Rearrangement Fischer-Hepp

Transformation of A -nitroso-anilines to the corresponding para-nitroso anilines. Cf. Orton rearrangement. 

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Fischer-Hepp rearrangement The nitros-amines of aromatic secondary amines when treated with hydrochloric acid give nuclear substituted nitrosoamines. Among the benzene derivatives, if the para position is free the -NO group displaces the hydrogen atom there in naphthalene derivatives it enters the 1-position ... 

Dibenz[6,/]azepine, 10,11-dihydro-N-nitroso-Fischer-Hepp rearrangement, 7, 527 Dibenz[6,/]azepine, 10,11-ethoxyring opening, 7, 526 Dibenz[6,/]azepine, N-nitroso-synthesis, 7, 527... 

Migration of the Nitroso Group The Fischer-Hepp Rearrangement... 

The Fischer-Hepp rearrangement generally gives only the 4-isomer and, apart from examples in the naphthyl series, the 2-isomer has rarely been identified. Now the 2-isomer has been characterized96 as the minor product from the reaction of the diphenylamine derivative 96. The 2-nitroso product gives the cyclized product 97 on treatment with hydrogen peroxide (Scheme 17). 

Quite different from the Fischer-Hepp rearrangement is the reaction of N-nitrosodehydromorpholine 98 which, in methylene chloride containing HC1, gives at room temperature l-azo-4-oxa-3-oximinocyclohexene 99, which ring-opens on treatment... 

Fischer-Hepp rearrangement, 22 151 Fischer-Tropsch catalysis, by graphite intercalation compounds, 23 318 Fish, arsenic in, 44 150, 167, 168, 170, 180 Fission... 

One of the best-knbwn methods for the preparation of aromatic nitroso compounds is the Fischer-Hepp rearrangement of A-nitrosoamines (Eq. 2). In effect, this reaction is the C-nitrosation of secondary aromatic amines. 

Typical primary amines which undergo such nitrosation are m-toluidine, p-xylidine, m-anisidine, 2-amino-4-methoxytoluene, 3-amino-4-methoxy-toluene, m-aminophenol, a-naphthylamine, l-naphthylamine-2-, -6-, -7-, and -8-monosulfonic acids, and l-naphthylamine-4-monosulfonic acid (which reacts with displacement of the sulfonic acid group). The secondary amines derived from these primary amines also can be nitrosated directly (i.e., without the intermediate formation of an JV-nitroso compound which needs to be subjected to the Fischer-Hepp rearrangement). The entering nitroso group appears to substitute exclusively in the para position. 

See M. B. Smith, J. March in March s Advanced Organic Chemistry, 5lh ed., John Wiley and Sons, Inc., New York, 2001, pp. 728-730 for the Fischer-Hepp Rearrangement as well as the Orton and Hofmann-Martius Rearrangements. 

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