Publisher Summary This chapter reviews the developments in the chemistry of Reissert compounds. Reissert compounds are prepared from quinoline or isoquinoline and an acid chloride, using trimethylsilyl cyanide and a catalytic amount of aluminum chloride in methylene chloride. The chapter presents the chemical properties and reactions of Reissert compounds focusing on the reactions under acidic conditions; reactions involving the formation of an anion of the Reissert compound; and reduction reactions. The spectral properties of Reissert compound are also reviewed. The mass spectra of Reissert compounds derived from quinoline, isoquinoline, and phthalazine are discussed. Proton magnetic resonance spectra of Reissert compounds are presented emphasizing the stereochemistry, and some tentative assignment of predominant tautomers. The chapter also discusses several related compounds and reactions of Reissert compounds including reduced and open-chain analogs; analogs with groups other than cyano; and analogs with groups other than acyl.

Developments in the Chemistry of Reissert Compounds (1968-1978)

Publisher Summary This chapter discusses the formation, stability, detection, estimation, and reactions, including rearrangements of 1,2-dihydroisoquinoline. The 1,2-dihydroisoquinolines, possessing a heteroaromatic ring system instead of the benzene ring of the benzyl group are obtained via the anions of the Reissert compounds. To obtain the analogs of 1,2-dihydroisoquinolines, in which the aromatic carbocycle is replaced by various heteroaromatic systems, the furopyridines, the thieno[3,2-c] pyridines, and the thieno[2,3-c]-pyridines are synthesized. Depending on the substitution pattern of the starting 1,2-dihydroisoquinoline is accompanied by disproportionation, elimination, and intramolecular cyclization as side reactions. The disproportionation reaction is considered to be a migration of a hydride ion. Depending on the substitution pattern in such 1,2-dihydroisoquinolines, which are rearranged by acids, the disproportionation reaction can occur to a small extent. A further reaction of 1,2-dihydroisoquinolines with acids is the elimination of the C-1 substituent. The reaction can occur if the C-1 substituent is a benzyl or a heteroanalogous benzyl group. In 1,2-dihydroisoquinolines that are able to rearrange, the elimination reaction is observed only to a small extent. It is favored if the C-1 substituent bears negative substituents. If the benzyl is replaced by a picolyl group, only elimination occurs even at room temperature. The cyclization of 1,2-dihydroisoquinolines leading to pavinanes has been known for a long time. It is found to be a competition reaction of the rearrangement of 1-benzyl-1,2-dihydroisoquinolines, depending on the reaction conditions.

1,2-Dihydroisoquinolines and Related Compounds

Vor kurzem haben wir uber die Synthese des 1-Picolyl-1,2-dihydroisochinolins 3a berichtet, das unter Einwirkung verdunnter Sauren, aber auch bereits in polaren Losungsmitteln, Eliminierung des C-1-Substituenten unter Bildung von 4 und 5a erleidet2).

[Transposition of dihydroisoquinolines. 24. 1-picolyl-1,2 dihydroisoquinolin, elimination instead of transposition].

Fur den Mechanismus der Umlagerung der 1-Benzyl-1,2-dihydroisochinoline wird ein neuer Vorschlag prasentiert, der sich mit allen bisherigen Befunden zwanglos vereinbaren last. Er bezieht die als Nebenreaktion beobachtete Eliminierung als Startreaktion in die Umlagerung ein und formuliert einen Verlauf uber Ionenpaare in einer SN2′-Reaktion. Der erste Schritt der Umlagerungsreaktion wird experimentell abgesichert.



Dihydroisoquinoline Rearrangement, XXVII: Proposal of a New Mechanism



For the mechanism of the rearrangement of 1-benzyl-1,2-dihydroisoquinolines a new proposal is presented, which is compatible with all presently known facts. The elimination, which was formerly regarded as a side reaction, is now considered to be the starting reaction. The rearrangement is assumed to proceed via ion pairs as an SN2′-reaction. The first step of this mechanism was confirmed by experiments.

Dihydroisochinolinumlagerung, 27. Mitt. Ein neuer Vorschlag zum Mechanismus

Quaternary Isoquinolinium Salts

Es wird uber die Synthese des 1-Picolyl-1,2-dihydroisochinolins 7 berichtet. 7 erleidet bei Behandlung mit Sauren nicht die erwartete Umlagerung, sondern quantitativ Eliminierung des C-1-Substituenten unter Bildung von 8 und 9. Diese Eliminierung erfolgt uberraschenderweise bereits in polaren Losungsmitteln wie Methanol oder Wasser quantitativ bei Raumtemperatur.



Dihydroisoquinoline-Rearrangement.



The synthesis of 1-picolyl-1,2-dihydroisoquinoline 7 is reported. With acids 7 gives not the expected rearrangement, but elimination of the C-1-substituent leading to the products 8 and 9. Surprisingly this elimination-reaction occurs also in the polar solvents methanol or water at room temperature in quantitative yield.

G. Link

Papers

Dihydroisochinolinumlagerung, 22. Mitt.: 1-Picolyl-1,2-dihydroisochinolin

Dihydroisochinolinumlagerung 22. mitt. 1‐picolyl‐1,2‐dihydroisochinolin