From glycols

Regioselectivity of C—C double bond formation can also be achieved in the reductiv or oxidative elimination of two functional groups from adjacent carbon atoms. Well estab llshed methods in synthesis include the reductive cleavage of cyclic thionocarbonates derivec from glycols (E.J. Corey, 1968 C W. Hartmann, 1972), the reduction of epoxides with Zn/Nal or of dihalides with metals, organometallic compounds, or Nal/acetone (seep.lS6f), and the oxidative decarboxylation of 1,2-dicarboxylic acids (C.A. Grob, 1958 S. Masamune, 1966 R.A. Sheldon, 1972) or their r-butyl peresters (E.N. Cain, 1969). 

Polymerization of an AB monomer is illustrated by the polyester formed from glycolic acid. The repeat unit in this polymer has the structure... 

Hydroxyriboflavin. This compound [86120-61 -8] (26) was isolated as a green coen2yme of the NADH dehydrogenase from Peptostreptococms elsdenii and also from glycolate oxidase of porcine Hver. It is not fluorescent, and its stmcture was estabflshed by synthesis (106). The 5 -monophosphate serves as a cofactor for glycolate oxidase from pig Hver. 

Polyester Resins. Reinforced polyester resins are thermosets based on unsaturated polyesters from glycols and dibasic acids, either or both of which contain reactive double bonds. The ratio of saturated to unsaturated components controls the degree of cross-linking and thus the rigidity of the product (see Polyesters, unsaturated). Typically, the glycols and acids are esterified until a viscous Hquid results, to which an inhibitor is added to prevent premature gelation. Addition of the monomer, usually styrene, reduces the viscosity to an easily workable level. 

COREY - WINTER Alkene synthesis Alkene synthesis from glycols via cyclic t, 2-lhionocartx)nates... 

KUHN - WINTERSTEIN Olefinatlon OMin formation from glycols by means of P2 te... 

Scheme 1-10. Formation of ketals from glycols and 2-substituted cyclohexanone 22.

Scheme 4.34 Preparation of cyclic sulfites from glycols.

In the free state and in their reactions the simple aldehydes and ketones are in general known only in the aldo- and keto-forms. Erlen-meyer suggested the rule that the isomeric enol-structure, which might be formed at first in the production of acetaldehyde from glycol, for example, should in no case be capable of existence. 

Serine has been prepared by the Strecker method from glycol-aldehyde 1 and from ethoxyacetaldehyde,2 3 by the condensation of ethyl formate with ethyl hippurate followed by reduction and hydrolysis,4 5 from the reaction product of chloromethyl ether with ethyl sodium phthalimidomalonate,6 and by amination of a-bromo-/3-methoxypropionic acid with subsequent demethyla-tion.7... 

This mixture is the Huang Minion modification of the Wolff Kishner reaction. In the editor s experience it often leaps from the flask with sudden gas evolution. In addition to the expected nitrogen, at the operating temperature of around 200°C it is uncomfortably near the temperature of hydrogen evolution from glycol decomposition. The reduction proceeds much cooler in dimethyl sulfoxide or some of the alkoxyethanols as solvent. 

Cramer, the discoverer, showed that, when serine was treated with nitrous acid, it was converted into glyceric acid, and he recognised it as an aminolactic acid. It was regarded as a-amino-jS-oxypropionic acid, but this was only definitely proved when it was synthesised by Fischer and Leuchs in 1902 from glycollic aldehyde, hydrogen C anide and ammonia, which is the first instance of the employment of Strecker s method to build up oxyamino acids from oxyaldehydes. 

CH 20. CHOCH(CH OH)CHOH. CHOH.CHOHj mw 386.36 / form, cryst, mp 131 8u- It was prepd from glycol, glucose, water and emulsin (Ref 4)... 

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