Imide

<h2 id="examples">Examples</h2>
<p>Simple example is diacetamide with the formula HN(COCH3)2, formally the diacetylated derivative of ammonia. Commonly encountered imides, however, are cyclic, being derived from <a href="/facts/Dicarboxylic_acid/d69GkIAc">dicarboxylic acids</a>.  A common example is <a href="/facts/Succinimide/v3eRV6hY">succinimide</a> derived from <a href="/facts/Succinic_acid/v3KJqrQC">succinic acid</a> and ammonia.  The names of these cyclic imides reflect the parent acid.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> 
</p><p>Many imides are derived from primary <a href="/facts/Amine/JvfYJfP6">amines</a> as opposed to ammonia.  These are indicated by <i>N</i>-substituent in the prefix. For example, N-ethylsuccinimide is derived from succinic acid and <a href="/facts/Ethylamine/Tj9X5ESb">ethylamine</a>. 
</p>
Cyclic imides.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a><table><tbody><tr><th>n</th><th>Common name</th><th>Systematic name</th><th>Structure</th><th>PubChem</th><th>Parent acid</th><th>Structure</th></tr><tr><td>2</td><td><a href="/facts/Succinimide/v3eRV6hY">Succinimide</a></td><td>Pyrrolidine-2,5-dione</td><td></td><td><a href="https://pubchem.ncbi.nlm.nih.gov/compound/11439">11439</a></td><td><a href="/facts/Succinic_acid/v3KJqrQC">Succinic acid</a></td><td></td></tr><tr><td>2, unsaturated, cis carbon-carbon double bonds</td><td><a href="/facts/Maleimide/96kezkLr">Maleimide</a></td><td>Pyrrole-2,5-dione</td><td></td><td><a href="https://pubchem.ncbi.nlm.nih.gov/compound/10935">10935</a></td><td><a href="/facts/Maleic_acid/cdMjU0Lb">Maleic acid</a></td><td></td></tr><tr><td>3</td><td><a href="/facts/Glutarimide/IPKf8MVk">Glutarimide</a></td><td>Piperidine-2,6-dione</td><td></td><td><a href="https://pubchem.ncbi.nlm.nih.gov/compound/70726">70726</a></td><td><a href="/facts/Glutaric_acid/yDCNYN6s">Glutaric acid</a></td><td></td></tr><tr><td>6</td><td><a href="/facts/Phthalimide/89QnMhAE">Phthalimide</a></td><td>Isoindole-1,3-dione</td><td></td><td><a href="https://pubchem.ncbi.nlm.nih.gov/compound/6809">6809</a></td><td><a href="/facts/Phthalic_acid/bh1keeDw">Phthalic acid</a></td><td></td></tr></tbody></table>
<h2 id="properties">Properties</h2>
<p>Being highly polar, imides exhibit good solubility in polar organic solvents. Unlike the structurally related acid anhydrides, they resist hydrolysis and some can even be <a href="/facts/Recrystallization_(chemistry)/4jYdB7YM">recrystallized</a> from boiling water.  
</p><p>The N–H center for imides derived from ammonia is acidic and can participate in <a href="/facts/Hydrogen_bond/85V86IIg">hydrogen bonding</a>. The N-H group is weakly acidic as indicated in the case of maleimide, with a <a href="/facts/PKa/t4YyRtKC">pKa</a> estimated at 10.<a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
<h2 id="occurrence-and-applications">Occurrence and applications</h2>
<p>Many high strength or electrically conductive polymers contain imide subunits, i.e., the <a href="/facts/Polyimide/4nW9HVKF">polyimides</a>. One example is <a href="/facts/Kapton/NwTwLMeE">Kapton</a> where the repeat unit consists of two imide groups derived from aromatic tetracarboxylic acids.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> Another example of polyimides is the polyglutarimide typically made from polymethylmethacrylate (PMMA) and ammonia or a primary amine by aminolysis and cyclization of the PMMA at high temperature and pressure, typically in an extruder. This technique is called reactive extrusion. A commercial polyglutarimide product based on the methylamine derivative of PMMA, called Kamax, was produced by the Rohm and Haas company. The toughness of these materials reflects the rigidity of the imide functional group.
</p><p>Interest in the bioactivity of imide-containing compounds was sparked by the early discovery of the high bioactivity of the <a href="/facts/Cycloheximide/n4vb6su6">Cycloheximide</a> as an inhibitor of protein biosynthesis in certain organisms. <a href="/facts/Thalidomide/FWQGuD2A">Thalidomide</a>, famous for its adverse effects, is one result of this research. A number of <a href="/facts/Fungicide/c1twQBYo">fungicides</a> and herbicides contain the imide functionality. Examples include <a href="/facts/Captan/4ABHb3Ck">Captan</a>, which is considered carcinogenic under some conditions, and <a href="/facts/Procymidone/soPD7T1U">Procymidone</a>.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a>
</p>

<p>In the 21st century new interest arose in thalidomide's immunomodulatory effects, leading to the class of immunomodulators known as <a href="/facts/Immunomodulatory_imide_drug/jJWjy4Uo">immunomodulatory imide drugs</a> (IMiDs).
</p>
<h2 id="preparation">Preparation</h2>
<p>Most common imides are prepared by heating dicarboxylic acids or their anhydrides and <a href="/facts/Ammonia/MtLtJFtz">ammonia</a> or primary <a href="/facts/Amine/JvfYJfP6">amines</a>. The result is a <a href="/facts/Condensation_reaction/wMG0F6La">condensation reaction</a>:<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a>
</p>
(RCO)2O + R′NH2  →  (RCO)2NR′ + H2O
<p>These reactions proceed via the intermediacy of <a href="/facts/Amide/C6kCzYEA">amides</a>. The intramolecular reaction of a carboxylic acid with an amide is far faster than the intermolecular reaction, which is rarely observed.
</p><p>They may also be produced via the oxidation of <a href="/facts/Amide/C6kCzYEA">amides</a>, particularly when starting from <a href="/facts/Lactam/2VVAzXVX">lactams</a>.<a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a>
</p>
R(CO)NHCH2R'  + 2 [O] →  R(CO)N(CO)R'  +  H2O
<p>Certain imides can also be prepared in the isoimide-to-imide <a href="/facts/Mumm_rearrangement/tLPKIcJk">Mumm rearrangement</a>.
</p>
<h2 id="reactions">Reactions</h2>
<p>For imides derived from ammonia, the N–H center is weakly acidic. Thus, alkali metal salts of imides can be prepared by conventional bases such as potassium hydroxide. The conjugate base of phthalimide is <a href="/facts/Potassium_phthalimide/FD4NIKjq">potassium phthalimide</a>. These anion can be alkylated to give <i>N</i>-alkylimides, which in turn can be degraded to release the primary amine. Strong nucleophiles, such as potassium hydroxide or <a href="/facts/Hydrazine/G7P5ITzU">hydrazine</a> are used in the release step.
</p><p>Treatment of imides with halogens and base gives the <i>N</i>-halo derivatives. Examples that are useful in <a href="/facts/Organic_synthesis/aprl6Iq7">organic synthesis</a> are <a href="/facts/N-Chlorosuccinimide/J7XhLHol"><i>N</i>-chlorosuccinimide</a> and <i>N</i>-<a href="/facts/Bromosuccinimide/kcW9F19d">bromosuccinimide</a>, which respectively serve as sources of "Cl+" and "Br+" in <a href="/facts/Organic_synthesis/aprl6Iq7">organic synthesis</a>.
</p>
<h2 id="isoimides">Isoimides</h2>
<p>Isoimides are isomeric with imides and have the formula RC(O)OC(NR′)R″. They are often intermediates that convert to the more symmetrical imides.  Isoimides upon heating rearrange to imides:<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a>
</p>
RC(O)OC(NR′)R  →  [RC(O)]2NR′
<h2 id="related-compounds">Related compounds</h2>
<p>Organic compounds called <a href="/facts/Carbodiimide/e02KT0rw">carbodiimides</a> have the formula RN=C=NR. They are unrelated to imides.
</p>

<h2 id="external-links">External links</h2>
<ul><li><a href="https://web.archive.org/web/20120716211320/http://www.chem.qmul.ac.uk/iupac/class/oneN.html#52">IUPAC: imides</a></li></ul>

<h2 id="see-also">See also</h2>
<ul><li><a href="/facts/Inorganic_imide/mmRpNx6a">Inorganic imide</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>"Imides". IUPAC Compendium of Chemical Terminology. 2009. doi:10.1351/goldbook.I02948. ISBN 978-0-9678550-9-7. <a href="978-0-9678550-9-7" target="_blank">978-0-9678550-9-7</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>Martynov, A. V. (2005-12-06). "New Approach to the Synthesis of trans-Aconitic Acid Imides". ChemInform. 36 (49): no. doi:10.1002/chin.200549068. ISSN 1522-2667. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Hargreaves, Michael K.; Pritchard, J. G.; Dave, H. R. (1970). "Cyclic carboxylic monoimides". Chemical Reviews. 70 (4): 439–469. doi:10.1021/cr60266a001. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Barradas, Remigio Germano; Fletcher, Stephen; Porter, John Douglas (1976). "The hydrolysis of maleimide in alkaline solution". Canadian Journal of Chemistry. 54 (9): 1400–1404. doi:10.1139/v76-200. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Walter W. Wright and Michael Hallden-Abberton "Polyimides" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a21_253 <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
<li id="fn:6"><p>Peter Ackermann, Paul Margot, Franz Müller "Fungicides, Agricultural" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a12_085 <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li>
<li id="fn:7"><p>Vincent Rodeschini, Nigel S. Simpkins, and Fengzhi Zhangi (2009). "Illustrative imide formation from amine and anhydride". Organic Syntheses{{cite journal}}:  CS1 maint: multiple names: authors list (link); Collected Volumes, vol. 11, p. 1028. <a href="http://www.orgsyn.org/demo.aspx?prep=CV11P1028" target="_blank">http://www.orgsyn.org/demo.aspx?prep=CV11P1028</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li>
<li id="fn:8"><p>Sperry, Jonathan (2011). "The Oxidation of Amides to Imides: A Powerful Synthetic Transformation". Synthesis (22): 3569–3580. doi:10.1055/s-0030-1260237. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li>
<li id="fn:9"><p>Sperry, Jonathan (2011). "The Oxidation of Amides to Imides: A Powerful Synthetic Transformation". Synthesis (22): 3569–3580. doi:10.1055/s-0030-1260237. <a href="/wiki/Doi_(identifier)" target="_blank">/wiki/Doi_(identifier)</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li>
</ol>

Imide open-in-new

Imide