Oxidation of 1-Oxa-5-azaspiro[5.5]undecane with cyclohexanone

Abstract

SHORT COMMUNICATIONSWe previously reported that oxidation of five-membered cyclic N,O-acetals (oxazolidines) with carbonyl compounds leads to the formation of pyrroles [1]. In the present communication we describe the oxidation of 1-oxa-5-azaspiro[5.5]undecane (I) with cyclohexanone to produce 5,6,7, as an example of synthesis of pyridine derivatives via oxidation of perhydro-1,3-oxazines having no substituent on the nitrogen atom with carbonyl compounds. oxazine I) gives imino aldehyde A which undergoes intramolecular condensation (like crotonization) to 2,3,5,6,7,8-hexahydroquinoline B, and the latter is oxidized with the second cyclohexanone molecule to quinoline II.A mixture of 31 g (0.2 mol) of compound I, 39.2 g (0.4 mol) of cyclohexanone, and 4.48 g (0.08 mol) of powdered potassium hydroxide was heated for 5 h under reflux. The mixture was cooled, 25.2 ml (0.21 mol) of 36% hydrochloric acid was added, and the aqueous phase was separated, extracted with diethyl ether (3 × 50 ml), made alkaline by addition of potassium hydroxide, and extracted with benzene. The benzene extract was subjected to distillation to isolate 4.2 g (16%) of 5,6,7,8-

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

“…This was due to the participation not only of allene but also of acetylene carbanions in reaction with the aryl isothiocyanate [99,398]. In the case of 1-oxa-5-azaspiro [5.5]undecane it was shown (B. F. Kukharev, V. K. Stankevich) that the oxidation of 1,3-oxazinanes, unsubstituted at the nitrogen atom, by carbonyl compounds led to tetrahydroquinolines [400]. The heterocyclization of the nitriles of α,β-acetylenic γ-hydroxy acids with pyridine, quinoline, 6-methyl-1, 2,3,4,7,8,9,10- Pioneering investigations in the chemistry of vinyl derivatives of six-membered azaheterocyclespyridylalkanols, 8-quinolinol, 1-methyl-3-piperidinol, 2-(1-piperidinyl)ethanol, 2(1H)-pyridinone, and 4-methyl-2-(1H)-quinolinone -were carried out by G. G. Skvortsova et al [178].…”

Multicomponent Synthesis and Molecular and Crystal Structure of New Derivatives of Partially Hydrogenated Quinolines

“…They are suitable for the treatment of Alzheimer's disease [1], arteriosclerosis [2], asthma [3], tumors [4], and infl ammation [5]. The main method for the synthesis of this class of compounds is based on the extension of the pyridine ring to the cyclohexanone ring [6][7][8][9]. Continuing research in this scientifi c area [10][11][12][13], we have developed a new method for the synthesis of this type of compounds, involving a Knoevenagel condensation-Stork reaction-intramolecular transamination-alkylation reaction sequence.…”