The Reaction of Ammonia with some Acetylated and Benzoylated Monosaccharides. III. Derivatives of D-Galactose

Deferrari, Jorge O.; Deulofeu, Venancio

doi:10.1021/jo50008a005

Cited by 20 publications

(8 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The glycosyl acceptors 1α/β and 2α/β were prepared employing protecting group chemistry while trying to simplify the reaction sequences and to optimize the yields. Methyl galactopyranosides 7 and 8 were synthesized from per-O-benzoyl-α-ᴅ- Galp 6, prepared by benzoylation of galactose in pyridine [16] at low temperature (0 ºC) in order to avoid the formation of furanosic forms, which are usually generated from ᴅ-Gal [17]. The β-anomer 7 was obtained by BF 3 •OEt 2 -promoted glycosylation [18] with a short reaction time, exploiting anchimeric assistance, followed by Zemplén de-O-acylation.…”

Section: Synthesis Of the Glycosyl Acceptorsmentioning

confidence: 99%

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

Vigo¹,

Stortz²,

Marino³

2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

Regioselective glycosylations allow planning simpler strategies for the synthesis of oligosaccharides, and thus reducing the need of using protecting groups. With the idea of gaining further understanding of such regioselectivity, we analyzed the relative reactivity of the OH-3 and OH-4 groups of 2,6-diprotected methyl α- and β-galactopyranoside derivatives in glycosylation reactions. The glycosyl acceptors were efficiently prepared by simple methodologies, and glycosyl donors with different reactivities were assessed. High regioselectivities were achieved in favor of the 1→3 products due to the equatorial orientation of the OH-3 group. A molecular modeling approach endorsed this general trend of favoring O-3 substitution, although it showed some failures to explain subtler factors governing the difference in regioselectivity between some of the acceptors. However, the Galp-(β1→3)-Galp linkage could be regioselectively installed by using some of the acceptors assayed herein.

show abstract

Section: Synthesis Of the Glycosyl Acceptorsmentioning

confidence: 99%

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

Vigo¹,

Stortz²,

Marino³

2019

Beilstein J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Several products were formed, one major of which co-chromatographed with the authentic sample 22,23 of 1,2,3,4,6-penta- O -benzoyl- α -D-galactopyranose ( 11 ). 23,24 It has been reported that high proportion of furanoses is formed during benzoylation of D-galactose at both elevated 19 and sub-ambient 25 temperatures. The products were difficult to separate; hence accurate yield of individual compounds formed could not be determined.…”

Section: Resultsmentioning

confidence: 99%

“…24 Mp 161.5–162.5 °C (EtOH); [ α ] D +193.9 ( c 1.0, CHCl 3 ); lit. 24 Mp 158–159 °C (MeOH); [ α ] D +187.0 ( c 4.0, CHCl 3 ); 1 H NMR (600MHz, CDCl 3 ) δ : 6.96 (d, 1H, J 1,2 = 3.7 Hz, H-1), 6.20 (br d, 1H, H-4), 6.13 (dd, 1H, J 2,3 = 10.7, J 3,4 = 3.4 Hz, H-3), 6.03 (dd, 1H, H-2), 4.84 (t, 1H, J = 6.8 Hz, H-5), 4.64 (dd, 1H, J 6a,6b = 11.4, J 5,6a = 6.4 Hz, H-6a), 4.43 (dd, 1H, J 5,6b = 6.9 Hz, H-6b); 13 C NMR (150 MHz, CDCl 3 ): δ 90.65 (C-1), 69.41 (C-5), 68.50 (C-3), 68.43 (C-4), 67.66 (C-2), 61.80 (C-6). ESI-HRMS calcd for C 41 H 36 NO 11 [M+NH 4 ] + : 718.2288; found: 718.2258; Anal.…”

Section: Methodsmentioning

confidence: 99%

Benzoylated ethyl 1-thioglycosides: direct preparation from per-O-benzoylated sugars

Sail

Kòváč

2012

Carbohydrate Research

View full text Add to dashboard Cite

D-Glucose, lactose, maltose, and melibiose were benzoylated with Bz2O–Et3N reagent to give fully benzoylated β products. Under the same conditions, D-mannose produced a mixture where the β-benzoate predominated. Treatment of the foregoing compounds with EtSH at slightly elevated temperature (50– 60 °C) in the presence of BF3·Et2O as a promoter gave the corresponding ethyl 1-thio glycosides in high yields. The α-products predominated in all cases in the anomeric mixtures formed. Individual products of all reactions were isolated by chromatography, they were obtained in analytically pure state, and were fully characterized by 1H and 13C NMR data and physical constants.

show abstract

“…Benzobromogalactose 13 was prepared from 1,2,3,4,6-penta-O-benzoyl-a-d-galactopyranose [35] as described in ref. [20].…”

Section: Methodsmentioning

confidence: 99%

Synthetic Fragments of Antigenic Lipophosphoglycans from Leishmania major and Leishmania mexicana and Their Use for Characterisation of the Leishmania Elongating α‐D‐Mannopyranosylphosphate Transferase

Higson

Ross

Tsvetkov

et al. 2005

Chemistry A European J

View full text Add to dashboard Cite

The phosphorylated branched heptasaccharides 7 and 8, the octasaccharide 9 and the phosphorylated trisaccharides 5 and 6, which are fragments of the phosphoglycan portion of the surface lipophosphoglycans from Leishmania mexicana (5) or L. major (6-9), were synthesised by using the glycosyl hydrogenphosphonate method for the preparation of phosphodiester bridges. The compounds were tested as acceptor substrates/putative inhibitors for the Leishmania elongating alpha-D-mannosylphosphate transferase.

show abstract

The Reaction of Ammonia with some Acetylated and Benzoylated Monosaccharides. III. Derivatives of D-Galactose

Cited by 20 publications

References 8 publications

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

Regioselectivity of glycosylation reactions of galactose acceptors: an experimental and theoretical study

Benzoylated ethyl 1-thioglycosides: direct preparation from per-O-benzoylated sugars

Synthetic Fragments of Antigenic Lipophosphoglycans from Leishmania major and Leishmania mexicana and Their Use for Characterisation of the Leishmania Elongating α‐D‐Mannopyranosylphosphate Transferase

Contact Info

Product

Resources

About