Diazo

This MedLibrary.org supplementary page on Diazo is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:

Diazo

Diazo refers to a type of organic compound that has two linked nitrogen (azo) compounds. The general formula is R2C=N2. The simplest example of a diazo compound is diazomethane. The electronic structure of diazo compounds involves a positive charge on the central nitrogen and negative charge distributed between the terminal nitrogen and the carbon. Some of the most stable diazo compounds are α-diazoketones and α-diazoesters since the negative charge is delocalized into the carbonyl. In contrast, most alkyldiazo compounds are explosive.

Diazo compounds are used as precursors to carbenes, which are generated by thermolysis or photolysis, for example in the Wolff rearrangement. They are also used in transition metal-catalyzed cyclopropanation reactions for example in a synthesis of tranylcypromine 1 2 in scheme 1 [1] in which the sodium salt of benzaldehyde tosyl hydrazone is converted to a rhodium metal carbene through the diazo intermediate.

Scheme 1. Diazo cyclopropanation

An unusual biomolecule sporting a diazo group was synthesized in 2006 with in its final stage the reaction of a carbonyl group with the hydrazine 1,2-bis(tert-butyldimethylsilyl)hydrazine to the hydrazone followed by reaction with the periodinane difluoroiodobenzene to the diazo compound 3 4

Kinamycin C Synthesis

Another commercially relevant diazocompound is Ethyl diazoacetate N2CHCOOEt.

A group of isomeric compounds with similar properties are the diazirines, where the carbon and two nitrogens are linked as a ring.

See also

References

  1. ^ Catalytic Cyclopropanation of Alkenes Using Diazo Compounds Generated in Situ. A Novel Route to 2-Arylcyclopropylamines Varinder K. Aggarwal, Javier de Vicente, and Roger V. Bonnert Org. Lett.; 2001; 3(17) pp 2785 - 2788; (Letter) Abstract
  2. ^ Notes: benzaldehyde reacts with p-toluenesulfonyl hydrazide to the hydrazone.Its sodium salt reacts with N-Vinylphthalimide and rhodium acetate, a phase transfer catalyst and PTC to the cyclopropane. The phthalimide group is removed by hydrazine. The product is the cis isomer but by switching to ClFeTPP the amount of trans isomer increases to 33%
  3. ^ Total Synthesis of the Diazobenzofluorene Antibiotic (-)-Kinamycin C1 Xiaoguang Lei and John A. Porco, Jr. J. Am. Chem. Soc.; 2006; ASAP Web Release Date: 26-Oct-2006; (Communication) doi: 10.1021/ja066621v
  4. ^ Elusive Natural Product Is Synthesized Stu Borman Chemical & Engineering News October 31, 2006 Link.

Wikipedia content modification information:

  • This page was last modified on 11 September 2008, at 09:37.

Wikipedia Authorship and Review

Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.

Wikipedia Usage Guidelines

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Diazo".

The URL for this specific entry is:

All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.