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formose reaction
The formose reaction, discovered by Aleksandr Butlerov in 1861,〔A. Boutlerow (1861) ("Formation synthétique d'une substance sucrée" ) (Synthetic formation of a sugary substance), ''Comptes rendus'' ... 53: 145-147. Reprinted in German as: Butlerow, A. (1861), ("Bildung einer zuckerartigen Substanz durch Synthese" ) (Formation of a sugar-like substance by synthesis), Justus Liebigs ''Annalen der Chemie'', 120: 295-298.〕 involves the formation of sugars from formaldehyde. Formose is a portmanteau of formaldehyde and aldose.
==Reaction and mechanism==
The reaction is catalyzed by a base and a divalent metal such as calcium. The intermediary steps taking place are aldol reactions, reverse Aldol reactions, and aldose-ketose isomerizations. Intermediates are glycolaldehyde, glyceraldehyde, dihydroxyacetone, and tetrose sugars. In 1959, Breslow proposed a mechanism for the reaction, consisting of the following steps:
The reaction begins with two formaldehyde molecules condensing to make glycolaldehyde 1 which further reacts in an aldol reaction with another equivalent of formaldehyde to make glyceraldehyde 2. An aldose-ketose isomerization of 2 forms dihydroxyacetone 3 which can react with 1 to form ribulose 4, and through another isomerization ribose 5. Molecule 3 also can react with formaldehyde to produce tetrulose 6 and then aldoltetrose 7. Molecule 7 can split into 2 in a retro-aldol reaction.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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