反应详情

5.0 g. (14.6 mmoles) of 4,4-dimethyl-9-hydroxy-7-(3-methyl-2-octyl)-1,2,3,4-tetrahydrocyclopenta[c][ l] benzopyran, 3.14 g. (15.2 mmoles) of dicyclohexylcarbodiimide and 3.15 g. (15.2 mmoles) of γ-piperidinobutyric acid hydrochloride (m.p. 190°-192°), Cruickshank & Sheehan, J. Am. Chem. Soc. 83, 2891 (1961), were combined with 250 ml. of methylene chloride and stirred for a total of 40 hours at room temperature. The insoluble by-product of dicyclohexylurea was separated by filtration and the methylene chloride was removed using a rotary evaporator. The brown residue was treated with approximately 75 ml. of benzene, and filtered to remove a small amount of insoluble material. The benzene was evaporated and the brown viscous residue was triturated with about 200 ml. of ether to give 4.3 g. of crude product as a light brown solid, m.p. 174°-176°. Recrystallization from benzene gave a total of 3.5 g. (45%) of product as colorless crystals, m.p. 174°-176°. The infrared and nmr spectra are in agreement with the proposed structure.

1. customThe insoluble by-product of dicyclohexylurea was separated by filtration
2. customthe methylene chloride was removed
3. customa rotary evaporator
4. additionThe brown residue was treated with approximately 75 ml
5. filtrationof benzene, and filtered
6. customto remove a small amount of insoluble material
7. customThe benzene was evaporated
8. customthe brown viscous residue was triturated with about 200 ml
9. customof ether to give 4.3 g
10. customRecrystallization from benzene
11. customgave a total of 3.5 g