- Exploitation of a Candida antarctica lipase B-catalysed in situ carboxylic acid activation method for the synthesis of acetanilides
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An efficient biocatalytic method has been developed which provides acetanilides in good yields which are otherwise inaccessible using Candida antarctica lipase B. The process exploits the enzyme-catalysed synthesis of an acyl donor and its in situ reaction with anilines. The method is potentially useful for the synthesis of bulky acetanilides since amide formation occurs through an active site-independent step.
- Lal, Samridhi,Snape, Timothy J.
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- Chemoenzymatic synthesis of a glycolipid library and elucidation of the antigenic epitope for construction of a vaccine against lyme disease
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Lyme disease (LD) is the most common tick-borne disease in Europe, North America, and Asia. The etiologic agents of LD are spirochetes of the group Borrelia burgdorferi sensu lato, which possess a lipid content of 25-30% of the dry weight. The major glycolipid cholesteryl 6-O-acyl-ss-D- galactopyranoside (ACGal), present in B. burgdorferi sensu stricto, B. afzelii, and B. garinii, is a specific and highly prevalent antigen frequently recognized by antibodies in late-stage LD. Here we report a convenient route for the chemical synthesis of ACGal by employing a combination of chemical synthesis steps with enzymatic transformations. This synthesized molecule was compared with bacterial extracts by immunoblots with patient sera, confirming the preserved antigenicity. Next, a glycolipid library derived from the native molecules with variations in the fatty acyl moiety and derivatives in which the cholesterol has been replaced was designed and synthesized. The chemical structures were confirmed by lD and 2D NMR spectroscopy and mass spectrometry. The native and synthetic glycolipids were utilized in immunoblots to determine the epitope recognized by antibodies in patient sera. By this method we could demonstrate that galactose, cholesterol, and a fatty acid with a minimal chain length of four carbon atoms comprises the essential structure for recognition by antibodies. Finally, this finding allowed the synthesis of a functionalized ACGal with an ω-mercapto group at the fatty acid and a facile protection and deprotection strategy. This antigenic hapten can be conjugated to a carrier protein to effect immunization against Lyme disease.
- Stuebs, Gunthard,Rupp, Bernd,Schumann, Ralf R.,Schroeder, Nicolas W. J.,Rademann, Joerg
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supporting information; experimental part
p. 3536 - 3544
(2010/07/06)
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- Te-1-acylmethyl and Te-1-iminoalkyl telluroesters: Synthesis and thermolysis leading to 1,3-diketones and O-alkenyl and O-imino esters
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A series of Te-1-acylmethyl carbotelluroates was prepared in good isolated yields from the reaction of potassium carbotelluroates with -haloketones in acetonitrile. Thermolysis of the telluroesters afforded vinyl esters in 20-50% yields, while treatment of the carbotellurorates with potassium t-butanolate led to 1,3-diketones in 30-75% yields with the liberation of black tellurium. The reaction of potassium carbotelluroates with -haloaceto oximes gave O-acyl oximes in 50-70% yields via Te-1-iminomethylcarbotelluroates. Copyright Taylor & Francis Group.
- Nakaiida, Shoho,Kato, Shinzi,Niyomura, Osamu,Ishida, Masaru,Ando, Fumio,Koketsu, Jugo
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experimental part
p. 930 - 946
(2010/08/04)
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- Acylation and alkoxycarbonylation of oximes through an enzymatic oximolysis reaction
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Ketone or benzaldehyde O-acyloximes and O-(tert-butoxycarbonyl)oximes can be prepared by reaction of oximes with vinyl esters and di-tert-butyl dicarbonate, respectively, using lipases as biocatalysts.
- Menendez,Gotor
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