Cycloalkane analogues of sinefungin as EHMT1/2 inhibitors

Article abstract of DOI:10.1016/j.bmc.2017.06.032

A series of cycloalkyl substituted analogues of the natural product sinefungin lacking the amino-acid moiety was designed and synthesized. Two stereoisomers (6-R and 6-S) were separated and their bioactivities examined against EHMT1/2. Of which, compound 14d showed an inhibitory activity against EHMT1/2 (88.9%, IC₅₀ = 21.8 μM for EHMT1 and 77.6%, IC₅₀ = 39.6 μM for EHMT2, respectively) similar to that of sinefungin (100.0%, IC₅₀ = 28.4 μM for EHMT1 and 79.5%, IC₅₀ = 30.1 μM for EHMT2, respectively). Further studies against other methyltransferases such as PRMT1 showed no activity except that 12d displayed about 20% inhibition.

Full text of DOI:10.1016/j.bmc.2017.06.032

Accepted Manuscript
Cycloalkane analogues of sinefungin as EHMT1/2 inhibitors
Qing Liu, Xiaoqing Cai, Dehua Yang, Yi Chen, Liming Shao, Ming-Wei Wang
PII:
S0968-0896(16)31064-1
DOI:
http://dx.doi.org/10.1016/j.bmc.2017.06.032
BMC 13815
Reference:
Bioorganic & Medicinal Chemistry
To appear in:
Received Date:
Revised Date:
Accepted Date:
27 October 2016
15 June 2017
19 June 2017
Please cite this article as: Liu, Q., Cai, X., Yang, D., Chen, Y., Shao, L., Wang, M-W., Cycloalkane analogues of
sinefungin as EHMT1/2 inhibitors, Bioorganic & Medicinal Chemistry (2017), doi: http://dx.doi.org/10.1016/j.bmc.
2017.06.032
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Cycloalkane analogues of sinefungin as EHMT1/2 inhibitors
Qing Liu1,2,3, Xiaoqing Cai2,3, Dehua Yang2,3, Yi Chen4, Liming Shao1,* and Ming-Wei Wang1,2,3,4,*
2
1School of Pharmacy, Fudan University, Shanghai 201203, China; The CAS Key Laboratory of
Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai
3
4
201203, China; The National Center for Drug Screening, Shanghai 201203, China; Shanghai
Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203
*Correspondence to Liming Shao (limingshao@fudan.edu.cn) or Ming-Wei Wang
(mwwang@simm.ac.cn).
ABSTRACT
A series of cycloalkyl substituted analogues of the natural product sinefungin lacking the amino-acid
moiety was designed and synthesized. Two stereoisomers (6-R and 6-S) were separated and their
bioactivities examined against EHMT1/2. Of which, compound 14d showed an inhibitory activity
against EHMT1/2 (88.9%, IC50 = 21.8 μM for EHMT1 and 77.6%, IC50 = 39.6 μM for EHMT2,
respectively) similar to that of sinefungin (100.0%, IC50 = 28.4 μM for EHMT1 and 79.5%, IC50 =
30.1 μM for EHMT2, respectively). Further studies against other methyltransferases such as PRMT1
showed no activity except that 12d displayed about 20 % inhibition.
Keywords
Methyltransferase inhibitor; cycloalkyl substituted analogue; natural product; sinefungin
INTRODUCTION
Epigenetic regulation of gene transcription is mediated by a group of regulatory enzymes, including
DNA methyltransferases, protein methyltransferases, protein demethylases, histone
acetyltransferases, histone deacetylases and ubiquitin ligases.1,2 Among them, histonelysine
methyltransferases (HKMTs) are recognized as an important family playing key roles in cell
1

differentiation, gene regulation, DNA recombination and damage repair and carcinogenesis.3-6
HKMTs transfer the methyl group from the cofactor (S)-adenosylmethionine (SAM), which contains
a highly reactive methylthiol group, to the tailed nitrogen of the substrate lysine residue, producing
mono-, di- or tri-methylated products and its analogue (S)-adenosylhomocysteine (SAH) (Figure
1).7-9
Figure 1. Methylation of lysine residue by histone lysine methyltransferases (HKMTs) utilizing
(S)-adenosylmethionine (SAM) as cofactor.
Euchromatin histone methyltransferases10-11 (EHMTs), including G9a encoded by EHMT2 and
GLP (G9a-like protein) encoded by EHMT1, regulate transcriptional repression and activation in the
process of germ cell formation, embryogenesis and cardiac morphogenesis in the form of
heterodimeric complex.12-13 G9a is highly expressed in a variety of human cancers such as leukemia,
prostate cancer, lung cancer and hepatocellular carcinoma with a poor prognosis.14 Several small
molecules have been reported as inhibitors of EHMTs and were divided into two categories,
substrate-competitive and AdoMet-competitive inhibitors, according to their different mechanisms of
action (Figure 2). Substrate-competitive inhibitors such as BIX0129415-16 and UNC063817-18 showed
IC50 values of 1.9 µM and <15 nM for G9a, and 0.7 µM and 19 nM for GLP, respectively. UNC0638
2

also dose-dependently increased the expression of human γ-globin and HbF.18 SAM-competitive
inhibitors include SAH19 and sinefungin20-22 which is a natural product isolated from Streptomyces
incamatus and Streptomyces griseolus. Both compounds have similar structures and displayed no
selectivity over a wide range of methyltransferases. We have previously reported a series of
sinefungin analogues capable of inhibiting EHMTs at micromolar potency with little effect on three
other methyltransferase (DNMT1, PRMT1 and SET7/9) at 200 μM.23 However, the lead compound 1
was a mixture of two epimers (6-R and 6-S) and no further structure-activity relationship (SAR)
analysis was conducted.
Figure 2. Reported small molecule EHMT inhibitors.
Our follow-up studies presented here were focused on the continuous modification around the
cyclohexyl moiety and stereochemistry at C-6 (Figure 3). We designed and synthesized a series of
7-cycloalkyl (C3-6) and 8-cyclohexyl substituted analogues, followed by isolation of two 6-R/S
epimers, to examine the effects of ring size, chain elongation and C-6 conformation on their ability to
inhibit
EHMT1/2.
Also,
we
synthesized
a
series
of
N-cyclohexylmethyl-N-alkyl-5'-deoxy-5'-amino-adenosine analogues to inspect the effects of
3

nitrogen-position change on the inhibitory effect on EHMT1/2.
Figure 3. Structural modifications based on compound 1.
RESULTS AND DISCUSSION
For the series of cycloalkyl substituted analogues, our synthetic strategy consisted of three parts: the
construction of different substituent-containing β-furanoside moiety derived from
5,6-deoxy-6-cyano-6-diethoxyphosphono-2,3-O-isopropylidene-β-D-hexo-furanoside 2, the coupling
of N6-benzoyl protected adensine 7 with 1,2,3-O-triacetyl protected β-D-furanoside moiety 6 and the
rearrangement of amide to amino group as outlined in Scheme 1.
1
Condensation of different aldehydes with cyanophosphonate 2 led to unsaturated nitriles 3. H
NMR spectrum showed two groups of alkene hydrogen signals indicating the existence of E and Z
configuration at a ratio of 1:3. Reduction of 3 gave 7-cycloalkyl (C3-C6) or 8-cyclohexyl substituted
nitriles 4. It was worthy to mention that 4d (7-cyclopropyl substituted analogue) was hydrogenated
under higher pressure (0.6 MPa) compared with other compounds (4a-c, e: 0.3 MPa). Compound 4
was oxidatively hydrolyzed under basic condition to its corresponding amide 5, which was
subsequently refluxed in 0.2 N sulphuric acid to obtain its triol. Without further purification, this triol
4

was protected with acetyl group in the mixture of acetic anhydride and pyridine to obtain the
1,2,3-O-triacetate 6. Intermediate 6 was a mixture of anomers, which was difficult to separate by
silica gel chromatography. It was utilized for the subsequent adenosylation directly.
Next, the key Vorbrüggen reaction was conducted by two steps: 1) persilylation of
N6-benzoyladenine 7 with N,O-bis(trimethylsilyl)acetamide (BSA) in acetonitrile at reflux for 2 h to
afford N6,N9-bis(trimethylsilyl)-N6-benzoyladenine; 2) anomeric adenosylation of 6 with the
resulting N6,N9-bis(trimethylsilyl)-N6-benzoyladenine in the presence of trimethylsilyl
trifluoromethanesulfonate (TMSOTf) in dichloroethane at reflux for 2 h to afford β-nucleoside 8a-e22
in 40-92% yield after silica gel chromatography. Interestingly, the amount of TMSOTf was different
depending on cycloalkyl substitutes (8a,b: 1 eq; 8c: 3 eq; 8d: 2 eq; 8e: 2.5 eq) and the 9-ribo product
8 was the only product, which was in agreement with the previous reports22, 24 that 7- and
1-regioisomers were kinetic products and transglycosylation was undergone after a prolonged
13
reaction time. Two stereoisomers existed in compound 8a-e as suggested by1H NMR and C NMR.
13
For compound 8a, two groups of peaks existed in 1H NMR and C NMR around C-1, 2, 3, 4 and 6,
indicating the existence of two epimers (6-R and 6-S).
Finally, we tried to transform 6-amide 8 to the corresponding amine by Hoffmann rearrangement
in the presence of [bis(trifluoroacetoxy)iodo]benzene and found unsuccessful. Alternative strategy
was thus carried out by saponification of acetate 8 with 2N NH3 in methanol and followed by
isopropylidene protection catalyzed by TMSOTf in acetone to obtain two 6-epimers of 9 and 10 at a
ratio of about 1:1, which were easy to separate by prep-TLC (0.4-0.5 mm). Hofmann rearrangement
of 9 and 10 gave the corresponding amines 11 and 13 as their N-(tert-butyloxy)carbonyl derivatives,
respectively. The conformation at C-6 was retained during the Hofmann rearrangement as indicated
1
by H NMR signals between the two epimers (9 vs. 11 and 10 vs. 13). For 7-cyclohexyl substituted
analogues, it was found that H-6 of 9a and 11a (2.32 ppm for 9a and 3.55 ppm for 11a) showed up in
a relative upfield than that of 10a and 13a (2.52 ppm for 10a and 3.72 ppm for 13a). Deprotection of
5

11 or 13 was accomplished in the mixture of trifluoroacetic acid and water (1:1) to obtain the final
product 12 or 14 (6-S or 6-R) as their trifluoroacetates.
Scheme 1. Synthetic route of 12 a-e and 14 a-e. (i) RCHO, NaH/THF at room temperature for 4 h,
96.0-97.6% yield; (ii) 10% Pd/C/MeOH hydrogenated at 30°C under 0.3 or 0.6 MPa for 5-6 h,
82.0-98.0% yield; (iii) 2N NaOH/H2O2/DMSO/MeOH at reflux for 1 h, 69.6-99.1% yield; (iv) 1)
0.2N H2SO4/dioxane/H2O at reflux for 5 h, 2) Ac2O/Py at room temperature overnight, 69.3-99.1%
yield; (v) 1) N6-benzoyl-adenine 7 in BSA/CH3CN at reflux for 2 h, 2) 6, TMSOTf in dichloroethane
at reflux for 2 h, 40.5-91.7% yield; (vi) 1) 2N NH3 in MeOH at 40°C overnight, 2) acetone/TMSOTf
at room temperature for 1 h, 90.5-99.7% yield (R and S); (vii) 1) (CF3CO2)2IC6H5 in CH3CN/H2O at
6

room temperature for 2 h, 2) Boc2O/TEA, 10.1-83.7% yield; (viii) TFA/H2O at room temperature for
30 min, 34.0-97.2% yield.
The Mosher’s method was used to determine the absolute stereochemistry of C-6. We prepared
the 2,3-O-isopropylidene derivative of 14a by catalysis with TMSOTf in acetone, followed by
acylation with both (R)- and (S)-Mosher's acid chloride (MTPA-Cl) to form a pair of diastereomeric
1
amides. H NMR data for the two diastereomers, (R)-MTPA and (S)-MTPA amide were compared.
The protons in the L1 portion of (S)-MTPA amide are shifted downfield relative to that of (R)-MTPA
amide, while the protons in the L2 portion of (S)-MTPA amide are shifted upfield relative to that of
(R)-MTPA amide due to the anisotropic shielding effect of phenyl ring. Δδ S-R values for the shifts of
protons located near the C-6 stereo-center in the amide diastereomers were calculated, and the results
were analyzed against the models. In the end, the conformation of 14 was assigned to be 6-S, while
12 was designated as 6-R (Scheme 2).
7

Scheme 2. Procedure for the C-6 conformation assignment of 14a.
Next, to investigate the effect of nitrogen-position, we synthesized a series of
5'-deoxy-5'-amino-adenosine derivatives starting from 2,3-O-isopropylideneadenosine 15, which
underwent Mitsunobu reaction followed by hydrazinolysis to obtain 17. Two rounds of reductive
amination of 17 with cyclohexanecarbaldehyde and C1-3 alkyl substituted aldehyde were carried out
sequentially to obtain 19a-c, which were deprotected in the mixture of trifluoroacetic acid and water
(1:1) to afford the final products 20a-c (Scheme 3).
8

Scheme 3. Synthetic route of 20a-c. (i) Phthalimide/DIAD/Ph3P/THF at room temperature
overnight, 95.1% yield; (ii) N2H4·H2O/C2H5OH at reflux overnight, 90.5% yield; (iii)
C6H11CH2CHO/HAc/NaCNBH3/MeOH at room temperature overnight, 49.0% yield; (iv)
RCHO/HAc/NaCNBH3/MeOH at room temperature overnight, 50.0-91.9% yield; (v) TFA/H2O at
room temperature for 3 h, 69.4-98.1% yield.
Initial characterization of these compounds was performed at a concentration of 200 μM on
EHMT1 and 400 μM on EHMT2, and the results were shown in Figures 4, 5 and Table 1. Most
cycloalkyl (C3-6) substituted analogues demonstrated moderate to strong inhibition on EHMT1/2
while N-cyclohexylmethyl-N-alkyl-5'-deoxy-5'-amino-adenosine analogues showed weak inhibitory
activities, indicating the importance of nitrogen position. Compounds with >50% inhibition on
EHMT1 (12a, c-d, 14a-d) and EHMT2 (12d, 14b-d) were selected and further assessed for
dose-response characteristics against EHMT1/2.
9

A
B
C
Figure 4. Bioactivities of sinefungin and its analogues on EHMT1. (A) Inhibition of EHMT1 by
sinefungin and its analogues at 200 μM in the HTRF assay. (B) Dose-response characteristics of
sinefungin on EHMT1. (C) Dose-response characteristics of the analogues that showed more than
50% inhibition on EHMT1. Each value represents mean±SEM of 3-4 independent experiments
performed in triplicate.
10

A
B
C
Figure 5. Bioactivities of sinefungin and its analogues on EHMT2. (A) Inhibition of EHMT2 by
sinefungin and its analogues at 400 μM in the TR-FRET assay. (B) Dose-response characteristics of
sinefungin on EHMT2. (C) Dose-response characteristics of the analogues that showed more than
50% inhibition on EHMT2. Each value represents mean±SEM of 3-4 independent experiments
performed in triplicate.
The results on EHMT1 showed that the 6-S epimers were markedly more effective than 6-R
epimers with the same substitutes at C-6 (14a vs. 12a, 14b vs. 12b, 14c vs. 12c and 14d vs. 12d) and
this conformation difference was weakened when the side chain was elongated (12e vs. 14e). The
length of side chain also affected their bioactivities on EHMT1. For analogues with the same
cyclohexyl substitutes (14a vs. 14e and 12a vs. 12e), both elongation and reduction of the length
(data not shown) weakened or totally destroyed their activities. For the 6-S epimers 14a-d, different
cycle size also influenced their inhibitory activities with cyclopropyl substituted analogue 14d as the
most effective inhibitor of EHMT1, which exhibited a similar potency as the natural product
sinefungin (IC50 = 21.8 μM for 14d vs. IC50 = 28.4 μM for sinefungin). It was noted that the 6-NH2
11

conformation affected the analogues substituted with 7-cyclopentyl group (14b vs. 12b) most, with
6-fold higher inhibitory activity for 6-S epimer than that of 6-R epimer. The results on EHMT2 were
slightly different from that on EHMT1. The same tendency was observed that 6-S epimers displayed
stronger inhibitory activities than 6-R epimers except for 7-cyclohexyl (14a and 12a) and
8-cyclohexyl (14e and 12e) analogues, which exhibited almost the same inhibitory activities between
different epimers. Among all the 6-S epimers 14a-d, cyclopropyl substituted analogue 14d was the
most potent one, showing a similar potency as the natural product sinefungin (IC50 = 39.6 μM for
14d vs. IC50 = 30.1 μM for sinefungin). None of the compounds discriminated significantly between
EHMT1 and EHMT2. However, when we selected compounds 12a, 12d and 14a-d demonstrating
good inhibitory activities towards EHMTs and tested their ability to inhibit other methyltransferases,
e.g. PRMT1, 12a and 14a-d did not exhibit any inhibition at the concentration of 400 μM, only 12d
showed 20 % inhibition on PRMT1 (Figure 6). The effect of the sinefungin analogues were
examined in HL60 (human promyelocytic leukemia) and MDA-MB-231 (human breast
adenocarcinoma) cell lines at 200 μM. The results showed that compound 14d and sinefungin had
similar growth inhibitory effects (38%-43%) on these cancer cells (Table S1).
Table 1. Inhibition by sinefungin and its analogues on EHMT1/2.
EHMT2 IC50 (μM)a
30.1 (19.4-46.7)
N.D.c
Inhibition (%)b
79.5±0.9
45.3±1.3
43.6±2.0
44.0±5.6
65.7±4.8
47.8±1.2
43.7±4.9
55.3±7.1
EHMT1 IC50 (μM)a
28.4 (12.465.2)
145.8 (100.8210.8)
N.D.c
Inhibition (%)b
100.0±0.0
58.1±0.7
Compound
Sinefungin
12a
N.D.c
12.5±1.3
12b
N.D.c
115.0 (83.6158.1)
794.3 (405.11557.0)
N.D.c
53.2±1.7
12c
67.2 (41.8-108.2)
N.D.c
52.2±1.9
12d
46.3±0.6
12e
N.D.c
203.7 (142.2291.9)
95.1 (71.6126.2)
72.7±2.1
14a
191.3 (106.8-342.8)
75.7±1.0
14b
12

169.0 (110.3-258.8)
39.6 (28.8-54.5)
N.D.c
58.9±6.4
77.6±0.7
42.7±1.0
31.9±1.0
39.1±1.5
19.8±1.9
47.7 (29.278.0)
21.8 (17.527.1)
N.D.c
69.7±0.9
88.9±0.1
40.9±1.3
N.A. d
14c
14d
14e
N.D.c
N.A.d
20a
20b
20c
N.D.c
N.D.c
24.1±3.3
N.A.d
N.D.c
N.A.d
aIC50 value shown represents an average of 4 independent experiments. Numbers in the brackets
indicate 95% confidence interval data.
bInhibition of methyltransferase EHMT1/2 activities by sinefungin and its analogues at
concentrations of 200 μM and 400 μM, respectively. Each value represents mean±SEM of 3
independent experiments performed in triplicate.
cN.D., not determined.
dN.A., no activity.
A
B
Figure 6. Bioactivities of sinefungin and its analogues on PRMT1. (A) Inhibition of PRMT1 by
sinefungin (10 μM) and its analogues (400 μM) in the HTRF assay. (B) Dose-response
characteristics of sinefungin on PRMT1. Each value represents mean±SEM of 3 independent
experiments performed in triplicate.
CONCLUSION
In this paper we reported a series of cycloalkyl substituted sinefungin analogues as inhibitors of
13

EHMT1/2. Two epimers (6-R and 6-S) were separated. Their structures were determined by 1H NMR,
13C NMR, LR-MS and HR-MS, and the conformation at C-6 was assigned by Mosher's method. The
inhibitory activities of these compounds on methyltransferases EHMT1/2 were subsequently
examined and cyclopropyl substituted analogue 14d showed the most potent effect, similar to that of
the natural product sinefungin. Further studies are ongoing to improve synthetic routes and to
understand the SAR around the adenine part of the compounds. Nevertheless, this scaffold of
cycloalkyl substituted sinefungin analogues provides a sound starting point for follow-up
investigations on EHMTs.
EXPERIMENT
Chemistry.
General Statement. Reagents were commercial grades and used as received unless otherwise noted.
1
The structures of all new compounds were consistent with their H, 13C NMR, and mass spectra, and
were judged to be ≥95% pure by HPLC. NMR spectra were recorded on Varian Mercury 300,
AVANCE III 500 spectrometers. Chemical shifts were reported in parts per million (ppm), with the
1
13
solvent resonance as the internal standard (CD3OD 3.31 ppm for H NMR,49.15 ppm for C NMR;
1
CDCl37.27 ppm for H NMR,77.23 ppm for 13C NMR). Low resolution mass spectral data
(electrospray ionization) were acquired on a Finnigan LCQ-DECA mass spectrometer. High
resolution mass spectral data (TOF) were acquired on an Agilent 6224 mass spectrometer. Samples
were analyzed for purity on a HP1100 series equipped with a Zorbax SB-C18 column (5 μm, 4.6
mm×250 mm). Purities of final compounds were determined using a 5 μL injection with quantitation
by AUC at 210 and 254 nm. Reversed-phase silica gel (20−45 μm) was used for column
chromatography. Specific optical rotation was determined on Autopol VI-Rudolph polarimeter.
5,6-Deoxy-6-cyano-6-diethoxyphosphono-2,3-O-isopropylidene-β-D-hexo-furanoside (2)
5,6-Deoxy-6-cyano-6-diethoxyphosphono-2,3-O-isopropylidene-β-D-hexo-furanoside
2
was
synthesized according to the same procedures described in the previous paper23. HRMS (TOF) m/z
14

calcd for C15H27NO7P [M+H]+ 364.1525, found 364.1529. R:S = 1:1. 1H NMR (CDCl3, 300 MHz)
1.31 (s, 6H), 1.39 (t, J = 6.6 Hz, 12H), 1.47 (s, 6H), 1.80 (m, 4H), 2.88 (m, 2H), 3.33 (s, 6H), 3.36 (s,
6H), 4.25 (q, J = 7.2 Hz, 8H), 4.39 (dd, J = 3.3 Hz, J = 8.1 Hz, 2H), 4.59 (t, J = 5.4 Hz, 2H), 4.60 (t,
J = 6.0 Hz, 2H), 4.97 (d, J = 3.3 Hz, 2H).13C NMR (CDCl3, 75 MHz) 15.7, 16.5, 16.6, 25.2, 26.6,
32.8, 55.8, 64.1, 64.2, 83.7, 83.9, 85.4, 110.2, 110.4, 113.0.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside
(3a)
Sodium hydride (60%, 0.51 g, 12.8 mmol, 4 eq) was added into the solution of
5,6-deoxy-6-cyano-6-diethoxyphosphono-2,3-O-isopropylidene-β-D-hexo-furanoside (2, 1.16 g, 3.2
mmol, 1 eq) in anhydrous tetrahydrofuran (20 mL) under nitrogen and the mixture was stirred for 10
min followed by addition of cyclohexanecarbaldehyde (1.43 g, 12.7 mmol, 4 eq) . The reaction was
stirred at room temperature for 3 h. It was terminated by addition of 10% oxalic acid/methanol
solution (2 mL) and evaporated in vacuo. The residue was extracted with ethyl acetate (310 mL)
and the organic phase was combined, washed with water (310 mL) and dried over anhydrous
sodium sulphate. After filtration, the solvent was removed in vacuo and the residue was purified on
the Biotage SNAP Cartridge KP-Sil 100 g eluting with petroleum ether, 20% ethyl acetate/petroleum
ether to give the product as yellowish oil (1.0 g, yield: 97.1 %). The purity was 96% by HPLC
analysis. HRMS (TOF) m/z calcd for C18H28NO4[M+H]+ 322.2018, found 322.2016. E:Z = 1:3. 1H
NMR (CDCl3, 300 MHz) 1.21 (m, 10H), 1.24 (s, 6H), 1.40 (s, 6H), 1.65 (m, 10H), 2.28 (m, 1H),
2.37 (m, 4H), 2.50 (m, 1H), 3.26 (s, 3H), 3.30 (s, 3H), 4.29 (m, 2H), 4.48 (d, J = 6.0 Hz, 1H), 4.55
(m, 1H), 4.54 (d, J = 5.7 Hz, 1H), 4.57 (d, J = 6.0 Hz, 1H), 4.87 (s, 1H), 4.90 (s, 1H), 6.02 (d, J = 9.9
Hz, 1H), 6.23 (d, J = 9.9 Hz, 1H). 13C NMR (CDCl3, 75 MHz) 25.0 (4C), 25.2 (2C), 25.7 (2C), 26.2
(2C), 34.0 (2C), 37.7 (4C), 39.5, 40.8, 55.3, 55.5, 83.4, 84.9, 85.4, 109.9, 110.1, 112.6, 112.7, 117.2
(2C), 119.8 (2C), 155.5, 155.6.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside
15

(3b)
Compound 3b was prepared according to the same procedure of 3a, in which
cyclopentanecarbaldehyde was used and 3b was obtained as yellowish oil in 96.9 % yield. The purity
was 97% by HPLC analysis. HRMS (TOF) m/z calcd for C17H26NO4[M+H]+ 308.1862, found
1
308.1865. E:Z = 1:3. H NMR (CDCl3, 300 MHz) 1.25 (m, 8H), 1.27 (s, 3H), 1.31(s, 3H), 1.44 (s,
3H), 1.47 (s, 3H), 1.66 (m, 8 H), 2.27 (m, 1H), 2.43 (m, 2H), 2.57 (m, 1H), 2.74 (m, 1H), 2.98 (m,
1H), 3.33 (s, 3H), 3.36 (s, 3H), 4.10 (m, 1H), 4.39 (t, J = 7.8 Hz, 1H), 4.55 (d, J = 5.7 Hz, 2H), 4.61
(d, J = 5.4 Hz, 2H), 4.91(s, 1H), 4.95 (s, 1H), 6.13 (d, J = 10.2 Hz, 1H), 6.38 (d, J = 10.2 Hz, 1H).
13C NMR (CDCl3, 75 MHz) 25.2 (2C), 25.7 (4C), 26.7 (2C), 33.3 (4C), 39.3, 39.6, 42.5, 42.7, 55.6,
55.7, 83.5, 83.6, 85.2 (2C), 85.6 (2C), 110.5 (2C), 112.8 (2C), 116.5 (2C), 155.9, 155.6.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside(3
c)
Compound 3c was prepared according to the same procedure of 3a, in which
cyclobutanecarbaldehyde was used and 3c was obtained as yellowish oil in 95.7% yield. The purity
was 96% by HPLC analysis. HRMS (TOF) m/z calcd for C16H24NO4[M+H]+ 294.1705, found
1
294.1708.E:Z = 1:3. H NMR (CDCl3, 300 MHz) 1.30 (s, 6H), 1.46 (s, 6H), 1.96 (m, 8H), 2.28 (m,
4H), 2.42 (m, 4H), 3.33 (s, 3H), 3.35 (s, 3H), 3.45 (m, 2H), 4.37 (t, J = 7.8 Hz, 2H), 4.54 (d, J = 6.0
Hz, 2H), 4.60 (d, J = 6.3 Hz, 2H), 4.94 (s, 2H), 6.32 (d, J = 9.6 Hz, 1H), 6.57 (d, J = 9.6 Hz, 1H). 13C
NMR (CDCl3, 75 MHz) 19.1 (2C), 25.2 (2C), 26.6 (2C), 28.9 (4C), 37.4 (2C), 39.5 (2C), 55.6 (2C),
83.5, 83.6, 85.2 (2C), 85.4, 85.6, 108.7 (2C), 110.1 (2C), 112.8 (2C), 117.5 (2C), 154.6, 154.9.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclopropyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside
(3d)
Compound 3d was prepared according to the same procedure of 3a, in which
cyclopropanecarbaldehyde was used and 3d was obtained as yellowish oil in 97.6 % yield. The
purity was 98% by HPLC analysis. HRMS (TOF) m/z calcd for C15H22NO4[M+H]+ 280.1549,
16

1
found 280.1546. E:Z = 1:3. H NMR (CDCl3, 300 MHz) 0.59 (m, 4H), 0.65 (m, 4H), 1.01 (dd, J =
2.4 Hz, J = 7.5 Hz, 2H), 1.31 (s, 6H), 1.48 (s, 6H), 2.43 (m, 2H), 2.51 (m, 1H), 2.63 (m, 1H), 3.33 (s,
3H), 3.37 (s, 3H), 4.37 (t, J = 7.2 Hz, 1H), 4.44 (t, J = 7.5 Hz, 1H), 4.57 (t, J = 6.0 Hz, 1H), 4.60 (t, J
= 5.7 Hz, 1H), 4.63 (d, J = 7.8 Hz, 2H), 4.95 (s, 1H), 4.98 (s, 1H), 5.57 (d, J = 10.2 Hz, 1H), 5.77 (d,
J = 10.2 Hz, 1H).13C NMR (CDCl3, 75 MHz) 8.7 (2C), 9.3 (2C), 14.5 (2C), 25.3 (2C), 26.7 (2C),
39.4 (2C), 55.5, 56.0, 83.6 (2C), 85.4 (2C), 85.6 (2C), 98.6 (2C), 110.1, 110.7, 113.0 (2C), 121.8
(2C), 154.3, 155.0.
1-Methyl-5,6,7,8-deoxy-6-cyano-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-6-enofuranoside
(3e)
Compound 3e was prepared according to the same procedure of 3a, in which
2-cyclohexaneacetaldehyde was used and 3e was obtained as yellowish oil in 96.0% yield. The
purity was 96% by HPLC analysis. HRMS (TOF) m/z calcd for C19H30NO4[M+H]+ 336.2175,
1
found 336.2174. E:Z = 1:3. H NMR (CDCl3, 300 MHz) 1.01 (m, 3H), 1.20 (m, 6H), 1.31 (s, 6H),
1.48 (s, 6H), 1.69 (m, 13H), 2.09 (m, 2H), 2.30 (t, J = 7.2 Hz, 2H), 2.47 (dd, J = 5.7 Hz, J = 11.7 Hz,
2H), 2.47 (m, 2H), 3.36 (s, 6H), 4.39 (t, J = 6.6 Hz, 2H), 4.56 (d, J = 5.7 Hz, 2H), 4.62 (d, J = 6.3 Hz,
13
2H), 4.96(s, 1H), 4.97 (s, 1H), 6.27 (t, J = 7.5 Hz, 1H), 6.52 (m, 1H). C NMR (CDCl3, 75 MHz)
25.2 (4C), 26.4 (4C), 26.7 (2C), 33.1 (4C), 37.9 (2C), 39.6 (2C), 39.8 (2C), 55.5, 55.7, 83.6 (2C),
85.3 (2C), 85.6 (2C), 110.1, 110.3, 111.9, 112.9, 117.7 (2C), 122.6 (2C), 149.6, 150.1.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4a)
10%
Palladium/carbon
(0.1
g)
was
added
into
the
solution
of
1-methyl-5,6,7-deoxy-6-cyano-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside (3a,
1.03 g) in methanol (100 mL). The mixture was hydrogenated under the pressure of 0.3 MPa at 30°C
for 56 h. After filtration, the solution was evaporated in vacuo and the product was used in the next
step directly (1.0 g, yield: 97.1 %). The purity was 95% by HPLC analysis. HRMS (TOF) m/z calcd
for C18H30NO4[M+H]+ 324.2175, found 324.2169. R:S or S:R = 1:1.1. 1H NMR (CDCl3, 300 MHz)
17

0.96 (m, 4H), 1.28 (m, 10H), 1.31 (s, 6H), 1.48 (s, 6H), 1.52 (m, 12H), 1.73 (m, 4H), 2.80 (m, 2H),
3.33 (s, 3H), 3.38 (s, 3H), 4.26 (dd, J = 5.7 Hz, J = 9.9 Hz, 1H), 4.42 (dd, J = 5.1 Hz, J = 10.2 Hz,
13
1H), 4.53 (t, J = 5.7 Hz, 2H), 4.61 (t, J = 5.7 Hz, 2H), 4.96 (s, 2H). C NMR (CDCl3, 75MHz) 21.8,
25.1, 25.3, 25.8, 26.2, 27.2, 29.9, 32.2, 32.5, 34.0, 35.6, 55.7, 67.5, 84.2, 85.6, 110.1, 110.4, 112.9.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4b)
Compound 4b was prepared according to the same procedure of 4a, in which
1-methyl-5,6,7-deoxy-6-cyano-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside (3b)
was used and 4b was obtained as yellowish oil in 98.0% yield. The purity was 98% by HPLC
analysis. HRMS (TOF) m/z calcd for C17H28NO4[M+H]+ 310.2018, found 310.2013. R:S or S:R =
1:1.5. 1H NMR (CDCl3, 300 MHz) 1.31 (s, 6H), 1.48 (s, 6H), 1.60 (m, 18H), 1.74 (m, 4H), 2.03 (m,
4H), 2.75 (m, 2H), 3.34 (s, 3H), 3.38 (s, 3H), 4.27 (dd, J = 5.4 Hz, J = 9.9 Hz, 1H), 4.42 (t, J = 8.1
13
Hz, 1H), 4.53 (t, J = 5.7 Hz, 2H), 4.61 (t, J = 4.8 Hz, 2H), 4.96 (s, 2H). C NMR (CDCl3, 75 MHz)
22.9, 25.1, 25.2 (2C), 27.8, 29.9, 32.1, 32.8, 33.0, 33.2, 55.7, 68.7, 84.1, 85.6, 110.1, 110.4, 112.8.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4c)
Compound 4c was prepared according to the same procedure of 4a, in which
1-methyl-5,6,7-deoxy-6-cyano-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside (3c)
was used and 4c was obtained as yellowish oil in 91.5% yield. The purity was 97% by HPLC
analysis. HRMS (TOF) m/z calcd for C16H26NO4[M+H]+ 296.1862, found 296.1859. R:S or S:R =
1
1:1.1. H NMR (CDCl3, 300 MHz) 1.31 (s, 6H), 1.48 (s, 6H), 1.60 (m, 4H), 1.80 (m, 9H), 2.13 (m,
9H), 2.50 (m, 1H), 2.62 (m, 1H), 3.34 (s, 3H), 3.37 (s, 3H), 4.26 (dd, J = 5.7 Hz, J = 9.9 Hz, 1H),
4.39 (dd, J = 6.0 Hz, J = 10.2 Hz, 1H), 4.52 (t, J = 5.7 Hz, 2H), 4.61 (t, J = 5.7 Hz, 2H), 4.96 (s, 2H).
13C NMR (CDCl3, 75 MHz) 18.7, 22.9, 25.3, 27.3, 28.4, 28.7, 29.9, 34.0, 37.6, 55.7, 84.2, 84.6, 86.9,
109.5, 110.4, 112.9.
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclopropyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4d)
10%
Palladium/carbon
(0.26
g)
was
added
into
the
solution
of
18

1-methyl-5,6,7-deoxy-6-cyano-7-cyclopropyl-2,3-O-isopropylidene-β-D-hepta-6-enofuranoside (2.3
g) in methanol (100 mL). The mixture was hydrogenated under the pressure of 0.6 MPa at 30°C for
56 h. After filtration, the solvent was removed in vacuo and the residue was separated on the silico
gel column eluting with 5-10% ethyl acetate/petroleum ether. The product was obtained as yellowish
oil (1.9 g, yield: 82.0%). The purity was 95% by HPLC analysis. HRMS (TOF) m/z calcd for
1
C15H24NO4 [M+H]+ 282.1705, found 282.1709. R:S or S:R = 1:1.2. H NMR (CDCl3, 300 MHz)
0.11 (m, 4H), 0.20 (m, 2H), 0.55 (m, 4H), 1.30 (s, 6H), 1.46 (s, 6H), 1.58 (m, 4H), 1.83 (m, 4H), 2.83
(m, 2H), 3.32 (s, 3H), 3.37 (s, 3H), 4.20 (m, 1H), 4.38 (m, 1H), 4.55 (m, 2H), 4.59 (m, 2H), 4.90 (s,
13
1H), 4.94 (s, 1H). C NMR (CDCl3, 75 MHz) 4.3, 4.6, 5.0, 5.2, 8.6, 8.8, 21.2 (2C), 25.1, 25.2, 26.6
(2C), 28.8, 29.5, 37.3, 37.8, 55.6 (2C), 84.1, 84.3, 84.6 (2C), 85.3, 85.5, 110.1 (2C), 110.3 (2C),
112.8 (2C).
1-Methyl-5,6,7,8-deoxy-6-cyano-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-furanoside (4e)
Compound 4e was prepared according to the same procedure of 4a, in which
1-methyl-5,6,7,8-deoxy-6-cyano-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-6-enofuranoside (3e)
was used and 4e was obtained as yellowish oil in 88.7% yield. The purity was 98% by HPLC
analysis. HRMS (TOF) m/z calcd for C19H32NO4[M+H]+ 338.2331, found 338.2333. R:S = 1:1. 1H
NMR (CDCl3, 300 MHz) 1.25 (m, 14H), 1.31 (s, 6H), 1.48 (s, 6H), 1.71 (m, 20 H), 2.71 (m, 2H),
3.33 (s, 3H), 3.38 (s, 3H), 4.26 (dd, J = 5.4 Hz, J = 10.2 Hz, 1H), 4.40 (dd, J = 5.7 Hz, J = 9.6 Hz,
1H), 4.54 (dd, J = 6.0 Hz, J = 9.3 Hz, 2H), 4.61 (t, J = 4.5 Hz, 2H), 4.96 (s, 2H).
1-Methyl-5,6,7-deoxy-6-amide-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5a)
1-Methyl-5,6,7-deoxy-6-cyano-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4a, 2.65 g,
8.2 mmol) was dissolved in the mixture of DMSO (710 L), 30% hydroperoxide (3.82 mL), 2N
NaOH solution (61.2 mL, 122 mmol) and methanol (200 mL). The mixture was refluxed for 1 h and
cooled. The solvent was removed in vacuo and the residue was extracted with dichloromethane
(350 mL). The organic phase was combined, washed with water and dried over anhydrous sodium
19

sulphate. After filtration, the solvent was removed in vacuo and the residue was separated on the
silico gel column eluting with 10-50% ethyl acetate/petroleum ether. The product was obtained as
colorless oil (2.2 g, yield: 78.6 %). The purity was 96% by HPLC analysis. HRMS (TOF) m/z calcd
1
for C18H32NO5[M+H]+ 342.2281, found 342.2285. LR-ESI: 364.2 (M+Na). R:S or S:R = 1:1.1. H
NMR (CDCl3, 300 MHz) 1.22 (m, 12H), 1.29 (s, 3H), 1.31 (s, 3H), 1.45 (s, 3H), 1.47 (s, 3H), 1.62
(m, 18H), 2.46 (m, 1H), 2.61 (m, 1H), 3.36 (s, 3H), 3.37 (s, 3H), 4.19 (t, J = 6.9 Hz, 2H), 4.50 (t, J =
5.4 Hz, 2H), 4.60 (d, J = 5.7 Hz, 2H), 4.94 (s, 2H), 5.38 (brs, CONH2), 5.63 (brs, CONH2). 13C NMR
(CDCl3, 75 MHz) 24.8, 25.0, 26.1 (2C), 26.2 (2C), 26.4 (2C), 26.5 (2C), 32.8, 33.0, 33.7, 34.0, 35.2,
35.4, 38.4 (2C), 39.9 (2C), 40.5, 40.9, 55.1, 55.3, 84.0, 84.3, 84.9, 85.0, 85.3, 85.4, 109.5, 110.0,
112.1, 112.4, 178.3, 178.5.
1-Methyl-5,6,7-deoxy-6-amide-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5b)
Compound 5b was prepared according to the same procedure of 5a, in which
1-methyl-5,6,7-deoxy-6-cyano-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4b) was
used and 5b was obtained as colorless oil in 69.6 %yield. The purity was 99% by HPLC analysis.
HRMS (TOF) m/z calcd for C17H30NO5[M+H]+ 328.2124, found 328.2122. LR-ESI: 350.2
1
(M+Na). R:S or S:R = 1:1.5. H NMR (CDCl3, 300 MHz) 1.29 (s, 3H), 1.31 (s, 3H), 1.45 (s, 3H),
1.47 (s, 3H), 1.63 (m, 14H), 1.80 (m, 12H), 2.34 (m, 1H), 2.45 (m, 1H), 3.36 (s, 3H), 3.37 (s, 3H),
4.20 (dd, J = 8.1 Hz, J = 12.3 Hz, 2H), 4.50 (t, J = 5.7 Hz, 2H), 4.60 (d, J = 6.0 Hz, 2H), 4.94 (s, 2H),
5.41 (brs, CONH2), 5.62 (brs, CONH2). 13C NMR (CDCl3, 75 MHz) 24.7 (2C), 24.9 (2C), 25.0 (2C),
26.2, 26.4, 32.2, 32.4, 32.9, 33.1, 37.8 (2C), 37.9 (2C), 38.1, 38.6, 39.0, 39.7, 54.9, 55.2, 83.9, 84.2,
84.9 (2C), 85.2, 85.3, 109.4, 109.9, 112.0, 112.3, 178.3, 178.5.
1-Methyl-5,6,7-deoxy-6-amide-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5c)
Compound 5c was prepared according to the same procedure of 5a, in which
1-methyl-5,6,7-deoxy-6-cyano-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4c) was
used and 5c was obtained as white needles in 78.7 % yield. The purity was 96% by HPLC analysis.
20

HRMS (TOF) m/z calcd for C16H28NO5[M+H]+ 314.1968, found 314.1963. LR-ESI: 336.2 (M+23).
R:S or S:R = 1:1.2. 1H NMR (CDCl3, 300 MHz) 1.29 (s, 3H), 1.31 (s, 3H), 1.45 (s, 3H), 1.47 (s, 3H),
1.62 (m, 12H), 1.81 (m, 10H), 2.31(m, 2H), 3.35 (s, 3H), 3.37 (s, 3H), 4.21 (t, J = 8.1 Hz, 2H), 4.50
(t, J = 5.1 Hz, 2H), 4.60 (d, J = 6.0 Hz, 2H), 4.93 (s, 2H), 5.35 (brs, CONH2), 5.58 (brs, CONH2).
13C NMR (CDCl3, 75 MHz) 18.0, 18.2, 24.5, 24.7, 26.1, 26.2, 28.2 (2C), 28.3 (2C), 33.8, 34.0, 37.5,
37.7, 39.3, 39.6, 41.2, 41.3, 54.7, 54.9, 83.7, 84.1, 84.8, 84.9, 85.1, 85.2, 109.1, 109.7, 111.9, 112.1,
178.1, 178.2.
1-Methyl-5,6,7-deoxy-6-amide-7-cyclopropyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5d)
Compound 5d was prepared according to the same procedure of 5a, in which
1-methyl-5,6,7-deoxy-6-cyano-7-cyclopropyl-2,3-O-isopropylidene-β-D-hepta-furanoside (4d) was
used and 5d was obtained as colorless oil in 71.9 % yield. The purity was 97% by HPLC analysis.
1
HRMS (TOF) m/z calcd for C15H26NO5[M+H]+ 300.1811, found 300.1808. R:S or S:R = 1:1.2. H
NMR (CDCl3, 300 MHz) 0.03 (m, 4H), 0.41 (d, J = 7.5 Hz, 2H), 0.69 (m, 2H), 0.85 (m, 2H), 1.26 (s,
3H), 1.28 (s, 3H), 1.42 (s, 3H), 1.43 (s, 3H), 1.62 (m, 4H), 1.80 (m, 2H), 1.89 (m, 2H), 2.39 (m, 1H),
2.52 (m, 1H), 3.32 (s, 3H), 3.33 (s, 3H), 4.18 (m, 2H), 4.48 (t, J = 5.1 Hz, 2H), 4.56 (d, J = 5.7 Hz,
13
2H), 4.90 (s, 1H), 4.93 (s, 1H), 5.91 (brs, CONH2), 5.98 (brs, CONH2). C NMR (CDCl3, 75 MHz)
4.3, 4.6, 4.8, 5.0, 9.2, 9.3, 25.0, 25.2, 26.5, 26.7, 37.2, 37.7, 37.9, 38.3, 43.9, 44.1, 55.2, 55.4, 84.2,
84.5, 85.1, 85.3, 85.5, 85.6, 109.6, 110.2, 112.4, 112.6, 178.0, 178.3.
1-Methyl-5,6,7,8-deoxy-6-amide-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-furanoside (5e)
Compound 5e was prepared according to the same procedure of 5a, in which
1-methyl-5,6,7,8-deoxy-6-cyano-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-furanoside (4e) was
used and 5e was obtained as colorless oil in 99.1% yield. The purity was 98% by HPLC analysis.
1
HRMS (TOF) m/z calcd for C19H34NO5[M+H]+ 356.2437, found 356.2435. R:S = 1:1. H NMR
(CD3OD, 300 MHz) 1.20 (m, 14H), 1.29 (s, 3H), 1.30 (s, 3H), 1.41 (s, 3H), 1.42 (s, 3H), 1.70 (m, 20
H), 2.35 (m, 1H), 2.49 (m, 1H), 3.34 (s, 3H), 3.36 (s, 3H), 4.05 (dd, J = 7.2 Hz, J = 11.7 Hz, 1H),
21

4.12 (d, J = 7.5 Hz, 1H), 4.57 (t, J = 5.7 Hz, 2H), 4.60 (brs, 2H), 4.88 (s, 1H), 4.89 (s, 1H). 13C NMR
(CDCl3, 75 MHz) 25.2 (2C), 26.9 (2C), 27.6 (2C), 27.9 (2C), 31.0 (2C), 31.9 (2C), 34.4 (2C), 34.8
(2C), 36.3 (2C), 39.0 (2C), 39.1, 39.2, 42.6, 44.8, 55.5, 55.7, 85.4, 85.8, 86.5, 86.7, 86.9, 87.0, 111.1,
111.4, 113.4, 113.5, 181.0, 181.1.
5,6,7-Deoxy-6-amide-7-cyclohexyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6a)
0.2
N
Sulphuric
acid
(3
mL)
was
added
into
a
solution
of
1-methyl-5,6,7-deoxy-6-amide-7-cyclohexyl-2,3-O-isopropylidene-β-D-hepta-furanoside 5a (0.2 g)
in the mixture of water and dioxane (1:1, 40 mL) and the resulted solution was refluxed for 5 h. After
cooling, the mixture was adjusted to pH = 7 with saturated sodium carbonate solution and the solvent
was removed in vacuo. The residue was dissolved in pyridine (6 mL), followed by addition of acetic
anhydride (3 mL). The solution was stirred at room temperature overnight. Water was added and the
mixture was extracted with dichloromethane (25 mL3). The organic phase was combined, washed
with water, and dried over anhydrous sodium sulphate. After filtration, the solution was evaporated
in vacuo to obtain the product as yellowish oil, which was used directly in the next step (0.24 g, yield:
99.1%).
5,6,7-Deoxy-6-amide-7-cyclopentyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6b)
Compound 6b was prepared according to the same procedure of 6a, in which
1-methyl-5,6,7-deoxy-6-amide-7-cyclopentyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5b) was
used and 6b was obtained as yellowish oil in 98.4% yield.
5,6,7-Deoxy-6-amide-7-cyclobutyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6c)
Compound 6c was prepared according to the same procedure of 6a, in which
1-methyl-5,6,7-deoxy-6-amide-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5c) was
used and 6c was obtained as yellowish oil in 97.6% yield.
5,6,7-Deoxy-6-amide-7-cyclopropyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6d)
Compound 6d was prepared according to the same procedure of 6a, in which
22

1-methyl-5,6,7-deoxy-6-amide-7-cyclobutyl-2,3-O-isopropylidene-β-D-hepta-furanoside (5d) was
used and 6d was obtained as yellowish oil in 96.7% yield.
5,6,7,8-Deoxy-6-amide-8-cyclohexyl-1,2,3-O-triacetyl-β-D-octa-furanoside (6e)
Compound 6e was prepared according to the same procedure of 6a, in which
1-methyl-5,6,7,8-deoxy-6-amide-8-cyclohexyl-2,3-O-isopropylidene-β-D-octa-furanoside (5e) was
used and 6e was obtained as yellowish oil in 69.3% yield.
N6-Benzoyl-adenine (7)
Benzoyl chloride (3.41 mL, 29.6 mmol) was added into the solution of adenine (2 g, 14.8 mmol) in
anhydrous pyridine (25 mL) and the resulted mixture was stirred at 60°C overnight. The solvent was
removed in vacuo and the residue was dissolved in methanol (30 mL). It was adjusted to pH = 9-10
with 2N NaOH solution and stirred for another 30 min. After neutralization with 20% HCl solution,
the solvent was removed in vacuo and the crude powder was obtained, which was recrystallized with
ethanol to obtain N6-benzoyl-adenineas white powder (3.198 g, yield: 90.3%).The purity was 95%
1
by HPLC analysis. HRMS (TOF) m/z calcd for C12H10N5O[M+H]+ 240.0885, found 240.0888. H
NMR (CD3OD, 300 MHz) 7.57 (t, J = 7.2 Hz, 2H), 7.65 (t, J = 7.5 Hz, 1H), 8.10 (d, J = 6.9 Hz, 2H),
13
8.48 (s, 1H), 8.71 (s, 1H). C NMR (DMSO-d6) 93.3, 128.5 (2C), 128.6 (2C), 132.1, 132.7, 133.0,
145.9, 151.2, 161.0, 166.6.
N6-Benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclohexyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')a
denine (8a)
A mixture of N6-benzoyl-adenine 7 (192 mg, 0.8 mmol, 1 eq) in acetonitrile (10 mL) and
N,O-bis(trimethylsilyl)acetamide (10 mL) was refluxed for 2 h. After evaporation in vacuo, the
residue was dissolved in dichloroethane (30 mL), followed by addition of the mixture of
5,6,7-deoxy-6-amide-7-cyclohexyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (0.48 g, 1.16 mmol, 1.45
eq) in dichloroethane (30 mL). Trimethylsilyl trifluoromethanesulfonate (144 μL, 0.8 mmol, 1 eq)
was added and the reaction was refluxed for 2 h. After cooling, water was added and the mixture was
23

extracted with dichloromethane (25 mL3). The organic phase was combined, washed with saturated
Na2CO3 solution and water, and dried over anhydrous sodium sulphate. After filtration, the solvent
was removed in vacuo and the residue was separated on the prep-TLC eluting with 5%
methanol/dichloromethane. The product was obtained as yellowish oil (192 mg, yield: 40.5 %). The
purity was 97% by HPLC analysis. HRMS (TOF) m/z calcd for C30H37N6O7[M+H]+ 593.2724,
found 593.2720. R:S or S:R = 1:1.1. 1H NMR (CD3OD, 300 MHz) 0.89 (m, 4H), 1.20 (m, 22H), 1.65
(m, 4H), 2.06 (s, 6H), 2.14 (s, 3H), 2.16 (s, 3H), 2.58 (m, 2H), 4.20 (m, 1H), 4.29 (m, 1H), 5.53 (t, J
= 5.4 Hz, 1H), 5.55 (t, J = 5.4 Hz, 1H), 6.04 (t, J = 5.4 Hz, 1H), 6.13 (t, J = 5.4 Hz, 1H), 6.27 (d, J =
2.1 Hz, 1H), 6.29 (d, J = 2.1 Hz, 1H), 7.56 (t, J = 7.5 Hz, 4H), 7.66 (t, J = 7.5 Hz, 2H), 8.08 (d, J =
13
7.2 Hz, 4H), 8.54 (s, 1H), 8.56 (s, 1H), 8.74 (s, 1H), 8.76 (s, 1H). C NMR (CD3OD, 75 MHz) 20.5
(2C), 20.7 (2C), 27.4 (4C), 27.5 (2C), 27.7 (2C), 34.1, 34.2, 34.9, 35.1, 36.7 (2C), 37.5 (2C), 41.5,
41.6, 74.4, 74.6, 75.1 (2C), 81.9, 82.2, 88.6, 88.9, 125.4, 125.5, 129.6 (4C), 129.9 (4C), 134.1 (2C),
135.0 (2C), 145.1, 145.3, 151.3, 151.4, 153.2 (2C), 153.6 (2C), 168.4 (2C), 171.4 (2C), 171.7 (2C),
180.9, 181.2.
N6-Benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclopentyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')a
denine (8b)
Compound 8b was prepared according to the same procedure of 8a, in which N6-benzoyl-adenine (1
eq), 5,6,7-deoxy-6-amide-7-cyclopentyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6b, 1.5 eq) and
trimethylsilyl trifluoromethanesulfonate (1 eq) were used. The product 8b was obtained as yellowish
oil in 91.7% yield. The purity was 98% by HPLC analysis. HRMS (TOF) m/z calcd for
C29H35N6O7[M+H]+ 579.2567, found 579.2569. LR-ESI: 579.3 (M+1), 601.3 (M+Na). R:S or S:R=
1:1.5. 1H NMR (CD3OD, 300 MHz) 1.57 (m, 18H), 1.79 (m, 8H), 2.06 (s, 6H), 2.17 (s, 3H), 2.18 (s,
3H), 2.53 (m, 2H), 4.20 (m, 1H), 4.31 (dt, J = 5.1 Hz, J = 9.6 Hz, 1H), 5.54 (t, J = 5.4 Hz, 1H), 5.55
(t, J = 5.4 Hz, 1H), 6.05 (t, J = 5.4 Hz, 1H), 6.16 (t, J = 4.8 Hz, 1H), 6.28 (d, J = 4.8 Hz, 1H), 6.29 (d,
J = 5.1 Hz, 1H), 7.57 (t, J = 6.9 Hz, 4H), 7.66 (t, J = 7.2 Hz, 2H), 8.09 (d, J = 7.2 Hz, 4H), 8.55 (s,
24

13
1H), 8.57 (s, 1H), 8.74 (s, 1H), 8.76 (s, 1H). C NMR (CDCl3, 75 MHz) 20.5 (2C), 20.7 (2C), 25.1
(2C), 25.2 (2C), 32.6 (2C), 33.0 (2C), 36.4 (2C), 37.9 (2C), 39.9 (2C), 42.0 (2C), 72.8 (2C), 73.6
(2C), 80.7 (2C), 86.9 (2C), 124.1 (2C), 128.3 (4C), 128.9 (4C), 133.0 (2C), 133.5 (2C), 142.4 (2C),
150.1 (2C), 151.8 (2C), 152.7 (2C), 165.8 (2C), 169.6 (2C), 169.8 (2C), 178.0 (2C).
N6-Benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclobutyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')a
denine (8c)
Compound 8c was prepared according to the same procedure of 8a, in which N6-benzoyl-adenine (1
eq), 5,6,7-deoxy-6-amide-7-cyclobutyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6c, 1.6 eq) and
trimethylsilyl trifluoromethanesulfonate (3 eq) were used. The product 8c was obtained as yellowish
oil in 60.7% yield. The purity was 96% by HPLC analysis. HRMS (TOF) m/z calcd for
C28H33N6O7[M+H]+ 565.2411, found 565.2408. R:S or S:R = 1:1.1. 1H NMR (CD3OD, 300 MHz)
1.63 (m, 14H), 1.80 (m, 8H), 2.03 (s, 3H), 2.06 (s, 3H), 2.14 (s, 3H), 2.15 (s, 3H), 2.35 (m, 2H), 4.13
(m, 1H), 4.28 (m, 1H), 5.52 (t, J = 5.4 Hz, 2H), 6.04 (t, J = 5.1 Hz, 1H), 6.13 (t, J = 4.8 Hz, 1H), 6.27
(t, J = 4.8 Hz, 2H), 7.56 (t, J = 7.2 Hz, 4H), 7.66 (t, J = 7.2 Hz, 2H), 8.09 (d, J = 7.2 Hz, 4H), 8.54 (s,
13
1H), 8.56 (s, 1H), 8.74 (s, 1H), 8.77 (s, 1H). C NMR (CDCl3, 75 MHZ) 19.4 (2C), 20.5 (2C), 20.7
(2C), 29.5 (2C), 29.7 (2C), 35.5, 35.9, 37.0, 37.1, 41.0, 41.3, 42.4, 42.5, 74.4, 74.6, 75.1 (2C), 81.9,
82.2, 88.5, 88.8, 125.3, 125.5, 129.6 (4C), 129.9 (4C), 134.1 (2C), 135.0 (2C), 145.1, 145.3, 151.3
(2C), 151.4 (2C), 153.2, 153.6, 168.4 (2C), 171.5 (2C), 171.7, 171.8, 180.6, 180.9.
N6-Benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclopropyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')
adenine (8d)
Compound 8d was prepared according to the same procedure of 8a, in which N6-benzoyl-adenine (1
eq), 5,6,7-deoxy-6-amide-7-cyclopropyl-1,2,3-O-triacetyl-β-D-hepta-furanoside (6d, 1.6 eq) and
trimethylsilyl trifluoromethanesulfonate (2 eq) were used. The product 8d was obtained as yellowish
oil in 65.0% yield. The purity was 95% by HPLC analysis. HRMS (TOF) m/z calcd for
C27H31N6O7[M+H]+ 551.2254, found 551.2251. R:S or S:R = 1:1.2. 1H NMR (CD3OD, 300 MHz)
25

0.04 (m, 4H), 0.41 (m, 4H), 0.69 (m, 1H), 0.88 (m, 1H), 1.29 (m, 4H), 1.50 (m, 4H), 2.05 (s, 6H),
2.13 (s, 3H), 2.15 (s, 3H), 2.59 (m, 2H), 4.19 (m, 1H), 4.29 (m, 1H), 5.53 (dd, J = 5.4 Hz, J = 7.5 Hz,
1H), 5.55 (dd, J = 3.6 Hz, J = 5.7 Hz, 1H), 6.04 (t, J = 4.8 Hz, 1H), 6.10 (t, J = 5.1 Hz, 1H), 6.26 (d,
J = 6.0 Hz, 1H), 6.28 (d, J = 4.8 Hz, 1H), 7.53 (t, J = 6.9 Hz, 4H), 7.63 (t, J = 6.9 Hz, 2H), 8.07 (d, J
= 7.8 Hz, 4H), 8.54 (s, 1H), 8.56 (s, 1H), 8.71 (s, 1H), 8.72 (s, 1H). 13C NMR (CD3OD, 75 MHz) 5.0,
5.1, 5.3, 5.4, 9.9, 10.0, 20.5 (2C), 20.7 (2C), 36.6, 36.7, 38.8, 39.7, 44.4 (2C), 74.5, 74.6, 75.0 (2C),
81.8, 82.1, 88.4, 88.7, 125.3, 125.4, 129.5 (4C), 129.9 (4C), 134.1 (2C), 134.9 (2C), 145.0, 145.2,
151.3 (2C), 153.1 (2C), 153.5 (2C), 167.7, 168.2, 171.4 (2C), 171.6 (2C), 180.6, 180.9.
N6-Benzoyl-9-(5',6',7',8'-deoxy-6'-amide-8'-cyclohexyl-2',3'-O-diacetyl-β-D-octa-furanoside-1')
adenine (8e)
Compound 8e was prepared according to the same procedure of 8a, in which N6-benzoyl-adenine (1
eq), 5,6,7,8-deoxy-6-amide-8-cyclohexyl-1,2,3-O-triacetyl-β-D-octa-furanoside (6e, 1.17 eq) and
trimethylsilyl trifluoromethanesulfonate (2.5 eq) were used. The product 8e was obtained as
yellowish oil in 70.5% yield. The purity was 96% by HPLC analysis. HRMS (TOF) m/z calcd for
1
C31H39N6O7[M+H]+ 607.2880, found 607.2884. R:S or S:R = 1:1. H NMR (CD3OD, 300 MHz)
0.90 (m, 4H), 1.20 (m, 18H), 1.68 (m, 12H), 2.06 (s, 6H), 2.14 (s, 3H), 2.16 (s, 3H), 2.42 (m, 2H),
4.22 (m, 1H), 4.32 (m, 1H), 5.54 (t, J = 6.0 Hz, 1H), 5.55 (t, J = 6.6 Hz, 1H), 6.04 (t, J = 5.7 Hz, 1H),
6.13 (t, J = 5.4 Hz, 1H), 6.28 (d, J = 5.1 Hz, 1H), 6.32 (d, J = 4.8 Hz, 1H), 7.56 (t, J = 7.2 Hz, 4H),
7.66 (t, J = 7.2 Hz, 2H), 8.09 (d, J = 7.2 Hz, 4H), 8.56 (s, 1H), 8.58 (s, 1H), 8.74 (s, 1H), 8.76 (s, 1H).
13C NMR (CD3OD, 75 MHz) 20.5 (2C), 20.7 (2C), 27.5 (4C), 27.9 (2C), 34.4 (2C), 34.5 (2C), 34.6,
34.7, 36.1, 36.9, 39.0 (2C), 39.1 (2C), 44.3, 44.4, 74.4, 74.6, 75.1, 75.2, 82.0, 82.1, 88.6, 88.8, 125.3
(2C), 129.6 (4C), 129.9 (4C), 134.2 (2C), 135.0 (2C), 145.1, 145.4, 151.3, 151.4, 153.2 (2C), 153.6
(2C), 168.4 (2C), 171.4, 171.6, 171.7, 172.0, 180.7, 181.0.
6'(R)-9-(5',6',7'-Deoxy-6'-amide-7'-cyclohexyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')
adenine
(9a)
and
26

6'(S)-9-(5',6',7'-deoxy-6'-amide-7'-cyclohexyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')a
denine (10a)
2N
NH3
in
methanol
(26
mL)
was
added
into
the
solution
of
N6-benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclohexyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')adenin
e (8a, 81 mg, 0.14 mmol) in methanol (26 mL) and the resulted solution was stirred at 40°C
overnight. After evaporation in vacuo, the residue was dissolved in acetone (25 mL) followed by
addition of trimethylsilyl trifluoromethanesulfonate in dichloroethane (83 μL TMSOTf in 250 μL
DCE). After stirring for 1 h, the solvent was removed in vacuo and the residue was separated on the
prep-TLC eluting with 5% methanol/dichloromethane. Two epimers were obtained as yellowish oil
(9a: 30 mg, 10a: 32 mg, total: 62 mg, yield: 99.7 %). 9a: The purity was 95% by HPLC analysis.
1
HRMS (TOF) m/z calcd for C22H33N6O4[M+H]+ 445.2563, found 445.2558. H NMR (CD3OD,
300 MHz) 0.65 (m, 3H), 1.01 (m, 8H), 1.31 (m, 2H), 1.38 (s, 3H), 1.56 (s, 3H), 1.78 (m, 2H), 2.32
(m, 1H), 4.17 (dt, J = 2.7 Hz, J = 9.9 Hz, 1H), 4.92 (dd, J = 2.7 Hz, J = 6.3 Hz, 1H), 5.64 (dd, J = 1.8
Hz, J = 6.3 Hz, 1H), 6.17 (d, J = 2.1 Hz, 1H), 8.24 (s, 1H), 8.30 (s, 1H). 13C NMR (CD3OD, 75 MHz)
25.6, 27.3, 27.4, 27.6, 30.8, 34.3, 34.4, 36.4, 37.7, 41.2, 42.1, 85.0, 86.3, 86.9, 91.8, 115.3, 120.7,
142.1, 150.5, 154.1, 157.6, 181.1. 10a: The purity was 95% by HPLC analysis. HRMS (TOF) m/z
1
calcd for C22H33N6O4[M+H]+ 445.2563, found 445.2559. H NMR (CD3OD, 300 MHz) 0.89 (m,
3H), 1.26 (m, 8H), 1.38 (s, 3H), 1.58 (s, 3H), 1.77 (m, 2H), 1.94 (m, 2H), 2.52 (m, 1H), 4.17 (dt, J =
3.3 Hz, J = 10.2 Hz, 1H), 4.92 (dd, J = 3.6 Hz, J = 6.3 Hz, 1H), 5.46 (dd, J = 2.4 Hz, J = 6.3 Hz, 1H),
13
6.12 (d, J = 2.7 Hz, 1H), 8.22 (s, 1H), 8.27 (s, 1H). C NMR (CD3OD, 75 MHz) 25.8, 27.4, 27.5,
27.6, 29.7, 34.1, 35.0, 36.7, 37.7, 41.4, 41.6, 85.4, 85.6, 86.2, 91.1, 116.0, 120.7, 142.0, 150.4, 154.1,
157.5, 181.2.
6'(R)-9-(5',6',7'-Deoxy-6'-amide-7'-cyclopentyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')
adenine
(9b)
and
6'(S)-9-(5',6',7'-deoxy-6'-amide-7'-cyclopentyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')
27

adenine (10b)
Compounds 9b and 10b were prepared according to the same procedure of 9a and 10a, in which
N6-benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclopentyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')adeni
ne (8b) was used and the two epimers were obtained as yellowish oil (9b:10b = 1:1.76, yield: 99.2%).
9b: The purity was 97% by HPLC analysis. HRMS (TOF) m/z calcd for C21H31N6O4[M+H]+
431.2407, found 431.2410. LR-ESI: 431.3 (M+1), 453.2 (M+Na). 1H NMR (CD3OD, 300 MHz) 1.16
(m, 2H), 1.38 (s, 3H), 1.46 (m, 7H), 1.56 (s, 3H), 1.78 (m, 4H), 2.25 (m, 1H), 4.17 (dt, J = 2.4 Hz, J
= 10.5 Hz, 1H), 4.92 (dd, J = 2.4 Hz, J = 6.3 Hz, 1H), 5.67 (dd, J = 1.8 Hz, J = 6.0 Hz, 1H), 6.17 (d,
J = 2.1 Hz, 1H), 8.23 (s, 1H), 8.29 (s, 1H). 13C NMR (CD3OD, 75 MHz) 25.6, 26.0, 26.1, 27.4, 30.1,
33.6, 37.5, 39.0, 40.9, 43.2, 85.0, 86.4, 86.8, 91.9, 115.3, 120.7, 142.2, 150.5, 154.1, 157.6, 181.1.
10b: The purity was 97% by HPLC analysis. HRMS (TOF) m/z calcd for C21H31N6O4[M+H]+
431.2407, found 431.2412. LR-ESI: 431.3 (M+1), 453.2 (M+Na). 1H NMR (CD3OD, 300 MHz) 1.38
(s, 3H), 1.58 (s, 3H), 1.63 (m, 6H), 1.80 (m, 5H), 1.95 (m, 2H), 2.44 (m, 1H), 4.17 (dt, J = 3.6 Hz, J
= 10.8 Hz, 1H), 4.92 (dd, J = 3.9 Hz, J = 6.3 Hz, 1H), 5.47 (dd, J = 2.7 Hz, J = 6.3 Hz, 1H), 6.12 (d,
J = 2.7 Hz, 1H), 8.21 (s, 1H), 8.27 (s, 1H). 13C NMR (CD3OD, 75 MHz) 25.8, 26.1, 26.2, 27.6, 33.5,
34.1, 37.6, 39.3, 40.4, 43.5, 85.5, 85.6, 86.3, 91.1, 115.9, 120.7, 142.0, 150.4, 154.1, 157.5, 181.2.
6'(R)-9-(5',6',7'-Deoxy-6'-amide-7'-cyclobutyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')a
denine(9c)
and
6'(S)-9-(5',6',7'-deoxy-6'-amide-7'-cyclobutyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')a
denine (10c)
Compounds 9c and 10c were prepared according to the same procedure of 9aand 10a, in which
N6-benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclobutyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')adenin
e (8c) was used and the two epimers were obtained as white powder (9c:10c = 1:1.06, yield: 94.6%).
9c: The purity was 95% by HPLC analysis. HRMS (TOF) m/z calcd for C20H29N6O4[M+H]+
1
417.2250, found 417.2257. H NMR (CD3OD, 300 MHz) 1.25 (m, 2H), 1.38 (s, 3H), 1.56 (s, 3H),
28

1.72 (m, 5H), 1.90 (m, 4H), 2.14 (m, 1H),4.15 (dt, J = 3.9 Hz, J = 10.5 Hz, 1H), 4.89 (dd, J = 3.0 Hz,
J = 6.6 Hz, 1H), 5.65 (dd, J = 2.1 Hz, J = 6.0 Hz, 1H), 6.16 (d, J = 2.1 Hz, 1H), 8.25 (s, 1H), 8.30 (s,
1H). 13C NMR (CD3OD, 75MHz) 19.3, 25.6, 27.4, 29.3, 29.4, 35.3, 37.3, 41.7, 42.1, 85.0, 86.3, 86.6,
91.8, 115.4, 120.7, 142.2, 150.5, 154.2, 157.6,180.8. 10c: The purity was 95% by HPLC analysis.
1
HRMS (TOF) m/z calcd for C20H29N6O4[M+H]+ 417.2250, found 417.2255. H NMR (CD3OD,
300 MHz) 1.38 (s, 3H), 1.58 (s, 3H), 1.65 (m, 2H), 1.76 (m, 5H), 2.02 (m, 4H), 2.30 (m, 1H),4.15 (dt,
J = 3.9 Hz, J = 11.1Hz, 1H), 4.90 (dd, J = 3.9 Hz, J = 6.3 Hz, 1H), 5.46 (dd, J = 2.4 Hz, J = 6.3 Hz,
13
1H), 6.12 (d, J = 2.4 Hz, 1H), 8.22 (s, 1H), 8.26 (s, 1H). C NMR (CD3OD, 75 MHz) 19.4, 25.8,
27.6, 29.5, 29.6, 35.5, 37.3, 41.2, 42.4, 85.5, 85.6, 86.2, 91.1, 115.9,120.7, 142.0, 150.4, 154.1, 157.5,
180.9.
6'(R)-9-(5',6',7'-Deoxy-6'-amide-7'-cyclopropyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1'
)adenine
(9d)
and
6'(S)-9-(5',6',7'-deoxy-6'-amide-7'-cyclopropyl-2',3'-O-isopropylidene-β-D-hepta-furanoside-1')
adenine (10d)
Compounds 9d and 10d were prepared according to the same procedure of 9aand 10a, in which
N6-benzoyl-9-(5',6',7'-deoxy-6'-amide-7'-cyclopropyl-2',3'-O-diacetyl-β-D-hepta-furanoside-1')adeni
ne (8d) was used and the two epimers were obtained as yellowish oil (9d:10d = 1:1.44, yield: 91.1%).
9d: The purity was 98% by HPLC analysis. HRMS (TOF) m/z calcd for C19H27N6O4[M+H]+
403.2094, found 403.2089. 1H NMR (CD3OD, 300 MHz) -0.11 (m, 2H), 0.28 (m, 2H), 0.42 (m, 1H),
1.15 (m, 2H), 1.39 (s, 3H), 1.56 (s, 3H), 1.82 (m, 2H), 2.36 (m, 1H),4.18 (dt, J = 3.3 Hz, J = 6.6 Hz,
1H), 4.90 (m, 1H), 5.62 (dd, J = 2.1 Hz, J = 6.3 Hz, 1H), 6.16 (d, J = 2.4 Hz, 1H), 8.22 (s, 1H), 8.29
(s, 1H). 13C NMR (CD3OD, 75 MHz) 5.0, 5.1, 9.9, 25.6, 27.5, 37.2, 39.5, 44.5, 85.0, 86.2, 86.6, 91.7,
115.5, 120.8, 142.1, 150.6, 154.2, 157.6, 180.8. 10d: The purity was 96% by HPLC analysis. HRMS
(TOF) m/z calcd for C19H27N6O4[M+H]+ 403.2094, found 403.2093. 1H NMR (CD3OD, 300 MHz)
0.04 (m, 2H), 0.40 (m, 2H), 0.65 (m, 1H), 1.38 (s, 3H), 1.58 (s, 3H), 1.81 (m, 2H), 1.96 (m, 2H),
29