20(29)-Lupene-3β,28β-diacetate

Abstract

Key indicatorsSingle-crystal X-ray study T = 293 K Mean (C-C) = 0.004 Å R factor = 0.042 wR factor = 0.118 Data-to-parameter ratio = 8.8For details of how these key indicators were automatically derived from the article, see

X-Ray Crystal Structure of Betulin–DMSO Solvate

“…A similar ring conformation was also observed in 3,28-O,O-diacetylbetulin [15], 3,28-O,O-diacetyl-29-bromobetulin [16], and betulin-ethanol solvate [9]. The cyclopentane ring is characterized by envelope conformation with the C17 atom being displaced from C18-C19-C21-C22 plane about 0.668 Å so that the C17-C18-C19-C21 and C19-C21-C22-C17 torsion angles are equal to 28.76°and -24.26°correspondingly (for betulin-ethanol solvate 0.654 Å , 29.23°and -23.06°, respectively [9]).…”

“…It is important to emphasize that the C29-C20-C19-C21 torsion angle describing the orientation of the isopropenyl group is equal to -96.84°, while for betulinethanol solvate and the 3,28-O,O-diacetylbetulin it was 88.64° [9] and -107.18° [15], respectively. Figure 3 shows different orientations of isopropenyl group in two conformational polymorphic structures of betulin.…”

Polymorphic forms of lupane triterpenoid betulonic aldehyde (betulonal)

“…All the ring junctions in the lupane nucleus are trans-fused. Similar ring conformations were also described for other derivatives of betulin, for example, 3,28-diacetoxy-29-bromo-betulin (Ding et al, 2009), 20 (29)-lupene-3,28-diacetate (Mohamed et al, 2006), betulin ethanol solvate (Drebushchak et al, 2010), betulin dimethyl sulfoxide solvate and betulinic acid dimethyl sulfoxide solvate . In all three molecules, viz.…”

Lup-20(29)-en-28-ol-3-one (betulone)

“…All the ring junctions in the lupane nucleus are trans-fused. A similar ring conformation is also observed in 20 (29)lupene-3β,28β-diacetate (Mohamed et al, 2006), 3,28-diacetoxy-29-bromo-betulin (Ding et al, 2009) and also in betulinethanol (Drebushchak et al, 2010), betulin-DMSO (Boryczka et al, 2011), betulinic acid-DMSO (Boryczka et al, 2012a) solvates. However, the conformation of ring A in betulone differs significantly from that observed earlier for betulonic acid-DMSO and DMF solvate, where ring A adopts a boat conformation.…”

“…For the biological activity of betulone, see: Alakurtti et al (2010); Hata et al (2002); Reyes et al (2006). For related structures, see: Mohamed et al (2006); Ding et al (2009) ;Drebushchak et al (2010); Boryczka et al (2011Boryczka et al ( , 2012a Refinement R[F 2 > 2(F 2 )] = 0.051 wR(F 2 ) = 0.141 S = 1.03 5036 reflections 609 parameters H atoms treated by a mixture of independent and constrained refinement Á max = 0.55 e Å À3 Á min = À0.50 e Å À3 Table 1 Hydrogen-bond geometry (Å , ). Data collection: CrysAlis CCD (Oxford Diffraction, 2008); cell refinement: CrysAlis RED (Oxford Diffraction, 2008); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: Mercury (Macrae et al, 2006); software used to prepare material for publication: publCIF (Westrip, 2010).…”