Premium
Oligosaccharide Analogues of Polysaccharides, Part 21 , Towards New Cellulose I Mimics: Synthesis of Dialkynyl C ‐glucosides of peri ‐Substituted Anthraquinone
Author(s) -
Murty Kadiyala V. S. N.,
Vasella Andrea
Publication year - 2001
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/1522-2675(20010418)84:4<939::aid-hlca939>3.0.co;2-a
Subject(s) - chemistry , trimethylsilyl , trifluoromethanesulfonate , cellulose , trimethylsilyl trifluoromethanesulfonate , trisaccharide , stereochemistry , acetylation , oligosaccharide , medicinal chemistry , organic chemistry , catalysis , biochemistry , gene
The bis‐ C ‐glucoside 2 has been synthesised as the first representative of a series of templated glucosides and cellooligosaccharides that mimick part of the unit cell of cellulose I. As expected, there are, at best, weakly persistent H‐bonds between the two glucosyl residues in (D 6 )DMSO and (D 7 )DMF solution. The acetylated oct‐1‐ynitol 7 and deca‐1,3‐diynitol 12 were prepared from the gluconolactone 5 ( Scheme 1 ). Coupling of 12 to PhI and 2‐iodothiophene yielded 13 and 14 , respectively, while dimerisation of the benzylated and acetylated deca‐1,3‐diynitols 10 and 12 afforded the bis‐ C ‐glucosyloctatetrayne 15 and the less stable 16 , respectively. The 2‐glucosylthiophene 17 was obtained by treating the C ‐silylated deca‐1,3‐diynitol 9 with Na 2 S. Cross‐coupling of (trimethylsilyl)acetylene (TMSA) with 1,8‐bis(triflyloxy)‐9,10‐anthraquinone ( 20 ) at elevated temperature gave the dialkynylated 21 ; its structure was established by X‐ray analysis ( Scheme 2 ). Sequential coupling of 6 or 7 and TMSA to 20 gave the symmetric dialkyne 21 , the mixed dialkynes 23 (from 6 ) and 25 (from 7 ), and the symmetric diglucoside 36 (from 7 ) in modest yields; a stepwise coupling to the acetylated monotriflate 28 proved advantageous. It led to the oct‐1‐ynitol 29 and the deca‐1,3‐diynitol 33 that were transformed into the triflates 30 and 34 , respectively. Coupling of the triflate 34 to the oct‐1‐ynitol 7 gave the unsymmetric bis‐ C ‐glucoside 35 ; this was obtained in higher yields by coupling the triflate 30 to the deca‐1,3‐diynitol 12 . Coupling of the bistriflate 20 with either 7 or 12 afforded the symmetric bis‐ C ‐glucosides 36 and 37 , respectively. Deacetylation (KCN in MeOH) of 35 – 37 provided the unsymmetric bis‐ C ‐glucoside 2 and the symmetric analogues 3 and 4 .