{"id":1854,"date":"2018-11-30T15:23:39","date_gmt":"2018-11-30T15:23:39","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/suny-potsdam-organicchemistry2\/?post_type=chapter&p=1854"},"modified":"2019-01-09T07:09:41","modified_gmt":"2019-01-09T07:09:41","slug":"21-5-hydrolysis-of-nitriles","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/suny-potsdam-organicchemistry2\/chapter\/21-5-hydrolysis-of-nitriles\/","title":{"raw":"21.5. Hydrolysis of nitriles","rendered":"21.5. Hydrolysis of nitriles"},"content":{"raw":"
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\r\n\r\nA nitrile contains a triply bonded C=<\/span>N group, which is another common type of polar bond.\u00a0 However, the carbon in a nitrile is at an oxidation state of +3, higher than the +2 for ketones or +1 for aldehydes.\u00a0 For this reason, nitriles are not carbonyl equivalents like imines; rather, they are at the same oxidation state as carboxylic acids.\r\n\r\nThe C=<\/span>N triple bond undergoes nucleophilic additions in a similar way to a C=O.\u00a0 As with the carbonyl group, so often protonation is needed in order to activate it for the addition of weak nucleophiles such as water.\u00a0 As expected, when nitriles are hydrolyzed (by nucleophilic addition of water followed by nucleophile elimination), they form either carboxylic acids or amides, depending on the conditions.\r\n
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General reaction<\/h3>\r\n\"1.jpg\"\r\n\r\nWater is used along with the acid, to provide the reagent for the hydrolysis.\r\n\r\n<\/div>\r\n
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Example<\/h3>\r\n
\r\n\r\n\"2.jpg\"<\/span>\r\n\r\n<\/div>\r\n<\/div>\r\nSince nitriles can be prepared from alkyl halides + cyanide ion via an SN2 reaction, this hydrolysis step can be used to provide a two step synthesis sequence for making a carboxylic acid with one additional carbon.\u00a0 In this example, a four carbon alkyl halide is converted to a five carbon carboxylic acid.\r\n
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Contributors<\/h3>\r\n<\/div>\r\n
\r\n\r\nProf. Steven Farmer (Sonoma State University<\/a>)\r\n\r\n
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Conversion of nitriles to amides<\/h2>\r\n
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Nitriles can be converted to amides. This reaction can be acid or base catalyzed.\u00a0 In the case of acid catalysis the nitrile becomes protonated. Protonation increases the electrophilicity of the nitrile so that it will accept water, a poor nucleophile.\r\n
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General reaction<\/h3>\r\n\"1.jpg\"\r\n\r\n<\/div>\r\n
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Example<\/h3>\r\n\"2.jpg\"\r\n\r\n<\/div>\r\n \r\n\r\n<\/div>\r\n
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Mechanism<\/h3>\r\n1) Protonation\r\n\r\n\"3.jpg\"\r\n\r\n2)\u00a0 Nucleophilic attack by water\r\n\r\n\"4.jpg\"\r\n\r\n3) Proton Transfer\r\n\r\n\"5.jpg\"\r\n\r\n4) Resonance\r\n\r\n \r\n\r\n\"6.jpg\"\r\n\r\n5) Deprotonation\"\"\r\n\r\n<\/div>\r\n
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Contributors<\/h3>\r\n