Unsaturated nitrogen compounds containing fluorine. Part IV. Thermal reactions of hexafluoroacetone azine with hydrocarbon terminal olefins to give (1-pyrazolin-1-ylio)methanides or pyrazolines
- 1 January 1975
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 6,p. 538-542
- https://doi.org/10.1039/p19750000538
Abstract
Hexafluoroacetone azine reacts with olefins of the type CH2:CMeR (R = Me, Et, or Pri) at 60–70 °C to give the stable 1,3-dipolar azomethinimines [2-(1-pyrazolin-1-ylio)propan-2-ides](CF3)2[graphic omitted]MeR in high yield (>90%), while with olefins of the type CH2:CHR (R = Pri or But) the corresponding 3-pyrazolines (CF3)2CH·[graphic omitted]R are formed in high yield (>85%). Reaction of the azomethinimine (R = Pri) with isobutene at room temperature or with propene at 0°C gives the corresponding criss-cross adducts (100%), but the pyrazoline (R = Pri) does not react with 3-methylbut-1-ene at 120°C. Flow pyrolysis of the azomethinimines (R = Me or Et) at 400°C gives quantitative yields of the azine and the corresponding olefin, while flow pyrolysis of the pyrazoline (R = Pri) at 450 °C affords 1,1,1,3,3,3-hexafluoro-2-trifluoromethylpropane (100%) and the pyrazole Me2CH·[graphic omitted]H (100%).Keywords
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