You are using Science Of Synthesis as a Guest.
Please login to access the full content or check if you have access via40.1.1.4.1.5.2 Variation 2: Hofmann–Martius Rearrangement
Please login to access the full content or check if you have access via
Purchase, R.; Sainsbury, M., Science of Synthesis, (2009) 40, 389.
In another classical rearrangement an anilinium chloride bearing a single N-alkyl group is transformed into a mixture of 2- and 4-alkylanilinium chlorides on heating at a temperature greater than 200°C (Scheme 36).[134] The reaction is known as the Hofmann–Martius rearrangement {see also Science of Synthesis, Vol. 31b [Arene—X (X = N, P) (Section 31.28.1.33.3)]. The migration is intermolecular in nature and there is evidence that an alkyl chloride 126 and an aniline 127 are initially formed (Scheme 36).[135] This electrophilic alkyl chloride subsequently enters into a Friedel–Crafts alkylation of the aniline, or its equivalent, to afford a mixture of 2- and 4-alkylated anilines in a ratio that depends upon the alkyl chloride that is generated; polyalkylated products may also form. In at least one case the drastic conditions traditionally employed to bring about such rearrangements can be reduced by the use of an acid catalyst; thus, 3-(N-phenylamino)indol-2-one 128 is converted into a mixture of 3-(2-aminophenyl)indol-2-one 129A and 3-(4-aminophenyl)indol-2-one 129B simply by treatment with a catalytic amount of trifluoroacetic acid in benzene at 25°C. Its analogue 130 gives the related indol-2-ones 131A and 131B under the same conditions or, alternatively, by heating it in toluene (without trifluoroacetic acid) at 80°C (Scheme 36).[136]
Meeeee 88 Meeeeeeee ee Meeeeeee Meeeee ee eee Meeeeee–Meeeeee Meeeeeeee[888–888]
Me eeeeeee eeeeeeeeee eeeeee Meeeeee–Meeeeee eeeeeeeee ee ee eeeee eeee M,8-eeeeeeee-8M-eeeeeee-8-eeeee (888, M = M) eeeeeeeeee eeee 8-(8-eeeeeeeeeee)-8-eeeeee-8M-eeeeeeee (888, M = M) eeee ee ee eeeeee ee eeeeeeeeeeee eeeeeeeeeeee eeee eee eeeeee eeee ee 888°M; eee eeeee ee 88%. Mee eeee eee eeeeee eeeeeeeee ee eee eeeeeeee eeeeeeee eeeeee ee eee eeee eee eee eeee eee eeeeeeeeeeeee eeeeeeeeeeeee eeeeeeee eeee eeeeeee eeeeeeeeee (Meeeee 88).[888]
Meeeee 88 Meeeeee–Meeeeee Meeeeeeeeeeeee ee M,8-Meeeeeee-8M-eeeeeee-8-eeeee eee Mee Meeeee ee Meeeeeee Meeeeeeee[888]
References
[134] | Meeeeee, M. M.; Meeeeee, M. M.; Mee. Meeee. Meee. Mee., (8888) 8, 888. |
[135] | Meeee, M.; Meeeeee, M.; Meeeeee, M., Meeeeeeeeee, (8888) 88, 8888. |
[136] | Meeeee, M.; Meeeeeee, M., Mee. Meee., (8888) 8, 8888. |
[137] | Meee, M.; Meeeeee, M.; Meeeeee, M.; Mee, M. M.; Meeeeeee, M.; Meeee, M., M. Meee. Mee., Meeeee Meeee. 8, (8888), 8888. |
Meeeeee Meeeeeeeeee
- 8.Meeeee-Meee, (8888) 88/8, 888.