added the mixture was further subjected to a reflux for 3 hours and then cooled to room temperature after insoluble matters were filtered off under reduced pressure the filtrate was washed with 60 ml of dichloromethane the ph of the water phase was adjusted to 11 by an addition of an aqueous solution of 25 sodium hydroxide the deposited crystal was filtered off under reduced pressure washed with a small quantity of water and then dried in vacuo to yield 9 76 g of a white crystal according to an analysis based on the internal standard material method the crystal contained 6 95 g yield 33 2 of the aimed product v the mother liquid of the above mentioned filtration was extracted with 200 ml of dichloromethane the resulting organic phase was concentrated to yield 2 25 g of a white crystal according to an analysis based on the internal standard material method this crystal contained 1 42 g yield 6 8 of the aimed product v into a 100 ml reaction flask 3 0 g 20 1 mmol of trans 1 2 indandiol i 39 trans configuration 98 3 cis configuration 1 7 optical purity 93 0 e e and 40 ml of acetonitrile were introduced while this mixture was stirred at room temperature 4 06 g 40 2 mmol of 97 sulfuric acid was added thereto in a period of 30 minutes the resulting mixture was stirred at the same temperature for 1 hour and then at 60 u00b0 c for 4 hours after 20 ml of water was added thereto the mixture was further stirred at room temperature for one night under normal pressure 44 ml of an acetonitrile water azeotrope was distilled off the remaining mixture was further subjected to a reflux for.