Search results
Results from the WOW.Com Content Network
The Grignard reaction between phenylmagnesium bromide (1) and carbon dioxide in the form of dry ice gives the conjugate base of benzoic acid (2). The desired product, benzoic acid (3), is obtained by the following work-up: [2] Synthesis of benzoic acid with work-up step in red.
Bogdanovic and Bolte identified the nature and mode of action of the active species in some classical McMurry systems, [5] and an overview of proposed reaction mechanisms has been published. [3] It is of note that titanium dioxide is not generally a product of the coupling reaction.
Acid–base extraction is a subclass of liquid–liquid extractions and involves the separation of chemical species from other acidic or basic compounds. [1] It is typically performed during the work-up step following a chemical synthesis to purify crude compounds [2] and results in the product being largely free of acidic or basic impurities.
2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (or DDQ) is the chemical reagent with formula C 6 Cl 2 (CN) 2 O 2. This oxidant is useful for the dehydrogenation of alcohols, [3] phenols, [4] and steroid ketones. [5] DDQ decomposes in water, but is stable in aqueous mineral acid. [6]
4 HCrO 4 − + 3 RCH 2 OH + 16 H + + 11 H 2 O → 4 [Cr(H 2 O) 6] 3+ + 3 RCOOH. The inorganic products are green, characteristic of chromium(III) aquo complexes. [2] Like many other oxidations of alcohols by metal oxides, the reaction proceeds via the formation of a mixed chromate ester: [3] [4] These esters have the formula CrO 3 (OCH 2 R) −
For example, nonylmagnesium bromide reacts with methyl p-chlorobenzoate to give p-nonylbenzoic acid, in the presence of Tris(acetylacetonato)iron(III) (Fe(acac) 3), after workup with NaOH to hydrolyze the ester, shown as follows. Without the Fe(acac) 3, the Grignard reagent would attack the ester group over the aryl halide. [21]
The mechanism of reductions of aldehydes and ketones by samarium(II) iodide is based primarily on mechanisms elucidated for similar one-electron reducing agents. [12] Upon single-electron transfer, a ketyl dimer iv forms. In the absence of protic solvent, this dimer collapses to form 1,2-diols.
After workup, recrystallization from H 2 O gave, in two crops, 0.69 g (66%) of pure guanosine, which was homogeneous (R f 0.3) in the partition system n-butanol:acetic acid:H 2 O (5:1:4) and whose 1 H NMR spectrum at 400 MHz in D 2 O showed only traces of the undesired N 7-anomer of guanosine.