反应详情

Diethyl azodicarboxylate (DEAD, 11.9 mL; 75.6 mmol) was added dropwise over a 10 min period to a solution of triphenylphosphine (19.8 g; 75.6 mmol), (2-methyl-5-furanyl)propanol (ex 1a, 9c and 12a) (10.6 g; 75.6 mmol), and 4-hydroxy-3,5-dimethyl-benzonitrile (12.2 g; 83.2 mmol) in methylene chloride cooled in an ice-bath under nitrogen with stirring. After 10 min, a solid formed. Additional methylene chloride (50 mL) was added to the mixture and the resulting suspension was filtered. The filtrate was washed with water (2×100 mL) and brine (1×100 mL). The organic layer was dried over anhydrous magnesium sulfate, and concentrated in vacuo to yield a brown oil which crystallized on standing. The solid product was chromatographed on silica gel eluting with ethyl acetate/hexane (2:8), and the appropriate fractions were concentrated in vacuo to afford 16.43 g (81%) of 2-methyl-5-[3-(2,6-dimethyl-4-cyanophenoxy)-propyl)furan. The cyano moiety is then elaborated to a suitably substituted 5-tetrazolyl moiety as in the preparation of Intermediates 5-6 or oxadiazolyl as in Intermediates 7-8, giving a compound of formula II wherein R3 is methyl, R4 is hydrogen, R1, R2 is 3,5-dimethyl Y is 1,3-propylene and R5 is as described.

1. temperaturecooled in an ice-bath under nitrogen
2. customa solid formed
3. filtrationthe resulting suspension was filtered
4. washThe filtrate was washed with water (2×100 mL) and brine (1×100 mL)
5. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
6. concentrationconcentrated in vacuo
7. customto yield a brown oil which
8. customcrystallized
9. customThe solid product was chromatographed on silica gel eluting with ethyl acetate/hexane (2:8)
10. concentrationthe appropriate fractions were concentrated in vacuo