Cold microwave chemistry: synthesis using pre-cooled reagents

• Published in: Tetrahedron letters Vol. 47; no. 19; pp. 3213 - 3215
• Main Authors: Bose, Ajay K., Ganguly, Subhendu N., Manhas, Maghar S., He, William, Speck, Jeffrey
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 08.05.2006; Elsevier
• Subjects: Chemistry; Chemistry, Organic; Microwave assisted nitration reactions; Microwave irradiation of pre-cooled reagents; Nitration of phenols; Physical Sciences; Science & Technology; Selective nitration reactions; Microwave assisted nitration reactions; Nitration of phenols; Microwave irradiation of pre-cooled reagents; Selective nitration reactions; selective nitration reactions; microwave assisted nitration reactions; nitration of phenols; microwave irradiation of pre-cooled reagents
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2006.03.059

Selective nitrations of 4-hydroxycinnamic acid under microwave irradiation are discussed. A novel experimental procedure for chemical reactions has been devised that involves mixing and then freezing the reagents (organic solvent-free) to a sub-zero temperature such as −30 °C. This frozen mixture is exposed to microwave irradiation for a brief period of time. The use of pre-cooled reagents may give a single product not obtained by traditional microwave irradiation at room temperature. Interestingly, such a product may provide information about mechanisms by identifying the first step of a multiple step reaction.