Umlagerung von quartären Allyl‐, Benzyl‐ und Propargyl‐hydraziniumsalzen

Abstract

R 1, I-Disubstituierte I-Allyl-und I-Benzyl-hydrazmiumchloride lassen sich in Gegenwart von Basen unter HCI-Abspaltung zu 1.1 -disubstituierten 2-Allyl-bzw. 2-Benzyl-hydrazinen umldgern. Die Reaktion verlauft a i m Teil mit sehr guten Ausbeuten. Bei quartaren Propargylhydraziniumsalzen wird eine Umlagerung nur als Nebenreaktion beobachtet.Rearrangement of Quaternary Allyl-, Benzyl-, and Propargylhydrazinium Salts 1, I-Disubstituted 1 -ally]-and I -bcnzylhydrazinium chlorides rearrange in the presence of alkali to form I ,I-disubstituted 2-allyl-and 2-benzylhydrazines, respectively, in good yields. When the reaction was applied to quaternary propargylhydrazinium salts, rearrangement took place only to a small extent.I .2-Umlagerungen sind in der organischen Chemle haufige und oft praparativ wertvolle Reaktlonen. Dazu gehbren so altbekannte Reaktionen wie die Meisenheimer-Umlagerung der Aminoxidel, 2 ) . die Stevens-Umlagerung von Ammonium-3). Sulfonium-41, Stibonium-und Arsoniumsalzen~), die Wi'ittigsche kherumlagerung6' sowie die Grovenstein-Zimmermun-Reaktion7.81. Uber 1.2-Umlagerungen am Hydrazin-System ist nur wenig bekaiint geworden. So bildet sich 2.B. bei der Thermolyse des Amin-imids 1 das Hydrazid 2u): 1 ) J . Meisenheimer, Ber. dtsch. chem. Ges. 52, 1667 (1919): J. Meisenheimer, H. Greeske und A . Wilmersdorf, ebenda 55, 513 (1922).

The Rearrangement of N-Ben~yl-N,N-dimethylhydrazini~m Salts

“…The yield of N-benzyl-N,N-dimethylhydrazinium bromide, mp 147-8°C (lit. (4) 148-9°C) is 22.5 g (97.5%). This material is sufficiently pure to be used directly: if required it can be crystallized from ethanol-ether.…”

“…The remaining (aromatic) protons appear as an unresolved multiplet centered at r 2.42(5H), Heating with powdered potassium hydroxide produces (VI) in good yield, presumably via the ylid (V) since removal of a benzylic proton will not compete effectively with loss of the more acidic amino proton. A radical mechanism has been proposed (4) for this rearrangement, largely by analogy with the closely related Meisenheimer and Steven reactions, for which radical pathways have recently been established (-5, 6).…”

Synthesis of 1,3,4-Oxadiazinium Bromides from 1,1-Dimethylhydrazine Derivatives and 1,3-Dibromopropyne

“…The reactions of 1,1-dimethylhydrazine with propargyl bromide [1] and propargyl chloride [2] yield 1,1-dimethyl-1-(propyn-2-yl)hydrazinium bromide and chloride, respectively. Aroylethynyl bromides react with 1,1-dimethylhydrazine in MeCN at 20oC to give 1-(1-bromo-2-aroylvinyl)-1,1-dimethylhydrazinium bromides [3].…”

Preparation and pyrolysis of some N-protected derivatives of aminomethylene Meldrum’s acid

“…The N-benzyl substituent was chosen because of the high reactivity of benzyl-type hydrogen atoms to the transfer-cyclisation process, 1 and so the known N-benzylhydrazine 12 9 was synthesised and reacted with MMMA 3 to give the pyrolysis precursor 10 in 44% …”