Plants in the Diospyros genus (Ebenacea) are well documented as a rich sources of naphthoquinones and triterpenes, which have been found to exhibit ichthyotoxic, 1,2) antimicrobial, 2-4) and antitumor activities. 4, 5) Thirteen species of this genus are indigenous to Taiwan. Several species, including fruits of D. discolor WILLD., 6) leaves of D. kaki THUNB., 7) barks and stems of D. eriantha CHAMP., 8, 9) stems of D. morrisiana HANCE., 10-12) fruits of D. ferrea, 13) and bark, root, fruits,

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... ves, and twigs of D. maritima BLUME. [1] [2] [3] [4] [5] [14] [15] [16] [17] [18] [19] [20] [21] [22] have been studied for their chemical constituents, resulting in the isolation and structure elucidation of various triterpenes, lignans, steroids, benzoquinones, and naphthoquinone. Previously, we had reported on the isolation of some new naphthoquinones 15, 16) and triterpenes from stems of D. maritima. 5,17-21) As a part of our continuing interest in secondary metabolites from the Diospyros plants, we investigated the chemical principles of the twigs of D. discolor and isolated four new lanostane-type triterpenes: 24-ethyl-3b-methoxylanost-9(11)-en-25-ol (1), 3b-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3b -methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3b-methoxy-24-methyllanosta-9(11),25-dien-24-ol (4); in addition to three known triterpenes, betulinaldehyde, 23) betulinic acid methyl ester, 24) and ursaldehyde. 25) In this paper, we report the extraction, isolation, purification, and structural elucidation of four new lanostane-type triterpenes on the basis of extensive spectroscopic analysis, including 1D and 2D NMR experiments. Compound 1 gave a positive Liebermann-Burchard test and displayed a molecular ion peak at m/z 486.4422 in its HR-EI-MS, suggesting a molecular formula of C 33 H 58 O 2 . The IR spectrum showed the presence of hydroxyl (3438 cm Ϫ1 ) and double bond (1635, 875 cm Ϫ1 ) functionalities. The 1 H-NMR spectrum of 1 (Table 1) indicated the presence of seven tertiary methyls [d H 0.62, 0.72, 0.78, 0.95, 1.02 (3H each, s), 1.16 (3Hϫ2, s)], one secondary methyl [d H 0.88 (3H, d, Jϭ6.4 Hz)], a ethyl [d H 1.22 m, 0.94 (3H, t, Jϭ7.2 Hz)], a methoxyl [d H 3.35 (3H, s)], one axial-oriented methoxymethine [d H 2.62 (1H, dd, Jϭ4.0, 11.2 Hz)], and a typical H-11 proton of lanosta-9(11)-ene [d H 5.19 (1H, br d, Jϭ6.0 Hz)]. 26) The 13 C-NMR spectrum of 1 revealed 33 carbon signals, which were identified by the assistance of a DEPT experiment as nine methyls, one methoxy carbon, ten sp 3 methylenes, five secondary sp 3 carbinyl carbons, one oxygenated sp 3 methine, five sp 3 quaternary carbons, and two coupled sp 2 olefinic carbons (d C 115.0, 148.9). The MS spectrum of 1 show [M] ϩ at m/z 486 accompanied with the major fragment ions at m/z 468 [MϪH 2 O] ϩ , 453 [MϪH 2 OϪCH 3 ] ϩ , and 327 [MϪC 10 H 21 O (side chain)Ϫ2H] ϩ . In addition, the major fragment ions at m/z 255, 241 and 229 supported that the double bond located at C-9 and C-11. 27) From the above evidences, compound 1 was considered as lanosta-9(11)-ene triterpene with a C 10 H 21 O side chain. Detailed comparison of the 1 H-and 13 C-NMR data of 1 with those of the known lanostane-type triterpene, 25,26,27-trinor-3b -methoxylanost-9(11)-en-24-oic acid, isolated from the stem bark of Pinus luchuensis, 28) shows that the signals of the tetracyclic part were very similar to each other, except for the signals of C-20-C-27, C-31, and C-32 in the side chain part. A downfield singlet signal of methyl [d H 1.16 (3Hϫ2, s)] and the HMBC correlations between H-21 (d H 0.88) and C-17 (d C 51.0), C-20 (d C 37.2), and C-22 (d C 36.7); H-32 (d H 0.94) and C-24 (d C 52.3) and C-31 (d C 24.0); H-26 (d H 1.16) and C-24 and C-25 (d C 74.5) supported that a hydroxyl attached on C-25 and a ethyl [d H 1.22 (2H, m), 0.94 (3H, t, Jϭ7.2 Hz)] attached on C-24, respectively. Complete 1 H and 13 C chemical shifts were established by 1 H-1 H COSY, HMQC, HMBC and NOESY spectra. Thus, the structure of 908 Four new lanostane-type triterpenes, 24-ethyl-3b b-methoxylanost-9(11)-en-25-ol (1), 3b b-methoxy-24-methylenelanost-9(11)-en-25-ol (2), 3b b-methoxy-25-methyl-24-methylenelanost-9(11)-en-21-ol (3) and 3b b-methoxy-24methyllanosta-9(11),25-dien-24-ol (4) together with three known triterpenes, betulinaldehyde, betulinic acid methyl ester, and ursaldehyde have been isolated from the methanol extract of the twigs of Diospyros discolor. The structures of those new compounds were elucidated by spectroscopic methods.