Simple access toward 3-halo- and 3-nitro-pyrazolo[1, 5-a]pyrimidines through a one-pot sequence. Issue 45 (31st May 2017)

• Record Type: Journal Article
• Authors: Castillo, Juan-Carlos; Rosero, Hernán-Alejandro; Portilla, Jaime
• Is Part Of: RSC advances. Volume 7:Issue 45(2017)
• Page Start: 28483
• Page End: 28488
• Publication Date: 2017-05-31
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra04336h
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Herein, a regioselective, time-efficient and one-pot route for the synthesis of diversely substituted 3-halo- and 3-nitropyrazolo[1, 5- a ]pyrimidines in good to excellent yields through a microwave-assisted process is provided. Abstract : Herein, a regioselective, time-efficient and one-pot route for the synthesis of diversely substituted 3-halo- and 3-nitropyrazolo[1, 5- a ]pyrimidines in good to excellent yields through a microwave-assisted process is provided. The reaction features a sequential cyclocondensation reaction of β-enaminones with NH-5-aminopyrazoles, followed by a regioselective electrophilic substitution with easily available electrophilic reagents. This methodology is distinguished by its short reaction times, high-yield, operational simplicity, broad substrate scope and pot-economy. Furthermore, these 3-functionalized heterocycles have been successfully used in the synthesis of 3-alkynyl and 3-aminopyrazolo[1, 5- a ]pyrimidines in yields up to 92%.