1063-7745/05/5003- $26.00 © 2005 Pleiades Publishing, Inc. 0410 Crystallography Reports, Vol. 50, No. 3, 2005, pp. 410–414. From Kristallografiya, Vol. 50, No. 3, 2005, pp. 455–459. Original English Text Copyright © 2005 by Gupta, Rajnikant, Parsad, Thappa, Agarwal, Varghese, Goswami. 1 INTRODUCTION The present study of the compounds 2,4,5,6,7,7a- hexahydro-7a-hydroxy-3,6-dimethyl-2-benzofuranone (I) and β-cyclolavandulic acid (II) is part of a series of investigations on the crystal structures of terpene deriv- atives [1–4]. Compound I, a monoterpenoid, has been isolated from the leaves of Mentha piperate. Com- pound II, also a monoterpenoid, has been isolated from the seeds of Trachyspermum roxburghianum. Trachys- permum roxburghianum fruits commonly known as Ajmoda are widely used in the Indian system of medi- cines for the treatment of various gastrointestinal and other ailments [5–9]. The chemical structures assigned to compounds I and II on the basis of IR, UV, NMR, and mass spectral data are shown in Fig. 1. EXPERIMENTAL The solvent loss technique has been employed for the growth of single crystals of compounds I and II. For both compounds, three-dimensional X-ray intensity data were collected on an Enraf–Nonius CAD4 diffrac- tometer with CuK α radiation for the values of θ up to 70°. The data were corrected for Lorentz and polariza- tion effects. Absorption and extinction corrections were not applied. For both compounds structure solution was accom- plished by direct methods using the SHELXS86 pro- gram [10], the SHELXL93 program used to refine structure [11], molecular graphics ORTEP-3 [12], and 1 This article was submitted by the authors in English. software used to prepare material for publication PARST [13, 14]. In both compounds, all the hydrogen atoms were located from a difference Fourier map. The final refinement cycle converged at R = 0.031, wR(F 2 ) = 0.092 for compound I and R = 0.047, wR(F 2 ) = 0.158 for compound II. Atomic scattering factors were taken from International Tables for X-ray Crystallography (1992, Vol. C, Tables 4.2.6.8 and 6.1.1.4). The crystallographic data are summarized in Table 1. RESULTS AND DISCUSSION For both compounds, the atomic coordinates and equivalent isotropic displacement parameters are pre- sented in Table 2. Selected bond distances, bond angles, and torsion angles are listed in Table 3. Figure 2 shows the molecular structure and the atom-labeling scheme Crystal Structure Analysis of Two Terpene Derivatives 1 V. K. Gupta 1 , Rajnikant 1 , B. Parsad 1 , R. K. Thappa 2 , S. G. Agarwal 2 , B. Varghese 3 , and S. Goswami 1 1 Laboratory of Crystallography, Postgraduate Department of Physics, University of Jammu, Jammu Tawi, 180006 India e-mail: vivek_gupta2k2@hotmail.com 2 Division of Organic Chemistry, Regional Research Laboratory, Jammu, India 3 Regional Sophisticated Instrumentation Center, Indian Institute of Technology, Chennai, 600036 India Received October 16, 2003; in final form, April 28, 2004 Abstract—The crystal structures of two terpene derivatives, 2,4,5,6,7,7a-hexahydro-7a-hydroxy-3,6-dimethyl- 2-benzofuranone (compound I) and β-cyclolavandulic acid (compound II), were determined by single-crystal diffractometry. Compound I, C 10 H 14 O 3 , crystallizes in the orthorhombic space group P2 1 2 1 2 1 with the unit cell parameters a = 6.715(1) Å, b = 7.043(1) Å, c = 20.292(3) Å, and Z = 4. The six-membered ring has an ideal chair conformation. The five-membered ring is planar . Compound II, C 10 H 16 O 2 , crystallizes in the monoclinic space group P2 1 /n with the unit cell parameters a = 8.446(1) Å, b = 12.156(1) Å, c = 9.901(1) Å, β = 106.29(1)°, and Z = 4. The cyclohexene ring exhibits a half-chair conformation. Both the crystal structures are stabilized by intermolecular O–H⋅⋅⋅O hydrogen bonds. © 2005 Pleiades Publishing, Inc. STRUCTURE OF ORGANIC COMPOUNDS OH O(1) O(2) COOH I II 2 3 9 4a 4 5 7 6 8 7a 1 2 3 5 6 10 9 4 8 7 3 Fig. 1. Chemical structures of 2,4,5,6,7,7a-hexahydro-7a- hydroxy-3,6-dimethyl-2-benzofuranone (I) and β-cyclola- vandulic acid (II).