Two-step synthesis of the immunogenic bacterial glycolipid BbGL1.
Ontology highlight
ABSTRACT:
SUBMITTER: Kulkarni SS
PROVIDER: S-EPMC4492534 | biostudies-literature | 2008 Nov
REPOSITORIES: biostudies-literature
Publications
Two-step synthesis of the immunogenic bacterial glycolipid BbGL1.
Kulkarni Suvarn S SS Gervay-Hague Jacquelyn J
Organic letters 20080918 21
Chemical synthesis of a bacterial glycolipid BbGL1 is reported in two steps starting from per-O-TMS D-galactose. The key features are glycosyl iodide mediated beta-stereoselective glycosylation in the absence of neighboring group participation and regioselective acylation. ...[more]
Similar Datasets
Project description:Isoprenoids comprise a large class of chemicals of significant interest due to their diverse properties. Biological production of isoprenoids is considered to be the most efficient way for their large-scale production. Isoprenoid biosynthesis has thus far been dependent on pathways inextricably linked to glucose metabolism. These pathways suffer from inherent limitations due to their length, complex regulation, and extensive cofactor requirements. Here, we present a synthetic isoprenoid pathway that aims to overcome these limitations. This isopentenol utilization pathway (IUP) can produce isopentenyl diphosphate or dimethylallyl diphosphate, the main precursors to isoprenoid synthesis, through sequential phosphorylation of isopentenol isomers isoprenol or prenol. After identifying suitable enzymes and constructing the pathway, we attempted to probe the limits of the IUP for producing various isoprenoid downstream products. The IUP flux exceeded the capacity of almost all downstream pathways tested and was competitive with the highest isoprenoid fluxes reported.
| S-EPMC6329939 | biostudies-literature
Project description:Porphyrin synthesis under solvent-free conditions represents the "greening" of a traditional synthesis that normally requires large amounts of organic solvent, and has hindered the industrial-scale synthesis of this useful class of molecules. We have found that the four-fold acid-catalysed condensation of aldehyde and pyrrole to yield a tetra-substituted porphyrin is possible through mechanochemical techniques, without a solvent present. This represents one of the still-rare examples of carbon-carbon bond formation by mechanochemistry. Specifically, upon grinding equimolar amounts of pyrrole and benzaldehyde in the presence of an acid catalyst, cyclization takes place to give reduced porphyrin precursors (reversible), which upon oxidation form tetraphenylporphyrin (TPP). The approach has been found to be suitable for the synthesis of a variety of meso-tetrasubstituted porphyrins. Oxidation can occur either by using an oxidizing agent in solution, to give yields comparable to those published for traditional methods of porphyrin synthesis, or through mechanochemical means resulting in a two-step mechanochemical synthesis to give slightly lower yields that are still being optimized. We are also working on "green" methods of porphyrin isolation, including entrainment sublimation, which would hopefully further reduce the need for large amounts of organic solvent. These results hold promise for the development of mechanochemical synthetic protocols for porphyrins and related classes of compounds.
| S-EPMC4238103 | biostudies-literature
Project description:Lipoteichoic acid (LTA) is an important cell wall polymer in gram-positive bacteria and often consists a polyglycerolphosphate backbone chain that is linked to the membrane by a glycolipid. In Listeria monocytogenes this glycolipid is Gal-Glc-DAG or Gal-Ptd-6Glc-DAG. Using a bioinformatics approach, we have identified L. monocytogenes genes predicted to be involved in glycolipid (lmo2555 and lmo2554) and LTA backbone (lmo0644 and lmo0927) synthesis. LTA and glycolipid analysis of wild-type and mutant strains confirmed the function of Lmo2555 and Lmo2554 as glycosyltransferases required for the formation of Glc-DAG and Gal-Glc-DAG. Deletion of a third gene, lmo2553, located in the same operon resulted in the production of LTA with an altered structure. lmo0927 and lmo0644 encode proteins with high similarity to the staphylococcal LTA synthase LtaS, which is responsible for polyglycerolphosphate backbone synthesis. We show that both proteins are involved in LTA synthesis. Our data support a model whereby Lmo0644 acts as an LTA primase LtaP and transfers the initial glycerolphosphate onto the glycolipid anchor, and Lmo0927 functions as LTA synthase LtaS, which extends the glycerolphosphate backbone chain. Inactivation of LtaS leads to severe growth and cell division defects, underscoring the pivotal role of LTA in this gram-positive pathogen.
| S-EPMC2764115 | biostudies-literature
Project description:The direct nonpeptidic macrocycle synthesis of ?-isocyano-?-amines via the classical Ugi four-component reaction (U-4CR) is introduced. Herein an efficient and flexible two-step procedure to complex macrocycles is reported. In the first step, the reaction between unprotected diamines and isocyanocarboxylic acids gives high diversity of unprecedented building blocks in high yield. In the next step, the ?-isocyano-?-amines undergo a U-4CR with high diversity of aldehydes and carboxylic acids in a one-pot procedure. This synthetic approach is short and efficient and leads to a wide range of macrocycles with different ring sizes.
| S-EPMC5799868 | biostudies-literature
Project description:An operationally simple, one-pot, two-step cascade method has been developed to afford quinazolino[1,2,3]triazolo[1,4]benzodiazepines. This unique, atom-economical transformation engages five reactive centers (amide, aniline, carbonyl, azide, and alkyne) and employs environmentally benign iodine as a catalyst. The method proceeds via sequential quinazolinone-forming condensation and intramolecular azide-alkyne 1,3-dipolar cycloaddition reactions. Substrate scope, multicomponent examples, and mechanistic insights are discussed.
| S-EPMC3486955 | biostudies-literature
Project description:The design and synthesis of head-to-tail linked artificial macrocycles using the Ugi-reaction has been developed. This synthetic approach of just two steps is unprecedented, short, efficient and works over a wide range of medium (8-11) and macrocyclic (?12) loop sizes. The substrate scope and functional group tolerance is exceptional. Using this approach, we have synthesized 39 novel macrocycles by two or even one single synthetic operation. The properties of our macrocycles are discussed with respect to their potential to bind to biological targets that are not druggable by conventional, drug-like compounds. As an application of these artificial macrocycles we highlight potent p53-MDM2 antagonism.
| S-EPMC5660312 | biostudies-literature
Project description:Rare sugars offer a plethora of applications in the pharmaceutical, medicinal, and industries, as well as in synthetic chemistry. However, studies of rare sugars have been hampered by their relative scarcity. In this work, we describe a two-step strategy to efficiently and conveniently prepare 6-deoxy-L-psicose from L-rhamnose. In the first reaction step, the isomerization of L-rhamnose (6-deoxy-L-mannose) to L-rhamnulose (6-deoxy-L-fructose) catalyzed by L-rhamnose isomerase (RhaI), and the epimerization of L-rhamnulose to 6-deoxy-L-psicose catalyzed by D-tagatose 3-epimerase (DTE) were coupled with selective phosphorylation reaction by fructose kinase from human (HK), which selectively phosphorylate 6-deoxy-L-psicose at C-1 position. 6-deoxy-L-psicose 1-phosphate was purified by a silver nitrate precipitation method. In the second step, the phosphate group of the 6-deoxy-L-sorbose 1-phosphate was hydrolyzed with acid phosphatase (AphA) to produce 6-deoxy-L-psicose in 81% yield with respect to L-rhamnose. This method allows that the 6-deoxy-L-psicose to be obtained from readily available starting materials with high purity and without having to undergo isomer separation.
| S-EPMC4990140 | biostudies-literature
Project description:A two-step synthesis of solasodine pivalate from diosgenin pivalate is described. The key transformation involves the reaction of diosgenin pivalate with benzyl carbamate (CbzNH?) promoted by TMSOTf. During the reaction the F-ring of the spiroketal moiety opens up with a simultaneous introduction of a Cbz-protected amino group in position 26. A one-pot deprotection of 26-amine with AcBr/BuOH followed by the N-cyclization affords solasodine pivalate in 45% overall yield.
| S-EPMC6471385 | biostudies-literature
Project description:Organohydrogels with distinct antifreezing and antidehydration properties have aroused great interest among researchers, and various organohydrogels and organohydrogel-based applications have emerged recently. There are two popular synthesis strategies to prepare these antifreezing and antidehydration organohydrogels: the in-situ gelling and the solvent displacement strategies. Although both strategies have been widely applied, there is a lack of comparative study of these two strategies. In this work, to elucidate the comparative advantages of the two synthesis strategies, we studied and compared the mechanical and environmental tolerant properties of the organohydrogels synthesized from both strategies. The glycerol-based and ethylene glycol-based chemical polyacrylamide (PAAm) organohydrogel and the glycerol-based physical gelatin organohydrogel were synthesized and studied. Through the comparative study, we have found that the organohydrogels from different strategies with the same dispersion medium showed similar antifreezing and antidehydration properties but different mechanical properties. The mechanical properties of these organohydrogels are influenced by two opposite factors for each strategy: the enhanced physical interactions induced strengthening and solvent effect or swelling induced weakening. We hope this study may provide a better understanding of the synthesis strategies of organohydrogels and provide a valuable guide to choose the suitable synthesis strategy for each application.
| S-EPMC7696091 | biostudies-literature
Project description:A two-step procedure for preparing 2-alkyl-1,3-butadienes is described. Cuprate addition to commercially available 1,4-dibromo-2-butene yields 3-alkyl-4-bromo-1-butene, a product of S(N)2' substitution. Dehydrohalogenation gives 2-alkyl-1,3-butadienes.
| S-EPMC2764119 | biostudies-literature