is observed ph 7 it is poured onto 50 ml water and extracted 3 times with 20 ml chloroform the combined organic phases are dried over anhydrous sodium sulfate and the solvent is removed by distillation until dryness in a rotary evaporator the residue that is obtained is purified by column chromatography on silica gel using a gradient running from chloroform to ethanol nmr cdcl 3 c h 3 ch 2 u2014 1 10 ppm t 3 u2014 c h 2 u2014 n 3 25 ppm q 2 2 u00d7 c h 3 u2014 1 27 ppm s 6 u2550 c h 5 53 ppm s 1 u2014 c h 2 so 2 n 3 96 ppm s 2 h 5 aromatic 7 10 ppm s 1 h 7 aromatic 7 05 ppm d 1 h 8 aromatic 6 46 ppm d 1 h 2 c u2014 oh 4 47 ppm s 1 u2014 o u2014 c h 3 3 57 ppm s 1 c h piperidine c u2550 o 2 29 ppm m 1 n u2014 c hh u2032 piperidine 2 82 ppm and 3 53 ppm m 2 2 hc u2014 c hh u2032 piperidine 1 68 ppm and 1 73 ppm m 2 2 u2014 ch 2 u2014 o h nn in order to prepare 1 methyl 7 methoxy 2 2 dimethyl 1 2 3 4 tetrahydroquinol 4 yl methanesulfonic acid 3 5 0 g 1 methyl 7 methoxy 2 2 dimethyl 1.