(+)(2aR,4S)-l-benzoyl-6-iodo-4-(di-n-propylamino)-1,2,2a,3,4,5-hexahydrobenz[cd]indole → (2aR,4S)-1-benzoyl-6-(2-oxazolyl)-4-(di-n-propylamino)-1,2,2a,3,4, 5-hexahydrobenz[cd]indole

Participants

Reaction Steps

A solution of 5.0 g (13.8 mmol) of the crude 2-tributylstannyloxazole prepared above and 6.8 g (13.9 mmol) of (+)(2aR,4S)-1-benzoyl-6-iodo-4-(di-n-propylamino)-1,2,2a, 3,4, 5-hexahydrobenz[cd]indole in 100 ml of toluene was treated with 0.7 g (0.6 mmol) of tetrakis(triphenylphosphine)palladium then refluxed under nitrogen for 20 hours. After cooling the reaction mixture was washed with a saturated brine solution and then dried over Na2SO4. Concentration in vacuo provided a viscous oil which was chromatographed over a silica gel column using a solvent gradient progressing from toluene to 1:1 toluene/EtOAc. The product from the column was dissolved in 1M HCl. This solution was then washed with ether, made alkaline with 5M NaOH, and extracted with CH2Cl2. Concentration of the extract in vacuo gave about 4 g of a brown oil. When this oil was dissolved in pentane a small amount of a red/brown resin separated leaving a clear, yellow solution. The resin was separated and the pentane was evaporated to provide a residue. This residue was crystallized by dissolving it in a small amount of CH2Cl2 and slowly adding isoctane. The crystalline (-)(2aR,4S)-1-benzoyl-6-(2-oxazolyl)-4-(di-n-propylamino)-1,2,2a,3,4, 5-hexahydrobenz[cd]indole, obtained in four crops, weighed 2.63 g. mp 103°-104° C.

Provenance & Evidence