Inorganic Salt Catalyzed Isomerization of Morphinan Allyl Alcohols
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Solution Overview
Problem
Current methods for producing hydromorphone and hydrocodone are expensive, low-yielding, and produce impurities, with existing catalysts being air sensitive and costly, necessitating a more efficient and cost-effective process for meeting increasing demand.
Innovation Solution
A one-step isomerization process using inorganic salts of late transition metals to catalytically convert morphinan compounds with an allyl alcohol ring moiety into those with a saturated ketone ring moiety, specifically employing ruthenium or rhodium salts in a reaction mixture with a protic solvent and controlled pH, to produce high-purity hydromorphone or hydrocodone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transition metal complexes are used as catalysts in organic solutions, then the production of hydromorphone or hydrocodone can be achieved in a one-step process, but the catalysts are air sensitive and expensive to produce
Solution Approach 1:
The patent replaces expensive, air-sensitive transition metal complexes with inexpensive, stable inorganic salt catalysts (such as CuSO4, FeCl3, AlCl3, ZnCl2). These inorganic salts are not air-sensitive, can be easily handled, and are significantly cheaper to produce, thereby resolving the contradiction between achieving one-step process efficiency and avoiding costly, sensitive catalysts
Solution Approach 2:
The patent changes the chemical state of the catalyst from organic metal complexes to inorganic metal salts. This parameter change transforms the catalyst properties from air-sensitive and expensive to stable and inexpensive, while maintaining catalytic activity for the isomerization reaction
2Productivity
If a two-step oxidation/reduction route is used from morphine or codeine, then the production of hydromorphone or hydrocodone can be achieved, but the process is expensive, low yielding, and forms impurities that are difficult to remove
Solution Approach 1:
The patent merges the oxidation and reduction steps into a single isomerization step. The allyl alcohol intermediate undergoes direct isomerization to the saturated ketone product in one reaction step, eliminating the need for separate oxidation and reduction steps, thereby improving yield and simplifying the process
Solution Approach 2:
The patent extracts and eliminates the intermediate oxidation step from the traditional two-step sequence. By using inorganic salt catalysts that facilitate direct isomerization, the process removes the oxidation/reduction sequence and its associated impurities, achieving cleaner production with higher yield
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This process achieves high yields and purity of hydromorphone or hydrocodone, reducing production costs and overcoming the limitations of existing methods by utilizing stable and cost-effective late transition metal catalysts.
Implementation Method 1
contacting a morphinan comprising an allyl alcohol ring moiety with an inorganic salt of a late transition metal such that the allyl alcohol ring moiety is catalytically isomerized to the saturated ketone ring moiety
Data Source
AI summary
The present invention provides processes for the preparation of saturated ketone morphinan compounds. In particular, the invention provides processes for the conversion of a morphinan comprising an allyl alcohol ring moiety into a morphinan comprising a saturated ketone ring moiety by an isomerization reaction catalyzed by an inorganic salt of a late transition metal.