Reaction #1483092

Reaction equation

DDAIP

4

dodecyl 2-(dimethylamino)propanoate

1,5-napthalene disulfonic acid

→

dodecyl 2-(dimethylamino)propanoate 1,5-napthalene disulfonate salt

Yield 92.3%

Solvents

methanol

Conditions

Workup

1. 1
   workup.ADDITIONAfter addition the temperature of the reaction mixture
2. 2
   ConcentrationThe reaction mixture was concentrated under vacuum
3. 3
   Otherflushed with ethyl acetate (2×30 mL)
4. 4
   workup.STIRRINGstirred at RT for ½ h (sticky solid)
5. 5
   ConcentrationThe reaction mixture was concentrated under vacuum
6. 6
   Otherflushed with hexane (3×100 mL)

Procedure

A stirred solution of DDAIP base 4 (80 g, 280 mmol) in methanol (500 mL) was cooled to 0° C., then 1,5-napthalene disulfonic acid 22 (50.5 g, 140 mmol) was added in one lot. After addition the temperature of the reaction mixture was slowly raised to RT and stirred at RT for 72 h; the reaction mixture was monitored by TLC. The reaction mixture was concentrated under vacuum and flushed with ethyl acetate (2×30 mL). The obtained residue was taken in n-hexane (200 mL) and stirred at RT for ½ h (sticky solid). The reaction mixture was concentrated under vacuum and flushed with hexane (3×100 mL) to afford dodecyl 2-(dimethylamino)propanoate 1,5-napthalene disulfonate salt (23, Nex-32) (120 g, 92.3%) as a white solid. Mp: 135-140° C. 1H-NMR (400 MHz, CDCl3): δ 0.9 (t, 3H), 1.2-1.3 (m, 18H), 1.6 (d, 3H), 1.65 (q, 2H), 2.9 (s, 6H), 4.15 (t, 2H), 4.2 (q, 1H), 7.55 (t, 2H), 8.22 (d, 2H), 9.1 (d, 2H); LCMS: 286 (M++1); HPLC: 80.48%.

Source