210
N. N. Win and H. Morita
O
O
R
3
O
O
R
2
R
1
O
R
4
391 (taungtangyiol A) R
1 = H, R
2 = R
3 = R
4 = OH
392 (taungtangyiol B) R
1 = R
3 = R
4 = OH, R
2 = H
391a (6,7-diacetoxytaungtangyiol A) R
1 = H, R
2 = OH, R
3 = R
4 = OAc
391b (5,6,7-triacetoxytaungtangyiol A) R
1 = H, R
2 = R
3 = R
4 = OAc
O
O
H
O
OH
O
O
401 (premnan A)
O
O
O
O
O
O
OH
OH
402 (premnam B)
O
OH HO
O
O
O
O
403 (taungtangyiol C)
404 (7,9-dihydroxydolichanthin B)
O
OH HO
O
O
O
O
OH
O
O
O
HO
O
O
O
O
405 (premnan C)
O
HO
O
O
O
O
O
O
406 ((3R,4S)-4-(1,3-benzodioxol-5-ylcarbonyl)
-3-[(R)-1-(1,3-benzodioxol-5-yl)
-1-hydroxy methyl]tetrahydro-2-furanone)
Fig. 78 Structures of the new lignans 391, 392, and 401–406, isolated from a chloroform-soluble
extract of P. integrifolia stem wood grown in Myanmar, and 391a and 391b obtained by acetylation
of 391
premnan C (405) [482], which was assumed to be an artifact and one natural product
lignan, (3R,4S)-4-(1,3-benzodioxol-5-ylcarbonyl)-3-[(R)-1-(1,3-benzodioxol-5-yl)1-hydroxymethyl]tetrahydro-2-furanone (406) [484] (Fig. 78), together with five
previously known plant constituents ((−)-aptosimon (407), (−)-diasesamin-di-γ -
lactone (408) [485], and (+)-epi-sesaminone (409) [486] (Fig. 79), oleanonic acid