6-(oxan-2-yloxy)hexanal

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Pyridine-sulphur trioxide complex (17.1 g., 0.108 mole) in dimethylsulphoxide (90 ml.) was added dropwise to a mixture of 6-(2-tetrahydropyranyloxy)-hexanol (7.2 g., 0.036 mole) and triethylamine (27 g., 0.27 mole) in dimethylsulphoxide (90 ml.) at 25°C. The mixture was stirred for a further hour, then 2N acetic acid (100 ml.), water (200 ml.) and diethyl ether (500 ml.) added successively, the layers separated and the aqueous layer extracted with diethyl ether. The combined ether solutions were washed quickly with 2N hydrochloric acid, aqueous sodium carbonate and then water, and dried over sodium sulphate. The solvent was evaporated and the residue distilled under reduced pressure to give 6-(2-tetrahydropyranyloxy)hexanal (4.65 g., 63%), b.p. 75°-105°C./0.15 mm.Hg. the layers separated the aqueous layer extracted with diethyl ether The combined ether solutions were washed quickly with 2N hydrochloric acid, aqueous sodium carbonate water, and dried over sodium sulphate The solvent was evaporated the residue distilled under reduced pressure

Conditions: temp:100.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 6-(2-tetrahydropyranyloxy)hexanal (23.2 g., 0.116 mole) and 1-morphdinocyclopentene (25.5 g., 0.16 mole) in benzene (30 ml.) was heated under reflux for 12 hours under nitrogen, and the water liberated was continuously removed with a Dean and Stark head. Benzene (12 ml.) and then, dropwise, 18% hydrochloric acid (28 ml.) were added and the mixture was stirred for 2 hours. The organic layer was separated and evaporated. Concentrated hydrochloric acid (84 ml.) and butanol (350 ml.) were added to the residue. The mixture was heated at 100°C. for 1 hour, and then the solution was concentrated to give an oil. Diethyl ether was added, and the ether solution was washed with aqueous sodium bicarbonate and then water, and dried over sodium sulphate. The solvent was evaporated and the residue was distilled under reduced pressure to give 2-(6-hydroxyhexyl)-2-cyclopenten-1-one (10.7 g., 50%), b.p. 105°-160°C./15 mm.Hg, nD25 1.491. was heated under reflux for 12 hours under nitrogen the water liberated was continuously removed with a Dean and Stark head Benzene (12 ml.) and then, dropwise, 18% hydrochloric acid (28 ml.) were added The organic layer was separated evaporated Concentrated hydrochloric acid (84 ml.) and butanol (350 ml.) were added to the residue the solution was concentrated to give an oil the ether solution was washed with aqueous sodium bicarbonate water, and dried over sodium sulphate The solvent was evaporated the residue was distilled under reduced pressure