From Renewable Levulinic Acid to a Diversity of 3‐(Azol‐3‐yl)Propanoates. (3rd December 2013)

• Record Type: Journal Article
• Authors: Flores, Alex F. C.; Piovesan, Luciana A.; Pizzuti, Lucas; Flores, Darlene C.; Malavolta, Juliana L.; Martins, Marcos A. P.
• Is Part Of: Journal of heterocyclic chemistry. Volume 51:Number 3(2014)
• Page Start: 733
• Page End: 740
• Publication Date: 2013-12-03
• Subjects: Heterocyclic compounds -- Periodicals; 547.59
• DOI: 10.1002/jhet.1774
• Languages: English
• ISSNs: 0022-152X

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <p>Efficient <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">heterocyclization</named-content> of methyl 7, 7, 7‐trifluoro‐4‐methoxy‐6‐oxo‐4‐heptenoate and methyl 7, 7, 7‐trichloro‐4‐methoxy‐6‐oxo‐4‐heptenoate into isoxazole and pyrazole derivatives that represent a new type of glutamate‐like 3‐(trihalomethylated‐1, 2‐azol‐3‐yl)propanoate is reported. Preparation of the key methyl 7, 7, 7‐trihalo‐4‐methoxy‐6‐oxohept‐4‐enoate precursors from levulinic acid is also described. The synthetic potential of this synthetic protocol was indicated by the production of several methyl and ethyl 3‐(isoxazol‐3‐yl)propanoates and 3‐(1<italic>H</italic>‐pyrazol‐3‐yl)propanoates, and the respective acid derivatives, in good (70–95%) yields. The crystal structure for ethyl 5‐(3‐ethoxy‐3‐oxopropyl)‐1<italic>H</italic>‐pyrazole‐3‐carboxylate (<bold>10c</bold>) has been determined by monocrystal X‐ray diffraction analysis. The N–H^…H <named-content content-type="reactionType" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink">intermolecular</named-content> hydrogen bonds join the molecules into catamer.</p> </abstract>