17791-36-5Relevant academic research and scientific papers
Mild selective hydrolysis of acetals in carbohydrates
Gomes Cioletti, Alessandra,Alves, Ricardo José,De Souza Filho, José Dias,Gomes Chaves, Josiano,Fontes Prado, Maria Auxiliadora
, p. 2019 - 2028 (2000)
A simple and inexpensive methodology for the selective hydrolysis of acetals using hydrogen chloride as catalyst is described.
Regioselective Reductive Ring Opening of 4-Methoxybenzylidene Acetals of Hexopyranosides. Access to a Novel Protective Group Strategy
Johansson, Rolf,Samuelsson, Bertil
, p. 201 - 202 (1984)
Reduction of fully protected 4,6-O-(4-methoxybenzylidene)hexopyranosides with sodium cyanoborohydride-trifluoroacetic acid in N,N-dimethylformamide, or with trimethylsilyl chloride in acetonitrile, gives the 6- and 4-O-(4-methoxybenzyl) ethers, respectively, in good yields and with good regioselectivity; the 4-methoxybenzyl ether linkage in products containing benzyl ethers or other protective groups is selectively cleaved upon treatment with cerium(IV) ammonium nitrate in aqueous acetonitrile.
Unexpected reaction using methanol dried over molecular sieves
Mizuno, Mamoru,Kobayashi, Katsuaki,Nakajima, Hitoshi,Koya, Masahiko,Inazu, Toshiyuki
, p. 1665 - 1670 (2002)
The absolute methanol dried over 3A molecular sieves cleaves the O-acetyl group due to the existence of methoxy species generated by the 3A molecular sieves.
Triethylamine-methanol mediated selective removal of oxophenylacetyl ester in saccharides
Rasool, Javeed Ur,Kumar, Atul,Ali, Asif,Ahmed, Qazi Naveed
, p. 338 - 347 (2021/01/29)
A highly selective, mild, and efficient method for the cleavage of oxophenylacetyl ester protected saccharides was developed using triethylamine in methanol at room temperature. The reagent proved successful against different labile groups like acetal, ketal, and PMB and also generated good yields of the desired saccharides bearing lipid esters. Further, we also observed DBU in methanol as an alternative reagent for the deprotection of acetyl, benzoyl, and oxophenylacetyl ester groups. This journal is
Synthesis of methyl 4,6-di-o-ethyl-α-d-glucopyranoside-based azacrown ethers and their effects in asymmetric reactions
Bagi, Péter,Bakó, Péter,Heged?s, László,Orbán, István,Rapi, Zsolt,Varga, Bertalan
, (2021/08/12)
Carbohydrate-based crown ethers have been reported to be able to generate asymmetric induction in certain reactions. Previously, it was proved that the monosaccharide unit, the anomeric substituent, and the sidearm could influence the catalytic activity of the monoaza-15-crown-5 macrocycles derived from sugars. In order to gain information about the effect of the flexibility, 4,6-di-O-ethyl-glucoside-based crown compounds were synthesized, and their efficiency was compared to the 4,6-O-benzylidene analogues. It was found that the absence of the two-ring annulation has a negative effect on the enantioselectivity in liquid-liquid two-phase reactions: in the Darzens condensation of 2-chloroacetophenone and in the epoxidation of chalcone. The same trend was observed in the solid-liquid phase Michael addition of diethyl acetamidomalonate. Surprisingly, in the solid-liquid phase cyclopropanation of benzylidenemalononitrile, one of the new catalysts was highly enantioselective (99% ee).
Systematic Study of Regioselective Reductive Ring-Opening Reactions of 4,6- O-Halobenzylidene Acetals of Glucopyranosides
Mez?, Erika,Herczeg, Mihály,Demeter, Fruzsina,Bereczki, Ilona,Csávás, Magdolna,Borbás, Anikó
, p. 12973 - 12987 (2021/09/18)
Reductive openings of cyclic acetals are widely used in modern synthetic organic chemistry for the regioselective introduction of protecting groups. A systematic study was performed on the applicability and efficacy of various hydride donor and protic or Lewis acid reagent combinations in the reductive ring opening of glucosidic 4,6-halobenzylidene acetals bearing an ortho-, meta-, and para-chloro- or -bromo substituent on the benzene ring. Most of the reagent combinations tested cleaved the 4,6-O-halobenzylidene acetal rings at O4 or O6 efficiently and with the expected regioselectivity. The LiAlH4-AlCl3 and the BH3·THF-TMSOTf combinations produced the 4-O-halobenzyl ether/6-OH products with complete regioselectivity and high yields. The use of Me3N·BH3-AlCl3 reagent system in toluene was also effective in cleaving the acetal ring at O6 but was accompanied by Al-chelation-assisted debenzylation side reactions. The NaCNBH3-HCl and the Et3SiH-BF3·Et2O combinations were highly effective in yielding the 6-halobenzyl ether/4-OH derivatives. Et3SiH, in combination with TfOH, produced the 6-O-ether/4-OH products in rapid reactions but also triggered silylation and reductive halobenzylation as secondary transformations. Reductive opening of the 1,3-dioxane ring of pyranosidic 4,6-O-halobenzylidene acetals by the proper reagent combination was found to be an efficient method for the regioselective introduction of versatile halobenzyl protecting groups onto the pyranose ring.
The 2,2-Dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) Group: A Novel Protecting Group in Carbohydrate Chemistry
Liu, Hui,Zhou, Si-Yu,Wen, Guo-En,Liu, Xu-Xue,Liu, De-Yong,Zhang, Qing-Ju,Schmidt, Richard R.,Sun, Jian-Song
supporting information, p. 8049 - 8052 (2019/10/11)
The 2,2-dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) group was introduced to synthetic carbohydrate chemistry as a protecting group (PG) for the first time. Benefiting from a unique chemical structure and novel deprotection conditions, the DMNPA group can be cleaved rapidly and mutually orthogonal to other PGs. Orchestrated application of the DMNPA group with other PGs led to the highly efficient synthesis of the glycan of thornasterside A.
Introducing Oxo-Phenylacetyl (OPAc) as a Protecting Group for Carbohydrates
Kumar, Atul,Gannedi, Veeranjaneyulu,Rather, Suhail A.,Vishwakarma, Ram A.,Ahmed, Qazi Naveed
, p. 4131 - 4138 (2019/04/30)
A series of oxo-phenylacetyl (OPAc)-protected saccharides, with divergent base sensitivity profiles against benzoyl (Bz) and acetyl (Ac) were synthesized, and KHSO5/AcCl in methanol was identified as an easy, mild, selective, and efficient deprotecting reagent for their removal in the perspective of carbohydrate synthesis. Timely monitoring of AcCl reagent was supportive in both sequential and simultaneous deprotecting of OPAc, Bz, and Ac. The salient feature of our method is the orthogonal stability against different groups, its ease to generate different valuable acceptors using designed monosaccharides, and use of OPAc as a glycosyl donar.
Approaches to Pyranuronic β-Sugar Amino Acid Building Blocks of Peptidosaccharide Foldamers
Goldschmidt G?z, Viktória,Pintér, István,Harmat, Veronika,Perczel, András
, p. 355 - 361 (2018/01/27)
Pyranuronic β-sugar amino acids (β-SAAs) are biocompatible and tuneable building blocks of foldamers and chimera-peptides. The scalable and economical total synthesis of two building blocks is described here. These C-4 epimers, Fmoc-GlcAPU(Me)-OH (7) and
Synthesis and mass spectrometric analysis of disaccharides from methanolysis of heparan sulfate
He, Qi Qi,Trim, Paul J.,Snel, Marten F.,Hopwood, John J.,Ferro, Vito
supporting information, p. 8791 - 8803 (2018/11/30)
The quantification of heparan sulfate (HS) in biological matrices, e.g., urine, cerebrospinal fluid, tissue samples etc., is of great importance for the diagnosis and prognosis of several of the mucopolysaccharidosis (MPS) disorders, which are lysosomal storage diseases of impaired glycosaminoglycan metabolism. The development of suitable assays for this purpose is challenging due to the high molecular weight and complexity of HS. Recent efforts towards this goal include the acid catalysed methanolysis of HS, which desulfates the polymer and results in the formation of disaccharide cleavage products which can be detected and quantified by LC-MS/MS. We have synthesized a library of 12 HS-derived disaccharides as methanolysis standards via the stereoselective 1,2-cis glycosylation of suitably protected GlcA and IdoA acceptors with a 2-deoxy-2-azido thioglucoside donor. This facilitated identification of the major peaks in the LC-MS/MS chromatograms, and potentially will allow the monitoring of specific metabolites as surrogate markers for genotype. This work also paves the way towards a fully quantitative LC-MS/MS assay for HS via the preparation of a suitably labelled derivative.
