Dimethyl Sulfoxide → Ethyl 4-formylpiperidine-1-carboxylate

A solution of 1.2 equivalents oxalyl chloride (12.69 g, 0.10 mol) in dichloromethane (150 mL) was cooled to approximately −78° C. and treated dropwise, under nitrogen, with a solution of 2.4 equivalents anhydrous dimethylsulfoxide (15.63 g, 0.20 mol) in dichloromethane (50 mL). 15 minutes after the addition was complete, a solution of 1.0 equivalents ethyl 4-(hydroxymethyl)-piperidine-1-carboxylate (15.60 g, 83.3 mmol) in dichloromethane (50 mL) was added dropwise. 30 minutes after the addition was complete, a solution of 3.0 equivalents triethylamine (25.30 g, 0.25 mol) in dichloromethane (50 mL) was added dropwise and the reaction warmed to room temperature. The reaction was stirred at room temperature for 1 hr, then quenched with saturated sodium bicarbonate (500 mL). The layers were separated and the aqueous layer extracted once with dichloromethane (200 mL). The pooled organic layers were washed with H2O (3×100 mL), saturated sodium bicarbonate (1×100 mL) and saturated brine, then dried (Na2SO4) and filtered. The filtrate was concentrated in vacuo to afford 13.84 g ethyl 4-formylpiperidine-1-carboxylate (D3) as a viscous amber oil. 1H-NMR (400 MHz, CDCl3) δ 9.64 (s, 1H), 4.10 (q, J=7.2 Hz, 2H), 4.00 (br m, 2H), 2.97 (m, 2H), 2.40 (m, 1H), 1.87 (br m, 2H), 1.54 (m, 2H), 1.23 (t, J=7.0 Hz, 3H).

1. addition15 minutes after the addition
2. addition30 minutes after the addition
3. customquenched with saturated sodium bicarbonate (500 mL)
4. customThe layers were separated
5. extractionthe aqueous layer extracted once with dichloromethane (200 mL)
6. washThe pooled organic layers were washed with H2O (3×100 mL), saturated sodium bicarbonate (1×100 mL) and saturated brine
7. dry with materialdried (Na2SO4)
8. filtrationfiltered
9. concentrationThe filtrate was concentrated in vacuo

ORD record

ord-04134088687e4545b51ea436dd4c3438

Source dataset

uspto-grants-2012_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08263605B2