- Photolabile 2-(2-Nitrophenyl)-propyloxycarbonyl (NPPOC) for Stereoselective Glycosylation and Its Application in Consecutive Assembly of Oligosaccharides
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A photolabile protecting group (PPG) 2-(2-nitrophenyl)-propyloxycarbonyl (NPPOC) was explored in glycosylation and applied in the consecutive synthesis of oligosaccharides. NPPOC displays a strong neighboring group participation (NGP) effect to facilitate the construction of 1,2-trans glycosides in excellent yield. Notably, NPPOC could be efficiently removed by photolysis, and the deprotection conditions are friendly to typical protecting groups. A branched and asymmetric oligomannose Man6 was rapidly prepared, and the consecutive assembly of oligosaccharides without intermediate purification was further investigated owing to the compatibility conditions between NPPPOC's photolysis and glycosylation.
- Wang, Jincai,Feng, Yingle,Sun, Taotao,Zhang, Qi,Chai, Yonghai
-
supporting information
p. 3402 - 3421
(2022/03/02)
-
- Me3SI-promoted chemoselective deacetylation: a general and mild protocol
-
A Me3SI-mediated simple and efficient protocol for the chemoselective deprotection of acetyl groups has been developedviaemploying KMnO4as an additive. This chemoselective deacetylation is amenable to a wide range of substrates, tolerating diverse and sensitive functional groups in carbohydrates, amino acids, natural products, heterocycles, and general scaffolds. The protocol is attractive because it uses an environmentally benign reagent system to perform quantitative and clean transformations under ambient conditions.
- Gurawa, Aakanksha,Kashyap, Sudhir,Kumar, Manoj
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p. 19310 - 19315
(2021/06/03)
-
- Substrate Substitution in Kanosamine Biosynthesis Using Phosphonates and Phosphite Rescue
-
Kanosamine is an antibiotic and antifungal compound synthesized from glucose 6-phosphate (G6P) inBacillus subtilisby the action of three enzymes: NtdC, which catalyzes NAD-dependent oxidation of the C3-hydroxyl; NtdA, a PLP-dependent aminotransferase; and
- Palmer, David R. J.,Vetter, Natasha D.
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p. 1926 - 1932
(2021/06/28)
-
- Automated Quantification of Hydroxyl Reactivities: Prediction of Glycosylation Reactions
-
The stereoselectivity and yield in glycosylation reactions are paramount but unpredictable. We have developed a database of acceptor nucleophilic constants (Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure high reproducibility and accuracy. A diverse range of glycosylation donors and acceptors with well-defined reactivity and promoters were organized and processed by the designed software program “GlycoComputer” for prediction of glycosylation reactions without involving sophisticated computational processing. The importance of Aka was further verified by random forest algorithm, and the applicability was tested by the synthesis of a Lewis A skeleton to show that the stereoselectivity and yield can be accurately estimated.
- Chang, Chun-Wei,Lin, Mei-Huei,Chan, Chieh-Kai,Su, Kuan-Yu,Wu, Chia-Hui,Lo, Wei-Chih,Lam, Sarah,Cheng, Yu-Ting,Liao, Pin-Hsuan,Wong, Chi-Huey,Wang, Cheng-Chung
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supporting information
p. 12413 - 12423
(2021/05/03)
-
- Triethylamine-methanol mediated selective removal of oxophenylacetyl ester in saccharides
-
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
- Rasool, Javeed Ur,Kumar, Atul,Ali, Asif,Ahmed, Qazi Naveed
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p. 338 - 347
(2021/01/29)
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- Stereoselective Phenylselenoglycosylation of Glycals Bearing a Fused Carbonate Moiety toward the Synthesis of 2-Deoxy-β-galactosides and β-Mannosides
-
A phenylselenoglycosylation reaction of glycal derivatives mediated by diphenyl diselenide and phenyliodine(III) bis(trifluoroacetate) under mild conditions is described. Stereoselective glycosylation has been achieved by installing fused carbonate on those glycals. 3,4-O-Carbonate galactals and 2,3-O-carbonate 2-hydroxyglucals are converted into corresponding glycosides in good yields with excellent β-selectivity, resulting in 2-phenylseleno-2-deoxy-β-galactosides and 2-phenylseleno-β-mannosides which are good precursors of 2-deoxy-β-galactosides and β-mannosides, respectively.
- Li, Zhongjun,Meng, Shuai,Yao, Wang,Zhong, Wenhe
-
supporting information
(2020/04/09)
-
- Chemical synthesis and preliminary biological evaluation of C-6-O-methyl-1-deoxynojirimycin as a potent α-glucosidase inhibitor
-
A facile and efficient synthesis of 6-O-methyl-1-deoxynojirimycin 4 from commercially available methyl α-D-glucopyranoside in 10 steps and 25% overall yield was reported. The synthetic strategy was based on the regioselective protection/deprotection at 6-
- Wang, Lin,Liang, Tingting,Fang, Zhijie
-
-
- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
-
A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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p. 16702 - 16707
(2020/10/27)
-
- Mapping mechanisms in glycosylation reactions with donor reactivity: Avoiding generation of side products
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The glycosylation reaction, which is key for the studies on glycoscience, is challenging due to its complexity and intrinsic side reactions. Thioglycoside is one of the most widely used glycosyl donors in the synthesis of complex oligosaccharides. However, one of the challenges is its side reactions, which lower its yield and limits its efficiency, thereby requiring considerable effort in the optimization process. Herein, we reported a multifaceted experimental approach that reveals the behaviors of side reactions, such as the intermolecular thioaglycon transformation and N-glycosyl succinimides, via the glycosyl intermediate. Our mechanistic proposal was supported by low temperature NMR studies that can further be mapped by utilizing relative reactivity values. Accordingly, we also presented our findings to suppress the generation of side products in solving this particular problem for achieving high-yield glycosylation reactions.
- Wang, Cheng-Chung,Chang, Chun-Wei,Lin, Mei-Huei,Wu, Chia-Hui,Chiang, Tsun-Yi
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p. 15945 - 15963
(2021/01/18)
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- Carbocyclic Substrate Analogues Reveal Kanosamine Biosynthesis Begins with the α-Anomer of Glucose 6-Phosphate
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NtdC is an NAD-dependent dehydrogenase that catalyzes the conversion of glucose 6-phosphate (G6P) to 3-oxo-glucose 6-phosphate (3oG6P), the first step in kanosamine biosynthesis in Bacillus subtilis and other closely-related bacteria. The NtdC-catalyzed r
- Vetter, Natasha D.,Jagdhane, Rajendra C.,Richter, Brett J.,Palmer, David R. J.
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p. 2205 - 2211
(2020/09/01)
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- Addressing the biochemical foundations of a glucose-based "trojan horse"-strategy to boron neutron capture therapy: From chemical synthesis to in vitro assessment
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Boron neutron capture therapy (BNCT) for cancer is on the rise worldwide due to recent developments of in-hospital neutron accelerators which are expected to revolutionize patient treatments. There is an urgent need for improved boron delivery agents, and herein we have focused on studying the biochemical foundations upon which a successful GLUT1-targeting strategy to BNCT could be based. By combining synthesis and molecular modeling with affinity and cytotoxicity studies, we unravel the mechanisms behind the considerable potential of appropriately designed glucoconjugates as boron delivery agents for BNCT. In addition to addressing the biochemical premises of the approach in detail, we report on a hit glucoconjugate which displays good cytocompatibility, aqueous solubility, high transporter affinity, and, crucially, an exceptional boron delivery capacity in the in vitro assessment thereby pointing toward the significant potential embedded in this approach.
- Ekholm, Filip S.,Matovic, Jelena,Jarvinen, Juulia,Bland, Helena C.,Sokka, Iris K.,Imlimthan, Surachet,Huttunen, Kristiina M.,Timonen, Juri,Peraniemi, Sirpa,Aitio, Olli,Airaksinen, Anu J.,Sarparanta, Mirkka,Johansson, Mikael P.,Rautio, Jarkko
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p. 3885 - 3899
(2020/11/12)
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- Chemical synthesis of human syndecan-4 glycopeptide bearing O-, N-sulfation and multiple aspartic acids for probing impacts of the glycan chain and the core peptide on biological functions
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Proteoglycans are a family of complex glycoproteins with glycosaminoglycan chains such as heparan sulfate (HS) attached to the core protein backbone. Due to the high structural heterogeneity of HS in nature, it is challenging to decipher the respective roles of the HS chain and the core protein on proteoglycan functions. While the sulfation patterns of HS dictate many activities, the core protein can potentially impact HS functions. In order to decipher this, homogeneous proteoglycan glycopeptides are needed. Herein, we report the first successful synthesis of proteoglycan glycopeptides bearing multiple aspartic acids in the core peptide and O- and N-sulfations in the glycan chain, as exemplified by the syndecan-4 glycopeptides. To overcome the high acid sensitivities of sulfates and base sensitivities of the glycopeptide during synthesis, a new synthetic approach has been developed to produce a sulfated glycan chain on a peptide sequence prone to the formation of aspartimide side products. The availability of the structurally well-defined synthetic glycopeptide enabled the investigation of their biological functions including cytokine, growth factor binding and heparanase inhibition. Interestingly, the glycopeptide exhibited context dependent enhancement or decrease of biological activities compared to the peptide or the glycan alone. The results presented herein suggest that besides varying the sulfation patterns of HS, linking the HS chain to core proteins as in proteoglycans may be an additional approach to modulate biological functions of HS in nature.
- Cole, Logan Emerson,Eken, Yigitcan,Huang, Xuefei,Liu, Jian,Ramadan, Sherif,Wilson, Angela K.,Xu, Yongmei,Yang, Weizhun,Zhang, Jicheng,Zhang, Zeren
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p. 6393 - 6404
(2020/07/15)
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- New class of alkynyl glycoside analogues as tyrosinase inhibitors
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A new series of alkynyl glycoside analogues were designed and synthesized from cheap and a commercially available sugar by introduction of various alkynyl and alkyl groups at C-1 and C-6 positions of the sugar ring. The inhibitory abilities of alkynyl gly
- Saehlim, Natthiya,Athipornchai, Anan,Sirion, Uthaiwan,Saeeng, Rungnapha
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- Design, synthesis and biological evaluation of 6-deoxy O-spiroketal C-arylglucosides as novel renal sodium-dependent glucose cotransporter 2 (SGLT2) inhibitors for the treatment of type 2 diabetes
-
In this work, aiming at finding a novel, potent, and selective sodium-dependent glucose cotransporter 2 (SGLT2) inhibitor with good pharmacokinetic profiles for the treatment of diabetes, we focus on modifying the sugar moiety of SGLT2 inhibitors, which dominates the binding with glucose binding site of hSGLT, via removing the C-6 hydroxy group to adjust the physicochemical properties and target-recognition manners of SGLT2 inhibitors. In addition, tofogliflozin containing a special O-spiroketal C-arylglucoside scaffold, displayed good efficacy and bioavailability both in animals and in humans. Therefore, a series of 6-deoxy O-spiroketal C-arylglucosides as novel SGLT2 inhibitors were designed, synthesized, and evaluated in this work. The structure-activity relationship (SAR) research on this novel series and a comprehensive in vitro and in vivo biological evaluation afforded compound 39 with high in vitro hSGLT2 inhibitory activity (IC50 = 4.5 nM), good pharmacokinetic profiles, and more remarkable efficacy in C57BL/6J mice and Sprague-Dawley rats than marketed drug tofogliflozin.
- Wang, Yibing,Lou, Yang,Wang, Jiang,Li, Dan,Chen, Hui,Zheng, Tiannan,Xia, Chunmei,Song, Xiaohan,Dong, Tiancheng,Li, Jingya,Li, Jia,Liu, Hong
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p. 398 - 416
(2019/07/19)
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- Peptide-Coated Platinum Nanoparticles with Selective Toxicity against Liver Cancer Cells
-
Peptide-stabilized platinum nanoparticles (PtNPs) were developed that have significantly greater toxicity against hepatic cancer cells (HepG2) than against other cancer cells and non-cancerous liver cells. The peptide H-Lys-Pro-Gly-dLys-NH2 was identified by a combinatorial screening and further optimized to enable the formation of water-soluble, monodisperse PtNPs with average diameters of 2.5 nm that are stable for years. In comparison to cisplatin, the peptide-coated PtNPs are not only more toxic against hepatic cancer cells but have a significantly higher tumor cell selectivity. Cell viability and uptake studies revealed that high cellular uptake and an oxidative environment are key for the selective cytotoxicity of the peptide-coated PtNPs.
- Shoshan, Michal S.,Vonderach, Thomas,Hattendorf, Bodo,Wennemers, Helma
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p. 4901 - 4905
(2019/01/25)
-
- From d-to l-Monosaccharide Derivatives via Photodecarboxylation-Alkylation
-
Photodecarboxylation-alkylation of conformationally locked monosaccharides leads to inversion of stereochemistry at C5. This allows the synthesis of l-sugars from their readily available d-counterparts. Via this strategy, methyl l-guloside was synthesized from methyl d-mannoside in 21% yield over six steps.
- Wan, I. C. Steven,Witte, Martin D.,Minnaard, Adriaan J.
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p. 7669 - 7673
(2019/10/08)
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- The 2,2-Dimethyl-2-(ortho-nitrophenyl)acetyl (DMNPA) Group: A Novel Protecting Group in Carbohydrate Chemistry
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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.
- Liu, Hui,Zhou, Si-Yu,Wen, Guo-En,Liu, Xu-Xue,Liu, De-Yong,Zhang, Qing-Ju,Schmidt, Richard R.,Sun, Jian-Song
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supporting information
p. 8049 - 8052
(2019/10/11)
-
- Introducing Oxo-Phenylacetyl (OPAc) as a Protecting Group for Carbohydrates
-
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.
- Kumar, Atul,Gannedi, Veeranjaneyulu,Rather, Suhail A.,Vishwakarma, Ram A.,Ahmed, Qazi Naveed
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p. 4131 - 4138
(2019/04/30)
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- C,O-SPIRO ARYL GLYCOSIDE COMPOUNDS, PREPARATION THEREFOR AND USE THEREOF
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The present invention provides C, O-spiro aryl glycoside compounds, preparation therefor and use thereof. Specifically provided are the compounds represented by the formula (I), wherein the definitions of each group are described in the specification. The
- -
-
Paragraph 0093
(2018/05/16)
-
- A five-component one-pot synthesis of phosphatidylinositol pentamannoside (PIM5)
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A practical and efficient synthesis of phosphatidylinositol pentamannoside (PIM5) was achieved based on a five-component one-pot sequential glycosylation protocol with exclusive regio- and stereo-selectivity. Two regioselective sequential glycosylations on inositol and p-tolyl thioglycosides as the sole type of building blocks made this protocol to avoid the tedious protective group manipulations. This synthetic strategy provides access to other important glycolipids with similar structures.
- Wang, Dong,Xiong, De-Cai,Ye, Xin-Shan
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p. 1340 - 1342
(2018/01/08)
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- Secondary amine salt catalyzed controlled activation of 2-deoxy sugar lactols towards alpha-selective dehydrative glycosylation
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A new organocatalytic glycosylation method exploiting the lactol functionality has been disclosed. The catalytic generation of glycosyl oxacarbenium ions from lactols under forcible conditions via weakly Br?nsted-acidic, readily available secondary amine salts affects the diastereoselective glycosylation of 2-deoxypyranoses and furanoses. This operationally simple iminium catalyzed activation of 2-deoxy hemi-acetals is a potential alternative to the existing cumbersome methods that need specialized handling. The mechanisms for this unique transformation and kinetic/thermodynamic effects have been discussed based on both experimental evidence and theoretical studies.
- Ghosh, Titli,Mukherji, Ananya,Srivastava, Hemant Kumar,Kancharla, Pavan K.
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supporting information
p. 2870 - 2875
(2018/05/03)
-
- Co2(CO)6-propargyl cation mediates glycosylation reaction by using thioglycoside
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We discovered that the cobalt-propargyl cation can mediate the glycosylation reaction by activating the thioglycoside donor. The glyco-oxacarbenium cation was formed by transferring the thio-aglycone to the cobalt-propargyl cation that was generated from the cobalt-propargylated acceptor in situ via the activating with Lewis acid. The reactivity of the donor (Armed or dis-armed) and the amount of the Lewis acid control the releasing rate of the cobalt-propargyl group.
- Xia, Meng-jie,Yao, Wang,Meng, Xiang-bao,Lou, Qing-hua,Li, Zhong-jun
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p. 2389 - 2392
(2017/05/29)
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- Method for preparing and removing saccharide hydroxyl protecting group dimethyl phenylacetyl DMNA
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The invention relates to a method for preparing and removing saccharide hydroxyl protecting group dimethyl phenylacetyl DMNA. The method comprises the following steps: (1) efficiently introducing saccharide hydroxyl protecting group dimethyl phenylacetyl into saccharide hydroxyl; and (2) efficiently removing a hydroxyl protecting group shown in the description. The method is environmentally friendly and has the advantages that the advantages that the preparation is simple, the introduction is efficient, the operation is easy, the removal is efficient, and the application range is wide; and furthermore, a protecting group has very good stereoselectivity when being used for protecting 2-hydroxyl of a glycosyl donor, so that the development and application of the protecting group are promoted.
- -
-
Paragraph 0026; 0027; 0028; 0035; 0036; 0037
(2017/08/29)
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- Chiron approach to the total synthesis of Amaryllidaceae alkaloid (+)-lycoricidine
-
A highly stereoselective total synthesis of Amaryllidaceae alkaloid starting from α-D-galactopyranoside has been described. The salient features of this total synthesis are Ferrier carbocyclization reaction for the synthesis of ring A and Suzuki Miyaura c
- Saidhareddy, Puli,Shaw, Arun K.
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p. 6773 - 6779
(2017/10/30)
-
- A novel O-fucosylation strategy preactivated by (p-Tol)2SO/Tf2O and its application for the synthesis of Lewis blood group antigen Lewisa
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Based on a preactivation strategy using (p-Tol)2SO/Tf2O, a new O-fucosylation method with thioglycoside as donor under mild conditions was reported. High yields and excellent α-stereoselectivities of the fucosylation were obtained wi
- Li, Cui-yun,Liu, Guang-jian,Du, Wei,Zhang, Yuan,Xing, Guo-wen
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p. 2109 - 2112
(2017/05/09)
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- Biomimetic Total Synthesis of Angiopterlactone B and Other Potential Natural Products
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A one-pot biomimetic synthesis of (-)-angiopterlactone B and its enantiomer (+)-angiopterlactone B has been accomplished via TBAF-catalyzed tandem ring contraction followed by oxa-Michael/Michael addition sequence. Comparison of specific optical rotations
- Kotammagari, Tharun K.,Gonnade, Rajesh G.,Bhattacharya, Asish K.
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p. 3564 - 3567
(2017/07/17)
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- Structure–Activity Studies of N-Butyl-1-deoxynojirimycin (NB-DNJ) Analogues: Discovery of Potent and Selective Aminocyclopentitol Inhibitors of GBA1 and GBA2
-
Analogues of N-butyl-1-deoxynojirimycin (NB-DNJ) were prepared and assayed for inhibition of ceramide-specific glucosyltransferase (CGT), non-lysosomal β-glucosidase 2 (GBA2) and the lysosomal β-glucosidase 1 (GBA1). Compounds 5 a–6 f, which carry sterically demanding nitrogen substituents, and compound 13, devoid of the C3 and C5 hydroxy groups present in DNJ/NB-DGJ (N-butyldeoxygalactojirimycin) showed no inhibitory activity for CGT or GBA2. Inversion of stereochemistry at C4 of N-(n-butyl)- and N-(n-nonyl)-DGJ (compounds 24) also led to a loss of activity in these assays. The aminocyclopentitols N-(n-butyl)- (35 a), N-(n-nonyl)-4-amino-5-(hydroxymethyl)cyclopentane- (35 b), and N-(1-(pentyloxy)methyl)adamantan-1-yl)-1,2,3-triol (35 f), were found to be selective inhibitors of GBA1 and GBA2 that did not inhibit CGT (>1 mm), with the exception of 35 f, which inhibited CGT with an IC50 value of 1 mm. The N-butyl analogue 35 a was 100-fold selective for inhibiting GBA1 over GBA2 (Ki values of 32 nm and 3.3 μm for GBA1 and GBA2, respectively). The N-nonyl analogue 35 b displayed a Ki value of ?14 nm for GBA1 inhibition and a Ki of 43 nm for GBA2. The N-(1-(pentyloxy)methyl)adamantan-1-yl) derivative 35 f had Ki values of ≈16 and 14 nm for GBA1 and GBA2, respectively. The related N-bis-substituted aminocyclopentitols were found to be significantly less potent inhibitors than their mono-substituted analogues. The aminocyclopentitol scaffold should hold promise for further inhibitor development.
- Gu, Xingxian,Gupta, Vijayalaxmi,Yang, Yan,Zhu, Jin-Yi,Carlson, Erick J.,Kingsley, Carolyn,Tash, Joseph S.,Sch?nbrunn, Ernst,Hawkinson, Jon,Georg, Gunda I.
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p. 1977 - 1984
(2017/11/30)
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- Study of Uridine 5′-Diphosphate (UDP)-Galactopyranose Mutase Using UDP-5-Fluorogalactopyranose as a Probe: Incubation Results and Mechanistic Implications
-
Uridine 5′-diphosphate-5-fluorogalactopyranose (UDP-5F-Galp, 7) was synthesized, and its effect on UDP-Galp mutase (UGM) was investigated. UGM facilitated the hydrolysis of 7 to yield UDP and 5-oxogalactose (24), but no 11 was detected. 19F NMR and trapping experiments demonstrated that the reaction involves the initial formation of a substrate-cofactor adduct followed by decomposition of the resulting C5 gem-fluorohydrin to generate a 5-oxo intermediate (10). The results support the current mechanistic proposal for UGM and suggest new directions for designing mechanism-based inhibitors.
- Lin, Geng-Min,Sun, He G.,Liu, Hung-Wen
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p. 3438 - 3441
(2016/07/26)
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- A Synthetic Toolbox for the In Situ Formation of Functionalized Homo- and Heteropolysaccharide-Based Hydrogel Libraries
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A synthetic toolbox for the introduction of aldehydo and hydrazido groups into the polysaccharides hyaluronic acid, alginate, dextran, pullulan, glycogen, and carboxymethyl cellulose and their use for hydrogel formation is reported. Upon mixing differently functionalized polysaccharides derived from the same natural precursor, hydrazone cross-linking takes place, which results in formation of a hydrogel composed of one type of polysaccharide backbone. Likewise, hydrogels based on two different polysaccharide strands can be formed after mixing the corresponding aldehydo- and hydrazido-modified polysaccharides. A second line of these studies paves the way to introduce a biomedically relevant ligand, namely, the adhesion factor cyclic RGD pentapeptide, by using an orthogonal click reaction. This set of modified polysaccharides served to create a library of hydrogels that differ in the combination of polysaccharide strands and the degree of cross-linking. The different hydrogels were evaluated with respect to their rheological properties, their ability to absorb water, and their cytotoxicity towards human fibroblast cell cultures. None of the hydrogels studied were cytotoxic, and, hence, they are in principal biocompatible for applications in tissue engineering.
- Dibbert, Nick,Krause, Andreas,Rios-Camacho, Julio-Cesar,Gruh, Ina,Kirschning, Andreas,Dr?ger, Gerald
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p. 18777 - 18786
(2016/12/26)
-
- Synthesis of l -Pyranosides by Hydroboration of Hex-5-enopyranosides Revisited
-
Extensive study of the diastereoselective synthesis of l-pyranosides utilizing hydroboration of substituted exo-glucals (5-enopyranosides) obtained from d-sugars is presented. On the basis of this study we present the empirical rules describing the reacti
- ?opatkiewicz, Grzegorz,Mlynarski, Jacek
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p. 7545 - 7556
(2016/09/09)
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- A new method testing the orthogonality of different protecting groups
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A new test was elaborated to identify a new set of orthogonal protecting groups. With the developed method eight different protecting groups were tested under various deprotection conditions and the complex reaction mixtures were analysed by HPLC. The dev
- ágoston, Károly,ágoston, ágnes,Dorgan, Colin R.,Fügedi, Péter
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supporting information
p. 98 - 103
(2015/11/25)
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- Stable analogues of nojirimycin-synthesis and biological evaluation of nojiristegine and manno-nojiristegine
-
Two novel iminosugars called nojiristegines, being structural hybrids between nor-tropane alkaloid calystegine and nojirimycins, have been synthesised and found to be stable molecules despite the presence of a hemiaminal functionality. The synthesised iminosugars were evaluated against a panel of glycosidases and the best inhibition (IC50), found against α-glucosidases, was in the micromolar region. The compounds were also evaluated as potential antibiotics but no useful level of activity was observed.
- Viuff, Agnete H.,Besenbacher, Louise M.,Kamori, Akiko,Jensen, Mikkel T.,Kilian, Mogens,Kato, Atsushi,Jensen, Henrik H.
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p. 9637 - 9658
(2015/09/28)
-
- Carbohydrate based hyper-crosslinked organic polymers with -OH functional groups for CO2 separation
-
Recently, microporous organic polymers, especially those hyper-crosslinked from functionalized aromatic monomers, have been shown to be effective for CO2 capture and storage with considerable capacity and selectivity. Herein, a class of novel m
- Li, Haiying,Meng, Bo,Mahurin, Shannon M.,Chai, Song-Hai,Nelson, Kimberly M.,Baker, David C.,Liu, Honglai,Dai, Sheng
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p. 20913 - 20918
(2015/11/03)
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- A mild and efficient method for the selective cleavage of primary p-methoxybenzyl protecting group of saccharides by Co2(CO)8-Me2PhSiH-CO system
-
A mild and efficient method to selectively cleave p-methoxybenzyl (PMB) ether with a catalytic amount of Co2(CO)8, hydrosilane and CO (1 atm) is presented. The cleavage reaction shows regioselectivity to primary O-PMB of a variety of
- Qian, Peng-Zhan,Yao, Wang,Huang, Lu-Bai,Meng, Xiang-Bao,Li, Zhong-Jun
-
supporting information
p. 5238 - 5241
(2015/08/19)
-
- Iodine monochloride (ICl) as a highly efficient, green oxidant for the oxidation of alcohols to corresponding carbonyl compounds
-
Iodine monochloride (ICl) was discovered to be a highly efficient, green oxidant, which can oxidize aldose hemiacetals, diarylmethanols, arylalkylmethanols, anddialkylmethanols to the corresponding aldose lactones, diarylmethanones, arylalkylmethanones, and dialkylmethanones, respectively, in high yields. ICl as a green, metal-free oxidant is characterized by mild reaction condition, short reaction time, good yield, and broad scope.
- Wei, Peng,Zhang, Datong,Gao, Zhigang,Cai, Wenqing,Xu, Weiren,Tang, Lida,Zhao, Guilong
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p. 1457 - 1470
(2015/05/20)
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- In(III) triflate-catalyzed detritylation and glycosylation by solvent-free ball milling
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A highly efficient In(III) triflate-assisted method for the detritylation of O-trityl derivatives of carbohydrates, phenols, and alcohols using solvent-free mechanochemical method is described. In the case of carbohydrates, further reaction in the presence of an acceptor sugar leads to highly efficient glycosylation in the same pot resulting in the formation of the desired glycoside-product in very high yields. The method was applied successfully to the synthesis of a combinatorial library of galactose-based (1,6)-linked cyclohexa-, hepta-, and octasaccharides on gram scale.
- Kumar, Vajinder,Yadav, Narender,Kartha, K.P. Ravindranathan
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- A 3,4-trans-fused cyclic protecting group facilitates α-selective catalytic synthesis of 2-deoxyglycosides
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A practical approach has been developed to convert glucals and rhamnals into disaccharides or glycoconjugates with high α-selectivity and yields (77-97 %) using a trans-fused cyclic 3,4-O-disiloxane protecting group and TsOH·H2O (1 mol %) as a catalyst. Control of the anomeric selectivity arises from conformational locking of the intermediate oxacarbenium cation. Glucals outperform rhamnals because the C6 side-chain conformation augments the selectivity.
- Balmond, Edward I.,Benito-Alifonso, David,Coe, Diane M.,Alder, Roger W.,McGarrigle, Eoghan M.,Galan, M. Carmen
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supporting information
p. 8190 - 8194
(2014/08/18)
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- Exploring glycosylation reactions under continuous-flow conditions
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The industrial development of carbohydrate-based drugs is greatly thwarted by the typical challenges inherent in oligosaccharide synthesis. The practical advantages of continuous-flow synthesis in microreactors (high reproducibility, easy scalability, and fast reaction optimization) may offer an effective support to make carbohydrates more attractive targets for drug-discovery processes. Here we report a systematic exploration of the glycosylation reaction carried out under microfluidic conditions. Trichloroacetimidates and thioglycosides have been investigated as glycosyl donors, using both primary and secondary acceptors. Each microfluidic glycosylation has been compared with the corresponding batch reaction, in order to highlight advantages and drawbacks of microreactors technology. As a significant example of multistep continuous-flow synthesis, we also describe the preparation of a trisaccharide by means of two consecutive glycosylations performed in interconnected microreactors.
- Cancogni, Damiano,Lay, Luigi
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supporting information
p. 2873 - 2878
(2015/01/16)
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- HClO4-silica-catalysed regioselective opening of benzylidene acetals and its application towards regioselective HO-4 glycosylation of benzylidene acetals in one-pot
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Here we report a high-yielding method for the regioselective reductive ring opening of 4,6-O-benzylidene acetals of hexapyranosides using inexpensive and robust HClO4-SiO2 as the acidic catalyst and triethylsilane as the hydride dono
- Dara, Saidulu,Saikam, Varma,Yadav, Mahipal,Singh, Parvinder Pal,Vishwakarma, Ram A.
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supporting information
p. 93 - 96
(2014/05/20)
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- In vitro characterization of LmbK and LmbO: Identification of GDP-d-erythro-α-d-gluco-octose as a key intermediate in lincomycin a biosynthesis
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Lincomycin A is a clinically useful antibiotic isolated from Streptomyces lincolnensis. It contains an unusual methylmercapto-substituted octose, methylthiolincosamide (MTL). While it has been demonstrated that the C 8 backbone of MTL moiety is derived from d-fructose 6-phosphate and d-ribose 5-phosphate via a transaldol reaction catalyzed by LmbR, the subsequent enzymatic transformations leading to the MTL moiety remain elusive. Here, we report the identification of GDP-d-erythro-α-d-gluco-octose (GDP-d-α-d-octose) as a key intermediate in the MTL biosynthetic pathway. Our data show that the octose 1,8-bisphosphate intermediate is first converted to octose 1-phosphate by a phosphatase, LmbK. The subsequent conversion of the octose 1-phosphate to GDP-d-α-d-octose is catalyzed by the octose 1-phosphate guanylyltransferase, LmbO. These results provide significant insight into the lincomycin biosynthetic pathway, because the activated octose likely serves as the acceptor for the installation of the C1 sulfur appendage of MTL.
- Lin, Chia-I,Sasaki, Eita,Zhong, Aoshu,Liu, Hung-Wen
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supporting information
p. 906 - 909
(2014/02/14)
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- Evaluation of potential Myt1 kinase inhibitors by TR-FRET based binding assay
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In the human cell cycle, the Myt1 kinase is a crucial regulator of the G2/M transition. Because this membrane-associated kinase is hard to obtain and assay, there is a distinct lack of data so far. Here we report the derivatization of a glycoglycerolipid which was shown previously to be active in a Myt1 activity assay. These compounds were tested in a binding assay together with a set of common kinase inhibitors against a full-length Myt1 expressed in a human cell line. Dasatinib exhibited nanomolar affinity whereas broad coverage inhibitors such as sunitinib and staurosporine derivatives did not show any effect. We also carried out docking studies for the most potent compounds allowing further insights into the inhibitor interaction of this kinase. The glycoglycerolipids showed no significant effects in the binding assay, endorsing the idea of a mechanism of action distant from the active site.
- Rohe, Alexander,Goellner, Christiane,Wichapong, Kanin,Erdmann, Frank,Al-Mazaideh, Ghassab M.A.,Sippl, Wolfgang,Schmidt, Matthias
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- Hafnium(IV) tetratriflate in selective reductive carbohydrate benzylidene acetal opening reaction and direct silylation reaction
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Hafnium(IV) tetratriflate was shown to be an effective catalyst for the regioselective reductive benzylidene ring opening with concurrent silylation reaction. The synthetic conditions were optimized, and the scope and limitations were identified. In addit
- Manabe, Shino,Ito, Yukishige
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p. 6838 - 6840
(2019/04/10)
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- Hydrophobic and hydrophilic balance and its effect on mesophase behaviour in hydroxyalkyl ethers of methyl glucopyranoside
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Four series of monosubstituted methyl a-d-glucopyranoside hydroxyal- kyl ethers were prepared and their thermotropic and lyotropic self-organising properties were investigated in terms of the hydrophobic-hydrophilic balance with respect to their molecular
- Singh, Madan K.,Xu, Rui,Moebs, Sylvie,Kumar, Anil,Queneau, Yves,Cowling, Stephen J.,Goodby, John W.
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p. 5041 - 5049
(2013/06/27)
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- Skeletal rearrangement of seven-membered iminosugars: Synthesis of (-)-adenophorine, (-)-1-epi-adenophorine and derivatives and evaluation as glycosidase inhibitors
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The mirror image of natural product (+)-adenophorine along with its 1-epi-, 1-homo-analogs and other derivatives have been synthesized and evaluated as glycosidase inhibitors. The synthetic strategy is based on the skeletal rearrangement of tetrahydroxylated C-alkyl azepanes obtained via a Staudinger/azaWittig/alkylation sequence starting from a sugar-derived azidolactol. Several organometallic species have been investigated for the alkylation step including organomagnesium, organolithium, organozinc, organoaluminum and organocerium reagents. While diallylzinc proved to be the most efficient to introduce an allyl substituent, disappointing results were obtained with the other organometallic species leading either to lower yields or no reaction. Enzymatic assays indicate that (-)-adenophorine is a moderate α-l-fucosidase inhibitor.
- Mondon, Martine,Lecornué, Frédéric,Guillard, Jér?me,Nakagawa, Shinpei,Kato, Atsushi,Blériot, Yves
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p. 4803 - 4812
(2013/08/23)
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- Cyanuric chloride/sodium borohydride: A new reagent combination for reductive opening of 4,6-benzylidene acetals of carbohydrates to primary alcohols
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In the first such example, NaBH4 in combination with cyanuric chloride (TCT) has been used to obtain 6-hydroxy-4-benzyl ether derivatives from 4,6-benzylidene acetals of carbohydrates. The nature of hydride donor determines the regioselectivity
- Tatina, Madhubabu,Yousuf, Syed Khalid,Aravinda, Subrayashastry,Singh, Baldev,Mukherjee, Debaraj
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supporting information
p. 142 - 145
(2013/10/22)
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- Ring-opening polymerization of lactones using binaphthyl-diyl hydrogen phosphate as organocatalyst and resulting monosaccharide functionalization of polylactones
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Binaphthyl-diyl hydrogen phosphate has been assessed for the first time as a catalyst for the ring-opening polymerization of ε-caprolactone (CL) and δ-valerolactone (VL). In the presence of benzyl alcohol as coinitiator at 40-60 °C, the polymerization is
- Miao, Yong,Phuphuak, Yupin,Rousseau, Cyril,Bousquet, Till,Mortreux, Andre,Chirachanchai, Suwabun,Zinck, Philippe
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p. 2279 - 2287
(2013/05/21)
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- Sulfonylcarbamate as a versatile and unique hydroxy-protecting group: A protecting group stable under severe conditions and labile under mild conditions
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The sulfonylcarbamate group is a unique hydroxyl protecting group. In contrast to typical acyl protecting groups, the sulfonylcarbamate group is stable under harsh basic conditions, while showing labile behavior under mild basic conditions. Its compatibility with other hydroxyl protecting groups and application to carbohydrate chemistry is demonstrated.
- Manabe, Shino,Yamaguchi, Masanori,Ito, Yukishige
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supporting information
p. 8332 - 8334
(2013/09/23)
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- DiGalactosyl-Glycero-Ether Lipid: Synthetic approaches and evaluation as SK3 channel inhibitor
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The recent discoveries of the involvement of SK3 channel in some cell motility mechanisms occurring in cancer disease have opened up the way to the synthesis of inhibitors that could reduce metastasis formation. On the basis of our recent previous works showing that both lactose-glycero-ether lipid (Ohmline) and some phosphate analogues (GPGEL) were efficient compounds to modulate SK3 channel activity, the present study, which found its inspiration in the structure of the natural glycolipid DiGalactosylDiacylGlycerol (DGDG), reports the incorporation of a digalactosyl moiety (α-galactopyranosyl- (1→6)-β-galactopyranosyl-) as the polar head of a glycero ether lipid. For the construction of the digalactosyl fragment, two synthetic approaches were compared. The standard strategy which is based on the use of the benzyl protecting group to produce 1→6 disaccharide unit, was compared with a second method that made use of the trimethylsilyl moiety as a protecting group. This second strategy, which is applied for the first time to the synthesis of (1→6)-disaccharide unit, presents a net advantage in terms of efficacy (better global yield) and cost. Finally, compound 16, which is characterized by a (1→6) DiGalactosyl unit (DG) as the polar head of the amphiphilic structure, was tested as a modulator of the SK3 channel activity. Patch-clamp experiments have shown that compound 16 reduced SK3 currents (-28.2 ± 2.0% at 5 μM) and cell migration assays performed at 300 nM have shown a reduction of cell migration (SK3 + HEK293T) by 19.6 ± 2.7%. The Royal Society of Chemistry 2013.
- Sevrain, Charlotte M.,Haelters, Jean-Pierre,Chant?me, Aurélie,Couthon-Gourvès, Hélène,Gueguinou, Maxime,Potier-Cartereau, Marie,Vandier, Christophe,Jaffrès, Paul-Alain
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p. 4479 - 4487
(2013/08/23)
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- The dimethoxyphenylbenzyl protecting group: An alternative to the p-methoxybenzyl group for protection of carbohydrates
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A reliable reagent system for the cleavage of 4-(3,4-dimethoxyphenyl)benzyl (DMPBn) ethers under acidic conditions has been established. Treatment of DMPBn-protected mono- and pseudodisaccharides with TFA in anhydrous CH 2Cl2 and 3,4-(methylenedioxy)toluene as a cation scavenger resulted in the selective cleavage of the DMPBn ether giving the corresponding deprotected products in moderate to high yields. Examples are reported which show that allyl, benzyl, and p-bromobenzyl ethers, esters, and glycosidic linkages are stable to these reaction conditions. The selective cleavage of allyl, p-bromobenzyl, and PMB ethers in protected carbohydrates containing DMPBn ethers are also demonstrated. This work establishes the 4-(3,4-dimethoxyphenyl) benzyl ether as an effective and robust alternative to p-methoxybenzyl as a protecting group for alcohols.
- Rankin, Gregory M.,Maxwell-Cameron, Isobel,Painter, Gavin F.,Larsen, David S.
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p. 5264 - 5272
(2013/07/25)
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