5,5-Dimethyl-2-n-pentyltetrahydro (CAS NO.: ), which is also known as Furan, tetrahydro-2,2-dimethyl-5-pentyl-, could be produced through the following synthetic routes.

In a 100-ml., three-necked, round-bottomed flask, fitted with a sealed mechanical stirrer, a reflux condenser, and a thermometer reaching to the bottom of the flask, are placed 37.6 g. (0.2 mole) of 2-methyl-2,5-decanediol (p.601) and 17 g. of 85% phosphoric acid. The limpid liquid obtained is heated and maintained at 125° for 40 minutes. Then the acidic lower layer is discarded, and the organic layer is washed with three or four 50-ml. portions of lukewarm distilled water.

Distillation of the resulting crude oil using a simple fractionating column gives 32–33 g. (94–97%) of pure 5,5-dimethyl-2-n-pentyltetrahydrofuran as a colorless liquid boiling at 31–33°/1.5 mm.; n_D25 1.4257.