepared by reaction
of nucleoside 12c with chlorophosphoramidate 13 in presence of t-BuMgCl
(Rp/Sp ¼ 1/1 ratio).
Nucleosides 12a-c and their corresponding phosphoramidate prodrugs
14a-c were evaluated against a panel of RNA viruses including HCV[31]

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
5
(clone B replicon), Ebola[32] (Zaire ebola virus replicon) and Zika[33]
(cytopathic effect reduction assay) viruses. In addition, cytotoxicity was
determined in primary human peripheral blood mononuclear (PBM)
cells, human lymphoblastoid CEM, African Green monkey Vero cells
and HepG2 cells.[34] Unfortunately, none of these derivatives exhibited
significant activity at concentration up to 20 mM against these
viruses nor toxicities in PBM, CEM and Vero cells at concentration up
to 100 mM.
In conclusion, several novel 7-trifluoromethyl-7-deazapurine ribonucleo-
side analogs (12a-c) were synthesized by using a key aromatic trifluorome-
thylation with MFSDA and CuI using HMPA and DMF as co-solvents.
Unfortunately, none of the synthesized compounds (12a-c and 14a-c)
showed marked activity when tested against HCV, Ebola or Zika viruses.
3. Experimental
Nuclear magnetic resonance (NMR) spectra (1H, 13C, 19F and 31P) were
recorded on a Varian Unity Plus 400 MHz and a Bruker AscendTM
400 MHz Fourier transform spectrometer at RT, with tetramethylsilane
(TMS) as an internal standard. Chemical shifts (d) are reported in
parts per million (ppm), and signals are quoted as s (singlet), d (doublet),
t (triplet), q (quartet), m (multiplet), br (broad), dd (doublet of doublets),
or ddd (doublet of doublets of doublets). The phosphoramidates are
an approximate 50:50 mixture of diastereomers (RP/SP) and the 13C NMR
data is reported as observed, that is, some carbon signals overlap. High-
resolution mass spectra (HRMS) were recorded on a Micromass Autospec
high-resolution mass spectrometer with electrospray ionization (ESI).
Thin-layer chromatography (TLC) was performed on 0.25 mm silica gel.
Purifications were carried out on silica gel column chromatography (60 Å,
63–200 mm, or 40–75 mm).
3.1. Compound 8
To a solution of 6-chloro-7-deazapurine (1.0 g, 6.51 mmol) in 20 mL of
anhydrous DMF was added N-iodosuccinimide (1.60 g, 7.16 mmol). The
reaction mixture was stirred for 2 h at room temperature and the solvent
removed under vacuum. The residue was purified by silica gel column
chromatography (hexanes:EtOAc ¼ 1:1 to 3;1v/v) to give compound 8
1
in quantitative yield. H NMR (400 MHz, CD3OD) d 8.55 (s, 1 H), 7.72
(s, 1 H); 13C NMR (100 MHz, CD3OD) d 151.7, 151.6, 150.2, 133.5, 116.3,
50.1; MS-ESIþ m/z 280 (M þ Hþ).

6
J. H. CHO ET AL.
3.1.1. (2R,3R,4R,5R)-2-((benzoyloxy)methyl)-5-(4-chloro-5-iodo-7H-pyrrolo[2,3-
d]pyrimidin-7-yl)tetrahydrofuran-3,4-diyl dibenzoate (10a)
To a solution of 6-chloro-7-iodo-7-deazapurine 8 (0.55 g, 1.96 mmol) in
10 mL of anhydrous CH3CN was added N,O-bis(trimethylsilyl)acetamide
(0.50 g, 2.45mmol) at room temperature under N2 atmosphere. After 30 min,
a solution of 1-O-Ac-2,3,5-tri-O-Bz-ribose 9a (0.90 g, 1.79mmol) in 10 mL of
anhydrous CH3CN and TMSOTf (0.56 g, 2.45 mmol) was added to the reac-
tion mixture at 0 ꢀC. The reaction mixture was then heated to 80ꢀC over 1 h
and stirred for 12 h at this temperature e. The solution was cooled to room
temperature and diluted with EtOAc (50 mL). The organic layer was washed
with a saturated NHCO3 aqueous solution (20mL), cold water (20 mL) and
brine (20mL). The organic layer was then dried over Na2SO4, filtered and
concentrated under reduced pressure. The residue was purified by silica gel
column chromatography (hexanes:EtOAc ¼ 5:1 to 2:1 v/v) to give compound
1
10a (0.83 g, 1.15 mmol) in 64% yield. H NMR (400MHz, CDCl3) d 8.58 (s,
1 H), 8.21 (d, J ¼ 7.2 Hz, 2 H), 7.99 (d, J ¼ 6.8 Hz, 2 H), 7.92 (d, J ¼ 8.4 Hz,
2 H), 7.64-7.49 (m, 6 H), 7.43-7.35 (m, 4 H), 6.67 (d, J ¼ 5.6 Hz, 1 H), 6.15 (t,
J ¼ 5.6 Hz, 1 H), 6.11 (dd, J ¼ 5.6, 4.4 Hz, 1 H), 4.90 (dd, J ¼ 12.4, 3.2 Hz,
1 H), 4.80 (q, J ¼ 3.6 Hz, 1 H), 4.68 (dd, J ¼ 12.4, 3.6 Hz, 1 H), 13C NMR
(100 MHz, CDCl3) d 166.3, 165.8, 165.3, 153.3, 151.5, 151.2, 134.1, 134.0,
133.8, 132.2, 130.1, 129.9, 129.5, 129.1, 128.9, 128.8, 128.7, 128.6, 118.0, 87.0,
80.9, 74.4, 71.6, 63.7, 53.9; MS-ESIþ m/z 724 (M þ Hþ); HRMS-ESIþ: m/z
calcd for C32H24ClIN3O7 (M þ Hþ) 724.0347, found 724.0331.
3.1.2. (2R,3R,4R,5R)-2-((benzoyloxy)methyl)-5-(4-chloro-5-(trifluoromethyl)-7H-
pyrrolo[2,3-d]pyrimidin-7-yl)tetrahydrofuran-3,4-diyl dibenzoate (11a)
To a solution of compound 10a (0.51 g, 0.71 mmol) in 20 mL of anhydrous
DMF and hexamethylphosphoric triamide (HMPA, 8.50 mL) was added
FSO2CF2CO2Me (170.0 mg, 0.88 mmol) and CuI (160.0 mg, 0.85 mmol)
under argon atmosphere. The reaction mixture was stirred for 13 h at 70 ꢀC
and then cooled down to room temperature before addition of a saturated
aqueous solution of NH4Cl (20 mL). The mixture was extracted with a
mixture of hexanes and EtOAc (50 mL ꢂ 2, 1:2 v/v). The combined organic
layers were washed with a saturated aqueous solution of NaHCO3 (20 mL),
water (20 mL), brine (20 mL) then dried over Na2SO4 and filtered. The fil-
trate was concentrated under reduced pressure and the residue was purified
by silica gel column chromatography (hexanes: EtOAc ¼ 10:1 to 5:1 v/v) to
1
give compound 11a (0.44 g, 0.66 mmol) in 93% yield. H NMR (400 MHz,
CDCl3) d 8.66 (s, 1 H), 8.11-8.08 (m, 2 H), 8.02-8.00 (m, 2 H), 7.93-7.91
(m, 2 H), 7.86 (s, 1 H), 7.62-7.34 (m, 9 H), 6.68 (d, J ¼ 5.6 Hz, 1 H), 6.22
(t, J ¼ 5.6 Hz, 1 H), 6.15 (dd, J ¼ 5.6, 4.4 Hz, 1 H), 4.92 (dd, J ¼ 9.2, 3.2 Hz,
1 H), 4.85 (q, J ¼ 3.6 Hz, 1 H), 4.72 (dd, J ¼ 12.4, 3.6 Hz, 1 H), 13C NMR

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
7
(100 MHz, CDCl3) d 166.2, 165.5, 165.2, 152.7, 152.4, 152.1, 134.0, 133.9,
130.0, 129.8, 128.9, 128.8, 128.7, 87.6, 81.1, 74.4, 71.6, 63.5; 19F NMR
(376 MHz, CDCl3) d -56.52; MS-ESIþ m/z 666 (M þ Hþ); HRMS-ESIþ:
m/z calcd for C33H24ClF3N3O7 (M þ Hþ) 666.1255, found 666.1245.
3.1.3. (2R,3R,4S,5R)-2-(4-Amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-d]pyrimidin-7-
yl)-5-(hydroxymethyl)tetrahydrofuran-3,4-diol (12a)
In a steel bomb at 0 ꢀC, NH3 was bubbled through a solution of compound
11a (0.16 g, 0.24mmol) in 30mL of MeOH for 20min. The reaction was
heated at 90 ꢀC for 12 h before being cooled down to 0 ꢀC. After evaporation
of the volatiles under reduced pressure, the residue was purified by silica gel
column chromatography (CH2Cl2: MeOH ¼ 20:1 to 10:1 v/v) to give com-
1
pound 12a (58.60 mg, 0.18 mmol) in 83% yield. H NMR (400 MHz, CD3OD)
d 8.20 (s, 1 H), 8.03 (s, 1 H), 6.11 (d, J¼ 6.0Hz, 1H), 4.59 (t, J¼ 5.6Hz, 1H),
4.30 (dd, J¼ 4.8, 3.2 Hz, 1 H), 4.13 (q, J¼ 3.2Hz, 1H), 3.87 (dd, J¼ 12.4,
2.4Hz, 1H), 3.76 (dd, J¼ 12.4, 2.8 Hz, 1 H); 13C NMR (100 MHz, CD3OD) d
158.1, 153.9, 152.7, 152.2, 129.9, 126.3, 123.7, 105.8, 100.7, 91.2, 87.5, 76.0, 72.3,
63.2; 19F NMR (376 MHz, CD3OD) d -57.14; MS-ESIþ m/z 335 (M þ Hþ);
HRMS-ESIþ: m/z calcd for C12H14F3N4O4 (M þ Hþ) 335.0967, found 335.0953.
3.1.4. Ethyl ((((2 R,3S,4R,5R)-5-(4-amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-d]pyr-
imidin-7-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methoxy)(phenoxy)phos-
phoryl)-L-alaninate (14a)
To a solution of compound 12a (0.05 g, 0.15 mmol) in 3.0 mL of anhydrous
THF was added t-BuMgCl (0.53 mL, 1.0 M in THF) at –78 0 ꢀC under N2
atmosphere. After 30 minutes at this temperature and an additional 10 min
at room temperature, a solution of phosphoramidate chloride 13 (67.0 mg,
0.23 mmol) in 2.0 mL of anhydrous THF was added to the reaction at
–78 ꢀC. The reaction mixture was stirred for 6 h at room temperature and
cooled down to 0 ꢀC before addition of a saturated aqueous solution of
NH4Cl (0.25 mL). The resulting solution was poured into EtOAc (50 mL)
and the organic layer was washed with a saturated aqueous solution
of NH4Cl (20 mL) and brine (20 mL). The organic layer was dried over
Na2SO4, filtered and concentrated under reduced pressure. The crude resi-
due was purified by silica gel column chromatography (CH2Cl2: MeOH ¼
20:1 to 10:1 v/v) to give compound 14a (53.0 mg, 0.09 mmol) as a mixture
1
of Rp-/Sp-isomers (ꢃ1:1) in 60% yield. H NMR (400 MHz, CD3OD) d
8.23 (s, 1 H), 7.91-7.89 (m, 1 H), 7.35-7.31 (m, 2 H), 7.23-7.15 (m, 3 H),
6.25-6.22 (m, 1 H), 4.48-4.35 (m, 4 H), 4.33-4.29 (m, 2 H), 4.28-4.20 (m,
2 H), 4.14-4.03 (m, 3 H), 3.92-3.84 (m, 1 H), 1.38-1.16 (m, 11 H); 31P NMR
(162 MHz, CD3OD) d 5.06, 4.83; 19F NMR (376 MHz, CD3OD) d -56.99,

8
J. H. CHO ET AL.
–57.03; MS-ESIþ m/z 590 (M þ Hþ); HRMS-ESIþ: m/z calcd for
C23H28F3N5O8P (M þ Hþ) 590.1627, found 590.1609.
3.1.5. (2S/R,3R,4R,5R)-5-((benzoyloxy)methyl)-3-methyltetrahydrofuran-2,3,4-triyl
tribenzoate (9 b)
To
a
solution of 2-C-methyl-, 2,3,5-tribenzoyl ribolactone (5.0 g,
10.54 mmol) in 50 mL of anhydrous THF was added LiAlH(Ot-Bu)3 (1.1 M
in THF, 15 mL) over 10 min at 0 ꢀC under N2 atmosphere. After stirring
for 1 h, the reaction was warmed up to room temperature and stirred for
2 h. The reaction was then quenched with a saturated solution of NH4Cl
(10 mL), poured into cold water (50 mL) and extracted with EtOAc (50 mL
x 3). The combined organic layers were dried over Na2SO4, filtered, and
concentrated under reduced pressure. The residue was purified by silica gel
column (hexanes:EtOAc ¼ 10:1 to 2:1 v/v) to give a 2-C-methyl-, 2,3,5-
tribenzoyl ribolactol in quantitative yield. To a solution of the lactol (2.08 g,
10.25 mmol) in 100 mL of anhydrous CH2Cl2 was added benzoyl chloride
(2.16 g, 15.38 mmol) and Et3N (1.25 g, 20.50 mmol) at 0 ꢀC under N2 atmos-
phere. After being stirred for 12 h at room temperature, the reaction
mixture was quenched with MeOH (10 mL) at 0 ꢀC, stirred for 1 h at room
temperature, and then poured into cold water (50 mL). The organic layer
was separated and washed with 0.1 N HCl aqueous solution (30 mL), water
(30 mL), brine (30 mL), dried over Na2SO4, and filtered. The filtrate was
concentrated under reduced pressure and the residue was purified by silica
gel column chromatography (CH2Cl2 to CH2Cl2: MeOH ¼ 50:1 v/v) to
give compound 9 b (5.81 g, 10.01 mmol) in 95% yield.
1H NMR (400 MHz, CDCl3) d 8.13-8.10 (m, 4 H), 8.07-8.05 (m, 2 H),
7.88 (dd, J ¼ 8.4, 1.2 Hz, 2 H), 7.64-7.60 (m, 3 H), 7.51-7.40 (m, 7 H), 7.15
(t, J ¼ 8.0 Hz, 2 H), 7.06 (s, 1 H), 5.95 (d, J ¼ 8.0 Hz, 1 H), 4.80-4.77
(m, 1 H), 4.68 (dd, J ¼ 12.4, 4.0 Hz, 1 H), 4.54 (dd, J ¼ 12.4, 4.8 Hz, 1 H),
1.95 (s, 3 H); MS-ESIþ m/z 581 (M þ Hþ).
3.1.6. (2R,3R,4R,5R)-5-((benzoyloxy)methyl)-2-(4-chloro-5-iodo-7H-pyrrolo[2,3-
d]pyrimidin-7-yl)-3-methyltetrahydrofuran-3,4-diyl dibenzoate (10 b)
To a solution of 6-chloro-7-iodo-7-deazapurine 8 (0.50 g, 1.79 mmol) in
20 mL of anhydrous CH3CN was added N,O-bis(trimethylsilyl)acetamide
(0.44 g, 2.16 mmol) at room temperature under N2 atmosphere. After
20 min, 1,2,3,5-tetra-O-Bz-2-methylribose 9 b (1.04 g, 1.80 mmol) and then
TMSOTf (0.49 g, 2.16 mmol) were added to the reaction mixture at 0 ꢀC
under N2 atmosphere. The mixture was warmed up to room temperature
for 30 min and then heated at 80 ꢀC for additional 8 h. The solution was
cooled down to room temperature and diluted with EtOAc (50 mL). The

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
9
organic layer was washed with a saturated solution of NHCO3 (30 mL),
cold water (30mL), and brine (20 mL). The organic layer was then dried
over Na2SO4, filtered and concentrated under reduced pressure. The residue
was purified by silica gel column chromatography (hexanes:EtOAc ¼ 10:1 to
1
3:1 v/v) to give compound 10b (0.97 g, 1.31 mmol) in 73% yield. H NMR
(400 MHz, CDCl3) d 8.75 (s, 1 H), 8.12-8.09 (m, 4 H), 7.96 (d, J ¼ 7.6 Hz,
2 H), 7.69 (s, 1 H), 7.63-7.53 (m, 3 H), 7.48-7.44 (m, 4 H), 7.34 (t, J ¼ 7.6 Hz,
2 H), 6.95 (s, 1 H), 6.04 (d, J ¼ 6.0 Hz, 1 H), 4.96 (dd, J ¼ 12.4, 3.6 Hz, 1 H),
4.86 (dd, J ¼ 12.4, 5.6 Hz, 1 H), 4.74-4.70 (m, 1 H), 1.59 (s, 3 H); 13C NMR
(100 MHz, CDCl3) d 166.5, 165.5, 165.3, 153.3, 151.4, 150.9, 133.9, 133.8,
133.6, 133.2, 130.1, 130.0, 129.9, 129.8, 129.7, 128.9, 128.8, 128.7, 117.9, 89.2,
85.1, 80.2, 75.8, 63.5, 52.9, 29.9, 18.1; MS-ESIþ m/z 738 (M þ Hþ); HRMS-
ESIþ: m/z calcd for C33H26ClIN3O7 (M þ Hþ) 738.0504, found 738.0488.
3.1.7. (2R,3R,4R,5R)-5-((benzoyloxy)methyl)-2-(4-chloro-5-(trifluoromethyl)-7H-
pyrrolo[2,3-d]pyrimidin-7-yl)-3-methyltetrahydrofuran-3,4-diyl diben-
zoate (11 b)
To a solution of compound 10b (0.24 g, 0.32 mmol) in 10 mL of anhydrous
DMF and 7.0 mL of HMPA was added FSO2CF2CO2Me (80.0 mg,
0.40 mmol) and CuI (73.0 mg, 0.38 mmol) under argon atmosphere. After
being stirred for 12 h at 70 ꢀC, the reaction mixture was cooled down to
temperature and treated with a saturated solution of NH4Cl (10 mL) and
then extracted with a mixture of hexanes and EtOAc (30 mL ꢂ 2, 1:2 v/v).
The combined organic layers were washed with a saturated solution of
NaHCO3 (10 mL), water (10 mL), brine (10 mL), dried over Na2SO4 and fil-
tered. The filtrate was concentrated under reduced pressure and the residue
was purified by silica gel column chromatography (hexanes: EtOAc ¼ 10:1
1
to 5:1 v/v) to give compound 11b (0.20 g, 0.29 mmol) in 90% yield. H
NMR (400 MHz, CDCl3) d 8.85 (s, 1 H), 8.13-8.08 (m, 4 H), 7.97-7.94 (m,
3 H), 7.64-7.52 (m, 3 H), 7.48-7.43 (m, 4 H), 7.33 (t, J ¼ 7.6 Hz, 2 H), 6.96
(s, 1 H), 6.03 (d, J ¼ 5.2 Hz, 1 H), 4.97-4.92 (m, 2 H), 4.76-4.72 (m, 1 H),
1.60 (s, 3 H); 13C NMR (100 MHz, CDCl3) d 166.6, 165.5, 165.3, 152.9,
152.4, 151.9, 134.90, 133.7, 130.2, 130.0, 129.9, 129.7, 129.6, 128.8, 128.7,
89.5, 84.8, 80.7, 75.9, 63.4, 18.2; 19F NMR (376 MHz, CDCl3) d –56.29; MS-
ESIþ m/z 680 (M þ Hþ); HRMS-ESIþ: m/z calcd for C34H26ClF3N3O7
(M þ Hþ) 680.1411, found 680.1400.
3.1.8. (2R,3S,4R,5R)-2-(4-Amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-d]pyrimidin-7-
yl)-5-(hydroxymethyl)-3-methyltetrahydrofuran-3,4-diol (12 b)
In a steel bomb at 0 ꢀC, NH3 was bubbled through a solution of compound
11b (0.20 g, 0.26 mmol) in 30 mL of MeOH for 20 min. The reaction was

10
J. H. CHO ET AL.
then heated at 90 ꢀC for 12 h and then cooled down to 0 ꢀC. The volatiles
were concentrated under reduced pressure and the residue was purified by
silica gel column chromatography (CH2Cl2: MeOH ¼ 20:1 to 10:1 v/v) to
give compound 12b (77.60 mg, 0.22 mmol) in 87% yield. 1H NMR
(400 MHz, CD3OD) d 8.32 (dd, J ¼ 1.2 Hz, 1 H), 8.23 (s, 1 H), 6.31 (s, 1 H),
4.13 (d, J ¼ 9.2 Hz, 1 H), 4.06-4.01 (m, 2 H), 3.85 (dd, J ¼ 12.4, 2.0 Hz, 1 H),
0.85 (s, 3 H); 13C NMR (100 MHz, CD3OD) d 158.1, 154.1, 152.3, 151.5,
126.5, 125.2, 125.1, 123.8, 106.2, 105.8, 100.0, 92.9, 84.2, 80.6, 73.3, 60.7,
20.2; 19F NMR (376 MHz, CD3OD) d -57.04; MS-ESIþ m/z 349 (M þ Hþ);
HRMS-ESIþ: m/z calcd for C13H16F3N4O4 (M þ Hþ) 349.1123,
found 349.1113.
3.1.9. Ethyl ((((2 R,3R,4S,5R)-5-(4-amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-d]pyr-
imidin-7-yl)-3,4-dihydroxy-4-methyltetrahydrofuran-2-yl)methoxy)(phenox-
y)phosphoryl)-L-alaninate (14 b)
To a solution of compound 12 b (40.0 mg, 0.12mmol) in 2.0 mL of anhyd-
rous THF was added t-BuMgCl (0.42 mL, 1.0 M in THF) at –78 0 ꢀC under
N2 atmosphere. After being stirred for 30 min at this temperature and for
10 min at room temperature, a solution of phosphoramidate chloride 13
(49.60 mg, 0.17 mmol) in 2.0mL of anhydrous THF was added to the solu-
tion –78ꢀC. The reaction mixture was stirred for 12 h at room temperature
and then cooled down to 0 ꢀC before addition of saturated aqueous solution
of NH4Cl (0.10mL). The resulting solution was poured into EtOAc (30 mL)
and washed with saturated aqueous NH4Cl (10 mL) and brine (10 mL). The
organic layer was dried over Na2SO4, filtered and concentrated under
reduced pressure. The crude residue was purified by silica gel column chro-
matography (CH2Cl2: MeOH ¼ 15:1 to 10:1 v/v) to give compound 14 b
(42.0 mg, 0.07mmol) as a mixture of Rp-/Sp-isomers (ꢃ1:1) in 58% yield.
1H NMR (400MHz, CD3OD) d 8.25 (s, 1 H), 7.88-7.85 (m, 1 H), 7.36-7.32
(m, 2 H), 7.26-7.23 (m, 2 H), 7.19-7.16 (m, 1 H), 6.35-6.33 (s, 1 H), 4.89-4.42
(m, 2 H), 4.33-4.29 (m, 2 H), 4.25-4.18 (m, 1 H), 4.13-3.99 (m, 3 H), 3.97-3.90
(m, 1 H), 1.32-1.27 (m, 4 H), 1.22-1.14 (m, 3 H), 0.88-0.86 (s, 3 H); 31P NMR
(162 MHz, CD3OD) d 5.28, 4.94; 19F NMR (376 MHz, CD3OD) d –56.68,
–56.78; MS-ESIþ m/z 604 (M þ Hþ); HRMS-ESIþ: m/z calcd for
C24H30F3N5O8P (Mþ Hþ) 604.1784.1627, found 604.1771.
3.1.10. ((2R,3R,4R,5R)-3-(benzoyloxy)-5-bromo-4-fluoro-4-methyltetrahydrofuran-
2-yl)methyl benzoate (9c, a-isomer)
To a solution of 3,5-O-di-Bz-2-F-2-Me-ribolactone (3.0 g, 8.10 mmol) in
40 mL of anhydrous THF was added LiAlH(Ot-Bu)3 (1.1 M in THF,
8.80 mL) over 10 min at 0 ꢀC under N2 atmosphere. After being stirred for

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
11
2 h at this temperature, the reaction was warmed up to room temperature
and stirred for an additional 1 h. The reaction was then quenched with a
saturated solution of NH4Cl (5.0 mL), poured into cold water (30 mL) and
extracted with EtOAc (40 mL ꢂ 3). The combined organic layers were
dried over Na2SO4 and filtered. The filtrate was concentrated under
reduced pressure and the residue was purified by silica gel column
(hexanes:EtOAc ¼ 10:1 to 2:1 v/v) to give 3,5-O-di-Bz-ribolactol in quanti-
tative yield. To a solution of the lactol (3.0 g, 8.01 mmol) in 50 mL of
anhydrous CH2Cl2 was added acetyl chloride (0.79 g, 10.02 mmol) and Et3N
(1.22 g, 12.02 mmol) at 0 ꢀC under N2 atmosphere. After being stirred for
3 h, the reaction mixture was quenched with MeOH (10 mL) at 0 ꢀC and
poured into cold water (50 mL). The organic layer was separated and
washed with 0.1 N-HCl (20 mL), water (20 mL), brine (20 mL) and then
dried over Na2SO4, and filtered. The filtrate was concentrated under
reduced pressure and the residue was purified by silica gel column chroma-
tography (CH2Cl2 to CH2Cl2: MeOH ¼ 50:1 v/v) to give 1-O-Ac-3,5-O-di-
Bz-2-F-2-Me-ribose (3.20 g, 7.69 mmol) as an a-/b-isomers (1:1) in 95%
1
yield. H NMR (400 MHz, CDCl3) d 8.13-8.10 (m, 2 H), 8.06-8.03 (m, 2 H),
7.66-7.62 (m, 1 H), 7.57-7.53 (m, 1 H), 7.52-7.48 (m, 2 H), 7.41-7.37 (m,
2 H), 6.25 (d, J ¼ 8.7 Hz, 1 H), 5.70 (dd, J ¼ 23.6, 8.2 Hz, 1 H), 4.74 (dd,
J ¼ 12.0, 4.0 Hz, 1 H), 4.69-4.66 (m, 1 H), 4.46 (dd, J ¼ 12.0, 4.4 Hz, 1 H),
2.00 (s, 3 H), 1.55 (d, J ¼ 22.4 Hz, 3 H); 13C NMR (100 MHz, CDCl3) d
168.9, 165.9, 165.7, 133.9, 133.2, 130.1, 129.7, 129.6, 128.6, 128.3, 100.4,
98.4 (d, J ¼ 34.8 Hz), 78.7, 73.7 (d, J ¼ 15.1 Hz), 63.6, 20.9, 16.5 (d,
J ¼ 23.0 Hz); 19F NMR (376 MHz, CDCl3) d -170.72; MS-ESIþ m/z 417
(M þ Hþ). To a solution of 1-O-Ac-3,5-O-di-Bz-2-F-2-Me-ribose (2.0 g,
4.80 mmol) in 20 mL of CH2Cl2 was added 2.5 mL of 33% HBr in acetic
acid solution at room temperature. The solution was stirred for 16 h at
room temperature and then concentrated under reduced pressure. The resi-
due was dissolved in 50 mL of CH2Cl2 and then washed with cold water
(20 mL) and saturated aqueous NaHCO3. The organic layer was dried over
anhydrous MgSO4 and filtered. The filtrate was concentrated and purified
by silica gel column chromatography to give a-isomer (9c) (1.80 g,
4.13 mmol) in 86% yield and b-Isomer (0.21 g, 0.48 mmol) in 10% of yield.
1
a-Isomer (bottom spot on TLC): H NMR (400MHz, CDCl3) d 8.17-8.14
(m, 2 H), 8.06-8.04 (m, 2 H), 7.66-7.59 (m, 2 H), 7.52-7.45 (m, 4 H), 6.37 (s,
1 H), 5.31 (dd, J ¼ 5.2, 2.8 Hz, 1 H), 4.92-4.88 (m, 1 H), 4.80 (dd, J ¼ 12.4,
3.6 Hz, 1 H), 4.65 (dd, J ¼ 12.4, 4.4 Hz, 1 H), 1.75 (d, J ¼ 21.6 Hz, 3 H); 13C
NMR (100MHz, CDCl3) d 166.0, 165.8, 133.7, 133.4, 130.1, 129.7, 129.3, 128.8,
128.6, 128.5, 95.6, 93.6, 92.0 (d, J ¼ 23.6 Hz), 81.9 (d, J ¼ 1.9 Hz), 73.4 (d,
J ¼ 15.4 Hz), 62.4, 22.9 (d, J ¼ 26.3 Hz); 19F NMR (376 MHz, CDCl3) d -151.36;
MS-ESIþ m/z 437 (M þ Hþ).

12
J. H. CHO ET AL.
1
b-Isomer (upper spot on TLC): H NMR (400 MHz, CDCl3) d 8.12-8.10
(m, 2 H), 8.08-8.06 (m, 2 H), 7.66-7.62 (m, 1 H), 7.56-7.48 (m, 3 H), 7.40-
7.36 (m, 2 H), 6.45 (d, J ¼ 11.4 Hz, 1 H), 6.07 (dd, J ¼ 23.0, 7.7 Hz, 1 H),
4.81 (m, 2 H), 4.64 (dd, J ¼ 13.2, 6.6 Hz, 1 H), 1.79 (d, J ¼ 22.4 Hz, 3 H); 19F
NMR (376 MHz, CDCl3) d –160.06. OK
3.1.11. ((2R,3R,4R,5R)-3-(benzoyloxy)-5-(4-chloro-5-iodo-7H-pyrrolo[2,3-d]pyrimi-
din-7-yl)-4-fluoro-4-methyltetrahydrofuran-2-yl)methyl benzoate (10c)
A solution of powdered KOH (0.23 g, 3.52 mmol, 85%) and TDA-1 (0.03 g,
0.09 mmol) in 10 mL of anhydrous CH3CN was stirred for 15 min at room
temperature under N2 atmosphere. 6-Chloro-7-iodo-7-deazapurine 8
(0.41 g, 1.47 mmol) was then added to the solution. After stirring for
20 min, a solution of compound 9c (0.77 g, 1.76 mmol) in 10 mL of anhyd-
rous CH3CN was added to the mixture at once. The reaction mixture was
stirred to 40 ꢀC for 48 h and then quenched with a saturated solution of
NH4Cl (30 mL) and extracted with EtOAc (50 mL ꢂ 2). The combined
organic layers were dried over Na2SO4, filtered and concentrated under
reduced pressure. The residue was purified by silica gel column chromatog-
raphy (hexanes:EtOAc ¼ 10:1 to 5:1 v/v) to give compound 10c (0.76 g,
1
1.20 mmol) in 68% yield. H NMR (400 MHz, CDCl3) d 8.65 (s, 1 H), 8.12-
8.08 (m, 4 H), 7.65-7.58 (m, 3 H), 7.52-7.46 (m, 4 H), 6.64 (d, J ¼ 18.0 Hz,
1 H), 5.90 (dd, J ¼ 22.0, 5.6 Hz, 1 H), 4.92 (dd, J ¼ 12.8, 2.4 Hz, 1 H), 4.78-
4.74 (m, 1 H), 4.62 (dd, J ¼ 12.8, 2.4 Hz, 1 H), 1.20 (d, J ¼ 22.8 Hz, 3 H); 13C
NMR (100 MHz, CDCl3) d 166.3, 165.7, 153.5, 151.6, 150.7, 134.2, 133.6,
131.4, 130.3, 129.9, 129.1, 128.9, 128.6, 117.7, 101.3, 99.5, 89.8 (d,
J ¼ 39.4 Hz), 72.5 (d, J ¼ 16.2 Hz), 62.3, 53.8, 17.4 (d, J ¼ 24.7 Hz); 19F NMR
(376 MHz, CDCl3) d –158.15; MS-ESIþ m/z 636 (M þ Hþ); HRMS-ESIþ:
m/z calcd for C26H21ClFIN3O5 (M þ Hþ) 636.0198, found 636.0186.
3.1.12. ((2R,3R,4R,5R)-3-(benzoyloxy)-5-(4-chloro-5-(trifluoromethyl)-7H-pyr-
rolo[2,3-d]pyrimidin-7-yl)-4-fluoro-4-methyltetrahydrofuran-2-yl)methyl
benzoate (11c)
To a solution of compound 10c (0.25 g, 0.39 mmol) in anhydrous DMF
(20 mL) and 8.50 mL of hexamethylphosphoric triamide was added
FSO2CF2CO2Me (63.0 mg, 0.49 mmol) and CuI (90.0 mg, 0.47 mmol) under
argon atmosphere. The reaction mixture was stirred for 24 h at 70 ꢀC under
argon atmosphere. The solution was then cooled down to room tempera-
ture and treated with a saturated aqueous solution of NH4Cl (20 mL) and
then extracted with a mixture of hexanes and EtOAc (40 mL ꢂ 2, 1:2 v/v).
The combined organic layers were washed with a saturated solution of
NaHCO3 (20 mL), water (20 mL), brine (20 mL), dried over Na2SO4 and fil-
tered. The filtrate was concentrated under reduced pressure and the residue

NUCLEOSIDES, NUCLEOTIDES AND NUCLEIC ACIDS
13
was purified by silica gel column chromatography (hexanes: EtOAc ¼ 10:1
1
to 5:1 v/v) to give compound 11c (0.22 g, 0.38 mmol) in 98% yield. H
NMR (400 MHz, CDCl3) d 8.76 (s, 1 H), 8.12-8.09 (m, 2 H), 8.06-8.04 (m,
2 H), 7.87 (s, 1 H), 7.65-7.56 (m, 2 H), 7.50-7.43 (m, 4 H), 6.66 (d,
J ¼ 18.0 Hz, 1 H), 5.92 (dd, J ¼ 21.6, 9.2 Hz, 1 H), 4.90 (dd, J ¼ 12.8, 2.8 Hz,
1 H), 4.81-4.77 (m, 1 H), 4.67 (dd, J ¼ 12.8, 4.0 Hz, 1 H), 1.24 (d,
J ¼ 22.0 Hz, 3 H); 13C NMR (100 MHz, CDCl3) d 166.4, 165.6, 153.0, 152.7,
151.7, 134.2, 133.7, 130.3, 129.9, 129.8, 129.4, 128.8, 128.5, 127.2, 123.2,
120.5, 114.1, 107.3 (q, J ¼ 38.5 Hz), 101.2, 99.3, 90.4 (d, J ¼ 40.1 Hz), 77.7,
72.6 (d, J ¼ 16.2 Hz), 62.2, 29.6, 17.6 (d, J ¼ 24.7 Hz); 19F NMR (376 MHz,
CDCl3) d –56.40, –157.73; MS-ESIþ m/z 578 (M þ Hþ); HRMS-ESIþ: m/z
calcd for C27H21ClF4N3O5 (M þ Hþ) 578.1106, found 578.1126.
3.1.13. (2R,3R,4S,5R)-5-(4-Amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-d]pyrimidin-
7-yl)-4-fluoro-2-(hydroxymethyl)-4-methyltetrahydrofuran-3-ol (12c)
In a steel bomb at 0 ꢀC, NH3 was bubbled through a solution of compound
11c (0.12 g, 0.21 mmol) in 20 mL of MeOH for 20 min and heated to 80 ꢀC
for 12 h. The volatiles were concentrated under reduced pressure and the
residue was purified by silica gel column chromatography (CH2Cl2: MeOH
¼ 20:1 to 10:1 v/v) to give compound 12c (63.10 mg, 0.18 mmol) in 85%
1
yield. H NMR (400 MHz, CD3OD) d 8.28 (d, J ¼ 1.2 Hz, 1 H), 8.24 (s,
1 H), 6.48 (d, J ¼ 17.2 Hz, 1 H), 4.59 (dd, J ¼ 24.8, 9.6 Hz, 1 H), 4.09-4.03
(m, 2 H), 3.86 (dd, J ¼ 12.8, 2.4 Hz, 1 H), 1.07 (d, J ¼ 22.0 Hz, 1 H); 13C
NMR (100 MHz, CD3OD) d 158.1, 154.4, 152.4, 126.3, 124.8 (d, J ¼ 6.2 Hz),
123.6, 106.7 (q, J ¼ 37.8 Hz), 103.4, 101.6, 100.0, 90.2 (d, J ¼ 38.6 Hz), 83.6,
72.2 (d, J ¼ 17.8 Hz), 60.3, 16.8 (d, J ¼ 25.5 Hz); 19F NMR (376 MHz,
CD3OD) d –57.26, –164.93; MS-ESIþ m/z 351 (M þ Hþ); HRMS-ESIþ: m/z
calcd for C13H15F4N4O3 (M þ Hþ) 351.1080, found 351.1069.
3.1.14. Ethyl ((((2 R,3R,4S,5R)-5-(4-amino-5-(trifluoromethyl)-7H-pyrrolo[2,3-
d]pyrimidin-7-yl)-4-fluoro-3-hydroxy-4-methyltetrahydrofuran-2-yl)me-
thoxy)(phenoxy)phosphoryl)-L-alaninate (14c)
To a solution of compound 12c (45.0 mg, 0.13 mmol) in 5.0 mL of anhyd-
rous THF was added t-BuMgCl (0.39 mL, 1.0 M in THF) at –78.0 ꢀC under
N2 atmosphere. After being stirred for 30 min at this temperature and for
10 min at room temperature, a solution of phosphoramidate chloride 13
(75.0 mg, 0.26 mmol) in 2.0 mL of anhydrous THF was added to the reac-
tion at –78 ꢀC. The reaction mixture was stirred for 6 h at room tempera-
ture and cooled down to 0 ꢀC before treatment with a saturated solution of
NH4Cl (0.20 mL). The resulting solution was poured into EtOAc (30 mL)
and washed with a saturated solution of NH4Cl (20 mL) and brine (10 mL).
The organic layer was dried over Na2SO4, filtered and concentrated under

14
J. H. CHO ET AL.
reduced pressure. The crude residue was purified by silica gel column chro-
matography (CH2Cl2: MeOH ¼ 20:1 to 10:1 v/v) to give compound 14c
(54.50 mg, 0.09 mmol) as a mixture of Rp-/Sp-isomers (1:1) in 69% yield.
1H NMR (400 MHz, CD3OD) d 8.25 (s, 1 H), 7.85 (d, J ¼ 1.6 Hz, 1 H),
7.36-7.32 (m, 2 H), 7.24-7.22 (m, 2 H), 7.20-7.15 (m, 1 H), 6.54-6.49 (s,
1 H), 4.65-4.60 (m, 1 H), 4.52-4.47 (m, 1 H), 4.26-4.22 (m, 2 H), 4.19-4.08
(m, 2 H), 4.92-3.88 (m, 1 H), 1.29-1.26 (m, 5 H), 1.21 (t, J ¼ 7.2 Hz, 3 H),
1.12-1.06 (s, 3 H); 13C NMR (100 MHz, CD3OD) d 175.1, 158.1, 154.6,
152.6, 152.3, 130.9, 126.3, 121.6 (d, J ¼ 4.6 Hz), 112.5, 103.0, 101.2, 100.1,
90.8, 81.4, 73.0, 65.8, 62.5, 51.8, 20.4 (d, J ¼ 7.0 Hz), 17.0, 16.7,14.6; 31P
NMR (162 MHz, CD3OD) d 5.23; 19F NMR (376 MHz, CD3OD) d -56.99,
-57.04, -163.59; MS-ESIþ m/z 606 (M þ Hþ); HRMS-ESIþ: m/z calcd for
C24H29F4N5O7P (M þ Hþ) 606.1740, found 606.1723. OK.
Funding
This work was supported in part by NIH Grant 5P30-AI-50409 (CFAR), BB 21 Plus and
the Dong-A University research fund (Korea).
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