A Regioselective Biginelli‐like Reaction Controlled by the Size of Alicyclic Mono‐ketones. (18th April 2014)

• Record Type: Journal Article
• Authors: Wan, Yu; Yuan, Rui; Xu, Hua‐hong; Wang, Chao; Qi, Jin‐long; Wu, Hui
• Is Part Of: Journal of heterocyclic chemistry. Volume 51:Number 1(2014:Jan.)
• Page Start: E123
• Page End: E128
• Publication Date: 2014-04-18
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.1893
• Languages: English
• ISSNs: 0022-152X

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>A <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">regioselective</named-content> Biginelli‐like reaction of alicyclic mono‐ketones, aromatic aldehydes, and urea in ionic liquid [BPY]BF<sub>4</sub> has been investigated. The process is controlled by the size of alicyclic mono‐ketones and the steric hindrance of aromatic aldehydes. The reaction of cyclopentanone with urea and aromatic aldehydes afforded 7‐arylidene‐3, 4, 6, 7‐tetrahydro‐4‐aryl‐1<italic>H</italic>‐cyclopenta[d]pyrimidin‐2(5<italic>H</italic>)‐ones (<bold>4</bold>). When cyclohexanone was used as the source of active methylene to react with urea and aldehydes with slight steric hindrance groups under the same condition, 8‐arylidene‐3, 4, 5, 6, 7, 8‐hexahydro‐4‐arylquinazolin‐2(1<italic>H</italic>)‐ones (<bold>6</bold>), a homologue of <bold>4</bold>, were yielded, whereas 4, 8‐bisaryloc‐tahydro‐1<italic>H</italic>‐pyrimido[5, 4‐<italic>i</italic>]‐quinazoline‐2, 10(3<italic>H</italic>, 11<italic>H</italic>)‐diones (<bold>7</bold>) were obtained via the simple <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">one‐pot reaction</named-content> of cyclohexanone, urea, and aromatic aldehydes with high steric hindrance groups. The possible transitional states and mechanism of the <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">regioselective</named-content> process were discussed.</p> </abstract>