A new triterpene 3-O-[α-L-Rhamnopyranosyl (1 ->2)-(β-D-xy-lopyranosyl 16β,23 (R): 16α,30α-diepoxy-20(S)-hydraxydammar-24-ene (1) was isolated from roots of Centrosema bracteosum. The structure of this triterpenoid glycoside was elucidated by spectroscopic analysis of the natural product (1) and its peracetyl derivative (1a), including 2D NMR experiments.
Keywords:
Centrosema bracteosum; Leguminosae-Faboideae; triterpene glycoside; spectral data.
| 1 | 13c | ||||||
|---|---|---|---|---|---|---|---|
| C | CDCI3 δHb | C6D6 | δC CDCI3 | δC C6D5N | δHb C6D5N | δC C6D5N | δH C6D5N |
| 1' | 4.46(d,J=5.9) | 4.70(d,J=5.7) | 103.47 | 106.62 | 4.86(d,J=6.7) | ||
| 2' | 3.80(dd, J=5.9,8.4) | 4.2-3.9 | 74.51 | 80.93 | 4.2 | ||
| 3' | 5.2-5.0 | 5.43(t,J=8) | 69.14 | 79.29 | 4.2 | ||
| 4' | 5.0-4.8 | 5.2-5.0 | 72.76 | 72.72 | 4.6 | ||
| 5' | 3.37(t,J=8.6) | 3.18(dd,J=8.6,11.6) | 62.01 | 66.91 | 4.3 | ||
| 1" | 4.2-3.9 | 4.2-3.9 | - | - | |||
| 2" | 4.63(d,J=6.6) | 4.79(d,J=6.2) | 100.94 | 103.19 | 5.72(d,J=6.6) | 102.60 | |
| 5.70(d,J=7.6) | |||||||
| 3" | 3.57(dd,J=6.6,8.6) | 3.82(dd,J=6.2,8.3) | 75.85 | 80.93 | 4.3 | 79.50 | |
| 4" | 5.2-4.9 | 5.41(t,J=8.3) | 69.36 | 78.52 | 4.7 | 78.24 | |
| 5" | 5.0-4.8 | 5.2-5.0 | 72.76 | 71.68 | 4.1 | 70.90 | |
| 1"' | 3.31 (t,J=8.6) | 3.31(dd,J=7.2,11.3) | 61.48 | 66.91 | 4.3 | 66.90 | |
| 2"' | 4.2-3.9 | 4.2-3.9 | - | - | |||
| 3"' | 4.89(br s) | 5.24(br s) | 97.94 | 102.31 | 6.35(s) | 102.40 | 6.37(br |
| s) | |||||||
| 4"' | 5.07(br s) | 5.50(d,J=2.9) | 69.78 | 72.52 | 4.7 | 72.40 | |
| 5"' | 5.2-4.9 | 5.67(dd.J=2.9.9.6) | 67.87 | 72.72 | 4.6 | 72.40 | |
| 6"' | 5.2-4.9 | 5.49(t, J=9.6) | 70.65 | 74.43 | 4.3 | 74.36 | |
| OAc | 4.1-3.9 | 4.47(dq,J=9.6,6.1) | 66.84 | 69.72 | 4.9 | 69.51 | |
| 1.15(d,J=5.8) | 1.53(d, J=6.1) | 17.09 | 19.09 | 1.79(d, J=5.9) | 18.91 | ||
| 2.08(s) | 2.01(s) | 170.24 | - | - | |||
| 2.06(s) | 1.97(s) | 170.11 | - | - | |||
| 2.05(s) | 1.79(s) | 169.88 | - | - | |||
| 2.01 (s) | 1.77(s) | 169.60 | - | - | |||
| 1.99(s) | 1.77(s) | 20.72 | - | - | |||
| 1.97(s) | 1.72(s) | 20.67 | - | - | |||
| 1.94(s) | 1.72(s) | 20.60 | - | - | |||
| 1a(CDCI3) | 1(C5D5N) | 9b | CDCI3 | C5D5N | |||
|---|---|---|---|---|---|---|---|
| C | δC δH | δC δH | δC | 10 11c 12c | |||
| 1 | 38.49 | 39.90 | 39.00 | 39.0 | 39.5 | ||
| 33.7 | |||||||
| 2 | 25.85 | 27.03 | 26.70 | 27.4 | 26.8 | ||
| 25.5 | |||||||
| 3 | 89.69 | 3.1-2.9 | 89.54 | 3.25(m) | 88.10 | 78.9 | 89.5 |
| 75.9 | |||||||
| 4 | 39.37 | - | 40.11 | - | 39.70 | 39.0 | 39.8 |
| 37.6 | |||||||
| 5 | 55.89 | 0.7 | 56.48 | 0.7 | 56.30 | 55.9 | 56.7 |
| 49.5 | |||||||
| 6 | 17.88 | 18.64 | 18.30 | 18.3 | 18.6 | ||
| 7 | 35.52 | 37.33 | 36.00 | 35.3 | 35.3 | ||
| 8 | 37.13 | - | 37.49 | 37.30 | 40.4 | 40.3 | |
| 9 | 52.51 | 0.8 | 53.29 | 0.8 | 53.00 | 50.7 | 50.4 |
| 10 | 36.98 | - | 37.49 | - | 37.30 | 37.1 | 37.2 |
| 11 | 21.30 | 22.03 | 21.80 | 21.6 | |||
| 12 | 27.91 | 28.77 | 28.60 | 25.4 | |||
| 13 | 36.85 | 38.96 | 2.80(m) | 35.70 | 42.3 | ||
| 14 | 53.29 | - | 53.96 | 53.70 | 50.3 | ||
| 15 | 35.39 | 1.6-1.4 | 37.77 | 2.48(d, J=11.7) | 37.10 | 31.2 | |
| 16 | 109.48 | - | 110.87 | - | 110.60 | 27.6 | |
| 17 | 52.62 | 1.1 | 54.15 | 1.4 | 53.90 | 49.9 | |
| 18 | 18.51 | 1.06(s) | 19.15 | 1.04(s) | 18.30 | 16.2* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". | 16.2* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". |
| 19 | 15.88 | 0.77(s) | 16.58 | 0.77(s) | 16.40 | 15.5* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". | 16.2* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". |
| 20 | 69.23 | - | 68.72 | - | 68.50 | 75.4 | |
| 21 | 29.84 | 1.14(s) | 30.27 | 1.29(s) | 30.00 | 24.9 | |
| 22 | 44.36 | 1.6-1.4 | 45.60 | 1.7 | 45.30 | 40.5 | |
| 23 | 68.60 | 4.60 | 68.93 | 5.27(dd, J=8.9,6.0) | 68.50 | 22.6 | |
| 24 | 125.04 | 5.15 | 127.21 | 5.51(d,J=6.0) | 127.00 | 124.8 | |
| 25 | 135.28 | - | 134.56 | - | 134.2 | 131.5 | |
| 26 | 18.26 | 1.63(br s) | 19.09 | 1.66(s) | 25.50 | 17.7 | |
| 27 | 25.51 | 1.67(br s) | 25.91 | 1.64(s) | 18.90 | 25.7 | |
| 28 | 27.60 | 0.94(s) | 28.77 | 1.22(s) | 28.00 | 28.0 | 28.2 |
| 28.5 | |||||||
| 29 | 16.02 | 0.80(s) | 16.71 | 1.04(s) | 16.80 | 15.4* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". | 16.6* * From the authors of the paper: "values in any vertical column may be reversed although those given here are preference". |
| 22.1 | |||||||
| 30 | 65.72 | 66.12 | 65.8 | 16.5 | |||
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