Fuson, Reynold C. published the artcileRing enlargement by rearrangement of the 1,2-aminochloroalkyl group; rearrangement of 1-ethyl-2-(chloromethyl)pyrrolidine to 1-ethyl-3-chloropiperidine, HPLC of Formula: 13444-24-1, the publication is Journal of the American Chemical Society (1948), 2760-2, database is CAplus.
Reduction of 1,2-dicarbethoxypyrrole over Raney Ni in dry MeOH at 70°/1500 lb. gives 95% 1,2-dicarbethoxypyrrolidine; further reduction over Cu chromite in EtOH at 250°/100 atm. gives 31% 1-ethyl-2-hydroxypyrrolidine (I); the HCl salt and benzoate-HCl are oils; benzoate picrate, m. 170.5-1.5°. Diethyl(tetrahydrofurfuryl)amine yields 43% 1-ethyl-3-hydroxypiperidine, which forms a HCl salt (II), m. 157-8°, and a benzoate picrate, yellow, m. 181.5-2.5°. I (4 g.) in 25 ml. CHCl3 at 0°, treated with HCl to form the HCl salt and then with 4.8 g. SOCl2 in CHCl3, and the mixture stirred 30 min. at room temperature and refluxed 1 hr., gives 56% 1-ethyl-2-(chloromethyl)pyrrolidine-HCl (III), m. 165-70° (heated 20°/min.), solidifies, and m. 153.5-4°; slowly heated, III contracts at 165° and m. 193.5-4°; picrate, m. 128.5-9.5°. The Me2CO used to wash the crude III yields 1.4 g. 1-methyl-2-(chloromethyl)pyrrolidine picrate (?) (IV), m. 163.5-4.5°; it is possible that I contained some 1-ethyl-2-(hydroxymethyl)pyrrolidine. II (5 g.) and 3.7 g. SOCl2 in 50 ml. PhMe, refluxed 3 hrs., give 87% 1-ethyl-3-chloropiperidine (V) as the HCl salt (VI), m. 193.5-4°; a mixture of III and VI also m. 193.5-4°. The base from III appears to undergo rearrangement to V as rapidly as it is liberated, an ethylenimonium ion probably being an intermediate. The base (V) from VI does not undergo rearrangement on liberation. The attempt to prepare 1-methyl-3-chloropiperidine from IV was inconclusive.
Journal of the American Chemical Society published new progress about 13444-24-1. 13444-24-1 belongs to piperidines, auxiliary class Piperidine,Alcohol, name is 1-Ethylpiperidin-3-ol, and the molecular formula is C7H15NO, HPLC of Formula: 13444-24-1.
Referemce:
https://en.wikipedia.org/wiki/Piperidine,
Piperidine | C5H11N – PubChem