18-Nor-Kaurane Type Diterpenoids from the Fruits of Atemoya

Abstract

A phytochemical investigation on the flesh fruits of atemoya led to the isolation of seven new kaurane type diterpenoids, (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-16-hydro-18-nor-kauran-4,17-diol (1), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-18-nor-kauran-4,16,17-triol (2), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-18-nor-kauran-4,16-diol (3), (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-18-nor-kauran-4,16,17-triol (4), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-16-hydro-18-nor-kauran-4-ol (5), (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-16,17-dihydroxy-19-nor-kauran-4-hydroperoxide (6), and (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-kauran-16,19-diol (7) along with 26 known ent-kaurane compounds. Their structures are determined on the basis of spectroscopic data and optical rotation. Compounds 1–5 were new 18-nor-kauran-4-ol type diterpenoids, which are very rarely obtained from natural sources.

Introduction

Annonaceae is a large family of flowering trees, shrubs, and lianas with approximately 107 genera and over 2400 species distributed mainly in tropical and subtropical regions.¹⁾ Annonaceae plants are widely used in traditional medicine to treat various diseases such as arthritis, rheumatism, asthma attacks, gastrointestinal ulcers, and colic pain.²⁾ Phytochemical analysis of Annonaceae plants showed that alkaloids, flavonoids, triterpenes, diterpenes, sterols, and lignans can be obtained from the leaves, stems, bark, and roots, and acetogenin, from the seeds.²⁾ The chemical constituents of the fruits of Annonaceae are less studied. Therefore, we performed a phytochemical study for the fruits of cherimoya (Annona cherimola Mill.) and reported four new ent-kaurane and 12 known ent-kaurane diterpenoids.³⁾ This suggests that ent-kaurane type diterpenoids are also present in the fruits of other plants of Annonaceae plants.

Atemoya is a Annonaceae plants, a hybrid cross between A. cherimola Mill. and A. squmosa L. Currently, atemoya is one of the most important commercial fruits of Annonaceae plants and is widely cultivated in the United States, Israel, Australia, and the Philippines. Phytochemical studies have shown the presence of various types of acetogenin analogs⁴⁾ in the seeds and some alkaloids⁵⁾ in the leaves. The chemical constituents of the fruits of atemoya are less studied. Therefore, we studied fresh fruits without the seeds of atemoya and identified seven new kaurane type diterpenoids, (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-16-hydro-18-nor-kauran-4,17-diol (1), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-18-nor-kauran-4,16,17-triol (2), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-18-nor-kauran-4,16-diol (3), (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-18-nor-kauran-4,16,17-triol (4), (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-16-hydro-18-nor-kauran-4-ol (5), (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-16,17-dihydroxy-19-nor-kauran-4-hydroperoxide (6), and (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-kauran-16,19-diol (7) together with 26 known compounds (8–33). In this paper, we describe their isolation and structural elucidation using two-dimensional (2D) NMR spectroscopic analysis and optical rotation.

Results and Discussion

The methanolic extract of fresh fruits without the seeds of atemoya was subjected to MCI gel CHP20P, octadecyl silica gel (ODS), and silica gel column chromatographies and finally to HPLC to obtain 33 compounds (1–33). Compounds 8–33 were identified as ent-kauran-16α-ol⁶⁾ (8), ent-kauran-16α,17-diol⁶⁾ (9), ent-kauran-16β,17-diol⁶⁾ (10), 16α-hydro-ent-kauran-17-oic acid⁷⁾ (11), 16β-hydro-ent-kauran-17-oic acid⁸⁾ (12), 16α-hydro-ent-kauran-17,19-diol⁹⁾ (13), 16β-hydro-ent-kauran-17,19-diol³⁾ (14), ent-kauran-16β,17,19-triol¹⁰⁾ (15), 19-acetoxy-ent-kauran-16β,17-diol¹⁰⁾ (16), 16β,17-dihydroxy-ent-kauran-19-al¹¹⁾ (17), 16α-hydro-17-hydroxy-ent-kauran-19-oic acid¹¹⁾ (18), 16β-hydro-17-hydroxy-ent-kauran-19-oic acid¹¹⁾ (19), 16α,17-dihydroxy-ent-kauran-19-oic acid¹¹⁾ (20), 16β,17-dihydroxy-ent-kauran-19-oic acid¹¹⁾ (21), 17-acetoxy-16α-hydro-ent-kauran-19-oic acid¹²⁾ (22), 17-acetoxy-16β-hydroxy-ent-kauran-19-oic acid¹³⁾ (23), 16α-hydro-ent-kauran-17,19-dioic acid¹⁴⁾ (24), 16β-hydro-ent-kauran-17,19-dioic acid¹⁴⁾ (25), Methyl 16α,17-dihydroxy-ent-kauran-19-oate⁶⁾ (26), 16α-hydro-19-nor-ent-kauran-4α,17-diol¹⁴⁾ (27), 19-nor-ent-kauran-4α,16β,17-triol¹¹⁾ (28), 16β,17-dihydroxy-18-nor-ent-kauran-4β-hydroperoxide¹⁴⁾ (29), ent-kaur-16-en-19-ol¹¹⁾ (30), ent-kaur-16-en-19-oic acid¹¹⁾ (31), 17-hydroxy-ent-kaur-15-en-19-oic acid¹⁵⁾ (32), 15α,16α-epoxy-17-hydroxy-ent-kauran-19-oic acid¹⁵⁾ (33), respectively, on the basis of their optical rotation and spectral data (Chart 1).

Chart 1. Structures of Compounds 1–33

Compound 1 was obtained as an amorphous powder, [α]_D −15.5°, and its elemental composition was determined to be the C₁₉H₃₂O₂ through observing a quasi-molecular ion peak ([M + Na]⁺, m/z 315.2322) in high-resolution (HR)-electrospray ionization (ESI)-MS. The ¹H-NMR spectrum exhibited characteristic signals for two tertiary methyl groups (δ 0.93 and 1.27), and one oxymethylene group (δ 3.60 and 3.64). The ¹³C-NMR spectrum and the heteronuclear multiple quantum coherence (HMQC) spectrum gave 19 carbon signals, including four methine carbons, ten methylene carbons, three quaternary carbons, and two methyl groups. The ¹H–¹H correlation spectroscopy (COSY) spectrum revealed the connectivity of three partial structures, C-1–C-3, C-5–C-7, C-9, and C-11–C-17 as shown in Fig. 1. The connections of C-3, C-5, and C-18 or C-19 via the oxygen-bearing quaternary carbon C-4 (δ 71.0), C-1, C-5, and C-9 via the quaternary carbon C-10 (δ 39.9), and C-7, C-9, C-14, and C-15 via the quaternary carbon C-8 (δ 44.8) were suggested by the heteronuclear multiple bond connectivity (HMBC) correlations for tertiary methyl proton (δ 1.27) to C-3, C-4, and C-5, tertiary methyl proton (δ 0.93) to C-1, C-5, C-9, and C-10, and H₂-15 (δ 1.03 and 1.55) to C-7, C-8, C-9, and C-14, respectively. These data indicated that led us to the plane structure of 1 as 18 or 19-nor-kauran-4,17-diol. The stereostructure was characterized by a nuclear Overhauser and exchange spectroscopy (NOESY) experiment, which showed nuclear Overhauser effect (NOE) correlations between the following proton pairs [H-5 (δ 1.31) and H-9 (δ 1.01); H-9 and H-15b (δ 1.55); H₃-19 (δ 1.27) and H₃-20 (δ 0.93); H₃-20 and H-14b (δ 1.82); H-14a (δ 1.06) and H-17b (δ 3.64)] (Fig. 2). Consequently, the NOESY experiment revealed that the hydroxyl group at C-4 had β orientation and that 1 was an 18-nor-kaurane type diterpenoid. In addition, the hydroxyl methylene at C-17 had α orientation. Accordingly, 1 was elucidated to be (4S*,5S*,8S*,9R*,10S*,13R*,16R*)-16-hydro-18-nor-kauran-4,17-diol.

Fig. 1. ¹H–¹H COSY and HMBC Correlations of 1 and 7

Fig. 2. NOE Correlations of 1–7

Compound 2 was isolated as an amorphous powder, [α]_D −42.5°, with the molecular formula C₁₉H₃₂O₃ on the basis of the quasi-molecular ion peak [M + Na]⁺ at m/z 331.2214 (calcd for 331.2249). The ¹H-NMR spectrum of 2 was very similar to that of 1. In the ¹³C-NMR spectrum of 2, the chemical shifts coincided with those of 1, except for a signal corresponding to the appearance of one oxygen-bearing quaternary carbon (δ 79.5) and the disappearance of one methine carbon. The HMBC correlations were observed between H₂-15 (δ 1.63, and 1.72) and the methine carbon at C-13 (δ 41.7), the oxygen-bearing quaternary carbon at C-16 (δ 79.5), and the hydroxy methylene carbon at C-17 (δ 70.2), resulting in the determination of the plane structure of 2. The identical NOESY cross-peak pattern with 1 decided that 2 had the same configuration as 1 had. Therefore, 2 was elucidated as 18-nor-kaurane type diterpenoid possessing a hydroxyl group instead of a proton at the C-16 position of 1.

Compound 3 was obtained as an amorphous powder, [α]_D −63.8°. The molecular formula was higher by C₂H₂O than that of 2. A comparative study of the ¹H-NMR spectrum with that of 2 revealed that they were identical, except for the appearance of an additional acetoxy proton [δ 1.94 (3H, s)]. In the HMBC experiment, correlations were observed between the two hydroxy methylene protons at C-17 [δ 4.26 (1H, d, J = 11.0 Hz) and 4.31(1H, d, J = 11.0 Hz)] and the carbonyl carbon (δ 171.3), resulting in the elucidation of the plane structure. Based on the NOESY experiment, it was concluded that the configuration is consistent with that of 2. Thus, 3 was identified as an 18-nor-kaurane type diterpenoid with an acetyl group attached to the hydroxyl group at C-17 of 2.

Compound 4 was isolated as an amorphous powder, [α]_D −8.2°, and its molecular formula was the same as that of 2, C₁₉H₃₂O₃, based on the quasi-molecular ion peak [M + Na]⁺ at m/z 331.2229 in the HR-ESI-MS. The plane structure was elucidated to be identical to that of 2 by detailed analysis of its 2D-NMR spectra. However, in comparisons with the ¹³C-NMR spectrum of 2, slight differences were observed for C-13 (+4.1), C-16 (+1.9), and C-17 (−3.9), and 4 was presumed to be the stereoisomer of 2 at C-16. NOESY cross-peaks were observed between the following pairs: H-5 (δ 1.34) and H-9 (δ 1.03); H-9 and H-15a (δ 1.63); H-15a and H-17a (δ 4.01); H₃-19 (δ 1.26) and H₃-20 (δ 0.94); H₃-20 and H-14a (δ 1.94) (Fig. 2). Consequently, the NOESY experiment determined that the hydroxy groups at C-4 and C-16 were β and α configurations, respectively. In addition, the signal due to H-14b of 4 (δ_H 2.00) was shifted to a lower field by 0.82 ppm as compared with that in 2 (δ_H 1.18), which must be caused by C-16 hydroxy group. This supports the configuration of the hydroxyl group at C-16 was α. Therefore, 4 was found to be a stereoisomer of 2 at the C-16 position.

Compound 5 was obtained as an amorphous powder, [α]_D −31.7°, and its molecular formula C₂₁H₃₄O₃ was determined by HR-ESI-MS ([M + Na]⁺ m/z 357.2406). The ¹H-NMR data indicated that 5 was an 18-nor-kaurane type diterpenoid closely related to 4. In a comparative study of the ¹H- and ¹³C-NMR data of 5 with those of 4, 5 showed one methine group [δ_H 2.22 (1H, m) and δ_C 39.3] instead of one oxygen-bearing quaternary carbon in 4, and one additional acetoxy group [δ_H 2.05 (3H, s) and δ_C 20.8 and 171.1]. Furthermore, the HMBC correlations for H₂-15 (δ 0.98 and 1.45) with the methine carbons at C-13 (δ 37.7) and C-16 (δ 39.3), the hydroxy methylene carbon at C-17 (δ 65.8), and two hydroxy methylene protons at C-17 (δ 4.16 and 4.26) with the carbonyl carbon (δ 171.1) indicated that 5 was a 17-acetoxy-nor-kauran-4-ol. The configuration was concluded to be the same as that of 4 on the basis of the NOESY experiment. Based on this, 5 was decided to be (4S*,5S*,8S*,9R*,10S*,13R*,16S*)-17-acetoxy-16-hydro-18-nor-kauran-4-ol.

Compound 6, [α]_D −42.5°, was isolated as an amorphous powder, and its elemental composition was determined to be C₁₉H₃₂O₄ by HR-ESI-MS ([M + Na]⁺, m/z 347.2175). The ¹H-NMR spectrum was similar to that of 2. In the ¹³C-NMR spectrum, the chemical shifts coincided with those of 2, except for slight differences in the data for C-3 (δ: 35.3, −8.1), C-4 (δ: 82.7, +11.6), and C-5 (δ: 55.8, −2.0). In addition, the MS spectrum showed an increase in one oxygen atom compared that of 2, indicating that 6 was substituted with a hydroperoxide group instead of a hydroxy group of 2 at C-4. NOESY cross-peaks were observed between the following pairs: H₃-18 (δ 1.42) and H-5 (δ 1.00); H-5 and H-9 (δ 1.09); H-9 and H-15b (δ 1.75); H₃-20 (δ 1.26) and H-14b (δ 2.03); H-14a (δ 1.13) and H-17b (δ 3.80) (Fig. 2). Therefore, the NOESY experiment determined that the hydroperoxide group at C-4 and the hydroxy group at C-16 had α and β orientations, respectively. Meanwhile, the α configuration of the hydroperoxide group at C-4 was supported by the signal due to H₃-20 (δ 1.26) was shifted to lower field by 0.27 ppm as compared with that of 2. Therefore, 6 was identified as (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-16,17-dihydroxy-19-nor-kauran-4-hydroperoxide, which was a stereoisomer of 29 at the C-4 position.

Compound 7 was obtained as an amorphous powder, [α]_D −47.4°, and the molecular formula of C₂₀H₃₄O₂ was resolved by HR-ESI-MS ([M + Na]⁺ m/z 329.2441). The ¹H-NMR spectrum contained signals for three tertiary methyl groups (δ 0.99, 1.16, and 1.54), one oxymethylene group (δ 3.59 and 3.98), and one methine proton (δ 2.44). The ¹³C-NMR spectrum displayed 20 carbon signals, including three quaternary carbons (δ 39.1, 39.4, and 45.4), one oxygen-bearing quaternary carbon (δ 77.8), and one oxygen-bearing methylene carbon (δ 63.8). These above data indicated that 7 was a kaurane type diterpenoid. In addition, ¹H–¹H COSY and HMBC let us to the plane structure of 7 as kauran-16,19-diol (Fig. 1). NOESY cross-peaks were observed between protons H₃-18 (δ 1.16) and H-5 (δ 0.90); H-5 and H-9 (δ 0.97); H-9 and H-15b (δ 1.92); H-19a and b (δ 3.59 and 3.98) and H₃-20 (δ 0.99); H₃-20 and H-14b (δ 1.97); H-14a (δ 1.89) and H₃-17 (δ 1.54) (Fig. 2). These results suggested that the configuration of the hydroxy group at C-16 was β. Consequently, 7 was elucidated to be (4R*,5S*,8S*,9R*,10S*,13R*,16S*)-kauran-16,19-diol. To the best of our knowledge, this is the first time that 7 was isolated from natural sources.

In the present study, seven new kaurane type diterpenoids 1–7 and 26 known compounds were isolated from flesh fruits with seeds removed. In the structural elucidation of these compounds, the NOESY experiment was a powerful tool for determining the configurations of C-4 and C-16. In particular, the stereochemistry at C-16 of kaurane type diterpenoids possessing hydroxyl methylene at C-17 was able to be elucidated from the correlations between H-15a (correlated H-9) and H-17a, and H-14a (uncorrelated H₃-20) and H-17b, respectively. Compounds 1–5 were new 18-nor-kauran-4-ol type diterpenoids, which are very rarely obtained from a natural sources, with only one case has been reported.¹⁶⁾ This is the first isolation of 18-nor-kaurane type diterpenoids (4β-hydroxy type: 1, 2, 3, 4, and 5; 4β-hydroperoxy type: 29) and 19-nor-kaurane type diterpenoids (4α-hydroxy type: 27 and 28; 4α-hydroperoxy type: 6) from a single plant species.

Experimental

General Procedure

Optical rotations were taken with a JASCO DIP-1000 automatic digital polarimeter. The NMR spectra were measured with a JEOL ECA 500 NMR spectrometer (JEOL, Tokyo, Japan). The chemical shifts (δ) are reported in parts per million (ppm) and J values in Hz, using pyridine-d₅ for ¹H-NMR (7.20 ppm) and ¹³C-NMR (123.5 ppm) as an internal standard. The MS were recorded with a JEOL JMS-T100LP spectrometer. HPLC was carried out using the Cosmosil AR-II (10.0 mm i.d. × 250 mm, Nacalai Tesque, Inc., Kyoto, Japan); column with a Tosoh CCPM pump, and Tosoh RI-8010 detector. TLC was performed on pre-coated Kieselgel 60 F₂₅₄ (Merck Ltd., Tokyo, Japan), and detection was achieved by spraying with 10% H₂SO₄ followed by heating. Column chromatography was carried out on Kieselgel (230–400 mesh, Merck Ltd., Tokyo, Japan), MCI gel CHP20P (Mitsubishi Chemical Group Corp., Tokyo, Japan), and ODS (PrePAK-500/C₁₈, Waters Corp., Tokyo, Japan).

Plant Material

Fresh atemoya fruits grown on a farm in Okinawa, Japan, were purchased at the Onna Village agricultural and marine products sales center in August 2012.

Extraction and Isolation

The fresh fruits of Annona atemoya (920 g) were extracted with MeOH at room temperature for one month. The MeOH extract was subjected to MCI gel CHP20P column chromatography (CC) [MeOH–H₂O (10 : 90→30 : 70→40 : 60→90 : 10, v/v)→MeOH→acetone] to afford two fractions [Fractions 1 (2305 mg), 2 (624 mg)]. Fraction 1 (2305 mg) was further separated by ODS CC [MeOH–H₂O (60 : 40→70 : 30→80 : 20→90 : 10, v/v)] to give 5 fractions [fr. 1-1–fr. 1-5]. Fraction 1-1 was further separated by silica gel CC [CHCl₃–MeOH–H₂O (8 : 2 : 0.2, v/v)], followed by HPLC [MeOH–H₂O (60 : 40, v/v)] to furnish compounds 2 (5.9 mg), 4 (0.7 mg), 15 (4.0 mg), 28 (2.4 mg), and 33 (1.0 mg). Fraction 1-2 was further separated by silica gel CC [CHCl₃–MeOH–H₂O (8 : 2 : 0.2, v/v)], followed by HPLC [MeOH–H₂O (60 : 40, v/v)] to furnish compound 6 (6.0 mg) and [MeOH–H₂O (65 : 35, v/v)] to furnish compounds 3 (1.7 mg), 20 (18.1 mg), 21 (35.1 mg), and 29 (6.6 mg). Fraction 1-3 was further separated by silica gel CC [CHCl₃–MeOH–H₂O (8 : 2 : 0.2, v/v)], followed by HPLC [MeOH–H₂O (65 : 35, v/v)] to furnish compounds 17 (2.3 mg) and 23 (4.9 mg) and [MeOH–H₂O (70 : 30, v/v)] to furnish compound 1 (1.3 mg), 13 (1.6 mg), 14 (1.4 mg), 16 (0.5 mg), 19 (19.9 mg), 24 (4.9 mg), 26 (12.6 mg), 27 (1.9 mg), and 32 (6.2 mg). Fraction 1-4 was further separated by silica gel CC [CHCl₃–MeOH–H₂O (8 : 2 : 0.2, v/v)], followed by HPLC [MeOH–H₂O (75 : 25, v/v)] to furnish compounds 5 (0.3 mg), 7 (0.6 mg), 18 (1.2 mg), and 25 (2.2 mg). Fraction 1-5 was further separated by silica gel CC [CHCl₃–MeOH–H₂O (8 : 2 : 0.2, v/v)], followed by HPLC [MeOH–H₂O (85 : 15, v/v)] to furnish compounds 9 (4.4 mg), 10 (13.9 mg), and 22 (3.8 mg) and [MeOH–H₂O (90 : 10, v/v)] to furnish compounds 11 (1.5 mg), 30 (1.6 mg), and 31 (51.0 mg). Fraction 2 (624 mg) was further separated by ODS CC [MeOH–H₂O (80 : 20→90 : 10, v/v)] and silica gel CC [CHCl₃–MeOH (20 : 1, v/v)], followed by HPLC [MeOH–H₂O (90 : 10, v/v)] to furnish compounds 8 (19.4 mg) and 12 (0.7 mg).

Compound 1: Amorphous powder; [α]_D −15.5° (c = 0.10, MeOH; HR-ESI-MS m/z 315.2322 [M + Na]⁺ (Calcd for C₁₉H₃₂O₂Na, 315.2300); ¹H- and ¹³C-NMR data (Table 1).

Compound 2: Amorphous powder; [α]_D −42.5° (c = 0.51, MeOH); HR-ESI-MS m/z 319.2249 [M + Na]⁺ (Calcd for C₁₉H₃₂O₃Na, 331.2249); ¹H- and ¹³C-NMR data (Table 1).

Compound 3: Amorphous powder; [α]_D −63.8° (c = 0.75, MeOH); HR-ESI-MS m/z 373.2363 [M + Na]⁺ (Calcd for C₂₁H₃₄O₄Na, 373.2355); ¹H- and ¹³C-NMR data (Table 1).

Compound 4: Amorphous powder; [α]_D −8.2° (c = 0.06, MeOH); HR-ESI-MS m/z 331.2229 [M + Na]⁺ (Calcd for C₁₉H₃₂O₃Na, 331.2249); ¹H- and ¹³C-NMR data (Table 1).

Compound 5: Amorphous powder; [α]_D −31.7° (c = 0.04, MeOH); HR-ESI-MS m/z 357.2388 [M + Na]⁺ (Calcd for C₂₁H₃₄O₃Na, 357.2406); ¹H- and ¹³C-NMR data (Table 1).

Compound 6: Amorphous powder; [α]_D −42.5° (c = 0.52, MeOH); HR-ESI-MS m/z 347.2175 [M + Na]⁺ (Calcd for C₁₉H₃₂O₄Na, 347.2198); ¹H- and ¹³C-NMR data (Table 1).

Compound 7: Amorphous powder; [α]_D −47.4° (c = 0.07, MeOH); HR-ESI-MS m/z 329.2468 [M + Na]⁺ (Calcd for C₂₀H₃₄O₂Na, 329.2456); ¹H- and ¹³C-NMR data (Table 1).

Table 1. ¹H- and ¹³C-NMR Data of 1–7 (Pyridine-d₅)

Position	1		2		3		4		5		6		7
	δC	δH	δC	δH	δC	δH	δC	δH	δC	δH	δC	δH	δC	δH
1a	40.0	0.73 dt (4.8, 12.8)	40.1	0.76 dt(4.6, 12.8)	40.1	0.75 dt(4.2, 13.2)	40.0	0.74 dt(4.6, 12.6)	39.8	0.73 dt(4.6, 12.6)	40.3	0.74 dt(3.4, 13.2)	40.6	0.74 dt(3.5, 13.2)
b		1.67 brd(12.8)		1.82 brd(12.8)		1.70 td(2.8, 13.2)		1.64 brd(12.6)		1.62 brd(12.6)		1.79 brd(13.2)		1.72 brd(13.2)
2a	19.9	1.48a)	20.0	1.49a)	20.0	1.48a)	20.0	1.50a)	20.0	1.50a)	18.1	1.34a)	18.6	1.38a)
b		1.48a)		1.54a)		1.55a)		1.61a)		1.50a)		1.96 tq(3.5, 13.2)		1.68a)
3a	43.4	1.65 dt(4.8, 13.2)	43.4	1.64 dt(4.6, 13.2)	43.4	1.65 dt(4.6, 13.2)	43.3	1.64a)	43.3	1.65 dt(6.3, 12.6)	35.3	1.14 dt(4.6, 13.7)	36.1	0.95 dt(4.6, 13.2)
b		1.92 brd(13.2)		1.92 td(4.0, 13.2)		1.93 td(3.4, 13.2)		1.92 brd(13.2)		1.92 brd(12.6)		2.43 brd(13.7)		2.16 brd(13.2)
4	71.0		71.1		71.0		71.0		71.0		82.7		39.4
5	57.8	1.31 brd(11.3)	57.8	1.34 brd(12.1)	57.8	1.35 dd(2.8, 11.5)	57.7	1.34 brd(12.6)	57.7	1.33 brd(11.9)	55.8	1.00 brd(12.0)	56.9	0.90 brd(11.5)
6a	20.0	1.34 dq(3.5, 13.2)	19.3	1.35 brdd(2.9, 12.1)	19.3	1.36 brdd(2.8, 12.8)	19.7	1.37 dq(2.9, 12.8)	19.6	1.30 brdd(2.9, 12.6)	20.1	1.66 brdd(2.9, 12.8)	20.9	1.35 brdd(2.9, 13.2)
b		2.22 brdd(2.9, 13.2)		2.20 dq(3.5, 12.8)		2.23a)		2.21 td(3.2, 12.8)		2.21a)		1.77a)		1.65 dq(3.5, 13.2)
7a	41.5	1.42 brdd(2.9, 13.2)	41.9	1.43 brdd(2.9, 12.8)	41.8	1.43 brdd(3.5, 12.8)	42.1	1.58 dt(5.2, 12.8)	41.7	1.40a)	42.1	1.35 dt(4.6, 12.8)	42.9	1.41 brdd(3.5, 12.8)
b		1.55a)		1.52a)		1.54 brdd(3.2, 12.8)		1.72 td(3.7, 12.8)		1.46a)		1.38 brdd(3.5, 12.8)		1.64 dt(4.6, 12.8)
8	44.8		43.8		44.0		44.8		44.3		43.6		45.4
9	56.3	1.01 brd(7.9)	57.3	1.20 brd(8.0)	57.2	1.18 brd(8.4)	56.8	1.03 brd(8.1)	57.0	0.94 brd(8.2)	56.5	1.09 brd(8.3)	57.3	0.97 brd(8.2)
10	39.9		40.0		40.0		39.8		39.8		39.3		39.1
11a	19.0	1.53 brdd(6.1, 14.9)	19.2	1.60 brdd(6.3, 15.0)	19.2	1.62 brdd(6.4, 14.6)	18.8	1.51a)	19.0	1.41a)	19.0	1.61 brdd(6.8, 15.3)	18.3	1.48 brdd(6.3, 14.8)
b		1.56a)		2.44a)		2.38 m		1.60 brdd(5.4, 15.1)		1.41a)		2.40 m		1.49a)
12a	31.9	1.44a)	27.5	1.56a)	27.2	1.59a)	26.6	1.51a)	26.1	1.48a)	27.2	1.48 ddt(2.9, 6.3, 13.2)	27.1	1.49a)
b		1.55a)		2.17 m		2.19 m		1.86 brd(13.2)		1.48a)		2.11 m		1.56a)
13	38.8	2.36 brs	41.7	2.43 brdd(4.0, 6.8)	42.2	2.24 brdd(4.0, 7.0)	45.8	2.44 brd(2.3)	37.7	2.10 brs	41.5	2.36 brdd(3.8, 6.9)	49.1	2.14 brs
14a	37.4	1.06 dd(4.6, 12.8)	38.5	1.18 dd(3.7, 12.0)	38.5	1.19a)	37.7	1.94 d(12.0)	40.4	0.93 dd(4.0, 12.8)	38.6	1.13a)	37.8	1.89 brd(12.8)
b		1.82 dd(2.8, 12.8)		1.99 dd(2.3, 12.0)		2.01 dd(2.8, 12.8)		2.00 dd(3.5, 12.0)		1.91 brd(11.9)		2.03 dd(2.3, 12.0)		1.97 dd(4.3, 12.8)
15a	45.8	1.03 dd(6.1, 14.1)	53.3	1.63 d(13.8)	53.4	1.63 d(14.2)	53.7	1.63 d(14.3)	43.9	0.98 dd(6.9, 13.8)	53.1	1.65 d(14.3)	58.4	1.62 d(14.0)
b		1.55 dd(7.7, 14.1)		1.72 dd(2.9, 13.8)		1.74 dd(2.8, 14.2)		1.77 d(14.3)		1.45 dd(12.8, 13.8)		1.75 dd(2.3, 14.3)		1.92 d(14.0)
16	43.9	2.15 m	79.5		77.7		81.4		39.3	2.22 m	79.5		77.8
17a	66.8	3.60 d(11.0)	70.2	3.74 d(10.9)	71.8	4.26 d(11.0)	66.3	4.01 d(10.9)	65.8	4.16 dd(8.0, 10.9)	70.1	3.73 d(10.9)	24.8	1.54 s
b		3.64 d(11.0)		3.82 d(10.9)		4.31 d(11.0)		4.08 d(10.9)		4.26 dd(8.0, 10.9)		3.80 d(10.9)
18											25.4	1.42 s	27.9	1.16 s
19a	23.3	1.27 s	23.2	1.27 s	23.2	1.28 s	23.1	1.26 s	23.1	1.26 s			63.8	3.59 d(10.3)
b														3.98 d(10.3)
20	17.2	0.93 s	17.3	0.99 s	17.2	1.00 s	17.4	0.94 s	17.3	0.89 s	17.9	1.26 s	18.4	0.99 s
OCOCH3					20.8	1.94 s			20.8	2.05 s
OCOCH3					171.3				171.1

a) Overlapped.

Conflict of Interest

The authors declare no conflict of interest.

Supplementary Materials

This article contains supplementary materials.

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