Reaction #1483088

Reaction equation

DDAIP

4

dodecyl 2-(dimethylamino)propanoate

benzene sulfonic acid

→

dodecyl 2-(dimethylamino)propanoate benzene sulfonate salt

Yield 99.5%

Solvents

ethyl acetate

Conditions

Workup

1. 1
   workup.ADDITIONAfter addition
2. 2
   ConcentrationThe reaction mixture was concentrated under vacuum
3. 3
   WashThe residue washed with hexane (2×30 mL)
4. 4
   workup.WAITThe obtained sticky solid was kept in deep freezer for 12 h

Procedure

A stirred solution of DDAIP base 4 (75 g, 263 mmol) in ethyl acetate (500 mL) was cooled to 0° C., then benzene sulfonic acid 14 (41.55 g, 263 mmol) was added in one lot. After addition, the temperature of the reaction mixture was slowly raised to RT and stirred at RT for 24 h; the reaction mixture was monitored by TLC. The reaction mixture was concentrated under vacuum. The residue washed with hexane (2×30 mL); after workup a sticky solid was observed. The obtained sticky solid was kept in deep freezer for 12 h to afford dodecyl 2-(dimethylamino)propanoate benzene sulfonate salt (15, Nex-16) (116 g, yield: 99.5%) as a solid, mp: 55-62° C. 1H-NMR (400 MHz, CDCl3): δ 0.9 (t, 3H), 1.3 (m, 18H), 1.65 (d, 3H), 1.65 (q, 2H), 3 (s, 6H), 4.2 (q, 1H), 4.2 (t, 2H), 7.4 (m, 3H), 7.9 (d, 2H); LCMS: 286 (M++1); HPLC: 80.48%.

Source