Nitrogen → 2-[5-(2-Methyl-[1,3]dioxolan-2-yl)-thiophen-2-ylmethyl]-4,5-dihydro-oxazole-4-carboxylic acid methyl ester

Participants

Reaction Conditions

Reaction Steps

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of 3-hydroxy-2-{2-[5-(2-methyl-[1,3]dioxolan-2-yl)-thiophen-2-yl]-acetylamino}-propionic acid methyl ester (470 mg, 1.43 mmol) in dry THF (5 mL) was added at 0° C. to solution of (methoxycarbonylsulfamoyl)triethylammonium hydroxide (455 mg, 1.83 mmol) in dry THF (10 mL) and the resulting suspension was stirred at 0° C. for 20 min, followed by 15 min at rt. The reaction mixture was then stirred at reflux for 1 h. The mixture was then allowed to cool down to rt and filtered. The filter cake was rinsed with ether and EA and the filtrate was concentrated under reduced pressure. Purification of the residue by FC (1:1→1:0 EA-Hept) gave the title compound as a yellow oil. TLC: rf (EA)=0.6. LC-MS-conditions 02: tR=0.70 min, [M+H2O+H]+=329.90.

Provenance & Evidence