Phosphorus oxychloride → Ethyl 3-methyl-1-(4-methylphenyl)sulfonyl-2,5-dihydropyrrole-2-carboxylate

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Reaction Steps

The pyrrolidine oil 82 (10.5 g, 32.11 mmol) was dissolved in pyridine (86 mL). POCl3 (7.48 mL, 80.27 mmol) was added dropwise and the resulting mixture stirred overnight at room temperature. The mixture was poured over ice, extracted with ether and washed with 5% aq. HCl, 5% sodium bicarbonate solution and water. The ether layer was dried over sodium sulfate, filtered and evaporated under reduced pressure to give the crude solid 83 (8.80 g, 88%). 1H-NMR (400 MHz, CDCl3): δ 1.28 (t, 3H), 1.69 (m, 3H), 2.43 (s, 3H), 4.10 (m, 1H), 4.20 (q, 2H), 4.21 (m, 1H), 7.31 (d, 2H), 7.75 (d, 2H) ppm. 13C-NMR (100 MHz, CDCl3): δ 13.58, 14.10, 21.56, 54.64, 61.62, 70.55, 110.02, 122.51, 127.51, 129.73, 169.87 ppm. DEPT (100 MHz, CDCl3): CH3 carbons: 13.58, 14.10, 21.56; CH2 carbons: 54.64, 61.62; CH carbons: 70.55, 122.51, 127.51, 129.73 ppm. LC/MS: 100%, m/z=309.

Provenance & Evidence