3,6-二氯哒嗪-4-羧酸的合成

以柠康酸酐和盐酸联氨为起始原料,经过三步反应制得3,6-二氯哒嗪-4-羧酸。通过红外、核磁共振对其结构进行了确证。考察了原料用量、氧化剂种类以及用量、反应温度、反应时间等对合成3,6-二氯哒嗪-4-羧酸的影响。较佳工艺条件为:合成3,6-二羟基-4-甲基哒嗪时,柠康酸酐和盐酸联氨摩尔比为1∶1.12;氯代反应时,3,6-二羟基-4-甲基哒嗪和三氯氧磷摩尔比为1∶6。以HNO3-KClO3为氧化剂,其与3,6-二氯-4-甲基哒嗪质量比为2∶1,在35~40℃反应3 h。总收率达到52%,纯度大于98%。

Synthesis of 3,6-dichloro-4-pyridazinecarboxylic acid

Using citraconic anhydride and hydrazin dihydrochloride as base materials,through three steps 3,6-dichloro-4-pyridazinecarboxylic acid was synthesized.Its structure was analyzed and characterized by IR and ~1H NMR.The effects of material,oxidant,dosage of oxidant,reaction temperature and time on the synthesis were studied.The better technology has been obtained：the mole ratio of citraconic anhydride to hydrazin dihydrochloride is 1 :1.12 when 3,6-dihydroxy-4-methyl pyridazine was synthesized.The mole ratio of 3,6-dihydroxy-4-methyl pyridazine to phosphorous oxychloride is 1 :6 during chloric reaction.Taking nitric acid-chlorate liquor as oxidant,mass ratio of it to 3,6-dichloro-4-methyl pyridazine is 2 : 1,reaction time is 3 h at 35~40 ℃.The yield of 3,6-dichloro-4-pyridazinecarboxylic acid is 52% and purity is over 98%.