Search Results

You are looking at 1 - 10 of 29 items

  • Author: Richard Kreher x
Clear All Modify Search

The reaction of 1-phenyl-3-alkyl-triazenes with lewis acids in benzene has been examined in order to evaluate the mechanism of the reaction of alkyl azides with electrophiles in benzene. Evolution of nitrogen gives rise to the formation of the corresponding substituted anilines by intramolecular alkylation. Alkyl benzenes are the result of an intermolecular alkylation process.

Azidodiazonium tetrafluoroborates are readily accessible by a general reaction sequence. Nitrosation of the corresponding azidoarylamines with nitrosonium tetrafluoroborate or with alkylnitrites/tetrafluoroboric acid affords crystallinic salts, which were characterized by analytical and spectroscopic methods.

Dehydrogenation of N-hydroxy-Δ3-pyrroline with mercuric oxide leads via the cyclic conjugated 2 H-pyrrolenine-N-oxide to the tautomeric N-hydroxy-pyrrole, which has pronounced reactivity towards dienophiles. With N-phenyl-maleic-imide the endoconfigurated Diels-Alder-adduct is formed, whose stability is increased by acylation of the N-hydroxy group. The O-acylated Diels-Alder adducts can be prepared independantly from N-acyloxy-pyrroles and the corresponding dienophile.

N-methane-sulfonyl-isoindolines substituted in the carbocyclic moiety can be prepared from the corresponding 1,2-bis-[brommethyl]benzenes and methane sulfonamid by cyclisation under basic conditions. The title compounds are interesting precursors for the generation of carbocyclic substituted 2H-isoindoles via base catalysed 1,2-elimination of methane sulfinic acid. By this reaction sequence the sulfonyl residue is simultaneously involved as a protecting group and as a leaving group.

Abstract

The reaction of phosphonyltriazenes with benzene in the presence of aluminiumchloride is involved with the elimination of nitrogen and followed by electrophilic substitution of benzene. The arylation reaction obviously proceeds via the intermediate formation of arene diazonium ions. Phosphinyltriazenes display the same chemical behaviour.

Reactions of 1-alkoxy-isoindolenines with electrophilic, nucleophilic and dienophilic reagents have been investigated as a general route for the synthesis of substituted isoindoles and isoindolenines.

5H-Dibenz[c,e]azepine-N-oxides were prepared by oxidation of the corresponding N-hydroxy-6,7-dihydro-5H-dibenz[c.e]azepines. Reactions of the isolated cyclic nitrones towards nucleophiles, dienophiles and dipolarophiles have been examined.