(R,S)-N-[(2-Oxocyclohexyl)methyl]-1-butanaminium Chloride
Edmont V. Stoyanov* and Ivo C. Ivanov
Faculty of Pharmacy, Medical University of Sofia,
Dunav 2, BG-1000 Sofia, Bulgaria
Tel.: (+359 2) 988 3142; Fax: (+359 2) 987 9874;
E-mail: [email protected]
Received: 20 January 2000 / Accepted: 15 May 2001 / Published: 25 May 2001
The Mannich bases of cyclohexanone with benzylamine
and 3,4-methylenedioxybenzylamine hydrochlorides have been prepared in
moderate yields using aqueous formaldehyde solution [1]. We report now
the synthesis of an analogous product from n-butylamine. A mixture
of cyclohexanone (2.00 g, 0.02 mol), paraformaldehyde (1.20 g, 0.04 mol)
and n-butylamine hydrochloride (2.22 g, 0.02 mol) was refluxed under
stirring in anhydrous ethanol (15 mL) for 5 h (TLC monitoring). The reaction
mixture gradually turned into a solution. The solvent was then removed
under reduced pressure and the residue was triturated with ice-cooled acetone
(20 mL). The separated crystals were filtered, washed with cold acetone,
recrystallized from n-butanol and air-dried. Yield: 2.85 g (61 %)
of the title compound as colorless
crystals.
TLC homogeneous product (TLC: silica gel Merck
GF254 Al-sheets, eluted by chloroform-ethanol 3:1).
Mp. 139-140 ºC (n-butanol).
1H NMR (300 MHz, d6-DMSO): 0.87 (t, J = 7.4 Hz, CH3), 1.22-1.41 (m, 3H), 1.47-1.70 (m, 4H), 1.70-1.83 (m, 1H), 1.95-2.05 (m, 1H), 2.17-2.32 (m, 2H), 2.36-2.49 (m, 1H), 2.67-2.78 (m, 1H), 2.83 (dd, J1 »J2» 6 Hz, 2H, COCHCH2N), 2.97 [sextet, J = 6.2 Hz, 1H, COCH(CH2)2], 3.10-3.20 (m, 1H), 9.0 (br. s, N+H2).
FT IR (fluorolube): 3050-3400, 2942, 2937, 2747, 2566, 2458, 1713 (C=O), 1622, 1588, 1478, 1460, 1445, 1390, 1345.
EI MS [70 eV; m/z (%)]: 184 (2; MH+),
183 (9; M.+), 140 (53), 86 (100), 44 (64), 30
(45);
FAB MS [glycerol; m/z (%)]:403 (17; M+2
glycerol+HCl), 367 (1; 2M+H+), 276 (4; 2M+H+), 184
(100; MH+ = C11H22NO+), 140
(2), 86 (27), 44 (3).
Anal. calcd. for C11H22NOCl (219.76): C 60.12, H 10.09, N 6.37, Cl 16.13; found C 60.04, H 9.99, N 6.33, Cl 16.43.
Reference
1. Mannich, C.; Hieronimus, O. Ber. Dtsch. Chem. Ges. 1942, 75, 49-55.
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