ELSEVIER The synthesis and in vitro activity of some A7'9<ll)-lanostadienes Bogdan A. Solaja,* Miodrag Dermanovi~,t Dong-Min Lim,~: Young-Ki Paik,$ Bernard Tinant,§ and Jean-Paul Declerq§ *Faculty of Chemistry, University of Belgrade, Belgrade, Yugoslavia; "['Institute of Chemisto,, Technology and Metallurgy, Belgrade, Yugoslavia; +Department of Biochemistry. and Bioproducts Research Centre, Yonsei University, Seoul, Korea; and §Laboratoire de Chimie Physique et de Cristallographie, Universitd Catholique de Louvain, Louvain-la-Neuve, Belgium The synthesis ~ A7~+~-lanostadiene derivatives functionalized at C(32) starting from 313-acetoxy-7e~,32- epoxylanostan-11-one has been presented. The A 7'9~1 i> moie~ was efficiently introduced in three steps in 71% yield by the regioselective abstraction of allylic 8[3 hydrogen. The formyl group of the key interntediate, 3[3-benzoylo~D,lanosta-7, 9(1 l )-dien-32-al, has been stereoselectively alkylated into (32S) derivative, whereas its oxidation unexpectedly afforded 313-benzoyloxy-7-oxolanost-8-ene-32,11c~-lactone and not the corresponding acid. AT~H~-lanostadienes possessing HC(32)=0, C(32)=-N, HC(32S)CH.+OH, HeC(32)OH, as well as some I l-keto hmostenes, were tested in vitro against several purified cholesterogenic enzymes showing moderate activity, with most the active aldehyde 16 having 1C~o : 86 IXM. (Steroids 62:709-718, 1997) © 1997 by Elsevier Science Inc. Keywords: ..~7.g<ll~lanostadienes; synthesis; inhibitory activity; cholesterogenic enzymes: X-ray analysis Introduction Because certain lanosterol metabolites (e.g., oxysterols 1-6; Figure l) were found to possess the feedback effect on its biosynthesis,~-3 they are interesting as potential cholesterol- lowering agents in mammals. A number of steroidal com- pounds were synthesized and tested as potential suppressors of lanosterol 14-demethylase activity 3 7 and downregulators of HMG-CoA reductase (HMGR) activity, s-~° as well as i nhibitors of fungal ergosterol biosynthesis. J~.12 Most of the synthesized compounds were 24,25-dihydrolanosteryl (DHL) derivatives that, beside various functional groups attached to C(32), contained AT-double bond instead of the natural A s bond. ~3 Analysis of available data ~,3-~j suggests that the potential lanostane-based inhibitor should possess (a) sp 2 hybridized C(8), (b) functionalized C(32), (c) 15c~ substituent or heteroatom in position 15, and (d) not to possess the axial /3-hydroxy group. A[though some other targets are currently also under investigation,~4 ~6 finding a specific inhibitor of HMGR or lanosterol 14~-methyl demethylation process seems prom- ising in the controlling of cholesterol levels in mammals. As the binding sites for oxysterols in corresponding enzymes This work originated at: Faculty of Chemistry, University of Belgrade. Address reprint requests to Dr. Bogdan golaja, Faculty of Chemistry, University of Belgrade, Studentski trg 16, PO Box 158, YU-11001 Bel- grade, Yugoslavia. E-mail: bsolaia@hf01.chem.bg.ac.yu Received March 21, 1997; accepted July I, 1997. Steroids 62:709-718. 1997 © 1997 by Elsevier Science Inc. All rights reserved. 655 Avemlc ~ff the Americas. New York, NY 10010 are not yet known, we decided to gather further information on their structural demand by the synthesis of flattened lanostene A7"9(11) system functionalized at C(32) and test them against several purified enzymes, such as HMGR, sterol 14-reductase, sterol 24-reductase, sterol 7-reductase, and sterol 8-isomerase. Experimental Chemisto" General Melting points (m.p.) were determined on a Mikro-Heiztisch Boe- tius PHMK apparatus and were not corrected. Specific rotations were measured on a Karl Zeiss Polamat A and Perkin-Elmer 141 MC polarimeters at the given temperatures. Ultraviolet (UV) spec- tra were recorded on a Beckman DU-420 spectrophotometer. In- frared (IR) spectra were recorded on Perkin-Elmer spectrophotom- eter FT-IR 1725X. tH nuclear magnetic resonance (~H NMR) spectra were recorded on a Bruker AM-6(/0, Bruker AM-250, Varian Gemini-200, and Varian VI'-80A (at 600, 250, 200, and 80 MHz, respectively) spectrometers in CDCI 3 using TMS as internal standard. Chemical shifts were expressed as ppm (<3) values and coupling constants (J) in Hz. Mass spectra were taken on a Finnigan-MAT 8230 spectrometer as indicated below. 1. 7~,32-Epoxylanostane-3jg, 1 l [3-diol (8) 313-Acetoxy-7c~,32-epoxylanostan-1 l-one (7:2 g, 4 mmol) was dissolved under argon in dry toluene (100 mL) at room tempera- ture (r.t.). Then, diisobutylaluminium hydride (DIBAH; 8.8 mE; 0039-128X/97/$17.00 Pll S0()39-128X(9T~(10(175-5