نتایج جستجو برای: chemoenzymatic
تعداد نتایج: 829 فیلتر نتایج به سال:
Chemoenzymatic reaction cascades can provide access to chiral compounds from low-cost starting materials in one pot. Here we describe one-pot asymmetric routes to tetrahydroisoquinoline alkaloids (THIAs) using the Pictet-Spenglerase norcoclaurine synthase (NCS) followed by a cyclisation, to give alkaloids with two new heterocyclic rings. These reactions operated with a high atom economy to gene...
A novel chemoenzymatic approach for the synthesis of disialyl tetrasaccharide epitopes found as the terminal oligosaccharides of GD1α, GT1aα, and GQ1bα is described. It relies on chemical manipulation of enzymatically generated trisaccharides as conformationally constrained acceptors for regioselective enzymatic α2-6-sialylation. This strategy provides a new route for easy access to disialyl te...
A chemoenzymatic synthesis of sialic acid from inexpensive N-acetyl-D-glucosamine is described. In a three-step Wittig-protection-ozonolysis strategy manno-configured aldehydes are obtained. Treatment with oxaloacetate in the presence of macrophomate synthase affords the signature α-keto-γ-hydroxy acid moiety with high diastereoselectivity.
Chemoenzymatic cascades are an important tool for advanced synthesis in chemistry. However, these often limited due to the incompatibility issue between two distinct catalysts and reactions. To address this issue, we present a simple multistep one-pot platform, which nanoparticle prepared allow chemo- biocatalytic reactions performed sequentially water Pickering emulsions. The preparation of pa...
Unnatural uridine diphosphate (UDP)-sugar donors, UDP-4-deoxy-4-fluoro-N-acetylglucosamine (4FGlcNAc) and UDP-4-deoxy-4-fluoro-N-acetylgalactosamine (4FGalNAc), were prepared using both chemical and chemoenzymatic syntheses relying on N-acetylglucosamine-1-phosphate uridylyltransferase (GlmU). The resulting unnatural UDP-sugar donors were then tested as substrates in glycosaminoglycan synthesis...
We report the development of a tandem chemoenzymatic transformation that combines alkene metathesis with enzymatic epoxidation to provide aryl epoxides. The development of this one-pot reaction required substantial protein and reaction engineering to improve both selectivity and catalytic activity. Ultimately, this reaction converts a mixture of alkenes into a single epoxide product in high ena...
Low-molecular-weight heparins (LMWHs) are carbohydrate-based anticoagulants clinically used to treat thrombotic disorders, but impurities, structural heterogeneity or functional irreversibility can limit treatment options. We report a series of synthetic LMWHs prepared by cost-effective chemoenzymatic methods. The high activity of one defined synthetic LMWH against human factor Xa (FXa) was rev...
We report the first total synthesis of trachycladines A (10 steps, 34.2% overall yield) and B (11 steps, 35.0% overall yield) by using 5-deoxy-1,2,3-tri-O-acetyl-β-D-ribofuranose as the starting material. The critical step was the SnCl4 assisted regio- and steroselective deprotection of perbenzylated 1-O-methyl-5-deoxyribofuranose. The enzyme adenylate deaminase (EC 3.5.4.6) was successfully ap...
The chemoenzymatic synthesis of heparan sulfate tetrasaccharide (1) and hexasaccharide (2) with a fluorous tag attached at the reducing end is reported. The fluorous tert-butyl dicarbonate ((F)Boc) tag did not interfere with enzymatic recognition for both elongation and specific sulfation, and flash purification was performed by standard fluorous solid-phase extraction (FSPE). Based on an (F)Bo...
(-)-Gephyrotoxin-223 was formally synthesized from chiral synthon 1 which has been chemoenzymatically synthesized in the presence of Candida Antartica lipase.
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