FORMATION OP PERFLUORO(N-ALKYL LACTAMS) BY THE REACTION OF PERFLUORO(N-ALKYL CYCLIC AMINES) WITH FUMING SULFURIC ACID

Abstract

Perfluoro(N-alkyl lactams) have been obtained in high yields by the reaction of perfluoro(N-alkyl cyclic amines) with fuming sulfuric acid.

The Chemistry of Highly Fluorinated Carbocations

“…Perfluorinated oxanes tend to be less stable toward AlCl 3 , as was shown by reaction of a mixture of 256 and 257 with AlCl 3 at 155 °C. The chlorooxolane 258 was again formed along with acyl chloride 259 , a result of a ring-opening reaction of 257 .…”

“…Perfluorinated alkanes are very stable toward the action of strong Lewis acids, but fluorine atoms are activated by an R-heteroatom, for example oxygen, and can be exchanged with AlCl 3 among other reagents. [201][202][203][204][205] Perfluorinated oxanes tend to be less stable toward AlCl 3 , 164 as was shown by reaction of a mixture of 256 and 257 with AlCl 3 at 155 °C. The chlorooxolane 258 was again formed along with acyl chloride 259, a result of a ring-opening reaction of 257.…”

“…c. Cyclic Amines . Despite the well-known chemical inertness of perfluorinated tertiary amines, these compounds will react with strong electrophiles such as SO 3 or H 2 SO 4 …”

“…Despite the well-known chemical inertness of perfluorinated tertiary amines, these compounds will react with strong electrophiles such as SO 3 163 or H 2 SO 4 . 164 Reaction of aluminum chloride with F-N-amylpiperidine (206) was reported in the 1960s to cause ring opening with concomitant Cl/F exchange. 165,166 Reaction proceeds at 60-70 °C in CCl 4 as solvent and leads to a mixture of small amounts of trichloropentane 207 and cyclic imine 208 along with two isomeric products of ring opening, imidoyl chlorides 209a,b, isolated in 65-70% yield.…”

“…Cyclic perfluoroamines hydrolyze by reaction with oleum to form the corresponding lactams. 224 The reaction is selective and the products were isolated in 49-65% yield. The reactivity of such heterocycles toward fuming sulfuric acid decreases in the order: Perfluorotriethylamine is far less reactive toward oleum and does not react up to 170 °C.…”