Pyrrolidine → 6-Bromo-3-methyl-2',4',5',6'-tetrahydrospiro[chroman-2,3'-pyran]-4-one

Participants

Reaction Steps

A mixture of 1-(5-bromo-2-hydroxyphenyl)propan-1-one (5.7 g, 25 mol), dihydro-2H-pyran-3(4H)-one (5 g, 50 mmol) and pyrrolidine (3.4 g, 48 mmol) in methanol (80 mL) was stirred overnight. The reaction mixture was removed in vacuo, and H2O was added. The resulting solution was extracted with ethyl acetate. The ethyl acetate solution was dried over anhydrous Na2SO4, filtered, and evaporated to give 6-bromo-3-methyl-2′,4′,5′,6′-tetrahydrospiro[chroman-2,3′-pyran]-4-one (1.2 g, 16%). 1HNMR (CDCl3): 1.16-1.27 (m, 3H), 1.51-1.57 (m, 1H), 1.66-1.73 (m, 1H), 1.91-2.08 (m, 2H), 2.59-2.69 (m, 1H), 3.46-3.56 (m, 2H), 3.88-3.98 (m, 2H), 6.97 (m, 1H), 7.58 (m, 1H), 7.95 (s, 1H).

Provenance & Evidence