Dimethyl Sulfoxide → Ethyl 2-methyl-5-oxo-1,3-dioxane-2-carboxylate

To a chilled (−78° C.) DCM solvent (10 mL) under nitrogen was added a 2 M stock solution of oxalyl chloride (6.03 mL, 12.05 mmol), followed by the slow addition of dimethyl sulfoxide (0.927 mL, 13.06 mmol). Once evolution of gases stopped, stirring continued for another 20 minutes forming a snow white suspension. A solution of the crude ethyl 5-hydroxy-2-methyl-1,3-dioxane-2-carboxylate (Step 2, 1.91 g, 10.04 mmol) in 5 mL of DCM was transferred into the cold Swern solution over a period of 2 minutes via a cannula. The reaction was allowed to proceed at −78° C. for 30 minutes, followed by the slow addition of triethylamine (3.36 mL, 24.10 mmol). The resulting pale suspension was stirred at −78° C. for a further 30 minutes, then at 4° C. (ice bath) for 15 minutes. The Rx was quenched with saturated sodium bicarbonate solution (20 mL), followed by extraction with DCM (5×25 mL). The organic layers were combined, evaporated to an oily material (1.81 gm, 96%). 1H NMR (400 MHz, CHLOROFORM-d) δ 4.45-4.37 (m, 2H), 4.31 (q, J=7.3 Hz, 2H), 4.33-4.26 (m, 2H), 1.58 (s, 3H), 1.36 (t, J=7.2 Hz, 3H).

1. customforming a snow white suspension
2. waitto proceed at −78° C. for 30 minutes
3. stirringThe resulting pale suspension was stirred at −78° C. for a further 30 minutes
4. waitat 4° C. (ice bath) for 15 minutes
5. customThe Rx was quenched with saturated sodium bicarbonate solution (20 mL)
6. extractionfollowed by extraction with DCM (5×25 mL)
7. customevaporated to an oily material (1.81 gm, 96%)

ORDレコード

ord-45e8af2ad872446e9b27430677ccf445

出典データセット

uspto-grants-2014_12

DOI

10.6084/m9.figshare.5104873.v1

特許番号

US08906889B2