Synthesis and Crystal Structures of Two C24 Epimeric 3-Acetyled 20(R)-Ocotillol Type Sapogenins Obtained from 20(R)-Protopanaxadiol

Abstract

Two C24 epimeric 3-acetylated ocotillol-type sapogenins, 20 R,24 S-epoxy-dammarane-3β,12β,25-triol acetate and 20 R,24 R-epoxy-dammarane-3β,12β,25-triol acetate have been achieved from 20( R)-protopanaxadiol. Their structures were confirmed by HRMS, 1H NMR, 13C NMR and single crystal X-ray diffraction which showed that their configurations were (20 R, 24 S) and (20 R, 24 R), respectively. In the crystal structure of the 24 ( S)-epimer, there were two intramolecular hydrogen bonds and a left-handed helical chain whilst in the 24 ( R)-epimer there was one intramolecular hydrogen bond and a right-handed helical chain.

Discovery, semisynthesis, biological activities, and metabolism of ocotillol-type saponins

“…The results indicated that the configurations of 31 and 32 were (20 R ,24 S ) and (20 R ,24 R ), respectively [34].…”

“…Two C24 epimeric 3-acetyled ocotillol-type sponins, (20 R ,24 S )-epoxy-dammarane-3β,12β,25-triol acetate ( M3 , 31 ) and (20 R ,24 R )-epoxy-dammarane-3β,12β,25-triol acetate ( M4 , 32; Table 3 ), were obtained from 20( R )-PPD, which made it possible to isolate 29 and 30 . The results indicated that the configurations of 31 and 32 were (20 R ,24 S ) and (20 R ,24 R ), respectively [34] .…”

The crystal structure of (8R,10R,12R,14R)- 12-hydroxy-16-(5-(2-hydroxypropan-2-yl)-2-methyltetrahydrofuran-2-yl)- 4,4,8,10,14-pentamethyltetradecahydro-3H- cyclopenta[a]phenanthrene-3,6(2H)-dione, C30H48O5

“…Ginsenosides can be classifed as ocotillol-type, oleanolic acid type, protopanaxadiol (PPD) type, protopanaxatriol (PPT) type [5][6][7]. The ocotillol-type triterpenes are a rare kind of ginsenosides characterized by a tetrahydrofuran ring on the side chain [8][9][10][11]. It has been reported that ocotillol-type triterpenes have antibacterial, antioxidative, anti-inflammatory, neuroprotective and cardioprotective properties [12][13][14][15][16].…”