title: Highly facile and regio-selective synthesis of pyrazolo[1,5-a]pyrimidines via reactions of 1,2-allenic ketones with aminopyrazoles.
abstract: 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.
authors.affiliation: School of Chemistry and Chemical Engineering, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Henan Normal University, Xinxiang, Henan 453007, P. R. China. xinyingzhang@htu.cn xuesen.fan@htu.cn.
authors.forename: Xinying
authors.initials: X
authors.lastname: Zhang
authors.forename: Yunping
authors.initials: Y
authors.lastname: Song
authors.forename: Lin
authors.initials: L
authors.lastname: Gao
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Guo
authors.forename: Xuesen
authors.initials: X
authors.lastname: Fan
mesh_terms: D007659:Ketones / Q000737:chemistry*; D015394:Molecular Structure; D011720:Pyrazoles / Q000138:chemical synthesis / Q000737:chemistry*; D011743:Pyrimidines / Q000138:chemical synthesis* / Q000737:chemistry; D011789:Quantum Theory; D013237:Stereoisomerism
chemical_list: D007659:Ketones; D011720:Pyrazoles; D011743:Pyrimidines; C527752:pyrazolo(1,5-a)pyrimidine