Tewahdron Vol. 50, No. 32, pp. 9679-9690. 1994 corlYtinJlt0 1994 Elsevia science Ltd -- _ PrintediaGnatBritaiaAllrightsrcsaved oo40_4M(y94 57.oDto.00 oo4o-4020(94)00555-9 Regioselective Synthesis of 20-Hydroxyecdysone Glycosides Jaroalav Pii*, Jii Hytd, Miloi BudWml@ and Juraj Humatha* Institute of Organic Chcmishy and Biochemisay,Academy ofsciarccs ofthe Czech Republic,16610 prapuc,Czech Replblic Ab&wct: Four p-D-glucowranosidcs of 20-hydmxyscdysone (1) wue pqartd. The regiosekctive coua of @ycosylation was achieved by the combination of hydnxyl and 1,ldiol protuXive guups, Le. acetates and phenylboronates, in the a&cone moiety. INTRODUCTION The growing number of ecdysteroid conjugates isolated from both animals’ and plants* suggests an active role in the ecdysteroid metabolism, transport or deactivation. The nonpolar esters and more polar ecdysteroid glycosides are the most common conjugates of natural origin. Their possible ecological signiftcance in plant-insect chemical interaction is conside&. Since these compounds are mostly inactive in the common ecdysone assays’, new biological tests must be developed. Some 20-hydroxyecdysone glycosides have been isolated from animal5 and plant6 sources, 20-hydroxyecdysone 25-P-D-glucopyranoside (5) has been isolated’ from the roots of zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA Pfu@ a iresinoides , however the structural variations and the amount available are rather limited. For new bioassays, as well as for analytical correlation, a suitable variety of conjugates must be prepared by chemical synthesis. This paper deals with the preparation of a series of bioanalogical glycosides 2-5. 0% OHI ‘8,. =‘4 s 1 R,=l$=Rg=R4.H 5 2 I&i R2=Rg=R4=H R,=B_DQlc 3 R,=%=R’=H Rp=&LbQk R* H 4 R,=R2=R4=H Ra+D-Qlc 0 6 R,=R2=RS=H R4+-D-Qk Fig. 1. Structures of 20-hydroxyecdysone and its glucosidea Regioselective manipulation of hydroxyl groups of polyols is Cequently required particularly in the chemistry of natural products. However, only a few examples of protection and deprotection sequences for 20-hydroxyecdysone (1) have been reported. They include acetonide*‘, acetate9 and boronate’Q” formation. 9679