mPEG8-Alkyne synthesis

Yield:880081-81-2 96%

Reaction Conditions:

Stage #1: 2-[2-[2-[2-[2-[2-[2-(2-methoxyethoxy)ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethoxy]ethanolwith sodium hydride in tetrahydrofuran at 0 - 5; for 0.0833333 h;
Stage #2: propargyl bromide in tetrahydrofuran at 0 - 5; for 1 h;

Steps:

261a Intermediate 261a

Into a 500-mL round-bottom flask, was placed a solution of 2-(2-(2-(2-(2-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethanol (15 g, 39.06 mmol, 1.00 equiv) in tetrahydrofuran (150 mL).
This was followed by the addition of sodium hydride (1.9 g, 79.17 mmol, 1.01 equiv), in portions at 0-5° C. in 5 min.
To this was added a solution of 3-bromoprop-1-yne (9.3 g, 78.81 mmol, 2.02 equiv) in toluene (20 mL) dropwise with stirring at 0-5° C. in 5 min.
The resulting solution was stirred for 1 h at 0-5° C. in a water/ice bath.
The reaction progress was monitored by LCMS/TLC (ethyl acetate/petroleum ether=1:1).
The solids were filtered out.
The resulting mixture was concentrated under vacuum.
This resulted in 15.9 g (96%) of 3-(2-(2-(2-(2-(2-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethoxy)ethoxy)prop-1-yne as brown oil

References:

US9301951,2016,B2 Location in patent:Page/Page column 494