Crystal structure of 3-(p-bromobenzoyl)-4-(p-bromophenyl)-1-isopropyl-4- piperidinol hydrochloride, C<inf>21</inf>H<inf>24</inf>Br<inf>2</inf>ClNO <inf>2</inf>

Abstract

(Equation presentation) (Table presentation) Source of material Themixture of suitable ketone, paraformaldehyde and isopropylamine hydrochloride in 2:2:1 mol ratios was stirred and heated without solvent in an oil bath. Mono Mannich base, namely 1-pbromophenyl- 3-isopropylamino-1-propanone hydrochloride, and a piperidinol type compound, namely 3-(p-bromobenzoyl)- 4-(p-bromophenyl)-1- isopropylamino-4-piperidinol hydrochloride were produced in the reaction medium at the same time. Corresponding mono Mannich base of the title compound produced in the reactionmedium was removed from the reactionmedium to obtain the title compound. Solution of NaOH (5%) was added on residue. Reaction content was stirred at water bath at 313 K. Stirring was continued for 48 h observing the solidification of oily residue. Purification by crystallization from chloroform-hexane gave a white solid, yield 14 %, m.p. 485-487 K). Although solution of NaOH %5 was used, the elemental analysis result suggested that the salt with N-protonation was obtained. This information was confirmed by X Ray study. [Yield: 14 %, m.p.: 485-487 K]. 1H NMR (400 MHz, CDCl3, ppm) δ 1.44 (d, J = 6.6 Hz, 3H), 1.53 (d, J = 6.6 Hz, 3H), 1.94 (br d, J = 14.3 Hz, 1H), 2.84-2.91 (m, 1H), 3.31-3.51 (m, 5H), 5.01 (d, J = 2.6 Hz, 1H, OH), 5.78 (dd, J = 12.1, 3.7 Hz, 1H), 7.36 (d, J = 8.4 Hz, 2H), 7.43 (d, J = 8.4 Hz, 2H), 7.61 (d, J = 8.4 Hz, 2H), 8.02 (d, J = 8.4 Hz, 2H); 13C NMR (100 MHz, CDCl3, ppm) δ 16.3, 17.6, 36.4, 43.7, 46.1, 47.7, 58.5, 72.2, 122.0, 126.6, 130.9, 131.3, 132.0, 132.3, 133.0, 143.2, 201.2; MS (EI) m/z: 482.4; IR (KBr,cm-1): 1675 (CO). Calcd. for C21H24Br2ClNO2 (517.68): C, 48.72; H, 4.67; N, 2.71. Found: C, 48.74; H, 4.70; N, 2.83. (Table presentation) Discussion The piperidinium ring (N1/C4-C8), (Fig.1), adopts a chair conformation with the puckering parameters [1] of QT = 0.593(4) Å, θ = 174.4(4)°, φ = 179(4)°. The dihedral angle between the benzene rings (C9-C14 and C16-C21) is 61.4(2)°. The O1-C15-C7-C6, O2-C6-C7-C15, C1-C2-N1-C8 and C3-C2-N1-C8 torsion angles are -74.3(5), -56.0(5), 159.8(4) and -74.4(5)°, respectively. The Br-C1 bond lengths are 1885(5) and 1.895(5) Å and the C6-O2 bond length is 1.429(5) Å. The C11-C12-Br1 and C9-C6-O2 bond angles are 119.2(4)° and 107.7(3)°, respectively. The values are in agreement with those in [2] (1.904(2) Å, 1.416(2) Å and 119.66(14)°, 105.76(14)°), respectively. An intramolecular O-H...O hydrogen bond forms a pseudo six-membered ring with S(6) ring motif [3]. The chloride counter anion is connected to the protonated nitrogen atom by a medium strong hydrogen bond. (Table presentation).