- Exploring the Promiscuous Enzymatic Activation of Unnatural Polyketide Extender Units in Vitro and in Vivo for Monensin Biosynthesis
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The incorporation of new-to-nature extender units into polyketide synthesis is an important source for diversity yet is restricted by limited availability of suitably activated building blocks in vivo. We here describe a straightforward workflow for the biogenic activation of commercially available new-to-nature extender units. Firstly, the substrate scope of a highly flexible malonyl co-enzyme A synthetase from Streptomyces cinnamonensis was characterized. The results were matched by in vivo experiments in which the said extender units were accepted by both the polyketide synthase and the accessory enzymes of the monensin biosynthetic pathway. The experiments gave rise to a series of predictable monensin derivatives by the exploitation of the innate substrate promiscuity of an acyltransferase and downstream enzyme functions.
- Grote, Marius,Schulz, Frank
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p. 1183 - 1189
(2019/03/11)
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- Preparation method of ticarcillin sodium key intermediate, namely 2-(3-thienyl) malonic acid
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The invention discloses a preparation method of a ticarcillin sodium key intermediate, namely 2-(3-thienyl) malonic acid, and belongs to the technical field of synthesis of ticarcillin sodium key intermediates. The key points of the technical scheme adopted by the invention are the reaction equation is as shown in the description. The preparation method provided by the invention has the outstanding characteristics that no high temperature exists in reaction conditions, the production danger is greatly reduced, the product yield is higher, and the production steps are simple to operate.
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Paragraph 0019; 0022; 0023; 0026; 0027; 0030
(2018/04/03)
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- Process for producing 3-thienylmalonic acid
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A process for preparing 3-thienyl malonic acid, comprising treatment of a 3-thienyl cyanoacetate of formula (III): STR1 where R1 represents an aryl or alkyl group, with at least a molar excess of an alkali metal hydroxide.
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- Chemical process
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An improved process for the preparation of 3-substituted thiophenes. The thiophenes are useful for the preparation of penicillins and cephalosporins. The process is for the preparation of a thiophene of formula (I): STR1 where R1 represents a carboxylic acid group, or an ester or amide thereof or a nitrile group; R2 represents a group suitable for use as an α-substituent in the side-chain of a penicillin or cephalosporin; which comprises treating under basic conditions a compound of formula (II): STR2 wherein X represents halogen or optionally functionalized hydroxyl, Y represents halogen, hydroxyl, or alkoxy; with a source of nucleophilic sulphur ionically bound to a polymeric support.
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