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- Title
Zinkchloridkatalysierte, thermische Umlagerungen von N-Allyl in C-Allyl-aniline; ladungsinduzierte, aromatische Amino-Claisen-Umlagerungen.
- Authors
Schmid, M.; Hansen, Hans-Jürgen; Schmid, Hans
- Abstract
N-Allyl-2-methylaniline ( 12) forms on heating at 140° in xylene in the presence of zinc chloride 2-allyl-6-methylanline ( 19) as major compound and 4-allyl-2-methylaniline ( 20) as well as 2,7-dimethyl-indoline ( 21) as minor products. Compound 21 is also formed when 19 is heated in the presence of zinc chloride (scheme 2). That 19 arises from a charge-induced [3 s, 3 s] sigmatropic rearrangement of 12 - and 20 from two consecutive [3 s, 3 s]-sigmatropic transformations - follows from the reaction of N-crotyl-2-methylaniline ( 13) in the presence of zinc chloride at 140°. 2-(1′-Methylallyl)-6-methylaniline ( 22) and 4-crotyl-2-methylaniline ( 23) are formed exclusively. Small amounts of 2,3,7-trimethyl-indoline ( 24) and 2-( cis- and trans-1′-methyl-propenyl)-6-methylaniline ( cis- and trans- 25) are observed as by-products. Compound 24 arises from 22 in the presence of zinc chloride (scheme 3). Similar results are obtained when N-allyl and N-(2′-methylallyl)-N-methyl-aniline ( 14 and 15, respectively) are heated in the presence of zinc chloride. Whereas 14 gives nearly exclusively 2-allyl-N-methyl-aniline ( 28) and only small amounts of the corresponding 1, 2-dimethyl-indoline ( 29) and of 2-( cis- and trans-propenyl)-N-methyl-aniline ( cis- and trans- 27), 15 forms comparable amounts of 2-(2′-methylallyl)-N-methyl-aniline ( 30), 1,2,2-trimethyl-indoline ( 31), and 2-isobutenyl-N-methyl-aniline ( 32) (scheme 4). Compound 30, and also 32, are transformed into 31 on heating in the presence of zinc chloride. Charge-induced aromatic amino- Claisen rearrangements are also observed when N-allylated anilinium tetraphenylborates are heated at 100-105° in hexamethyl phosphoric acid triamide. Thus, N-allyl- and N-crotyl-N, N-dimethyl-anilinium tetraphenylborate ( 16 and 17, respectively) yield 2-allyl- and 2-(1′-methylallyl)-N,N-dimethyl-aniline ( 33 and 34, respectively) besides small amounts of N, N-dimethyl-aniline. N-Cinnamyl-N, N-dimethyl-anilinium tetraphenylborate ( 18) gives, besides appreciable amounts of N,N-dimethyl-aniline, a mixture of 2-(1′-phenylallyl)-,2-cinnamyl-, and 4-cinnamyl-N, N-dimethyl-aniline ( 35, 36, and 37, respectively) in which the first two compounds predominate.
- Publication
Helvetica Chimica Acta, 1973, Vol 56, Issue 1, p105
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19730560105