反应详情

To a solution of 2-methyl-3-furoic acid (34.75 g, 0.3469 mol) in dry methylene chloride (200 ml) under an argon atmosphere, were added a catalytic amount of dimethylformamide followed by dropwise addition of oxalyl chloride (45.5 ml, 0.5216 mol). After the addition the reaction mixture was allowed to stir until the effervescence had subsided (4.0 hours). The excess oxalyl chloride/methylene chloride was evaporated and the residue was dissolved in methylene chloride (200 ml). The solution was cooled (ice/acetone) and diethylamine (75.0 ml, 0.725 mol) in methylene chloride (100 ml) was added dropwise. After the addition (1.0 hour) the reaction was poured into ice/water and the solution was acidified to a pH of 3.0. The mixture was extracted with diethyl ether (4×200 ml). The combined extracts were washed with saturated sodium carbonate solution (2×50 ml), water (4×50 ml), brine (2×25 ml), and dried (MgSO4). Solvent evaporation gave 59.75 g of crude product. The oil was distilled to give 52.45 g (83% yield) of product which crystallized upon standing (bp: 91° C./1.2 mmHg; mp 32°-34° C.).

1. additionAfter the addition the reaction mixture
2. custom(4.0 hours)
3. customThe excess oxalyl chloride/methylene chloride was evaporated
4. dissolutionthe residue was dissolved in methylene chloride (200 ml)
5. additionwas added dropwise
6. additionAfter the addition (1.0 hour) the reaction
7. extractionThe mixture was extracted with diethyl ether (4×200 ml)
8. washThe combined extracts were washed with saturated sodium carbonate solution (2×50 ml), water (4×50 ml), brine (2×25 ml)
9. dry with materialdried (MgSO4)
10. customSolvent evaporation
11. customgave 59.75 g of crude product
12. distillationThe oil was distilled