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Alpha-hydroxy ketones are also called acyloins. [1] They are commonly formed by condensation or reductive coupling of two carbonyl (C=O) compounds or oxidation of ketones. The simplest such compound is hydroxyacetone. If the alcohol is primary, alpha-hydroxy ketones give a positive Fehling's test. Beta-hydroxy ketones are a type of aldol.
Ketogenesis pathway. The three ketone bodies (acetoacetate, acetone, and beta-hydroxy-butyrate) are marked within orange boxes. Ketogenesis is the biochemical process through which organisms produce ketone bodies by breaking down fatty acids and ketogenic amino acids.
The concentration of ketone bodies in blood is maintained around 1 mg/dL. Their excretion in urine is very low and undetectable by routine urine tests (Rothera's test). [18] When the rate of synthesis of ketone bodies exceeds the rate of utilization, their concentration in blood increases; this is known as ketonemia.
Ketone bodies that commonly appear in the urine when fats are burned for energy are acetoacetate and beta-hydroxybutyric acid. Acetone is also produced and is expired by the lungs. [ 1 ] Normally, the urine should not contain a noticeable concentration of ketones to give a positive reading.
α-hydroxy ketones give positive Tollens' and Fehling's test. Some acyloins rearrange with positions swapped under the influence of base in the Lobry–de Bruyn–van Ekenstein transformation A similar reaction is the so-called Voigt amination [ 6 ] where an acyloin reacts with a primary amine and phosphorus pentoxide to an α-keto amine: [ 7 ]
Beta-hydroxy ketones (2 C, 2 P) H. Hydroxyquinones (5 C, 2 P) T. Tropolones (11 P) Pages in category "Hydroxyketones"
β-hydroxybutyrate (the conjugate base of β-hydroxybutyric acid, drawn above) despite chemically containing a carboxylate group instead of a ketone, is the principal "ketone body" in diabetic ketoacidosis. DKA is common in type 1 diabetes as this form of diabetes is associated with an absolute lack of insulin production by the islets of ...
The Evans–Tishchenko reaction is the diastereoselective reduction of β-hydroxy ketones to the corresponding 1,3-anti diol monoesters. The reaction employs a Lewis acid, often samarium iodide, and an aldehyde. It was first described in 1990 by David A. Evans and Amir Hoveyda, as a development of the well-known Tishchenko reaction discovered ...