Aniline → 1-Phenylpiperidine

Among the cyclic ethers suitable for the practice of this invention are those which contain only carbon and an oxygen atom in an unstrained ring (i.e., the ring contains at least four carbon atoms and an oxygen atom bonded to two separate carbon atoms of the ring). Examples of such cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydro-2-furancarbinol, 2-ethoxymethyl tetrahydrofuran, 2-butoxymethyl tetrahydrofuran, tetrahydrofuroic acid, methyl tetrahydrofuroate, tetrahydropyran, 2-methyltetrahydropyran, furan, dihydrofuran, pyran, dihydropyran, and the like. In the case of such cyclic ethers as tetrahydrofuran, tetrahydropyran and their suitably substituted congeners, reaction with primary aromatic amines such as aniline and nuclear alkylanilines (e.g., toluidines, xylides, o-, m-, p-ethylaniline, 2,3-, 2,4-, 2,5-, 2,6-, 3,4- and 3,5-diethylanilines, etc.) results in gem-dialkylation of the nitrogen atom with high conversions of the aromatic amines and very high product yields. For example, reaction between tetrahydrofuran and aniline at 250° C. using a TiO2 catalyst (LHSV of 0.2 per hour) gave a 98% conversion of aniline with a 97% yield of 1-phenylpyrrolidine. Similary, tetrahydropyran and aniline when reacted at 300° C. over a TiO2 catalyst (LHSV of 0.2 per hour) resulted in a 74% aniline conversion with a 98% yield of 1-phenylpiperidine.

ORD record

ord-818e320847174b01bfbf2123f5b4e806

Source dataset

uspto-grants-1989_03

DOI

10.6084/m9.figshare.5104873.v1

Patent number

USRE032896