Formation of Urea, Isourea, and Triazine Derivatives from Diisopropylcyanamide with Trifluoroacetic Anhydride and Trifluoromethanesulfonic Anhydride: Thermal Instability of Urea and Isourea Derivatives
| Autor: | Gregory S. Ostrom, Lawrence H. Merwin, William P. Norris, Richard Gilardi |
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| Rok vydání: | 1997 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 62:9070-9075 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/jo9710184 |
| Popis: | Diisopropylcyanamide reacts exothermically with trifluoroacetic anhydride to give 2, an equilibrium mixture, in C6D6 solution, of 1:1 adducts, N,N-diisopropyl-N‘,O-bis(trifluoroacetyl)isourea, 2a (10%), and N,N-diisopropyl-N‘,N‘-bis(trifluoroacetyl)urea, 2c (90%), at 27 °C. Compound 2c is a colorless solid, mp 49−51 °C. Thermolysis of 2, at 117 °C, shows first-order kinetics with the intital products being trifluoroacetonitrile, 4, and diisopropylcarbamic trifluoroacetic mixed anhydride, 3. Trifluoroacetonitrile trimerizes to 2,4,6-tris(trifluoromethyl)-1,3,5-triazine, and 3 is thermally labile giving diisopropyltrifluoroacetamide and CO2. In the thermolysis reaction 4 reacts with 2a to give a small amount of 4-(diisopropylamino)-4-(trifluoroacetoxy)-2,6-bis(trifluoromethyl)-4H-1,3,5-oxadiazine, 7. A related compound, 4,4-bis(diisopropylamino)-2,6-bis(trifluoromethyl)-4H-1,3,5-oxadiazine, 8, is formed from 7 and 2c going through a concentration maximum at 4000 s in the kinetic run. Compound 8 thermolytica... |
| Databáze: | OpenAIRE |
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