p-Toluenesulfonic acid → Tetrahydro-2-(2-propynyloxy)-2H-pyran

Temperature

0 °C

To a stirred solution of 112 g. (2.0 mol.) of 3-hydroxy-1-propyne and 260 g. (3.0 mol.), of dihydropyran in 1.20 1. of methylene chloride cooled to 0° C. in an ice bath, is added a solution of 20 mg. of para-toluenesulfonic acid in 100 ml. of methylene chloride, dropwise. The reaction mixture is stirred at 0° C. for one-half hour, and at ambient temperature for one hour. It is then poured into 200 ml. of a 5% solution of sodium bicarbonate, the organic phase is separated, the aqueous phase extracted with 100 ml. of methylene chloride, the combined organic phases washed with 100 ml. of a solution of brine, dried over sodium sulfate, and evaporated under vacuum (12 mm.) at 45° C., to give 300 g. of crude product, which is purified by fractional distillation, b,p, 71°-73° C. (14 mm.) to yield 250 g. (89%) of a liquid.

1. additionis added a solution of 20 mg
2. additionIt is then poured into 200 ml
3. customof a 5% solution of sodium bicarbonate, the organic phase is separated
4. extractionthe aqueous phase extracted with 100 ml
5. washof methylene chloride, the combined organic phases washed with 100 ml
6. dry with materialof a solution of brine, dried over sodium sulfate
7. customevaporated under vacuum (12 mm.) at 45° C.
8. customto give 300 g
9. distillationof crude product, which is purified by fractional distillation, b,p, 71°-73° C. (14 mm.)
10. customto yield 250 g

ORD record

ord-188074e052584821bace768b640ac371

Source dataset

uspto-grants-1980_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04219664