Flash vacuum pyrolysis of 1,2,5-oxadiazole 2-oxides and 1,2,3-triazole 1-oxides
作者:William R. Mitchell、R. Michael Paton
DOI:10.3998/ark.5550190.0011.a04
日期:——
The flashvacuumpyrolysis (FVP, 450-600 oC/10 -3 mmHg) of 3,4-diaryl- and 3,4-dialkyl-1,2,5oxadiazole 2-oxides (furoxans) has been investigated. In all cases the 1,2,5-oxadiazole ring cleaved cleanly at O(1)-N(2) and C(3)-C(4) to afford two nitrile oxide fragments, which were trapped in high yield (75-97%) as their isoxazoline cycloadducts by reaction with alk-1-enes. At higher temperatures (700-800
Isolation of nitrile oxides from the thermal fragmentation of furazan -oxides
作者:William R. Mitchell、R.Michael Paton
DOI:10.1016/s0040-4039(01)86315-2
日期:1979.1
Flash vacuum pyrolysis of furoxans generates nitrile oxides, which have been reacted with alkenes to yield 2-isoxazolines, and have been examined by 1H and 13C nmr spectroscopy.
呋喃喃的闪蒸真空热解生成一氧化氮,该氧化氮已与烯烃反应生成2-异恶唑啉,并已通过1 H和13 C nmr光谱进行了检查。
An improved procedure for the preparation of 2-isoxazolines
作者:Karl Erik Larsen、Kurt B.G. Torssell
DOI:10.1016/s0040-4020(01)91313-4
日期:1984.1
high yields by N-Chlorosuccinimide into hydroxamic acid chlorides, and corresponding nitrile oxides generated by addition of triethylamine at 40°–50° underwent 1,3-dipolar polar addition to alkenes, giving 2-isoxazolines. The whole procedure could be performed as a one-pot reaction. Oximes with other functions, sensitive to free chlorine could be converted selectively into hydroxamic acid chlorides by
Reaction of 2-Isoxazolines with Organolithiums in the Presence of Boron Trifluoride
作者:Hidemitsu Uno、Tetsuya Terakawa、Hitomi Suzuki
DOI:10.1246/bcsj.66.2730
日期:1993.9
In the presence of borontrifluoride, 3,4,5-tri-, 3,5,5-tri and 3,5-disubstituted 2-isoxazolines underwent nucleophilic addition of alkyl- and aryllithiums to give 3,3,4,5-, 3,3,5,5-, and 3,3,5-substituted isoxazolidines in moderate to good yields. On the other hand, in the case of 3,4,5,5-tetrasubstituted isoxazolines, the addition did not proceed at all but proton abstraction took place to afford
A process for forming isoxazolines or isoxazoles by contacting, in the presence of base, a nitro compound, a cyclic anhydride and a dipolarophile. The dicarboxylic acid is readily regenerated to be again reused as the dehydrating agent of additional nitro compound.