26927-44-6Relevant articles and documents
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
Stannous chloride as a low toxicity and extremely cheap catalyst for regio-/site-selective acylation with unusually broad substrate scope
Dong, Hai,Feng, Guang-Jing,Luo, Tao,Lv, Jian,Yu, Jian-Cheng
supporting information, p. 6936 - 6942 (2020/11/09)
This work reports stannous chloride (SnCl2)-catalyzed regio-/site-selective acylation with unusually broad substrate scope. In addition to 1,2- and 1,3-diols and glycosides containing cis-vicinal diol, the substrate scope also includes glycosides without cis-vicinal diol. For such a substrate scope, usually, only methods using stoichiometric amounts of organotin reagents can lead to the same protection pattern with high selectivities and highly isolated yields (84-97% in most cases). Therefore, SnCl2, as a low toxicity and extremely cheap reagent, should be the best catalyst for regio-/site-selective acylation compared with any previously reported reagents. This journal is
Experimental and theoretical study of the O3/O4 regioselectivity of glycosylation reactions of glucopyranosyl acceptors
Del Vigo, Enrique A.,Stortz, Carlos A.,Marino, Carla
, (2020/11/10)
The knowledge of the regioselectivity between different hydroxyl groups of glycosyl acceptors is valuable in planning simple strategies for the synthesis of oligosaccharides, minimizing the use of protecting groups. With the aim of obtaining deeper knowle
Regioselectivity of glycosylation reactions of galactose acceptors: An experimental and theoretical study
Del Vigo, Enrique A.,Stortz, Carlos A.,Marino, Carla
, p. 2982 - 2989 (2020/01/09)
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
P-Methylbenzyl Group: Oxidative Removal and Orthogonal Alcohol Deprotection
Ikeuchi, Kazutada,Murasawa, Kentaro,Ohara, Kenya,Yamada, Hidetoshi
, p. 6638 - 6642 (2019/09/30)
We describe the practical removal of p-methylbenzyl (MBn) protections of alcohols by treatment with 2,3-dichloro-5,6-dicyano-p-benzoquinone. When a molecule bears benzyl and MBn groups, the oxidant selectively removes the latter groups. Further, the MBn groups tolerate ceric ammonium nitrate, resulting in chemoselective removal of the p-methoxybenzyl group in the presence of the MBn groups. These orthogonal alcohol deprotections would provide novel synthetic strategies of organic compounds.
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.
Boronic esters as protective groups in carbohydrate chemistry: processes for acylation, silylation and alkylation of glycoside-derived boronates
Mancini, Ross S.,Lee, Jessica B.,Taylor, Mark S.
, p. 132 - 143 (2016/12/27)
Procedures for selective installation of acyl, silyl ether and para-methoxybenzyl (PMB) ether groups to glycoside substrates have been developed, employing phenylboronic esters as protected intermediates. The sequence of boronic ester formation, functiona
Donor specificity and regioselectivity in Lipolase mediated acylations of methyl α-d-glucopyranoside by vinyl esters of phenolic acids and their analogues
Mastihubova, Maria,Mastihuba, Vladimir
supporting information, p. 5389 - 5392 (2013/09/23)
Methyl α-d-glucopyranoside as a model acceptor was acylated by several phenolic and non-phenolic vinyl esters using immobilised Lipolase. Donor specificity and regioselectivity of reaction were investigated. Conversion and rate of acylation by structurally varied donors indicates that the synthetic reactivity of Lipolase corresponds to the hydrolytic activity of feruloyl esterase type A. Lipolase exhibited remarkable regioselectivity for primary position of methyl α-d-glucopyranoside. The acylation occurred exclusively at 6-O primary position when vinyl esters of phenolic acids (hydroxybenzoates, hydroxyphenylalkanoates and hydroxycinnamates) served as acyl donors (5-77%). In addition to the major 6-O-acyl products (52-79%), 2,6-di-O-acylated derivatives were isolated from reaction mixtures (2-13%) when non-phenolic donors were used (vinyl esters of fully methoxylated derivatives of phenolic acids, along with vinyl benzoates, cinnamates or some heterocyclic analogues).
Benzylation of hydroxy groups with tertiary amine as a base
Gathirwa, Jeremiah W.,Maki, Toshihide
scheme or table, p. 370 - 375 (2012/01/14)
The benzylation of hydroxy groups in the presence of tertiary amines is described. A mixture of an alcohol and a benzyl halide afforded the corresponding benzyl ether in good to excellent yields in the presence of diisopropylethylamine. The importance of solventless conditions was observed. The reaction showed high tolerance to many functional groups including benzoate, even at a reaction temperature of 150 °C. Sodium iodide was found to be an efficient catalyst to accelerate the reaction.
Regioselective benzoylation of glycopyranosides by benzoic anhydride in the presence of Cu(CF3COO)2
Evtushenko, Evgeny V.
, p. 111 - 119 (2012/11/07)
Benzoylation of methyl and benzyl glycopyranosides by benzoic anhydride in acetonitrile in the presence of copper(II) trifluoroacetate as a promoter has given monobenzoates with a good yield and high regioselectivity. The composition of monobenzoates depended both on a configuration of hydroxyl groups and on a configuration of aglycone. The simple syntheses of the monobenzoates of some glycosides are offered.
