Oligosaccharide Analogues of Polysaccharides, Part 16, Cross-Coupling of Partially Protected Dialkynyl Monosaccharides

Bohner, Tanja Verena; Beaudegnies, Renaud; Vasella, Andrea

doi:10.1002/(sici)1522-2675(19990210)82:2<143::aid-hlca143>3.0.co;2-0

Cited by 19 publications

(12 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…and NIS [34] to give 73% of the iodide 13. Cross-coupling of 10 and 13 in the presence of 5% [Pd 2 (dba) 3 ], 7% CuI, and 7% P(fur) 3 in toluene/NEt 3 1 : 1 at 238 [35] resulted in 70% of the dimer 14, which was purified by FC 6 ). Treatment of 14 with dilute aqueous CF 3 COOH at room temperature led to partial decomposition.…”

Section: Synthesis Of Uridine-derived Monomers and Dimersmentioning

confidence: 99%

See 1 more Smart Citation

Oligonucleosides with a Nucleobase-Including Backbone, Part 1, Concept, Force-Field Calculations, and Synthesis of Uridine-Derived Monomers and Dimers

Eppacher¹,

Solladié²,

Bernet³

et al. 2000

HCA

Self Cite

View full text Add to dashboard Cite

A new type of oligonucleosides has been devised to investigate the potential of oligonucleosides with a nucleobase-including backbone to form homo-and/or heteroduplexes (cf. Fig. 2). It is characterised by ethynyllinkages between C(5') and C(6) of uridine, and between C(5') and C(8) of adenosine. Force-field calculations and Maruzen model studies suggest that such oligonucleosides form autonomous pairing systems and hybridize with RNA. We describe the syntheses of uridine-derived monomers, suitable for the construction of oligomers, and of a dimer. Treatment of uridine-5'-carbaldehyde (2) with triethylsilyl acetylide gave the diastereoisomeric propargylic alcohols 6 and 7 (1 : 2, 80%; Scheme 1). Their configuration at C(5') was determined on the basis of NOE experiments and X-ray crystal-structure analysis. Iodination at C(6) of the (R)-configured alcohol 7 by treatment with lithium diisopropylamide (LDA) and N-iodosuccinimide (NIS) gave the iodide 17 (62%), which was silylated at OÀC(5') to yield 18 (89%; Scheme 2).

show abstract

Section: Synthesis Of Uridine-derived Monomers and Dimersmentioning

confidence: 99%

“…[35] [37], whereas the corresponding CCSiR 3 groups of the 2,5'-anhydrides 8 and 9 resonate in the narrow range of 95.2 ± 97.4 ppm. The CCH groups of 10 and 16 give rise to a doublet at 74.7 and 75.8 ppm, and a singlet at 81.3 and 81.7 ppm.…”

mentioning

confidence: 99%

Oligonucleosides with a Nucleobase-Including Backbone, Part 1, Concept, Force-Field Calculations, and Synthesis of Uridine-Derived Monomers and Dimers

Eppacher¹,

Solladié²,

Bernet³

et al. 2000

HCA

Self Cite

View full text Add to dashboard Cite

show abstract

“…Treatment of 131 with an eightfold excess of Me 3 SiCaCsLi and Et 2 AlCl in toluene/THF at 90h gave an 81 % yield of the disilylated diacetylene 132a [180] (Scheme 5.30). The orthogonally protected analogue 132b was similarly prepared in two steps and 53 % overall yield from 131, via 133 [191]. The exclusive formation of the b-d-glucopyranosylacetylene was explained by the postulated binding of alkynylated Lewis acid to HOsC(3) and OsC(6) to afford the intermediate A. Ring-opening to the conformationally biased oxycarbenium ion B and intramolecular acetylide transfer selectively affords 132a and 132b.…”

Section: -O-alkynyl-b-d-glucopyranosylacetylenesmentioning

confidence: 99%

“…The orthogonally protected diacetylene 132b (substituted with the newly developed DOPS group) was selectively monodesilylated to provide both 134b (0.25n NaOMe in MeOH; 94 %) and, in two steps, 135 (0.01n HCl in EtOH and cat. BuLi in THF at -78h; 94 %) [191]. Treatment of equimolar amounts of 134a and 135 with CuI in pyridine gave only the homocoupled dimers, while CadiotsChodkiewicz coupling between an O-protected iodoacetylene derived from 134a and 135 and subsequent deprotection gave the heterocoupled dimer 136a (64 % of the hetero-dimer together with 20 % of the homo-dimer derived from 135) [192].…”

Section: -O-alkynyl-b-d-glucopyranosylacetylenesmentioning

confidence: 99%

Acetylenosaccharides

Bernet¹,

Vasella²

2004

Acetylene Chemistry

Self Cite

View full text Add to dashboard Cite

“…Smaller J(4',5') values are observed for18,20,22, and 23a ± c than for 17 and 19, and indicate a stronger persistence of the intramolecular O(5')ÀH´´´N(3) H-bond. The persistence calculated according to[31] increases from 50 ± 52% (23a, 23c, and unit II of 18 and 20) to 55% (unit I of 20), 72%(22), and 82% (unit I of 18).…”

mentioning

confidence: 99%

Oligonucleosides with a Nucleobase-Including Backbone, Part 3, Synthesis of Acetyleno-Linked Adenosine Dimers

Gunji

Vasella

2000

HCA

Self Cite

View full text Add to dashboard Cite

The adenosine‐derived dimers 14a – d and 15b – d have been prepared by coupling the protected 8‐iodoadenosines 3 and 13 with the C(5′)‐ethynylated adenosine derivatives 5, 6, 11, and 12 (Scheme 4). Similarly, the 5′‐epimeric dimer 16 was prepared by coupling 3 with the alkyne 8 (Scheme 5). The propargylic alcohol 4 was transformed into the N‐benzoylated alkyne 5 and into the amine 6, while the epimeric alcohol 7 was converted to the epimeric amine 8 and the 5′‐deoxy analogues 11 and 12 (Scheme 3). Cross‐coupling of the iodoadenosine 13 with the alkyne 5 to 14a was optimised; it is influenced by the N‐benzoyl and the Et3SiO group of the alkyne, but hardly by the N‐benzoyl group of the 8‐iodoadenosine. The alkyne is most reactive when it is O‐silylated, but not N‐benzoylated. Cross‐coupling of the 5′‐deoxyalkynes proceeded more slowly. The dimers 14a – d, 15b – d, and 16 were obtained in good yields (Table 2). Deprotection of 14d and 16 led to 18 and 20, respectively (Scheme 5). The diols 17 and 19 and the hexols 18 and 20 prefer the syn‐conformation in (D6)DMSO, completely for unit II and ≥80% for unit I; they exhibit partially persistent intramolecular O(5′)−H⋅⋅⋅N(3) H‐bonds. The persistence increases from 18% (unit I of 19), 32% (unit II of 17 and 19), 45% (unit I of 17), 52% (unit II of 18 and 20), and 55% (unit I of 20) to 82% (unit I of 18).

show abstract

Oligosaccharide Analogues of Polysaccharides, Part 16, Cross-Coupling of Partially Protected Dialkynyl Monosaccharides

Cited by 19 publications

References 10 publications

Oligonucleosides with a Nucleobase-Including Backbone, Part 1, Concept, Force-Field Calculations, and Synthesis of Uridine-Derived Monomers and Dimers

Oligonucleosides with a Nucleobase-Including Backbone, Part 1, Concept, Force-Field Calculations, and Synthesis of Uridine-Derived Monomers and Dimers

Acetylenosaccharides

Oligonucleosides with a Nucleobase-Including Backbone, Part 3, Synthesis of Acetyleno-Linked Adenosine Dimers

Contact Info

Product

Resources

About