Procedure for the Production of Dihydromorphinones
As in German Patent 607,931, a method is decribed below for the production of dihydromorphinones by rearrangement without the use of hydrogen, but simply by heating the alkaloid in an acidic solution together with a platinum catalyst.While relatively large amounts of platinum catalyst is used in German Patent 607,931, we have found that only a fraction of that amount is needed, and sometimes with even better yields.
Example 1:
300g codeine freebase was dissolved in 2000ml dilute HCl, and was heated with 25g of finely powdered palladium, and boiled under reflux for an hour. The palladium was filtered off, and the filtrate basified with NaOH solution. The precipitated base was recrystallized from alcohol. Yield 85-95% of dihydrocodeinone, mp 195°C.
Example 2:
5 grams of codeine hydrochloride was dissolved in 30ml water, and acifified with a small amount of HCl, and after the addition of 0.5g of palladium black, the mixture was refluxed for five hours, and worked up as in example 1. The yield was 70% of theoretical.
Example 3:
5 grams of morphine hydrochloride was dissolved in a slightly acid HCl solution, and after the addition of 0.5g palladium black, the mixture was refluxed for three hours and worked up as in Example 1. The yield was 3g.
Example 4:
6 grams of codeine freebase was dissolved in 30ml water together with 4g of tartaric acid, and 0.5g of palladium black was added. The mixture was refluxed for one hour and worked up as in Example 1. The yield was 75% of theory.
Example 5:
6 grams of codeine phosphate was dissolved in 30ml water, and acidified with 5ml dilute phosphoric acid, and after the addition of 0.5g of palladium black, the solution was refluxed for an hour. After workup as in Example 1, 60-70% yield of dihydrocodeinone was isolated.
Example 6:
21 grams of codeine freebase was dissolved in an excess of dilute sulfuric acid, and two grams of palladium black was added and the solution refluxed for one hour. The yield was 90% of theory.
Example 7:
10 grams of ethylmorphine freebase was added to 50ml water, and HCl was added until the solution was slightly acidic and all ethylmorphine had dissolved. 1 gram palladium black was added, and the solution was boiled under reflux. The mixture was worked up as in Example 1. The yield of ethyldihydromorphinone was 75% of theory.
Procedure for the Production of Dihydromorphinones3
While the rearrangement in German Patent 617,238 is affected by the presence of acids, we have now found that the reaction with morphine and its ethers is taking place in an alcoholic solution in good yields without the addition of any acid.
Example 1:
5 grams morphine was dissolved in 50 ml of alcohol and after the addition of 0.5g of palladium black, the mixture was refluxed for 4 hours. After the catalyst wass filtered off and the solution concentrated, dihydromorphinone crystallized. Yield 3 grams.
Example 2:
10 grams of codeine was dissolved in 100ml alcohol, and after the addition of 0.5 grams palladium black the solution was refluxed for 4 hours. Workup as in Example 1. Yield 7 grams of dihydrocodeinone.
Example 3:
5 g ethylmorphine and 0.3g of palladium black was dissolved in alcohol and the solution was refluxed. Yield 3g of ethyldihydromorphinone.
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