An unambiguous synthesis of pyrazoles by sulphur extrusion from 1,2,6-thiadiazines
作者:José Barluenga、J. Francisco López-Ortiz、Miguel Tomás、Vicente Gotor
DOI:10.1039/p19810001891
日期:——
chloride and sulphur monochloride and dichloride giving different 1,2,6-thiadiazine S-oxides (3) and 1,2,6-thiadiazines (4), respectively. These last two compounds lead, by heating, to pyrazoles (6)via thermal extrusion of sulphur oxide or sulphur. On the other hand, 1,2,6-thiadiazine S-dioxides (5), which can be obtained by oxidation of (3) or (4), do not undergo the extrusion of sulphur dioxide.
二亚胺(1)与亚硫酰氯,一氯化硫和二氯化硫反应,分别得到不同的1,2,6-噻二嗪S-氧化物(3)和1,2,6-噻二嗪(4)。这最后两个化合物导致,通过加热,以吡唑(6)经由硫氧化物或硫的热挤压。另一方面,可以通过氧化(3)或(4)获得的1,2,6-噻二嗪S-二氧化物(5)不经历二氧化硫的挤出。