77464-05-2Relevant articles and documents
Formation of Urea, Isourea, and Triazine Derivatives from Diisopropylcyanamide with Trifluoroacetic Anhydride and Trifluoromethanesulfonic Anhydride: Thermal Instability of Urea and Isourea Derivatives
Norris, William P.,Merwin, Lawrence H.,Ostrom, Gregory S.,Gilardi, Richard D.
, p. 9070 - 9075 (2007/10/03)
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 thermolytically dissociates to generate 4 and tetraisopropylurea. Compound 2 is a trifluoroacetylating agent with methanol giving methyl trifluoroacetate in 97% yield. Accompanying this reaction is a methanol displacement of diisopropylamine giving a 1.7% yield of methyl-N-(trifluoroacetyl)urethane. Diisopropylcyanamide also reacts exothermically with trifluoromethanesulfonic anhydride to give 2,4,6-tris(diisopropylamino)-l-(trifluoromethanesulfonyl)triazinium trifluoromethanesulfonate, 15, in 96% yield. X-ray crystallographic structure drawing of 15 shows N1 (attached to CF3SO2) is pyramidal while N2, N4, and N6 (all diisopropylamino nitrogens) are sp2-planar. A small amount of O-ethyl-N,N-diisopropyl-N'-(trifluoromethanesulfonyl)isourea was also recovered, produced by the reaction of the initially formed intermediate, N,N-diisopropyl-N',O-bis(trifluoromethanesulfonyl)isourea, with ethanol contaminant in absolute ethyl ether solvent. Treatment of 15 with methanol, in the presence of K2CO3, gave a 90% yield of 2,4,6-tris-(diisopropylamino)-1-(trifluoromethanesulfonyl)-4-methoxy-1,4- dihydrotriazine.
