6-芳基取代吡唑并[1,5-a]嘧啶的合成

The Synthesis of 6-Arylsubstituted Pyrazolo [1,5-a] Pyrimidines

吡唑并[1,5-a]嘧啶类化合物是一类具有良好生物活性的含氮杂环化合物.以2,4-二氯苯乙腈和对三氟甲基苯甲酸甲酯为起始原料分别制备了5-氨基-4-(2,4-二氯苯基)-3-甲基-1H-吡唑(3)和5-氨基-3-(4-三氟甲基苯基)-1H-吡唑(6).然后,在三丁胺为溶剂160℃条件下,上述5-氨基-4-(2,4-二氯苯基)-3-甲基-1H-吡唑和5-氨基-3-(4-三氟甲基苯基)-1H-吡唑分别与苯基丙二酸二乙酯类化合物反应得到3个6-芳基吡唑并[1,5-a]嘧啶类化合物(8a-c).并通过红外光谱与核磁共振氢谱确定目标化合物的结构.

Pyrazolo [1,5-a] pyrimidinies have shown many excellent biological activities in the areas of medicine.In this paper,we report the synthesis and characterization of three new 6-arylsubstituted pyrazolo [1,5-a] pyrimidine derivatives.The intermediate 4-(2,4-dichlorophenyl)-3-methyl-1H-pyrazol-5-amine was synthesized from 2,4-dichlorobenzyl Cyanide,through acetylation with acetyl chloride,followed by condension with hydrazine hydrate;Methyl 4-(trifluoromethyl)benzoate were condensed with acetonitrile to yield 3-oxopropanenitrile that reacted with hydrazine hydrate to yield 3-(4-(trifluoromethyl)phenyl)-1H-pyrazol-5-amine.The desired 6-arylsubstituted pyrazolo [1,5-a] pyrimidines are prepared by the reaction of diethyl 2-phenylmalonates with 5-amino-1H-pyrazoles in good yields.The structure of two pyrazolo [1,5-a] pyrimidines was characterized by IR and 1HNMR.