43 mmol of 2 t butoxycarbonyl 5 hydroxy 1 2 3 4 tetrahydroisoquinoline example 7 2 77 g 10 5 mmol triphenylphosphine and 0 75 ml 12 6 mmol ethanol were dissolved in dry tetrahydrofuran and 1 63 ml 10 5 mmol diethylazodicarboxylate was added dropwise after completion of the reaction tlc 1 meoh the mixture was diluted with dichloromethane washed with aqueous sodium bicarbonate and with aqueous sodium chloride evaporated to dryness and purified by silicagel chromathography system b yield 1 55 g 66 1 h nmr cdcl 3 7 12 1h t 8 1 hz 6 69 2h t 8 1 hz 4 55 2h s 4 02 2h q 6 8 hz 3 63 2h t 5 6 hz 2 76 2h t 5 9 hz 1 48 9h s 1 41 3h t 7 1 hz excess of 3 mol l 1 hydrochloric acid in ethanol was added to a solution of 2 t butoxycarbonyl 5 ethoxy 1 2 3 4 tetrahydroisoquinoline example 8 1 55 g 5 6 mmol in ethanol after 3 hours the solution was evaporated to dryness and the hydrochloride salt of 5 ethoxy 1 2 3 4 tetrahydroisoquinoline was dissolved in water the solution was made strongly alkaline with sodium hydroxide and the product was extracted in dichloromethane dried over na 2 so 4 and evaporated the product was purified by recrystallization from absolute ethanol yield 0 69 g 71.