Redetermined structure, intermolecular interactions and absolute configuration of royleanone

Abstract

The structure of the title diterpenoid, C20H28O3, {systematic name: (4bS,8aS)-3-hy­droxy-2-isopropyl-4b,8,8-trimethyl-4b,5,6,7,8,8a,9,10-octa­hydro­phenanthrene-1,4-dione} is confirmed [Eugster et al. (1993 ▶). Private communication (refcode HACGUN). CCDC, Union Road, Cambridge] and its packing is now described. Its absolute structure was established by refinement against data collected with Cu radiation: the two stereogenic centres both have S configurations. One cyclo­hexane ring adopts a chair conformation whereas the other cyclo­hexane ring is in a half-chair conformation and the benzoquinone ring is slightly twisted. An intra­molecular O—H⋯O hydrogen bond generates an S(5) ring motif. In the crystal, mol­ecules are linked into chains along [010] by O—H⋯O hydrogen bonds and weak C—H⋯O inter­actions. The packing also features C⋯O [3.131 (3) Å] short contacts.

Extraction Optimization and Structural and Thermal Characterization of the Antimicrobial Abietane 7α-Acetoxy-6β-hydroxyroyleanone

“…One cyclohexane ring (C1−C5/C10) is in a standard chair conformation with the puckering parameters 38 Q = 0.5588 Å, θ = 5.79°, and φ = −28.18°, whereas the other (C5−C10) is in half chair conformation, with the puckering parameters Q = 0.5146 Å, θ = 51.18°, and φ = 28.12°. These values are similar to those found in royleanone 36 and 7αhydroxyroyleanone. 37 The benzoquinone ring (C8−C9/C11− C14) is slightly twisted with atoms C9 and C11 deviating from the plane by −0.032(3) and 0.041(3) Å, respectively.…”

“…The SCXRD study was carried out at 167 and 296 K. The molecular structure of AHR obtained at 296 K, with its corresponding atom labeling scheme, is shown in Figure 3. The geometrical parameters determined at the two temperatures are given in Tables S3 and S4 along with corresponding data previously reported, at 100 K, for royleanone 36 and for 7αhydroxyroyleanone. 37 The comparison indicates that analogous bond distances and angles are similar for the three compounds.…”

Crystal structure of 6,7-dehydroroyleanone isolated fromTaxodium distichum(L.) Rich.

“…A search of the Cambridge Structural Database (CSD, Version 5.27, last update Feb 2017; Groom et al, 2016) yielded the compound royleanone (HACGUN01; Fun et al, 2011), which has a similar structure to the title compound but without the double bond between C10 and C11.…”

Crystal structure of 7β-hydroxyroyleanone isolated fromTaxodium ascendens(B.)

“…These include two reports of a compound similar to the title compound, but with no hydroxy group in position 10, i.e. CSD refcodes HACGUN (Eugster et al, 1993) and HACGUN01 (Fun et al, 2011), and two reports of the stereoisomer of the title compound, with the hydroxy group in position 10 having an R configuration, i.e. QICLIX ( (2) 124Symmetry codes: (i) x; y À 1; z; (ii) x; y þ 1; z.…”