Nitrogen → HCID 66928550, compound

Participants

Reaction Steps

In a flame dried round-bottomed flask equipped with a magnetic stir bar and under inert atmosphere (N2), a solution of [5-(2-methyl-[1,3]dioxolan-2-yl)-thiophen-3-yl]-methanol (280 mg, 1.40 mmol) in dry CH2Cl2 (2.58 mL) was treated at 0° C. with Et3N (0.25 mL, 1.82 mmol) followed by DMAP (17 mg, 0.14 mmol) and Ms-Cl (0.13 mL, 1.68 mmol). The reaction mixture was stirred at rt for 2 h before being quenched with water (5 mL), extracted with CH2Cl2 (20 mL) and the combined org. extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure to give crude 2-(4-chloromethyl-thiophen-2-yl)-2-methyl-[1,3]dioxolane as a yellow oil. A solution of the crude material in acetone (3.5 mL) was treated, under inert atmosphere (N2) with K2CO3 (588 mg, 4.25 mmol) followed by 4-nitro-1H-pyrazole (181 mg, 1.42 mmol) and TBA bromide (91 mg, 0.28 mmol). The resulting mixture was stirred overnight at rt and then the solvent was removed under reduced pressure. Water (10 mL) and EA (20 mL) were added. The aq. layer was extracted with EA (80 mL) and the combined org. extracts were dried over MgSO4, filtered, and the solvents were removed under reduced pressure. Purification of the residue by FC (50:50 hept-EA) gave the title compound as a yellow solid. TLC: rf (50:50 hept-EA)=0.45. LC-MS-conditions 02: tR=0.96 min; [M+H]+=296.04.

Provenance & Evidence