Concise synthesis and PTP1B inhibitory activity of (R)- and (S)-dihydroresorcylide

Article abstract of DOI:10.1080/10286020.2017.1317752

The present study was designed to develop a concise synthetic route for macrolide, with the purpose of confirming the absolute configuration of natural dihydroresorcylide (1) and making it more easily accessible for biological evaluation. The absolute con

Full text of DOI:10.1080/10286020.2017.1317752

Journal of Asian Natural Products Research
ISSN: 1028-6020 (Print) 1477-2213 (Online) Journal homepage: http://www.tandfonline.com/loi/ganp20
Concise synthesis and PTP1B inhibitory activity of
(R)- and (S)-dihydroresorcylide
Cheng-Shi Jiang, Li Zhang, Jing-Xu Gong, Jing-Ya Li, Li-Gong Yao, Jia Li & Yue-
Wei Guo
To cite this article: Cheng-Shi Jiang, Li Zhang, Jing-Xu Gong, Jing-Ya Li, Li-Gong
Yao, Jia Li & Yue-Wei Guo (2017): Concise synthesis and PTP1B inhibitory activity
of (R)- and (S)-dihydroresorcylide, Journal of Asian Natural Products Research, DOI:
10.1080/10286020.2017.1317752
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Date: 27 April 2017, At: 02:38

Journal of asian natural Products research, 2017
https://doi.org/10.1080/10286020.2017.1317752
Concise synthesis and PTP1B inhibitory activity of (R)- and
(S)-dihydroresorcylide
Cheng-Shi Jianga,b§, Li Zhanga§, Jing-Xu Gonga, Jing-Ya Lia, Li-Gong Yaoa, Jia Lia and
Yue-Wei Guoa
astate Key laboratory of drug research, shanghai institute of Materia Medica, chinese academy of sciences,
shanghai 201203, china; bschool of Biological science and technology, university of Jinan, Jinan 250022,
china
ABSTRACT
ARTICLE HISTORY
received 30 december 2016
accepted 5 april 2017
The present study was designed to develop a concise synthetic
route for macrolide, with the purpose of confirming the absolute
configuration of natural dihydroresorcylide (1) and making it more
easily accessible for biological evaluation. The absolute configuration
of C-3 in natural 1 was revised to be R by comparison of the rotation
sign of synthetic (R)- and (S)-1. The synthetic (R)-1 was found to be a
novel highly specific PTP1B inhibitor with an IC50 value of 17.06 μM.
KEYWORDS
synthesis;
dihydroresorcylide; PtP1B
inhibitory activity; molecular
docking
1. Introduction
Natural occurring macrolides usually have significant and diverse bioactivities, which have
proved to be a prolific source of small-molecule chemical entities for developing clinical
drugs [1]. Specifically, the macrolides possessing lactone core fused to resorcinol fragment
produced by fungi usually exhibited a wide spectrum of biological properties, including
antitumoral, antibacterial, antimalarial activities [2,3]. (S)-Dihydroresorcylide (1, Figure 1)
was a phytotoxic resorcinol-fused twelve-membered macrolide isolated from the fermenta-
tion extracts of an endophyte Acremonium zeae by Poling et al. [4]. e first total synthesis
CONTACT Yue-Wei Guo
ywguo@simm.ac.cn
§these authors contributed equally to this work.
© 2017 informa uK limited, trading as taylor & francis Group

2
C.-S. JIANG ET AL.
Figure 1. the structure of (S)-dihydroresorcylide (1).
of (S)-1 was achieved in our group using the ring-closing metathesis (RCM) as a key step in
2013 [5]. However, the optical rotation sign of the synthetic (S)-1 ([ꢀ]2D4 − 40.0 (c 0.8, MeOH))
was unexpectedly opposite to that of natural (S)-1 ([ꢀ]2D5 + 15.0 (c 0.33, MeOH)), indicating
that the absolute configuration of C-3 in natural 1 might be R, instead of S. is deduction
was supported by the fact that the configuration of dihydroresprcylide biosynthesized in
Saccharomyces cerevisiae was also R in C-3 ([ꢀ] + 23.7 (c 1.12, MeOH)) [6]. In order to
confirm the absolute configuration of the naturaDl 1, (R)-1 and (S)-1 were synthesized via a
concise synthetic route in the present work.
As a member of protein tyrosine phosphatases (PTPs), PTP1B plays a key role in the
insulin-dependent signaling cascade. Selective PTP1B inhibitors are expected to have prom-
ising therapeutic effect on the treatment of type 2 diabetes and obesity [7]. In the past dec-
ades, numerous natural or synthetic drug-like PTP1B inhibitors have been developed [2,8].
However, the current PTP1B inhibitors usually have undesirable cell permeability and oral
bioavailability due to the presence of highly negative charged polar pharmacophore in their
structures [9]. erefore, in our project for discovering novel anti-diabetes drug candidates
[10–12], the low polar macrolides (R)- and (S)-1 were evaluated for their inhibitory activity
against PTP1B and homologous enzymes, including TCPTP, SHP-1, SHP-2 and LAR.
In this paper, we describe the synthesis and the revision of the absolute configuration of
natural (S)-dihydroresorcylide, as well as selective PTP1B inhibition and molecular docking
studies related to (R)- and (S)-1.
2. Results and discussion
2.1. Chemsitry
e synthesis of (R)-1 was shown in Scheme 1. e synthetic protocol was similar with
that of (S)-1 reported by Zhang et al. [5], but it was modified using chloromethyl methyl
ether (MOMCl) as the phenol protective reagent instead of methyl iodide (MeI). e MOM
group could be more easily deprotected in a mild acid condition avoiding the lactone
ring-opening [13]. Briefly, coupling the bis-MOM-protected acid 2 with 2-(trimethylsilyl)
ethanol under Mitsunobu conditions afforded the corresponding ester 3 in 72% yield [14].
e carbonylation reaction between 3 and Weinreb amide ((E)-N-methoxy-N-methylbut-
2-enamide) [5] proceeded smoothly in the presence of lithium diisopropylamide (LDA)
at −78 °C to give the desired product 4 [5]. Saponification of 4 with tetrabutylammonium
fluoride (TBAF) in THF overnight at room temperature produced acid 5, which was con-
verted to dienes 6 with R configuration in the chiral C-3 afer reacting with (S)-hept-6-en-
2-ol [15] under Mitsunobu conditions. e (R)-6 was cyclized with the second generation

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
3
Scheme 1. reagentsandconditionsforthesynthesisof(R)-1 and(S)-1: (a) dead, PPh3,thf, 2-(trimethylsilyl)
ethanol; lda, thf, −78 °c, Weinreb amide; (c) tBaf, thf; (d) dead, PPh3, thf, (S)-hept-6-en-2-ol for (R)-6,
or (R)-hept-6-en-2-ol for (S)-6; (d) Grubbs ii catalyst, ch2cl2, reflux; (e) h2, Pd/c, ch3oh, r.t.; (g) 2.5% hcl
in dioxane, r.t.
Grubbs catalyst [16] in refluxing CH2Cl2 to give the desired macrocyclic compound (R)-7
possessing exclusive trans double bonds. Subsequent catalytic hydrogenation of the double
bonds provided (R)-8 in excellent yield. Finally, the target compound (R)-1 was obtained
from (R)-8 afer MOM-deprotection of hydroxyl group in HCl solution (2.5% in dioxane)
at room temperature with 89% overall yield [17]. Later, the identical synthetic protocol was
carried out successfully to prepare (S)-1 starting from intermediate 5.
e physical and spectral data of synthetic (R)-1 and (S)-1 were totally identical except
for their optical rotation data, with [ꢀ]25 + 10.4 (c 0.5, MeOH) for (R)-1 and [ꢀ]2D5 − 20.1
(c 0.5, MeOH) for (S)-1. Previously, tDhe absolute configuration of C-3 in natural (S)-
dihydroresorcylide had been deduced to be R, only based on a biogenetic consideration
[4]. Herein, it was obvious that the optical rotation sign of the natural 1 ([ꢀ]25 + 15.0 (c 0.33,
MeOH)) is identical with that of synthetic (R)-1. erefore, with these datDa in hand it can
be clearly confirmed that the configuration of C-3 in natural dihydroresorcylide should be
R, instead of S.
2.2. PTP1B inhibition evaluation
e synthetic macrolides (R)-1, (S)-1 and their precursors were tested for in vitro inhibitory
activity against PTP1B, with oleanolic acid as the positive control [18]. e bioassay results
are shown in Table 1. Interestingly, only the macrolides with the R configuration in C-3
showed inhibition on PTP1B, and their enantiomers did not exhibit obvious activity at the
concentration of 100 μM. is result indicated that the configuration of C-3 in the lactone
ring played a key role in their activity. It seems that this is the first report about PTP1B
inhibitor possessing resorcylic macrolide skeleton according to the literature survey [19].

4
C.-S. JIANG ET AL.
Figure 2. docking results. (a) docking mode of (R)-1 (carbon in green) and (S)-1 (carbon in purple) in the
catalytic site of PtP1B; (B) the proposed interactions between macrolides and key amino acid residues.
In addition, the activity of (R)-8 (IC50 = 53.15 1.79 μM) was weaker than that of (R)-1
(IC50 = 17.06 2.04 μM), probably attributed to the steric hindrance of MOM groups in
(R)-8 decreasing its binding affinity to PTP1B. Subsequently, the bioactive (R)-1 and (R)-8
were subjected to bioassay for testing their selectivity toward PTPs. e result shown in
Table 1 indicated that both compounds showed high PTP1B selectivity over other PTPs.
2.3. Molecular docking study
e (R)-1 and (S)-1 were selected to perform the molecular docking analysis using Glide
5.5 [20] to understand the inhibitory activity against PTP1B. Figure 2 displayed the pro-
posed binding mode with the interactions between macrolides and key amino acid residues.
Although both compounds positioned themselves in the active-site pocket of PTP1B (Figure
2(A)), (R)-1 had more interactions with amino acid residues in the active site than (S)-1
(Figure 2(B)). For example, (R)-1 could form two kinds of essential interactions with the
key amino acids, including hydrogen-bond interactions with Lys116, Asp181, Gly183 and

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
5
Table 1. inhibitory activity of 1 and 8 against PtP1B and other PtPs presented as ic50 (μM).
Compound
PTP1B
TCPTP
SHP-1
SHP-2
LAR
(R)-8
53.15 1.79
na
17.06 2.04
na
naa
ndb
na
nd
nd
na
nd
na
nd
nd
na
nd
na
nd
nd
na
nd
na
nd
nd
(S)-8
(R)-1
(S)-1
oleanolic acid
3.01 0.37
ainactive, precentage inhibition is less than 20% at 100 μM.
bna, not tested.
Gln266, and Pi-Pi stacking interactions with key Arg221 in the catalytic A-site and Trp179
in B-site. In addition, this molecule could generate more hydrophobic interactions with
surrounding residues. All of these interactions would positively contribute to the affinity
of binding (R)-1 to the active site of PTP1B.
3. Conclusion
In the present study, a concise synthetic route for dihydroresorcylides was achieved in seven
steps with 34% overall yield. By comparison of their optical rotation data, the configuration
of C-3 in natural (S)-dihydroresorcylide was revised to be R. In addition, the synthetic (R)-
1 was found to be a novel selective PTP1B inhibitor. To the best of our knowledge, this is
the first example of macrolide with resorcinol fragment reported as PTP1B inhibitor. e
preliminary bioassay and docking study indicated the configuration of C-3 in lactone ring
played a key role in interaction between macrolides and the catalytic domain of PTP1B.
e further structural modification and activity study are in progress.
4. Experimental
4.1. General experimental procedures
Optical rotations were recorded on a Jasco P-1030 polarimeter (JASCO Inc., Tokyo, Japan).
1H, 13C NMR spectra were recorded on a DRX-400 (1H 400 MHz and 13C 125 MHz) (Bruker,
Karlsruhe, Germany) spectrometer (IS as TMS). Low- and high-resolution mass spectra
(LRMS and HRMS) were given with electric, electrospray (ESI) produced by Finnigan MAT-
95 (ermoFisher Scientific Inc., Massachusetts, American) and Agilent 1100 LC-MS spec-
trometer (Agilent Technologies Inc., California, American). All reagents purchased from
commercial sources were used without further purification. e compounds synthesized
were purified by column chromatography (CC) on commercial silica gel (SiO2, 200–300
mesh, Qingdao Haiyang Chemical Group Co., Qingdao, China).
4.2. Preparation of the compounds
4.2.1. 2-(Trimethylsilyl)ethyl 2,4-bis(methoxymethoxy)-6-methylbenzoate (3)
To a mixture of 2 (8.0 g, 31.3 mmol), PPh3 (12.3 g, 46.9 mmol), and 2-(trimethylsilyl)ethanol
(5.5 g, 46.9 mmol) in diethyl ether (80 ml) and toluene (40 ml) was slowly added DEAD
(8.2 g, 46.9 mmol) at 0 °C, and stirred for 1.5 h at room temperature. en, the solution was
concentrated and the obtained residue was purified by silica gel column chromatography

6
C.-S. JIANG ET AL.
1
with petroleum ether/ethyl acetate (v:v = 15:1) to give 3 as a yellow oil (9.1 g, 82%). H
NMR (300 MHz, CDCl3) δ: 6.66 (s, 1H), 6.54 (s, 1H), 5.14 (s, 2H), 5.13 (s, 2H), 4.41-4.35
(m, 2H), 3.46 (s, 3H), 3.45 (s, 3H), 2.29 (s, 3H), 1.13-1.07 (m, 2H), 0.06 (s, 9H); ESI-MS
m/z: 357 [M + H]+.
4.2.2. (E)-2-(Trimethylsilyl)ethyl 2,4-bis(methoxymethoxy)-6-(2-oxopent-3-en-1-yl)
benzoate (4)
To a solution of 3 (6.0 g, 16.8 mmol) in dry THF (150 ml) was slowly added LDA (2.0 M,
16.8 ml, 33.7 mmol) at −78 °C. Afer stirring for 30 min, (E)-N-methoxy-N-methylbut-
2-enamide (Weinreb amide, 2.6 g, 20.2 mmol) was added, and the reaction mixture was
stirred for another 2.5 h. e reaction was quenched by addition of saturated NH4Cl aqueous
solution (60 ml), and then it was warmed to room temperature. e reaction mixture was
concentrated and extracted with EtOAc (100 ml × 3). e combined organic phase was dried
over anhydrous MgSO4 and concentrated. e residue was purified by silica gel column
chromatography with petroleum ether/ethyl acetate (v:v = 15:1) to give 4 as a colorless oil
(5.7 g, 80%). 1H NMR (300 MHz, CDCl3) δ 6.90–6.92 (m, 1H), 6.75 (s, 1H), 6.51 (s, 1H),
6.17 (d, J = 15.7 Hz, 1H), 5.14 (s, 2H), 5.13 (s, 2H), 4.31 (t, J = 7.5 Hz, 2H), 3.82 (s, 2H),
3.47 (s, 3H), 3.44 (s, 3H), 1.87 (d, J = 6.8 Hz, 3H), 1.20 (t, J = 7.0 Hz, 2H), 0.04 (s, 9H); 13
C
NMR (300 MHz, CDCl3) δ 196.2, 167.8, 159.0, 156.3, 143.7, 135.3, 130.9, 119.0, 111.6, 102.8,
95.1, 94.4, 63.5, 56.4, 56.3, 45.6, 18.4, 17.5; ESI-MS: m/z 425 [M + H]+.
4.2.3. (E)-2,4-Bis(methoxymethoxy)-6-(2-oxopent-3-en-1-yl)benzoic acid (5)
To a solution of 4 (4.0 g, 9.4 mmol) in THF (40 ml) was added TBAF (1 M in THF, 28.4 ml,
28.4 mmol) at room temperature. e resulting mixture was stirred overnight, and then it
was hydrolyzed with saturated aqueous NH4Cl and extracted with EtOAc (50 ml × 3). e
combined organic phases were dried over anhydrous Na2SO4 and evaporated. e residue
was purified by flash chromatography with petroleum ether/ethyl acetate (v:v = 3:1) to give
5 as a white solid (2.7 g, 90%). 1H NMR (300 MHz, CDCl3) δ 6.97–6.99 (m, 1H), 6.86 (d,
J = 2.3 Hz, 1H), 6.60 (d, J = 2.3 Hz, 1H), 6.25 (dd, J = 1.2, 15.3 Hz, 1H), 5.31 (s, 2H), 5.18
(s, 2H), 4.16 (s, 2H), 3.53 (s, 3H), 3.46 (s, 3H), 1.92 (dd, J = 1.6, 6.8 Hz, 2H); 13C NMR
(300 MHz, CDCl3) δ 197.5, 169.5, 159.0, 156.0, 144.1, 135.4, 130.6, 118.8, 111.6, 102.1,
94.9,94.0, 55.2, 55.0, 44.5, 17.0; ESI-MS: m/z 325 [M + H]+.
4.2.4. (R,E)-Hept-6-en-2-yl 2,4-bis(methoxymethoxy)-6-(2-oxopent-3-en-1-yl)
benzoate ((R)-6)
To a mixture of 5 (1.0 g, 3.1 mmol), triphenylphosphine (PPh3, 1.2 g, 4.6 mmol) and (S)-6-
hepten-2-ol (0.5 g, 4.6 mmol) in diethyl ether (20 ml) and toluene (5 ml) was slowly added
DEAD (0.7 ml, 4.6 mmol) at 0 °C and stirred for 1.5 h. e solution was evaporated. e
residue was purified by silica gel column chromatography with petroleum ether/ethyl acetate
(v:v = 15:1) to give (R)-6 as a colorless oil (1.1 g, 86%). [ꢀ]2D4 − 2.3 (c 0.1, MeOH); 1H NMR
(300 MHz, CDCl3) δ 6.91–6.93 (m, 1H), 6.77 (d, J = 2.1 Hz, 1H), 6.52 (d, J = 2.1 Hz, 1H),
6.18 (dd, J = 1.5, 4.4 Hz, 1H), 5.80 (m, 1H), 5.14 (s, 2H), 5.14 (s, 2H), 5.00 (d, J = 4.4 Hz, 1H),
4.96 (s, 1H), 3.85 (q, J = 8.4 Hz, 2H), 3.46 (s, 3H), 3.45 (s, 3H), 2.05–2.07 (m, 2H), 1.88 (dd,
J = 1.4, 7.0 Hz, 3H), 1.54–1.58 (m, 5H), 1.28 (d, J = 6.3 Hz, 3H); ESI-MS: m/z 421 [M + H]+.

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
7
4.2.5. (S,E)-Hept-6-en-2-yl 2,4-bis(methoxymethoxy)-6-(2-oxopent-3-en-1-yl)
benzoate ((S)-6)
e synthetic procedure for (S)-6 was identical with that of (R)-6 described above, expected
for using (R)-6-hepten-2-ol as one of reactants, instead of (S)-6-hepten-2-ol. (S)-6: 1.1 g,
yield 85%, as a colorless oil. [ꢀ]D24 + 18.2 (c 0.3, MeOH); H NMR (300 MHz, CDCl3) δ
1
6.91–6.93 (m, 1H), 6.77 (d, J = 2.1 Hz, 1H), 6.52 (d, J = 2.1 Hz, 1H), 6.18 (dd, J = 1.5, 4.4 Hz,
1H), 5.79–5.81 (m, 1H), 5.14 (s, 2H), 5.14 (s, 2H), 5.00 (d, J = 4.4 Hz, 1H), 4.96 (s, 1H), 3.85
(q, J = 8.4 Hz, 2H), 3.46 (s, 3H), 3.45 (s, 3H), 2.05–2.07 (m, 2H), 1.88 (dd, J = 1.4, 7.0 Hz,
3H), 1.54–1.58 (m, 5H), 1.28 (d, J = 6.3 Hz, 3H); 13C NMR (300 MHz, CDCl3) δ 196.1,
167.5, 159.0, 156.1, 143.7, 138.6, 135.1, 130.9, 119.1, 114.9, 111.3, 102.5, 94.8, 94.4, 72.0,
56.4, 56.3, 45.4, 35.6, 33.7, 24.7, 20.2, 18.5; ESI-MS: m/z 421 [M + H]+.
4.2.6. (R,Z)-12,14-Bis(methoxymethoxy)-3-methyl-3,4,5,6-tetrahydro-1H-benzo[c][1]
oxacyclododecine-1,9(10H)-dione ((R)-7)
A mixture of diene (R)-6 (500 mg, 1.19 mmol) and the Grubbs II catalyst (50.52 mg,
0.06 mmol) in CH2Cl2 (400 ml) was heated to reflux for 2 h. e solution was concentrated
and filtered through a silica pad to give the crude product which was further purified by
silica gel column chromatography with petroleum ether/ethyl acetate (v:v = 20:1) to give
compound (R)-7 (360 mg, 80%) as a colorless oil. [ꢀ]24 − 8.0 (c 0.2, MeOH); H NMR
1
(300 MHz, CDCl3) δ 6.87–6.89 (m, 1H), 6.72 (dd, J = 1.6D, 13.5 Hz, 2H), 5.95 (d, J = 16.2 Hz,
1H), 5.18–5.20 (m, 1H), 5.13 (s, 2H), 5.12 (s, 2H), 4.56 (d, J = 12.4 Hz, 1H), 3.45 (s, 3H), 3.45
(s, 3H), 3.29 (d, J = 12.4 Hz, 1H), 2.26–2.28 (m, 2H), 1.75–1.77 (m, 1H), 1.37 (d, J = 6.3 Hz,
3H); ESI-MS: m/z 379 [M + H]+.
4.2.7. (S,Z)-12,14-Bis(methoxymethoxy)-3-methyl-3,4,5,6-tetrahydro-1H-benzo[c][1]
oxacyclododecine-1,9(10H)-dione ((S)-7)
e synthetic procedure for (S)-7 was identical with that of (R)-7 described above. (S)-7:
377 mg, 84%, as a colorless oil. [ꢀ]D24 + 14.1 (c 0.3, MeOH); 1H NMR (300 MHz, CDCl3) δ
6.87–6.89 (m, 1H), 6.72 (dd, J = 1.6, 13.5 Hz, 2H), 5.95 (d, J = 16.2 Hz, 1H), 5.18–5.20 (m,
1H), 5.13 (s, 2H), 5.12 (s, 2H), 4.56 (d, J = 12.4 Hz, 1H), 3.45 (s, 3H), 3.45 (s, 3H), 3.29 (d,
J = 12.4 Hz, 1H), 2.26–2.28 (m, 2H), 1.75–1.77 (m, 1H), 1.37 (d, J = 6.3 Hz, 3H); 13C NMR
(300 MHz, CDCl3) δ 198.9, 168.6, 159.0, 155.8, 150.0, 134.7, 131.0, 119.2, 111.4, 102.4, 94.9,
94.5, 72.4, 56.4, 56.4, 56.4, 42.9, 34.2, 31.8, 24.7, 20.7; ESI-MS: m/z 379 [M + H]+; ESI-HRMS:
m/z 401.1583 [M + Na]+ (calcd for C20H26O7Na, 401.1576).
4.2.8. (R)-Bis(methoxymethoxy)resorcylide ((R)-8)
A suspension of (R)-7 (300 mg, 0.79 mmol) and Pd/C (30 mg) in CH3OH (10 ml) was
stirred under H2 over 4 h. e catalyst was filtered off and the solvent was evaporated
to give the crude product which was purified by silica gel column chromatography with
petroleum ether/ethyl acetate (v:v = 1:1) to give (R)-8 (285 mg, yield 95%) as a colorless
oil. [ꢀ]2D4 + 6.3 (c 0.2, MeOH); 1H NMR (300 MHz, CDCl3) δ 6.75–6.77 (m, 1H), 6.51–5.52
(m, 1H), 5.25–5.28 (m, 1H), 5.15 (s, 4H), 4.12 (d, J = 18.2 Hz, 1H), 3.58 (d, J = 18.2 Hz,
1H), 3.47 (d, J = 1.1 Hz, 3H), 3.46 (d, J = 1.1 Hz, 3H), 2.43 (t, J = 6.3 Hz, 2H), 1.75–1.77 (m,
2H), 1.53–1.55 (m, 2H), 1.38–1.40 (m, 2H), 1.29 (dd, J = 0.9, 6.4 Hz, 3H), 0.84–0.86 (m,
2H); ESI-MS: m/z 381 [M + H]+.

8
C.-S. JIANG ET AL.
4.2.9. (S)-Bis(methoxymethoxy)resorcylide ((S)-8)
e synthetic procedure for (S)-8 was identical with that of (R)-8 described above. (S)-
8: 276 mg, yield 92%, as a colorless oil. [ꢀ]24 − 12.9 (c 0.3, MeOH); H NMR (300 MHz,
1
CDCl3) δ 6.75–6.77 (m, 1H), 6.51–6.53 (m,D1H), 5.25–5.27 (m, 1H), 5.15 (s, 4H), 4.12 (d,
J = 18.2 Hz, 1H), 3.58 (d, J = 18.2 Hz, 1H), 3.47 (d, J = 1.1 Hz, 3H), 3.46 (d, J = 1.1 Hz, 3H),
2.43 (t, J = 6.3 Hz, 2H), 1.75–1.77 (m, 2H), 1.53–1.55 (m, 2H), 1.38–1.40 (m, 2H), 1.29
(dd, J = 0.9, 6.4 Hz, 3H), 0.84–0.86 (m, 2H); 13C NMR (300 MHz, CDCl3) δ 208.1, 167.7,
158.7, 155.6, 133.8, 119.7, 112.0, 102.6, 94.9, 94.5, 72.2, 56.4, 56.3, 47.5, 41.5, 33.0, 27.2,
22.8, 22.6, 20.3; ESI-MS: m/z 381 [M + H]+; ESI-HRMS: m/z 403.1725 [M + Na]+ (calcd
for C20H28O7Na, 403.1733).
4.2.10. (R)-Dihydroresorcylide ((R)-1)
e mixture of (R)-8 (200 mg, 0.53 mmol) and 5 ml HCl solution (2.5% in dioxane) was
stirred at room temperature for 4 h, and then extracted with EtOAc (5 ml × 3). e combined
organic phases were washed with sat. NaHCO3 aqueous solution and water, and then dried
over anhydrous MgSO4 and filtered. e organic phase was concentrated under reduced
pressure to afford the crude product, which was purified by flash column chromatogra-
phy with petroleum ether/ethyl acetate (v:v = 2:1) to give target molecule (R)-1 (136 mg,
89%) as a white solid. [ꢀ]2D4 + 10.4 (c 0.5, MeOH); 1H NMR (300 MHz, CD3OD) δ 6.25 (d,
J = 2.3 Hz, 1H), 6.11 (d, J = 2.3 Hz, 1H), 5.11–5.13 (m, 1H), 4.70 (d, J = 18.8 Hz, 1H), 3.79
(d, J = 18.8 Hz, 1H), 2.69 (dd, J = 16.4, 9.9 Hz, 1H), 2.33 (dd, J = 16.4, 9.9 Hz, 1H), 2.01–2.03
(m, 1H), 1.80–1.82 (m, 1H), 1.63–1.65 (m, 2H), 1.50–1.53 (m, 4H), 1.29 (d, J = 6.2 Hz, 3H);
ESI-MS: m/z 293 [M+H]+.
4.2.11. (S)-Dihydroresorcylide ((S)-1)
e synthetic procedure for (S)-1 was identical with that of (R)-1 described above. (S)-1:
139 mg, 90%, as a white solid. [ꢀ]D24 − 40.8 (c 0.8, MeOH); 1H NMR (300 MHz, CD3OD) δ
6.25 (d, J = 2.3 Hz, 1H), 6.11 (d, J = 2.3 Hz, 1H), 5.11–5.13 (m, 1H), 4.70 (d, J = 18.8 Hz,
1H), 3.79 (d, J = 18.8 Hz, 1H), 2.69 (dd, J = 16.4, 9.9 Hz, 1H), 2.33 (dd, J = 16.4, 9.9 Hz,
1H), 2.01–2.03 (m, 1H), 1.80–1.82 (m, 1H), 1.63–1.64 (m, 2H), 1.50–1.53 (m, 4H), 1.29 (d,
J = 6.2 Hz, 3H); 13C NMR (125 MHz, CD3OD) δ 211.7, 172.4, 166.6, 163.8, 140.2, 113.7,
106.6, 102.9, 74.5, 51.7, 42.5, 32.7, 28.2, 22.2, 22.1, 19.4; ESI-MS: m/z 293 [M+H]+; ESI-
HRMS: m/z 315.1212 [M+Na]+ (calcd for C16H20O5Na, 315.1208).
4.3. Biological activity assays
Recombinant human PTP1B catalytic domain was expressed and purified according to
procedures described previously [15]. Enzymatic activity of PTP1B was determined at 30 °C
by monitoring the hydrolysis of pNPP. Dephosphorylation of pNPP generates product pNP,
which can be monitored at 405 nm. e assays were carried out in a final volume of 100 μl
containing 50 mmol/L MOPS, pH 6.5, 2 mmol/L pNPP, 30 nmol/L GST-PTP1B, and 2%
DMSO; the catalysis of pNPP was continuously monitored on a SpectraMax 340 microplate
reader at 405 nm for 2 min at 30 °C. e IC50 value was calculated from the nonlinear curve
fitting of percent inhibition [inhibition (%)] vs. the inhibitor concentration [I] using the
following equation: inhibition (%) = 100/{1+(IC50/[I])k}, where k is the Hill coefficient. To
study the inhibition selectivity on other PTP family members, human TCPTP, SHP1, SHP2

JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH
9
and LARD1 were prepared and assays were performed according to procedures described
previously [21].
4.4. Molecular docking
e LigPrep [22] panel was used to produce multiple output structures of macrolides by
generating different protonation states, stereochemistry, tautomers, and ring conformations
for molecular docking. e Protein Preparation Wizard Workflow was used to prepare the
protein structures. Residues located within 20 Å around 989 on PTP1B (PDB: 1nl9, [23])
were defined as binding sites in which the docking grids were created. e default settings
were used. Both macrolides were docked into the defined binding site using extra precision
(XP) mode without any constraint.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
is work was financially supported by the Natural Science Foundation of China [grant numbers
81520108028, 41476063, 21672230]; SCTSM Projects [grant number 14431901100], [grant number
15431901000]; e SKLDR/SIMM Project [grant number SIMM1501ZZ-03].
References
[1] K.S. Yeung and I. Paterson, Chem. Rev. 105, 4237 (2005).
[2] C.S. Jiang, L.F. Liang, and Y.W. Guo, Acta Pharmacol. Sin. 33, 1217 (2012).
[3] N. Winssinger and S. Barluenģa, Chem. Commun. 171, 22 (2007).
[4] S.M. Poling, D.T. Wicklow, K.D. Rogers, and J.B. Gloer, J. Agric. Food. Chem. 56, 3006 (2008).
[5] L. Zhang, W.Q. Ma, L. Xu, F. Deng, and Y.W. Guo, Chin. J. Chem. 31, 339 (2013).
[6] Y. Xu, T. Zhou, P. Espinosa-Artiles, T. Yang, J. Zhan, and I. Molnár, ACS Chem. Biol. 9, 1119
(2014).
[7] E. Panzhinskiy, J. Ren, and S. Nair, Curr. Med. Chem. 20, 2609 (2013).
[8] A.J. Barr, Future Med. Chem. 2, 1563 (2010).
[9] L.F. Iverson, K.B. Moller, A.K. Pedersen, G.H. Peters, A.S. Petersen, H.S. Andersen, S. Branner,
S.B. Mortensen, and P.N. Moller, J. Biol. Chem. 277, 19982 (2002).
[10] L. Zhang, C.S. Jiang, L.X. Gao, J.X. Gong, Z.H. Wang, J.Y. Li, X.W. Li, and Y.W. Guo, Bioorg.
Med. Chem. Lett. 26, 778 (2016).
[11] J. Chen, L.X. Gao, J.X. Gong, C.S. Jiang, L.G. Yao, J.Y. Li, J. Li, W. Xiao, and Y.W. Guo, Bioorg.
Med. Chem. Lett. 25, 2211 (2015).
[12] J. Chen, C.S. Jiang, W.Q. Ma, L.X. Gao, J.X. Gong, J.Y. Li, J. Li, Y.W. Guo, Bioorg. Med. Chem.
Lett. 23, 5061 (2013).
[13] R.L. Linderman, M. Jaber, and B.D. Griedel, J. Org. Chem. 59, 6499 (1994).
[14] O. Mitsunobu, Synthesis 1981, 1 (1981).
[15] N. Kawai, J.M. Lagrange, M. Ohmi, and J. Uenishi, J. Org. Chem. 71, 4530 (2006).
[16] E.A. Couladouros, A.P. Mihou, and E.A. Bouzas, Org. Lett. 6, 977 (2004).
[17] J.E. Day, S.Y. Sharp, M.G. Rowlands, W. Aherne, W. Lewis, S.M. Roe, C. Prodrmou, L.H. Pearl,
P. Workman, and C.J. Moody, Chemistry 16, 10366 (2010).
[18] L. Shi, H.P. Yu, Y.Y. Zhou, J.Q. Du, Q. Shen, J.Y. Li, and J. Li, Acta Pharmacol. Sin. 29, 278 (2008).
[19] J. Xu, C.S. Jiang, Z.L. Zhang, W.Q. Ma, and Y.W. Guo, Acta Pharmacol. Sin. 35, 316 (2014).

10
C.-S. JIANG ET AL.
[20] R.A. Friesner, J.L. Banks, R.B. Murphy, T.A. Halgren, J.J. Klicic, D.T. Mainz, M.P. Repasky, E.H.
Knoll, M. Shelley, J.K. Perry, D.E. Shaw, P. Francis, and P.S. Shenkin, J. Med. Chem. 47, 1739
(2004).
[21] Y.T. Chen, C.L. Tang, W.P. Ma, L.X. Gao, Y. Wei, W. Zhang, J.Y. Li, J. Li, and F.J. Nan, Eur. J.
Med. Chem. 69, 399 (2013).
[22] LigPrep, version 2.3 (Schrödinger, LLC, New York, NY, 2009).
[23] B.G. Szczepankiewicz, G. Liu, P.J. Hajduk, C. Abad-Zapatero, Z. Pei, Z. Xin, T. Lubben, J.M.
Trevillyan, M.A. Stashko, S.J. Ballaron, H. Liang, F. Huang, C.W. Hutchins, S.W. Fesik, and M.R.
Jirousek, J. Am. Chem. Soc. 125, 4087 (2003).