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

ORD record

ord-ad90064ec00641169fa1a61c2bc78374

Source dataset

uspto-grants-1978_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US04111959