2,4-Dichloro-5-(1,3-dioxolan-2-yl)thiazole synthesis

Yield:141764-85-4 100%

Reaction Conditions:

with toluene-4-sulfonic acid in toluene at 120;Dean-Stark;

Steps:

70.1 Step 1: Example 70b

A solution of Example 70a (1.0 g, 5.52 mmol, 1.0 eq.), ethane -1, 2 -diol (1.02 g, 16.57 mmol, 3.0 eq.) and p-TsOH (105 mg, 0.55 mmol, 0.1 eq.) in PhMe (15 mL) at 120°C with Dean-Stark trap and stirred overnight. TLC (PE/EtOAc=3/l) showed the starting material was consumed completely. The reaction mixture was cooled to room temperature and washed with sat. aq. NaHC0₃ (20 mL), brine (2*20 mL), dried over Na₂S0₄, filtered and concentrated to afford Example 70b ( 1.29 g, 100% yield) as a yellow liquid. LCMS [M+H]⁺=225.1

References:

WO2017/218960,2017,A1 Location in patent:Paragraph 00646