反应详情

A stream of diazomethane (from N-methyl-N-nitrosotoluene-4-sulphonamide, 18.0 g) in argon (P. Lombardi, Chem. and Ind., 1990, (21), 708) was passed into a solution of (RS)-tetrahydrofuroyl chloride [prepared from (RS)-tetrahydrofuroic acid (3.48 g, 30 mmol) as described in Example 2(a)] in dichloromethane (60 ml) cooled in an ice bath. When the diazomethane addition was complete, 48% aqueous hydrogen bromide (5.6 ml, 33.2 mmol) was added. The mixture was stirred 0.25 h then washed twice with water, dried, concentrated and flash chromaographed on silica gel eluting with 10% ethyl acetate in hexane to give the title compound as a pale yellow oil (4.44 g, 77%); νmax (CH2Cl2) 1733, 1245, 1073 and 938 cm-1 ; δH (CDCl3) 1.85-2.35 (4 H, m), 3.85-4.05 (2 H, m), 4.20 (2 H, s), 4.54 (1 H, dd, J 6.1, 8.2 Hz). [Mass spectrum: +ve ion (ammonia) MNH4+ (210)].

1. temperaturecooled in an ice bath
2. washthen washed twice with water
3. customdried
4. concentrationconcentrated