Monoalkylation of primary amines and N-sulfinylamides

José Luis García Ruano, Alejandro Parra, José Alemán, Francisco Yuste, Virginia M. Mastranzo
2009 Chemical Communications  
1 H-NMR spectra were acquired at 200 or 300 MHz and 13 C-NMR were acquired at 50 or 75 MHz (unless otherwise indicated). Chemical shifts (δ) are reported in ppm relative to CDCl 3 (7.26 and 77.0 ppm). Flash column chromatography was performed using silica gel Merk-60 (230-400 mesh). For synthesis of p-tolylsulfinamides 1 were used anhydrous solvents and under argon atmosphere. THF was distilled from sodiumbenzophenone under argon. n-BuLi (2.5 M solution in hexane) and amines were purchased from
more » ... were purchased from Aldrich. Products 1a-b, 2a-b and 4a-b were synthesized following experimental procedure described in the literature. 2 Ra-Ni was purchased from Fluka (reference 83440-Activated Nickel Catalyst, puriss-suspension in water). General Procedure for the Synthesis of the compounds 3a-b (Scheme 2) 2 To a solution of the corresponding amine (4a-b) or sulfinamide (1a-b) in EtOH (1.5 mL) was added a suspension of activated Raney nickel (1.2g). 3 The reaction was stirred for 2 hours, and the residue was purified by SCX column to afford pure amine. Yield is indicated in each case. N-Ethyl-1,2-diphenylethylamine (3a) Yield from 4a: 90%. Yield from 1a: 65%. Colorless oil. 1 H-NMR (200 MHz, CDCl 3 ): δ 7.35-7.10 (m, 10H), 3.85 (dd, N-Phenethylbutan-1-amine (8e) [CAS: 71594-24-6]. 16 Yield obtained from 2-phenylethanamine 7e using n-butanol as alcohol: 74%. Colorless oil. 1 H-NMR (300 MHz, CDCl 3 ): δ 7.22-7.17 (m, 2H), 7.15-7.08 (m, 3H), 2.78-2.66 (m, 2H), 2.64-2.50 (m, 2H), 2.43 (t, J = 5.9 Hz, 2H), 1.82 (bs, 1H), 1.41-1.36 (m, 2H), 1.35-1.29 (m, 2H), 0.84 (t, J = 7.0 Hz, 3H).
doi:10.1039/b816846f pmid:19137166 fatcat:idlpl5j2rrdozn6y7lxxjmtkz4