1,8-Diazabicyclo(5.4.0)undec-7-ene → HCID 19434056, compound

Participants

Reaction Steps

A solution of the product from Step B (36.25 g) and p-toluenesulfonic acid hydrate (2.0 g) in acetone (300 mL) was heated at reflux temperature for 6 h, cooled and a saturated aqueous solution of sodium bicarbonate (100 mL) was added. Acetone was evaporated and the aqueous mixture was extracted with ether (2×100 mL). The combined extracts were dried (MgSO4) and evaporated to give a dark brown oil which was dissolved in ethyl acetate (200 mL). DBU (2 mL) was added to this solution and after 1 h the reaction mixture was washed with 2N HCl and brine, dried (MgSO4), and evaporated to give a solid which was recrystallized from 25% ethyl acetate/hexane to give 9.95 g of product. The mother liquor was chromatographed (silica, 25% ethyl acetate/hexane) to give an additional 3.57 g of product (total 13.52 g, 50%): mp 97°-99° C.

Provenance & Evidence