Potassium Hydroxide → HCID 20311410, compound

Participants

Reaction Steps

2,2-Diethyl-2H-benzo[b]pyran (3.86 g.) was treated with N-bromosuccinimide (7.40 g.) under the conditions described in Example 5 yielding trans-3-bromo-3,4-dihydro-2,2-diethyl-2H-benzo[b]pyran-4-ol (5.70 g.), as a pale yellow solid m.p. 75°-77° after trituration with 60°-80° petroleum ether. Reaction of this bromohydrin (5.60 g.) with potassium hydroxide pellets (6.38 g.) in diethyl ether (300 ml.) for 4.5 days following Example 7 gave 3,4-epoxy-3,4-dihydro-2,2-diethyl-2H-benzo[b]pyran as a colourless liquid (4.28 g.) displaying signals centred at δ 3.66 and 3.78 (doublets, of coupling constant J = 4Hz) in its p.m.r. spectrum (CDCl3, with TMS as internal standard) corresponding to protons located at C-3 and C-4. Treatment of this epoxide (1.40 g.) with isopropylamine (3.50 g., an excess) and work-up as in Example 1, gave trans-4-isopropylamino-3,4-dihydro-2,2-diethyl-2H-benzo [b]pyran-3-ol hydrochloride (1.67 g.) m.p. 200°-202°.

Provenance & Evidence