Carbohydrate Research, 132 (1984) C5-C9 Elsevier Science Publishers B.V.. Amsterdam - Printed in The Netherlands c5 Preliminary communication Total synthesis of a heparin pentasaccharide fragment having high affinity for antithrombin III PIERRE SINA?, JEANCLAUDE JACQUINET, Laboratoire de Biochimie Structurale, E.R.A. 739, U.E.R. de Sciences Fondamentales et Appliqut!es, 45046 Orlkans (France) MAURICE PETITOU, PHILIPPE DUCHAUSSOY, ISIDORE LEDERMAN, JEAN CHOAY, Institut Choay, 46, Avenue lMophile Gautier, 75782 Paris (France) and GIANGIACOMOTORRI G. Ronzoni Institute for Chemical and Biochemical Research, Via G. Colombo 81,20133 M ilan (Italy ) (Received April 9th, 1984; accepted for publication, May 25th, 1984) Heparin is a sulfated glucosaminoglycan with a well-known anticoagulant activ- ity’ , and the active molecules have a high affinity for antithrombin III (AT-III), thereby enhancing the effects of this inhibitor on procoagulant proteases. The structures of high- affinity oligosaccharides, prepared from heparin by extraction, partial deaminative cleavage, or partial depolymerisation with bacterial heparinase, have been studied2. This work led to the hypothesis3 that the minimum sequence that binds to AT-III was con- tained in the pentasaccharide 1. H G -03SOHLC OH cti,oso,- HO 1R = so;or AC In order to confirm this conclusion unambiguously, we have synthesised 1 (R = SOB-). The monosulfated cll-L-idopyranosyluronate residue of 1 was derived from the orthoacetate 6, m.p. 67-68”, [(Y]: +19” (c I, chloroform), which was prepared from 3-U-benzyl-I ,2-O-isopropylidene-cD-glucofuranose4 (2), as illustrated in Scheme 1. *To whom enquiries should be sent. 0008-6215/84/$03.00 0 1984 Elsevier Science Publishers B.V.