Acetyl chloride → Dihydro-4-(2-methylpropyl)-2H-pyran-2,6(3H)-dione

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Reaction Steps

3-Isobutylglutaric acid (156 g) and acetyl chloride (130 g) are combined and placed under reflux for 16 hours. The mixture is distilled at atmospheric pressure until a distillate reflux temperature of 135° C. is reached. The mixture is then cooled and placed under vacuum distillation to give 129 g of 3-isobutylglutaric acid anhydride (boiling point 127°-128° C., 1 mm Hg). 1H-NMR (CDCl3, 200 MHz): δ 0.91 (d, 6H, J=6.6 Hz), 1.20-1.24 (m, 2H), 1.52-1.78 (m, 1H), 2.10-2.45 (m, 3H), 2.79-2.91 (m, 2H). 13C-NMR (CDCl3, 50 MHz): δ 166.53, 43.99, 36.48, 26.79, 25.08, 22.57. IR (neat): 559.3, 592.0, 609.4, 659.5, 837.0, 954.6, 1033.7, 1070.3, 1184.1, 1241.9, 1288.2, 1369.2, 1388.5, 1411.6, 1425.1, 1469.5, 1760.7, 1810.8, 2873.4, 2958.3, 3552.2 cm-1.

Provenance & Evidence