331978-90-6

Upstream product

• 93-91-4 1-phenylbutan-1,3-dione 
• 827-41-8 3-phenylpyrazol-5-amine 
• 69626-39-7 1-phenylbuta-2,3-dien-1-one 
• 1572-10-7 3⁽⁵⁾-phenylpyrazol-5⁽³⁾-amine 

Downstream Products

• 802983-72-8 3-iodo-5-methyl-2,7-diphenyl-pyrazolo[1,5-a]pyrimidine 

Relevant academic research and scientific papers

Highly facile and regio-selective synthesis of pyrazolo[1,5-a]pyrimidines via reactions of 1,2-allenic ketones with aminopyrazoles

An efficient procedure for the syntheses of pyrazolo[1,5-a]pyrimidines through reactions of 1,2-allenic ketones with aminopyrazoles under extremely mild conditions without using any catalyst or promoter has been developed. The reactions showed excellent regio-selectivity with all the allenic ketone substrates except for those bearing an alkyl group at the internal position of the allene moiety. The reason behind this regio-selectivity dissimilarity has been explored with the aid of the B3LYP/6-31G* level of density functional theory. Moreover, this novel procedure has been successfully applied in the preparation of nucleoside-pyrazolo[1,5-a]pyrimidine chimeras with potent antiviral activities.

Convenient synthesis of substituted 3-alkenylpyrazolo[1,5-a]pyrimidines via Heck cross-coupling reaction

3-Iodopyrazolo[1,5-a]pyrimidines 3 were easily obtained by direct iodination of pyrazolo[1,5-a]pyrimidines 2 with NIS and could be transformed into a series of new substituted 3-alkenyl-pyrazolo[1,5-a]pyrimidines 5 by Heck cross-coupling.

α-Aminoazoles in the synthesis of heterocycles: I. Synthesis of regioisomeric 5-methyl-2,7-diphenyl-and 7-methyl-2,5-diphenylpyrazolo[1,5-a]pyrimidines

4-Phenyl-3-butyn-2-one reacts with 3(5)-amino-5(3)-phenylpyrazole on heating in DMSO to give 7-methyl-2,5-diphenylpyrazolo[1,5-a]pyrimidine. The reaction of 3(5)-amino-5(3)-phenylpyrazole with benzoylacetone in chloroform, ethanol, and DMSO results in formation of a mixture of isomeric pyrazolopyrimidines, the major product being 5-methyl-2,7-diphenylpyrazolo[1,5-a]pyrimidine.