New orsellinic acid esters from fungus chaetomium globosporum

Article abstract of DOI:10.1002/hlca.201300329

Seven new orsellinic acid esters, 1-7, and four known compounds were isolated from the solid, fermented rice culture of Chaetomium globosporum (cib-132). Their structures were elucidated by 1D- and 2D-NMR spectra, and the relative configuration of compoun

Full text of DOI:10.1002/hlca.201300329

Helvetica Chimica Acta – Vol. 97 (2014)
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New Orsellinic Acid Esters from Fungus Chaetomium globosporum
by Guo-Bo Xua)b), Ni-Ni Wanga), Jin-Ku Baob), Tao Yanga), and Guo-You Li*a)
a) Key Laboratory of Environmental and Applied Microbiology, Chengdu Institute of Biology, Chinese
Academy of Sciences, Chengdu 610041, P. R. China
b) Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, School of Life
Sciences, Sichuan University, Chengdu 610064, P. R. China
(fax: þ 86-28-82890829; e-mail: ligy@cib.ac.cn)
Seven new orsellinic acid esters, 1 – 7, and four known compounds were isolated from the solid,
fermented rice culture of Chaetomium globosporum (cib-132). Their structures were elucidated by 1D-
and 2D-NMR spectra, and the relative configuration of compound 1 was determined by X-ray
crystallographic analysis.
Introduction. – Secondary metabolites from fungi are an important source for basic
chemical intermediate or drugs such as penicillin, cyclosporine A, griseofulvin, and
lovastatin [1 – 3]. In recent years, various bioactive metabolites from fungi were
reported [4 – 7], which inspired us to search for new bioactive compounds from fungi.
Previously, compounds of diverse structured types such as chaetoglobosins, orsellides,
azaphilones, depsidones, diketopiperazines, anthraquinones, and terpenoids have been
isolated and identified from the genus Chaetomium (Chaetomiaceae). Many com-
pounds from this genus were shown to possess significant biological features such as
cytotoxic, antibiotic, phytotoxic, and other activities [8 – 14]. In our continuing study on
Chaetomium globosporum obtained from wheat roots, seven new orsellinic acid esters,
1 – 7 (Fig. 1), together with four known compounds, orsellinic acid, divaric acid,
cochliodinol, and 1-O-hexadecanolenin, were isolated and identified from the solid
fermented rice culture of this fungus. Herein, the isolation and structure elucidation of
compounds 1 – 7 are described.
Results and Discussion. – Compound 1 was obtained as triclinic crystals (actone/
H2O, 100 :1), and its molecular formula, C13H18O7, was established from the quasi-
molecular ion at m/z 309.0943 ([M þ Na]þ) in HR-ESI-MS, indicating of five degrees of
unsaturation. The IR spectrum of 1 revealed the presence of OH (3411 cmꢀ1) and
phenyl groups (1622 cmꢀ1).
1
In the H-NMR spectrum of 1, signals of two meta-coupled aromatic H-atoms
(d(H) 6.20 (d, J ¼ 2.4) and 6.25 (d, J ¼ 2.4)) and two Me groups (d(H) 2.55 (s) and 1.31
(d, J ¼ 6.2)) (Table 1) were detected. Its 13C-NMR spectrum displayed signals of an
aromatic ring ((d(C) 102.2, 106.4, 112.9, 145.3, 164.3, and 166.5), four O-bearing C-
atoms ((d(C) 68.2, 68.9, 69.7, and 76.7), an ester CO group (d(C) 173.3), and two Me
groups ((d(C) 24.9 and 20.8) (Table 2). These spectroscopic features revealed that
compound 1 should be an orsellinic acid ester [9]. In the HMBC spectrum, correlations
HꢀC(4)/C(2) ((d(C) 106.4), C(3) ((d(C) 166.5), and C(5) ((d(C) 164.3), HꢀC(6)/C(4)
ꢀ 2014 Verlag Helvetica Chimica Acta AG, Zꢁrich

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Fig. 1. Compounds 1 – 7 isolated from C. globosporum
((d(C) 102.2) and C(2); and HꢀC(8)/C(7) ((d(C) 145.3), C(6), and C(2) (Fig. 2),
supported the presence of an orsellinic acid unit. Due to the five degrees of
unsaturation, there should be a linear side chain in compound 1. The following HMBCs
suggested a pentane-1,2,3,4-tetraol moiety and the connection of this moiety with
orsellinic acid: HꢀC(1’)/C(1) (d(C) 173.3), C(2’) (d(C) 69.7), and C(3’) (d(C) 76.7);
HꢀC(2’)/C(1’) (d(C) 68.2); HꢀC(3’)/C(4’) (d(C) 68.9) and C(5’) (d(C) 20.8), and
HꢀC(5’)/C(4’). Therefore, the constitution of compound 1 was elucidated as 2,3,4-
trihydroxypentyl orsellinate. The relative configuration, rel-(2’R,3’R,4’R), of 1 was
determined by X-ray crystallographic analysis (Fig. 3).
Compounds 2 and 3 were isolated as amorphous white powders and possessed the
same formula C13H18O7 as 1 on the basis of their HR-ESI-MS. Compound 2 was a
stereoisomer of 1 evidenced by 1D-NMR (Tables 1 and 2), HSQC, and HMBCs
Table 1. 1H-NMR Data (600 MHz, CD3OD) of Compounds 1 – 3. d in ppm, J in Hz. Arbitrary atom
numbering as indicated in Fig. 1.
Position
1
2
3
4
6
8
6.20 (d, J ¼ 2.4, 1 H)
6.25 (d, J ¼ 2.4, 1 H)
2.55 (s, 3 H)
6.22 (d, J ¼ 2.4, 1 H)
6.18 (d, J ¼ 1.8, 1 H)
6.22 (br. s, 1 H)
2.53 (s, 3 H)
6.27 (d, J ¼ 2.4, 1 H)
2.59 (s, 3 H)
1’
4.43 – 4.46 (m, 2 H)
4.64 (dd, J ¼ 11.6, 2.6, 1 H),
4.47 (dd, J ¼ 11.6, 6.7, 1 H)
3.96 – 3.99 (m, overlapped, 1 H)
3.57 (dd, J ¼ 7.3, 5.7, 1 H)
3.96 – 3.99 (m, overlapped, 1 H)
1.29 (d, J ¼ 6.4, 3 H)
1.41 (d, J ¼ 6.5, 3 H)
2’
3’
4’
5’
4.26 – 4.29 (m, 1 H)
3.30 (overlapped, 1 H)
3.85 – 3.87 (m, 1 H)
1.31 (d, J ¼ 6.2, 3 H)
5.48 (qd, J ¼ 6.4, 3.3, 1 H)
3.87 (d, J ¼ 8.3, 3.3, 1 H)
3.56 – 3.59 (m, 1 H)
3.82 (dd, J ¼ 11.3, 3.1, 1 H),
3.66 (dd, J ¼ 11.3, 6.1, 1 H)

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Table 2. 13C-NMR Data (150 MHz, CD3OD) of Compounds 1 – 3. d in ppm. Arbitrary atom numbering
as indicated in Fig. 1.
Position
1
2
3
1
2
3
4
5
6
7
8
173.3
106.4
166.5
102.2
164.3
112.9
145.3
24.9
173.1
106.3
166.1
101.9
163.9
112.6
145.1
24.6
172.3
106.5
166.1
101.2
163.8
112.6
144.9
24.7
1’
2’
3’
4’
5’
68.2
69.7
76.7
68.9
68.1
72.4
76.5
69.9
14.0
74.1
73.7
73.8
20.8
18.4
65.1
(Fig. 2). The HMBCs HꢀC(2’)/C(1) (d(C) 172.3) and C(1’) (d(C) 14.0); HꢀC(3’)/C(2’)
(d(C) 74.1) and C(1’), HꢀC(5’)/C(4’) (d(C) 73.8) and C(3’) (d(C) 73.7) suggested that
the pentane-1,2,3,4-tetraol moiety was also present in compound 3. However, the
Fig. 2. Key HMBCs of compounds 1 – 7

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Fig. 3. ORTEP Diagram of compound 1
pentane-1,2,3,4-tetraol unit was linked to orsellinic acid at C(2’) (Fig. 2). Thus,
compound 3 was determined as 3,4,5-trihydroxypentan-2-yl orsellinate. The relative
configurations of compounds 2 and 3 were not confirmed, but compound 3 in CD3OD
could be converted to 2 at room temperature within five days (Fig. 4), which was
confirmed by HPLC analysis. Accordingly, the corresponding configurations at C(2’/
4’), C(3’/3’) and C(4’/2’) in 2 and 3 could be deduced.
Fig. 4. 1H-NMR Spectra recorded on a Bruker Avance 600-MHz spectrometer in CD3OD. a) Spectrum of
1; b) spectrum of 2; c) spectrum of 3; d) spectrum of 3 after standing at room temperature for 5 d.

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Table 3. 1H- and 13C-NMR Data (600 and 150 MHz, resp; CD3OD) of Compounds 4 and 5. d in ppm, J in
Hz. Arbitrary atom numbering as indicated in Fig. 1.
Position
d(H)
d(C)
4
5
4
5
1’
2’
3’
4’
5’
6’
7’
8’
2
106.2
165.9
101.9
164.1
112.6
145.1
24.5
172.2
78.8
68.0
106.1
166.4
101.9
164.0
112.7
145.2
24.7
172.3
73.8
74.4
6.18 (d, J ¼ 2.2, 1 H)
6.24 (d, J ¼ 2.2, 1 H)
2.57 (s, 3 H)
6.21 (d, J ¼ 1.7, 1 H)
6.25 (d, J ¼ 1.7, 1 H)
2.53 (s, 3 H)
5.34 (d, J ¼ 3.4, 1 H)
4.31 – 4.35 (m, 1 H)
1.33 (d, J ¼ 6.5, 3 H)
4.47 (s, 1 H)
3
4
5.54 (br. s, 1 H)
1.44 (d, J ¼ 6.1, 3 H)
18.8
15.2
Compound 4 was obtained as an amorphous white powder with a molecular
formula of C12H14O7 (six degrees of unsaturation) deduced from the HR-ESI-MS (m/z
293.0635 ([M þ Na]þ; calc. 293.0632)). Comparing the 13C-NMR data with those of
compounds 1 – 3, the orsellinic acid unit (d(C) 24.5, 101.9, 106.2, 112.6, 145.1, 164.1,
165.9, 172.2) in compound 4 was identified (Table 3). A 2,3-dihydroxybutanoic acid
moiety was elucidated from the 13C-NMR signals, HR-ESI-MS analysis, and the
HMBCs HꢀC(4)/C(3) (d(C) 68.0) and C(2) (d(C) 78.8), HꢀC(2)/C(3) (Fig. 2). The
HMBC HꢀC(2)/C(8’)(d(C) 172.2 suggested the orsellinic acid and 2,3-dihydroxybut-
anoic acid moieties were connected via an O-atom between C(8’) and C(2). Compound
4 was finally identified as 2-[(2,4-dihydroxy-6-methylbenzoyl)oxy]-3-hydroxybutanoic
acid. The configuration of compound 4 was determined by comparing the optical
rotation of its hydrolysis product ([a]2D5 ¼ ꢀ19.0, c ¼ 0.1, H2O) with that of threo-l-2,3-
dihydroxybutyric acid ([a]2D5 ¼ ꢀ17.75, H2O; erythro-l-2,3-dihydroxybutyric acid:
[a]2D5 ¼ ꢀ9.5, H2O) [15]. Thus, compound 4 was finally determined as threo-l-2-[(2,4-
dihydroxy-6-methylbenzoyl)oxy]-3-hydroxybutanoic acid.
Compound 5 was obtained as an amorphous white powder with the same formula,
C12H14O7, as 4 from the quasi-molecular ion (m/z 293.0641 ([M þ Na]þ, calc. 293.0632))
1
in its HR-ESI-MS. The H- and 13C-NMR spectra are similar to those of 4 (Table 3).
However, an obvious upfield shift of HꢀC(2) and C(2), and downfield shift of HꢀC(3)
and C(3) in compound 5 were observed in the NMR spectra. These findings suggested
that the 2,3-dihydroxybutanoic acid and orsellinic acid moieties were linked through an
O-bridge between C(8’) and C(3). Compound 5 was thus identified as 3-[(2,4-
dihydroxy-6-methylbenzoyl)oxy]-2-hydroxybutanoic acid. The configuration of com-
pound 5 was also deduced by the method as described for 4. Compound 5 was,
therefore, determined as threo-l-3-[(2,4-dihydroxy-6-methylbenzoyl)oxy]-2-hydroxy-
butanoic acid.
Compound 6 was obtained as an amorphous white powder. The molecular formula,
C16H20O9, was deduced from the quasi-molecular ion at m/z 379.1002 ([M þ Na]þ) in
HR-ESI-MS, indicating seven degrees of unsaturation. On the basis of NMR data
(Table 4), the orsellinic acid unit in 6 was easily recognized. Based on 13C-NMR and

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Table 4. 1H- and 13C-NMR Data (600 and 150 MHz, resp; CD3OD) of 6 and 7. d in ppm, J in Hz.
Arbitrary atom numbering as indicated in Fig. 1.
Position
d(H)
d(C)
6
7
6
7
1
2
3
4
5
6
7
8
172.1
106.3
164.0
101.9
166.2
112.7
144.9
24.6
172.8
105.7
164.2
101.9
166.5
112.7
145.0
25.3
6.20 (d, J ¼ 2.1, 1 H)
6.24 (d, J ¼ 2.1, 1 H)
2.53 (s, 3 H)
6.20 (d, J ¼ 2.0, 1 H)
6.24 (d, J ¼ 2.0, 1 H)
2.53 (s, 3 H)
2’
3’
4’
179.2
69.8
34.3
179.5
69.8
34.6
4.68 (dd, J ¼ 9.1, 1 H)
2.74 (dd, J ¼ 13.3, 9.4, 1 H),
2.06 (dd, J ¼ 13.3, 8.2, 1 H)
4.07 (d, J ¼ 4.4, 1 H)
4.75 (d, J ¼ 9.0, 1 H)
2.82 (dd, J ¼ 13.3, 9.5, 1 H),
2.09 (dd, J ¼ 13.3, 8.7, 1 H)
3.63 (d, J ¼ 8.1, 1 H)
3.75 – 3.79 (m, 1 H)
6’
7’
8’
9’
75.2
72.6
16.3
65.4
78.0
68.8
21.6
68.5
5.37 – 5.42 (m, 1 H)
1.45 (d, J ¼ 6.4, 1 H)
1.33 (d, J ¼ 6.1, 1 H)
3.78 (d, J ¼ 12.2, 1 H),
3.66 (d, J ¼ 12.2, 1 H)
4.71 (d, J ¼ 12.2, 1 H),
4.61 (d, J ¼ 12.2, 1 H)
HSQC experiments, one Me group (d(C) 16.3), two CH2 (d(C) 34.3 and 65.4) and three
O-bearing CH groups (d(C) 72.6, 75.2, 69.8), an O-bearing quaternary C-atom (d(C)
89.8), and one ester CO group (d(C) 179.2) were identified. The remaining atoms
should form a ring deduced from degrees of unsaturation. In the HMBC spectrum, the
substructure from C(2’) to C(9’) could be postulated on the basis of following
correlations: HꢀC(7’)/C(8’), HꢀC(6’)/C(9’), C(8’), C(7’), C(5’), and C(4’), HꢀC(4’)/
C(3’) and C(2’), HꢀC(3’)/C(4’) and C(5’), and HꢀC(9’)/C(4’) and C(5’) (Fig. 2).
Meanwhile, a g-lactone formed between C(2’) and C(5’) was deduced from the
characteristic IR absorption at 1765 cmꢀ1, and the quaternary C-atom resonance at
d(C) 89.8 (C(5’)). The lactone moiety was linked with the orsellinic acid by an O-atom
between C(1) and C(7’), which was supported by the correlation HꢀC(7’)/C(1). Hence,
compound 6 was finally identified as 1-hydroxy-1-[4-hydroxy-2-(hydroxymethyl)-5-
oxotetrahydrofuran-2-yl]propan-2-yl orsellinate.
Compound 7 was assigned the molecular formula C16H20O9 based on the quasi-
molecular-ion peak at m/z 379.0997 ([M þ Na]þ), the same as that of 6. That the NMR
data of 7 (Table 4) were similar to thoes of 6, suggesting that compound 7 was an
isomer of 6. The g-lactone moiety was the same as in compound 6 on the basis of
HMBCs. However, the HMBC HꢀC(9’)/C(1) indicated that C(9’) was connected with
C(1) in 7 (Fig. 2). Therefore, compound 7 was determined as [2-(1,2-dihydroxypropyl)-
4-hydroxy-5-oxotetrahydrofuran-2-yl]methyl orsellinate. Attempts to obtain single
crystals of compounds 6 and 7 for X-ray crystallographic analyses have failed. The
relative configurations of compounds 6 and 7 could not be determined.

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Conclusions. – Orsellinic acid esters possessed diverse biological including
cytotoxic, antibacterial, antiviral, and other activities [9][16 – 21]. In this work, the
antibacterial activities of compounds 1 – 5 were evaluated. Compounds 6 and 7 could
not be evaluated due to insufficient amounts. Compounds 1 – 5 showed no activity
against Staphylococcus aureus, Bacillus subtilis, Escherichia colis, or Saccharomycetes
(c > 50 mg/ml).
This work was financially supported by the National Natural Science Foundation of China
(No. 21272228), the Knowledge Innovation Program of the Chinese Academy of Sciences (KSCX2-EW-
G-13-04), and the National New Drug Innovation Major Project of China (2011ZX09307-002-02).
Experimental Part
General. M.p.: X-6 precision micro melting-point apparatus; uncorrected. Optical rotations: Perkin-
Elmer 341 polarimeter. UV Spectra: PerkinElmer S2 Lambda 35 UV/VIS spectrometer; in MeOH; l in
nm. IR Spectra: PerkinElmer Spectrum One FT-IR spectrometer; as KBr tablets; ˜n in cmꢀ1. NMR
Spectra: Bruker Avance 600 MHz spectrometer; d in ppm, J in Hz; residual solvent peak as reference.
HR-ESI-MS: BioTOF-Q mass spectrometer.
Fungus Material. Chaetomium globosporum (cib-132) was isolated from wheat root collected in
Yaꢂan of Sichuan Province, P. R. China, and identified by T. Y., Chengdu Institute of Biology, Chinese
Academy of Sciences (CAS), P. R. China.
Extraction and Isolation. The fungal seed culture and fermentation process were identical to those
reported [14]. The fermented solid rice medium (7 kg) was soaked with AcOEt (13 l ꢁ 2, 1 d for each
time) at r.t. The soln. was concentrated under reduced pressure to afford a residue (41.0 g). This residue
was divided into four fractions, Frs. A, B, C, and D), by column chromatography (CC) (SiO2 (400 g, 300 –
400 mesh, f 45 cm ꢁ 8.5 cm); petroleum ether (PE)/acetone 6 :1, 3 :1, 1.5 :1, 0 :1, successively). Fr. C was
further separated by CC (Sephadex LH-20; CHCl3/MeOH 1:1) to afford Frs. C1 and C2. Compounds 1 –
3 (5.5, 27.0, and 14.3 mg, resp.) and 6 (3.5 mg) were obtained from Fr. C1 (2.1 g) by HPLC (MeOH/H2O
37:63). Compounds 4 (23.0 mg) and 5 (18.2 mg) were obtained from Fr. C2 (1.7 g) separated by HPLC
(MeOH/H2O 40 :60). Fr. C2 was further separated by HPLC (MeCN/H2O 27:73) to give compound 7
(3.0 mg).
Esters Hydrolysis. Compounds 4 (5.1 mg) and 5 (3.4 mg) were hydrolyzed with 5% NaOH at 708 for
2 h, neutralized with 1n HCl, and extracted with BuOH (3ꢁ), to furnish the hydrolysis products of 4 and
5, resp.
The crystallographic data of compound 1 were collected with a Xcalibur, Eos, diffractometer with
graphite-monochromated MoKa radiation; m(MoKa) ¼ 0.070. Crystal data: C13H20O8, Mr 304.29, triclinic
system, crystal size/mm3, 0.41 ꢁ 0.35 ꢁ 0.10. Space group: P1, a ¼ 7.1516 (3) ꢃ, b ¼ 7.9646 (4) ꢃ, c ¼
13.0796 (6) ꢃ, a ¼ 93.461, b ¼ 95.811(4), g ¼ 100.435(4) , V¼ 726.56 (6) ꢃ3, T¼ 293.15 K, Z ¼ 2, 6110
reflections measured, 4598 independent reflections [R(int) ¼ 0.0182]. The final R1 values were 0.0463
[I > 2s(I)], and the final wR2 values were 0.0765 [I >¼ 2s(I)]. The final R1 values were 0.0782 (all data),
and the final wR2 values were 0.0908 (all data). The crystal structure has been deposited with the
Cambridge Crystallographic Data Centre under the deposition No. CCDC-948632. Copies of the data can
be obtained free of charge via http://www.ccdc.cam.ac.uk/conts/retrieving.html (or from the CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK; e-mail:deposit@ccdc.cam.ac.uk; fax: þ 44(0)1223336033).
rel-(2’R,3’R,4’R)-2,3,4-Trihydroxypentyl Orsellinate (¼ rel-(2R,3R,4R)-2,3,4-Trihydroxypentyl 2,4-
Dihydroxy-6-methylbenzoate; 1): Triclinic crystals. M.p. 78 – 818. [a]2D0 ¼ ꢀ6.0 (c ¼ 0.1, MeOH). UV
(MeOH): 225 (4.32), 264 (4.10), 300 (3.67). IR (KBr): 3411, 2975, 2930, 1644, 1457, 1316, 1260, 1204,
1169, 997, 845. 1H- and 13C-NMR: see Tables 1 and 2, resp. HR-ESI-MS: 309.0943 ([M þ Na]þ,
C13H18NaOþ7 ; calc. 309.0950).
2,3,4-Trihydroxypentyl Orsellinate (¼2,3,4-Trihydroxypentyl 2,4-Dihydroxy-6-methylbenzoate; 2).
White amorphous powder. [a]2D0 ¼ ꢀ30.0 (c ¼ 0.1, MeOH). UV (MeOH): 225 (4.37), 264 (4.20), 300

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Helvetica Chimica Acta – Vol. 97 (2014)
(3.75). IR (KBr): 3433, 2980, 2936, 1642, 1457, 1316, 1264, 1168, 995, 845. 1H- and 13C-NMR: see Tables 1
and 2, resp. HR-ESI-MS: 309.0950 ([M þ Na]þ, C13H18NaO7þ ; calc. 309.0950).
3,4,5-Trihydroxypentan-2-yl Orsellinate (¼ 3,4,5-Trihydroxypentan-2-yl 2,4-Dihydroxy-6-methyl-
benzoate; 3). White amorphous powder. [a]2D0 ¼ ꢀ10.0 (c ¼ 0.1, MeOH). UV (MeOH): 225 (4.40),
1
264 (4.12), 300 (3.68). IR (KBr): 3401, 2978, 2935, 1642, 1452, 1314, 1265, 1204, 1169, 1061, 843. H-
and 13C-NMR: see Tables 1 and 2, resp. HR-ESI-MS: 309.0948 ([M þ Na]þ, C13H18NaOþ7 ; calc.
309.0945).
threo-l-2-[(2,4-Dihydroxy-6-methylbenzoyl)oxy]-3-hydroxybutanoic Acid (4). White amorphous
powder. [a]2D0 ¼ ꢀ15.0 (c ¼ 0.1, MeOH). UV (MeOH): 225 (4.30), 264 (4.13), 300 (3.70). IR (KBr): 3430,
2982, 2935, 1732, 1650, 1623, 1449, 1258, 1102, 997. 1H- and 13C-NMR: see Table 3. HR-ESI-MS: 293.0635
([M þ Na]þ, C12H14NaOþ7 ; calc. 293.0632).
threo-l-3-[(2,4-Dihydroxy-6-methylbenzoyl)oxy]-2-hydroxybutanoic Acid (5). White amorphous
powder. [a]2D0 ¼ ꢀ15.0 (c ¼ 0.1, MeOH). UV (MeOH): 225 (4.30), 264 (4.12), 300 (3.67). IR (KBr):
3435, 2983, 2930, 1717 1650, 1643, 1456, 1262, 1163, 1064, 995. 1H- and 13C-NMR: see Table 3. HR-ESI-
MS: 293.0641 ([M þ Na]þ, C12H14NaO7þ ; calc. 293.0632).
1-Hydroxy-1-[tetrahydro-4-hydroxy-2-(hydroxymethyl)-5-oxofuran-2-yl]propan-2-yl Orsellinate
(¼1-Hydroxy-1-[tetrahydro-4-hydroxy-2-(hydroxymethyl)-5-oxofuran-2-yl]propan-2-yl 2,4-Dihydroxy-
6-methylbenzoate; 6). White amorphous powder. [a]2D0 ¼ þ18.0 (c ¼ 0.1, MeOH). UV (MeOH): 225
1
(4.13), 264 (3.74), 300 (3.67). IR (KBr): 3430, 2982, 2935, 1732, 1650, 1623, 1449, 1258, 1102. H- and
13C-NMR: see Table 4. HR-ESI-MS: 379.1002 ([M þ Na]þ, C16H20NaOþ9 ; calc. 379.1000).
[2-(1,2-Dihydroxypropyl)tetrahydro-4-hydroxy-5-oxofuran-2-yl]methyl Orsellinate (¼ [2-(1,2-Dihy-
droxypropyl)tetrahydro-4-hydroxy-5-oxofuran-2-yl]methyl 2,4-Dihydroxy-6-methylbenzoate; 7). White
amorphous powder. [a]2D0 ¼ ꢀ7.0 (c ¼ 0.1, MeOH). UV (MeOH): 225 (4.10), 264 (3.68), 300 (3.65). IR
(KBr): 3446, 2927, 2855, 1771, 1622, 1451, 1316, 1260, 1112. 1H- and 13C-NMR: see Table 4. HR-ESI-MS:
379.0997 ([M þ Na]þ, C16H20NaOþ9 ; calc. 379.1000).
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Received August 29, 2013