Glycol-monoester intermediate

Enzyme catalysed hydrolysis of racemic epoxides is interesting from a practical point of view. This reaction is catalysed by epoxide hydrolases (EHs, EC 3.3.2.3) (Archelas and Furstoss, 1998). Mammalian EHs are the most widely studied and they are divided into five groups among which the soluble (cytosolic) epoxide hydrolases (sEH) and microsomal epoxide hydrolases (mEH) are best charactelised. The mechanism of sEH from rat starts with a nucleophilic attack by Asp333 on a carbon of the epoxide (usually the least hindered one) to form a glycol monoester intermediate which is stabilised by an oxyanion hole. A water molecule activated by His523 releases the 1,2-diol product. An... 

Many enzymes form covalent bonds with their substrates during catalysis, such as the acyl-enzyme intermediate in carboxyl ester hydrolysis (Scheme 2.1) or the glycol monoester intermediate in epoxide hydrolysis (Scheme 2.85). Despite the covalent enzyme-substrate bond, such species are metastable and should be regarded as activated intermediates . Some enzymes utilize cofactors, such as... 

SN2-Type Mechanism. A carboxylate residue - aspartate - performs a nucleophilic attack on the (usually less hindered) epoxide carbon atom by forming a covalent glycol-monoester intermediate [566-568]. The latter species can be regarded as a... 

Classification Ethoxylated hydantoin glycol monoester Definition Ester of PEG-15 DEDM hydantoin and oleic acid Uses Fiber lubricant intermediate for epoxies, urethane resins, and antistatic lubricants for the textiles industry emulsifier and emollient used in paper making and personal care prods. 

Two possible trioxo intermediates have been mentioned [0s03(0H)3 0(CH2)20H ]2, from reaction of ethylene glycol with 0s04 in base,602 and 0s03(02R), thought to be formed when monoesters 0s204(02R)2 are oxidized with H202.528... 

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