Cyclic Enamines Research Articles

The chemistry of cyclic enaminoketones. III. Synthesis of bi‐ and tricyclic enaminoketones from enamine esters and nitriles

AbstractThe cyclization of enamines derived from β‐aminoesters and β‐aminonitriles into bi‐ and tricyclic enaminoketones (6,9,13 and 24) has been investigated. The enamines derived from aminonitriles cyclize smoothly with magnesium perchlorate in benzene or toluene, whereas the enamines derived from aminoesters cyclize spontaneously during their formation. The scope and limitation of this process is discussed.

Polyamide synthesis via enamines

AbstractEnamines derived from cyclic ketones behave as difunctional intermediates when treated with phenyl isocyanate to produce dicarboxanilides. Reaction of bis(4‐isocyanatophenyl)‐methane with 1‐N‐morpholino‐1‐cyclopentene in DMSO leads to poly[iminocarbonyl(2‐morpholino‐1‐cyclopenten‐1.3‐ylene)carbonylimino‐p‐phenylenemethylene‐p‐phenylene], a polyamide. The effects of various cyclic enamines and diisocyanates on the polymerization are surveyed. Morpholine and piperidine are more effective than pyrrolidine or dimethylamine when incorporated into cyclopentanone enamines. The molecular weight of the polymer decreases when the ring size of the ketone component is increased. The efficiency of the diisocyanates decreases as follows: bis(4‐isocyanatophenyl)methane > tolylene diisocyanate > naphthylene diisocyanate > hexamethylene diisocyanate > sulfurly diisocyanate. Branched and crosslinked polymers were obtained in the presences of excess diisocyanate. A mechanism is proposed to account for these results.The polyamides obtained from 1‐N‐amino‐1‐cyclopentene were not thermally stable. The rate of degradation at 60°C was determined by measuring the decrease in viscosity with time. The enamine structural unit of the polyamides can be hydrolyzed with 98% formic acid to the corresponding polyketone, which yields a poly(2.4‐dinitrophenylhydrazone) upon treatment with DNPH in DMSO. Reaction of excess 2‐N‐morpholino‐1‐cyclopentene‐1‐carboxanilide with bis(4‐isocyanatophenyl)methane affords a model compound for the new polyamide. The infrared and NMR spectra of the polymers and their corresponding model systems were compared and found to be consistent with the proposed structures.

スパルテインより誘導される含窒素複素環化合物(第2報) : 5-Hydroxysparteine(Retamineの立体異性体)および5-Hydroxymethylsparteineの合成 : キノリチン誘導体の合成 第15報

5-Hydroxysparteine (I), the stereoisomer of retamine (II), was prepared by the reduction of 5-oxosparteine (V) with sodium borohydride. The hydroxyl group in 5-position with equatorial configuration was obtained almost selectively. By the utilization of the cyclic enamine activity of Δ5-dehydrosparteine (VI), 5-hydroxymethylsparteine (IX) was prepared via 5-ethoxycarbonyl-Δ1(6)-dehydrosparteinium ion (VII) and -sparteine (VIII). In this case, both equatorial and axial hydroxymethyl compounds (IXa and b) were obtained.

Reactions of Enamines. VII. The Reaction of Cyclic Enamines with Trichloroacetic Acid1

Reactions of Enamines. VII. The Reaction of Cyclic Enamines with Trichloroacetic Acid¹