Thiosucres. III. Réactions du substituant (benzylthio)‐acétyle. Communication préliminarie

Abstract

Thiosugars. III. Some reactions of the (benzylthio)‐acetyl substituent Preliminary Communication The (benzylthio)‐acetyl substituent as found in 6‐benzylthio‐6‐deoxy‐1, 2‐O‐isopropylidene‐3‐O‐methyl‐α‐D‐xylo‐hexofuranos‐5‐ulose (1) constitutes and useful synthon which can be transformed into ‘second generation’ synthons as, for example, the sulfylidene 10 or the chlorinated derivative 14. S‐Debenzylating C‐acylation of 10 leading to 11 is described as well as the ring‐forming condensation of 10 with the sulfene 12. Depending on the nature of the nucleophile reacted with 14, one can obtain the product of the substitution of the chlorine atom or of the chlorine atom and the benzylthio group or reactions taking place at both the carbonyl group and the terminal carbon atom, among them binucleophilic cyclizations. Some reactions of the conjugate base of 14 are also described.

Synthesis of disaccharide fragments of the AT-III binding domain of heparin and their sulfonatomethyl analogues

“…L-Iduronic acid trichloroacetimidate 39 was prepared on the basis of the well-established procedure elaborated for the appropriate 3-O-benzyl-L-iduronate donor. 22h, 23 The iduronic acid 36 was prepared from the corresponding D-glucofuranuronic acid derivative 24 by means of a two-step epimerization at C-5. 23 Deisopropylidenation of 36 with trifluoroacetic acid afforded the desired hemiacetal as a mixture of pyranoses and furanoses.…”

Toward Synthesis of the Isosteric Sulfonate Analogues of the AT-III Binding Domain of Heparin

“…Subsequent sulfation of the diol 27 gave the third analogue 28 of the EF fragment (Scheme ). For the synthesis of the GH analogues, l -iduronic acid trichloroacetimidate 32 was chosen as the donor prepared from 29 by a two-step epimerization of C-5 ( 30 ), followed by deisopropylidenation, acetylation ( 31 ), selective deacetylation of the anomeric position, and imidate formation (Scheme ).…”