Process of preparing 5beta-hydroxy-8-oxo-1, 4, 4aalpha, 5, 8, 8aalpha-hexahydronaphthalene-1beta-carboxylic acid

Claim 1

IN A PROCESS OF PREPARING 5B-HYDROXY-8-OXO-1,4,4AA, 5,8,8AA-HEXAHYDRONAPHTHALENE - 1B - CARBOXYLIC ACID, THE STEPS COMPRISING SUBJECTING A SUSPENSION OF 5,8-DIOXO-1,4 4AA,5,8,8AA-HEXAHYDRONAPHTHALENE-1B - CARBOXYLIC ACID IN A MEDIUM SELECTED FROM THE GROUP CONSISTING OF WATER, AQUEOUS METHANOL AND AQUEOUS TETRAHYDROFURAN TO THE ACTION OF A REDUCING AGENT SELECTED FROM THE GROUP CONSISTING OF SODIUM BORON HYDRIDE, POTASSIUM BORON HYDRIDE, AND AN ALKALINE EARTH METAL BORON HYDRIDE, IN THE PRESENCE OF A BUFFERING AGENT SELECTED FROM THE GROUP CONSISTING OF AN ALKALI METAL CARBONATE, AN ALKALI METAL BICARBONATE, AN ALKALI METAL PHOSPHATE, AN ALKALI METAL BORATE, AND AN ORGANIC BASE, SAID BUFFERING AGENT BEING ADDED IN AN AMOUNT SUFFICIENT TO MAINTAIN THE PH-VALUE DURING REDUCTION AT A PH BETWEEN ABOUT 6.0 AND ABOUT 7.0, WHILE MAINTAINING A TEMPERATURE BETWEEN -5*C. AND +10*C. AND PASSING NITROGEN THERETHROUGH, ACIDIFYING THE REACTION MIXTURE TO PRECIPITATE THE RESULTING 5BHYDROXY-8-OXO - 1,4,4AA,5,8,8AA - HEXAHYDRONAPTHALENE1B-CARBOXYLIC ACID, AND WASHING THE FILTERED ACID WITH WATER.