Everything about The Arndt-eistert Synthesis totally explained
The
Arndt-Eistert synthesis is a series of
chemical reactions designed to convert a
carboxylic acid to a higher carboxylic acid homologue (ie. contains one additional carbon atom) and is considered a
homologization process. Named for the German chemists
Fritz Arndt (
1885-
1969) and
Bernd Eistert (
1902-
1978), Arndt-Eistert synthesis is a popular method of producing
beta-amino-acids from
alpha-amino-acids.
Acid chlorides react with
diazomethane to give
diazoketones. In the presence of a
nucleophile (
water) and a metal catalyst (
Ag2O), diazoketones will form the desired acid homologue.
While the classic Arndt-Eistert synthesis uses
thionyl chloride to convert the starting acid to an
acid chloride, any procedure can be used that will generate an acid chloride.
Diazoketones are typically generated as described here, but other methods such as diazo-group transfer can also apply.
Since diazomethane is toxic and violently explosive, many safer alternatives have been developed, such as the usage of
ynolates or
trimethylsilyldiazomethane.
Reaction mechanism
The key step in the Arndt-Eistert synthesis is the metal-catalyzed
Wolff rearrangement of the diazoketone to form a
ketene.
Heat, light,
platinum,
silver, and
copper salts will also catalyze the Wolff rearrangement to produce the desired acid homologue.
Variations
Newman-Beal modification
The addition of
triethylamine to the diazomethane solution will avoid the formation of α-chloromethylketone side-products.
Further Information
Get more info on 'Arndt-eistert Synthesis'.
|
External Link Exchanges
Do you know how hard it is to get a link from a large encyclopaedia? Well we're different and will prove it. To get a link from us just add the following HTML to your site on a relevant page:
<a href="http://arndt-eistert_synthesis.totallyexplained.com">Arndt-Eistert synthesis Totally Explained</a>
Then simply click through this link from your web page. Our crawlers will verify your link, extract the title of your web page and instantly add a link back to it. If you like you can remove the words Totally Explained and embed the link in article text.
As long as your link remains in place, we'll keep our link to you right here. Please play fair - our crawlers are watching. Your site must be closely related to this one's topic. Any kind of spamming, dubious practises or removing the link will result in your link from us being dropped and, potentially, your whole site being banned. |
