Untitled

Abstract

Two dimeric monoterpenes obtusal A and B, and two dimeric diterpenes obtusanol A and B, along with (À)-(S)-citronellol, (À)-(S)-citronellic acid, ()-borneol, ()-sugiol, and (À)-6,12-dihydroxyabieta-5,8,11,13tetraen-7-one, have been isolated from the heartwood of Chamaecyparis obtusa var. formosana and were characterized by spectroscopic means, including 2D-NMR techniques and chemical methods. Synthesis of (À)obtusal A and ()-obtusal B were carried out.

Bioactive Dimeric Abietanoid Peroxides from the Bark of Cryptomeria japonica

“…Comparison of 1 H and 13 C-NMR data of 2 and 1 (Table 1) showed that the signals of constituent lower monomer-2 of 2 were almost the same as those of 1 , indicating the structure of constituent lower monomer-2 is related to 6,7-dehydroferruginol. The 1 H- and 13 C-NMR data of 2 (Table 1) also showed another set of dehydroabietane diterpene signals for constituent upper monomer-1 including three tertiary methyl groups (δ H 0.95, 1.02, and 1.37 (each 3H, s, Me-18, Me-19, and Me-20)), an isopropyl group attached to a phenyl group (δ H 1.16 (3H, d, J = 7.0 Hz, Me-17), 1.18 (3H, d, J = 7.0 Hz, Me-16), and 3.01 (1H, sept, J = 7.0 Hz, H-15)), two para aromatic protons (δ H 6.72 (1H, s, H-14) and 6.74 (1H, s, H-11)), a phenolic hydroxyl proton (δ H 4.52 (1H, s)), and a typical downshifted H β -1 signal of a dehydroabietane diterpene (δ H 1.93 (1H, br d, J = 12.0 Hz)) [33]. A downshifted benzyl proton connected with a peroxyl group (δ H 5.20 (1H, d, J = 8.0 Hz, H-7)) was assigned as H-7, suggesting by the 1 H- 1 H COSY correlations with the two methylene protons of H-6 (δ H 2.24 (1H, m, H α -6), δ H 2.40 (1H, br d, J = 8.0 Hz, H β -6)) and HMBC correlations with C-5 (δ C 47.6) and C-8 (δ C 147.2; Figure 3).…”

“…These data proved that the structure of constituent monomer-1 was related to 7α-peroxyferruginol. The 1 H- and 13 C-NMR data of 1 (Table 1) also exhibited another set of dehydroabietane diterpene signals for constituent lower monomer-2 including three tertiary methyl groups (δ H 0.94, 1.04, and 1.11 (each 3H, s, Me-18′, Me-19′, and Me-20′)), an isopropyl group attached to a phenyl group (δ H 0.81 (3H, d, J = 7.0 Hz, Me-16′), 0.98 (3H, d, J = 7.0 Hz, Me-17′), and 2.82 (1H, sept, J = 7.0 Hz, H-15′)), two para aromatic protons (δ H 6.98 (1H, s, H-11′) and 6.77 (1H, s, H-14′)), an ABX coupling system of one methine proton (δ H 2.07 (1H, dd, J = 3.0, 2.5 Hz, H-5′)), and two vinyl protons (δ H 5.87 (1H, dd, J = 9.5, 2.5 Hz, H-6′) and 6.45 (1H, dd, J = 9.5, 3.0 Hz, H-7′)), together with a typical downshifted H β -1 signal of a dehydroabietane diterpene (δ H 2.22 (1H, br d, J = 13.0 Hz)) [33]. The above NMR spectroscopic data suggested constituent lower monomer-2 was related to 6,7-dehydroferruginol [35].…”

“…The 1 H- and 13 C-NMR data of 1 (Table 1) showed one set of dehydroabietane diterpene signals for constituent upper monomer-1 including three tertiary methyl groups (δ H 0.97, 0.98, and 1.36 (each 3H, s, Me-18, Me-19, and Me-20)), an isopropyl group attached to a phenyl group (δ H 0.78 (3H, d, J = 7.0 Hz, Me-16), 1.01 (3H, d, J = 7.0 Hz, Me-17), and 2.85 (1H, sept, J = 7.0 Hz, H-15)), two para aromatic protons (δ H 6.34 (1H, s, H-14) and 6.69 (1H, s, H-11)), a phenolic hydroxyl proton (δ H 4.33 (1H, s, exchangeable with D 2 O)), and a typical downshifted H β -1 signal of a dehydroabietane diterpene (δ H 1.96 (1H, br d, J = 12.0 Hz)) [33]. A downshifted benzyl proton connected with a peroxyl group (δ H 5.86 (1H, br s, H-7)), instead of a hydroxyl group [19,33,34], was assigned as H-7, suggested by the 1 H- 1 H COSY correlations with the two methylene protons of H-6 (δ H 2.28 (1H, m), δ H 2.32 (1H, m)), and HMBC correlations with C-5 (δ C 43.5) and C-8 (δ C 145.6; Figure 3). In addition, the 1 H-NMR signal of H-7 was a broad singlet peak and showed the NOESY correlation with both H α -6 (δ H 2.32) and H β -6 (δ H 2.28), hinted that the peroxyl group was attached on C-7 in α-axial orientation [33] (Figure 3).…”

“…A downshifted benzyl proton connected with a peroxyl group (δ H 5.86 (1H, br s, H-7)), instead of a hydroxyl group [19,33,34], was assigned as H-7, suggested by the 1 H- 1 H COSY correlations with the two methylene protons of H-6 (δ H 2.28 (1H, m), δ H 2.32 (1H, m)), and HMBC correlations with C-5 (δ C 43.5) and C-8 (δ C 145.6; Figure 3). In addition, the 1 H-NMR signal of H-7 was a broad singlet peak and showed the NOESY correlation with both H α -6 (δ H 2.32) and H β -6 (δ H 2.28), hinted that the peroxyl group was attached on C-7 in α-axial orientation [33] (Figure 3). These data proved that the structure of constituent monomer-1 was related to 7α-peroxyferruginol.…”

“…Due to the anisotropic effect from the opposite phenyl group, H-14, H-15, H-16, H-17, H-14′, H-15′, H-16′, H-17′, and phenol of 1 were posited in the shielding region and thus showed the higher field chemical shifts than that of the usual dehydroabietane diterpene. In contrast, H-5, H-7, and H-20’ of 1 were located in the deshielding region and thus exhibit a lower field chemical shifts than that of the usual dehydroabietane diterpene [33]. Complete 1 H- and 13 C-NMR chemical shifts were established by 1 H- 1 H COSY, HMQC, HMBC, and NOESY spectra.…”