X-ray structure of lagochirsine

Abstract

The molecular structure of the lagochilin diterpenoid lagochirsine was determined by x-ray structure analysis. The crystallographic investigations were conducted on an automated four-circle STOE/STAD14 diffractometer at room temperature. The crystals were trigonal, space group P3 2 (No. 145), C 20 H 32 O 5 , a = b = 14.289(2) Å, c = 8.2320(16) Å, V = 1455.6(4) Å 3 , Z = 3, D calc = 1.206 g/cm 3 , R = 0.065 (R w = 0.1368).Diterpenoids isolated from plants of the Lagochilus genus are highly physiologically active. They can be used as starting materials for preparing highly effective medicinal preparations [1]. In particular, the medicinal preparation "Lagoden," which is used for various hemorrhages, is based on the lactone lagochirsine, which is isolated from L. hirsutissimus, L. setulosus, and L. gypsaceus. The structure of lagochirsine was established by chemical transformations and PMR spectroscopy. However, its confirmational structure was not elucidated. The present article reports results of an x-ray structure analysis of lagochirsine. Figure 1 shows the molecular conformation and atomic numbering. Asymmetry parameters that characterize the degree of deviation of this conformation from the ideal one were calculated using the RING program [3] in order to define more accurately the conformation of all rings. The six-membered cyclohexane lagochirsine rings A and B of starting lagochilin [4,5] and lagochilin derivatives [6, 7] have a slightly distorted chair conformation [for ring A: ∆C s = 2.8° (C2), ∆C 2 = 1.9° (C2-C3); for ring B: ∆C s = 0.9° (C8), ∆C 2 = 0.8° (C7-C8)]. Atoms C4 and C1 deviate from the plane of C2-C3-C5-C10 by 0.68 and 0.65 Å, respectively; atoms C6 and C9 from that of C7-C8-C10-C5, by 0.70 and 0.71 Å, respectively.The conformation of five-membered rings C and D is an envelope [∆C s (C12) = 4.4° and ∆C s (C13) = 2.5°, respectively]. Atoms C11, C9, O5, and C13 in ring C are planar with a maximum least-squares deviation of 0.02 Å. Atom C12 deviates by 0.46 Å. Atoms C14, C16, O3, and C15 of ring D are planar with a maximum least-squares deviation of 0.01 Å. Atom C13 deviates by 0.45 Å. Rings A and B are trans-fused.Methyls on C4 and C10 are axial; that on C8, equatorial. Fig. 1. Conformation of lagochirsine and atomic numbering.

Lagoden dimethylformamide hemisolvate dihydrate: absolute configuration, dipolar interactions and hydrogen-bonding interactions

“…The crystal structures of lagochilin in its anhydrous and hydrated forms (Izotova et al, 1997;Vorontsova et al, 1975), lagochirsin (Izotova et al, 2004) and several other labdanetype diterpenoids isolated from plants of the Lagochilus genus, or their derivatives, have been reported over the years (Talipov et al, 2001;Izotova et al, 2000;Zainutdinov et al, 1999). Recently, we succeeded in growing single crystals of lagoden from a dimethylformamide (DMF) solution and we report its crystal structure here as the title compound, (I).…”