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Carboxylic acid anhydrides tert, alcohols

Another chromium(VI) oxidant for the preparation of uronic acids is PDC [28]. The oxidation is carried out in an aprotic solvent like dimethylformamide (DMF) or dichloromethane. Acetals and sulfides are stable under these conditions [59]. Although PDC is also used for oxidation of primary alcohols to aldehydes, use of a larger excess and/or a longer reaction time will give the carboxylic acid [60]. PDC can be further activated by addition of acetic anhydride which will shorten the reaction time [61]. If tert-butanol is added to the reaction, the terf-butyl ester can be obtained directly as shown by the conversion of 15 into 16 (O Scheme 5) [62]. Presumably, the intermediate aldehyde forms a hemiacetal with terf-butanol which is then further oxidized to the ester. [Pg.187]

Mixed anhydrides of carboxylic acids (RCO2H) and thiohydroxamic acid react with Sb(SPh)3 in the presence of O2 and water to give alcohols (ROH) via RSb(SPh)2 intermediates (Scheme 14.7) [28]. Both thioethers and sulfoxides bearing a hydrogen atoms are converted to a-fluorothioethers by treatment wifh (diefhylamino)sulfur trifluoride under Sb(.T, catalysis (Scheme 14.8) [29]. Treatment of 2-amino-6-halo nucleosides with tert-butyl nitrite in the presence of SbCls affords the 2-chloro-6-halopurine nucleosides (Scheme 14.9) [30]. [Pg.756]

Lower valent tungsten halides are a new class of deoxygenation agents, e.g. for the conversion of carbonyl or epoxy compounds into olefins . A new reagent, generated in situ from iron pentacarbonyl and a small amount of base in moist solvents, selectively and efficiently hydrogenates the ethylenic portion of a,/ -unsaturated carbonyl compounds, such as ketones or lactones, under mild conditions. Aliphatic tert. amides can be easily reduced to alcohols by alkali metals in hexa-methylphosphoramide and a protic cosolvent such as tert-butanol. Aldehydes can be obtained from acids by catalytic reduction of intermediate carboxylic alkoxyformic anhydrides . Sec. nitro compds. are converted into ketones by the joint action of a nitrite ester and NaNOg under mild, non-acidic conditions . [Pg.9]

The reagent most often used to protect the amino group of an amino acid is di-terf-butyl dicarbonate. Notice that the amino group rather than the carboxylate group of the amino acid reacts with di-ferf-butyl dicarbonate because the amino group is a better nucleophile. When glycine reacts with d/-terf-butyl dicarbonate in an addition-elimination reaction, the anhydride bond breaks, forming CO2 and tert-butyl alcohol. [Pg.1077]


See other pages where Carboxylic acid anhydrides tert, alcohols is mentioned: [Pg.294]    [Pg.294]    [Pg.492]    [Pg.26]    [Pg.188]    [Pg.744]    [Pg.210]    [Pg.587]    [Pg.674]    [Pg.183]    [Pg.239]   
See also in sourсe #XX -- [ Pg.18 ]




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Alcohols carboxylation

Carboxyl anhydride

Carboxylic acid anhydrides

Carboxylic acid anhydrides alcohols)

Carboxylic acids acid anhydrides

Carboxylic acids alcohol)

Carboxylic anhydrides

Tert-Alcohols

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