33522-95-1

14-Hydroxymorphinone is converted to noroxymorphone, the immediate precursor of important opioid antagonists, such as naltrexone and naloxone, in a three-step reaction sequence. The initial oxidation of the N-methyl group in 14-hydroxymorphinone with in situ generated colloidal palladium(0) as the catalyst and molecular oxygen as the terminal oxidant constitutes the key transformation in this new route. This oxidation results in the formation of an unexpected oxazolidine ring structure. Subsequent hydrolysis of the oxazolidine under reduced pressure followed by hydrogenation in a packed-bed flow reactor using palladium(0) as the catalyst provides noroxymorphone in high purity and good overall yield. To overcome challenges associated with gas–liquid reactions with molecular oxygen, the key oxidation reaction was translated to a continuous-flow process.

Noroxymorphone was prepared from thebaine in seven operations. The key steps involved the successive N- A nd O-demethylations of an iron tricarbonyl complex of thebaine followed by the unusual ceric ammonium nitrate oxidation of the methoxydiene moiety to the corresponding enone-γ-nitrate during the decomplexation of the iron tricarbonyl functionality. A protocol for the conversion of thebaine to noroxymorphone via C-14 oxidation is described.

Codeine is converted to 7,8-dihydro-14-hydroxynorcodeinone (noroxycodone) in six steps and 52percent overall yield or to noroxymorphone in seven steps and 43percent overall yield.N-Demethylation and oxidation of codeine afford N-(ethoxycarbonyl)norcodeinone, which is converted to its dienol acetate derivative and oxidized with singlet oxygen to give N-(ethoxycarbonyl)-14-hydroxynorcodeinone in the key step.Hydrogenation of the latter affords N-(ethoxycarbonyl)noroxycodone, which upon acid hydrolysis yields noroxycodone.Alternatively, O-demethylation of N-(ethoxycarbonyl)noroxycodone with boron tribromide and subsequent acid hydrolysis gives noroxymorphone.The results of the singlet oxygen oxidation of the pyrrolidine dienamine derived from N-(ethoxycarbonyl)norcodeinone are also described.

Strategies for the generation of noroxymorphone from 14-hydroxymorphinone are presented. Noroxymorphone is the key intermediate in the synthesis of various opioid antagonists, including naloxone, naltrexone, and nalmefene, as well as mixed agonists-antagonists such as nalbuphine. The transformation requires removal of the N-methyl group from the naturally occurring opiates and double-bond hydrogenation. The pivotal reaction step thereby is an N-methyl oxidation with colloidal palladium(0) as catalyst and pure oxygen as terminal oxidant. The reaction produces a 1,3-oxazolidine intermediate, which can be readily hydrolyzed to the corresponding secondary amine. Different reaction sequences and the use of various phenol protecting groups were explored. The most direct route consumes only H2, O2, and H2O as stoichiometric reagents and produces only H2O as a byproduct. Challenges inherent to gas/liquid reactions with oxygen as oxidant have been addressed by developing a continuous flow process.

A brief synthesis of noroxymorphone is described which involves the oxidation of 3-O-(t)butyldimethylsilylmorphine by manganese dioxide. The initial product is the corresponding morphinone which is further oxidised to the 14-hydroxymorphinone. After hydrogenation the 7,8-dihydro-14-hydroxymorphinone is acetylated and N-demethylation of the 14-O-acetylated product is achieved using vinyl chloroformate as the reagent. The overall yield from morphine is 40-45%.

Thebaine was converted into its iron tricarbonyl complex, which underwent successive N- and O-demethylation with BrCN and BBr3, respectively. Decomplexation of the iron tricarbonyl moiety was accomplished with ammonium cerium(IV) nitrate (CAN) and base-catalyzed hydrolysis furnished nororipavine. When excess CAN was used the methoxydiene unit was converted into its C-14 nitrate that on hydrogenation and further hydrolysis furnished noroxymorphone. Full experimental and spectral data are provided for all key compounds.

Mu opioid receptors (MOR-1) mediate the biological actions of clinically used opioids such as morphine, oxycodone, and fentanyl. The mu opioid receptor gene, OPRM1, undergoes extensive alternative splicing, generating multiple splice variants. One type of splice variants are truncated variants containing only six transmembrane domains (6TM) that mediate the analgesic action of novel opioid drugs such as 3′-iodobenzoylnaltrexamide (IBNtxA). Previously, we have shown that IBNtxA is a potent analgesic effective in a spectrum of pain models but lacks many side-effects associated with traditional opiates. In order to investigate the targets labeled by IBNtxA, we synthesized two arylazido analogs of IBNtxA that allow photolabeling of mouse mu opioid receptors (mMOR-1) in transfected cell lines and mMOR-1 protein complexes that may comprise the 6TM sites in mouse brain. We demonstrate that both allyl and alkyne arylazido derivatives of IBNtxA efficiently radio-photolabeled mMOR-1 in cell lines and MOR-1 protein complexes expressed either exogenously or endogenously, as well as found in mouse brain. In future, design and application of such radio-photolabeling ligands with a conjugated handle will provide useful tools for further isolating or purifying MOR-1 to investigate site specific ligand–protein contacts and its signaling complexes.

Vaccination could be a promising alternative warfare against drug addiction and abuse. For this purpose, so-called haptens can be used. These molecules alone do not induce the activation of the immune system, this occurs only when they are attached to an immunogenic carrier protein. Hence obtaining a free amino or carboxylic group during the structural transformation is an important part of the synthesis. Namely, these groups can be used to form the requisite peptide bond between the hapten and the carrier protein. Focusing on this basic principle, six nor-morphine compounds were treated with ethyl acrylate and ethyl bromoacetate, while the prepared esters were hydrolyzed to obtain the N-carboxymethyl- and N-carboxyethyl-normorphine derivatives which are considered as potential haptens. The next step was the coupling phase with glycine ethyl ester, but the reactions did not work or the work-up process was not accomplishable. As an alternative route, the normorphine-compounds were N-alkylated with N-(chloroacetyl)glycine ethyl ester. These products were hydrolyzed in alkaline media and after the work-up process all of the derivatives contained the free carboxylic group of the glycine side chain. The acid-base properties of these molecules are characterized in detail. In the N-carboxyalkyl derivatives, the basicity of the amino and phenolate site is within an order of magnitude. In the glycine derivatives the basicity of the amino group is significantly decreased compared to the parent compounds (i.e., morphine, oxymorphone) because of the electron withdrawing amide group. The protonation state of the carboxylate group significantly influences the basicity of the amino group. All of the glycine ester and the glycine carboxylic acid derivatives are currently under biological tests.

The invention describes the process of catalytic O-demethylation of 3-methoxy-morphinane compounds using boron tribromide. Addition of catalysts reduces the reaction time, improves reacting the substrate to give the product in very good purity and yield. The said approach can be used, for example, for the preparation of oxymorphone, naltrexone, naloxone and nalbuphine from their respective O-methyl derivatives.

The present invention relates to a new process for obtaining 3,14-diacetyloxymorphone from oripavine, a process to transform the obtained 3,14-diacetyloxymorphone into a noroxymorphone and a process to transform said noroxymorphone into naloxone, naltrexone, nalbuphine, nalfurafine or nalmefene.

The present invention relates to processes useful in the preparation of morphine analogs and derivatives, such as naltrexone, naloxone and nalbuphine and intermediates in the synthesis of said morphine analogs and derivatives. In a particular example, the process begins with for example oxymorphone, oxycodone, 14-hydroxycodeinone or 14- hydroxymorphinone, and includes the formation of an oxazolidine-containing intermediate using catalytic oxidation.

Opioid analgesic tolerance remains a considerable drawback to chronic pain management. The finding that concomitant administration of delta opioid receptor (DOR) antagonists attenuates the development of tolerance to mu opioid receptor (MOR) agonists has led to interest in producing bifunctional MOR agonist/DOR antagonist ligands. Herein, we present 7-benzylideneoxymorphone (6, UMB 246) displaying MOR partial agonist/DOR antagonist activity, representing a new lead for designing bifunctional MOR/DOR ligands.

Oxymorphone was converted to its 3,14-diacetate and subjected to Fe(II)/t-BuOOH-catalyzed N-demethylation that occurred with concomitant acyl migration from the C-14 hydroxyl to the N-17 nitrogen. The resulting diacetyl compound was hydrolyzed in dilute s

The present provides a process for preparing a compound of formula (3), the process comprising the steps of: (a) providing an aqueous acidic solution comprising a compound of formula (1) and, as an impurity, a compound of formula (2); and (b) treating the aqueous acidic solution of step (a) such that the compound of formula (2) dehydrates to form a compound of formula (1) and the compound of formula (1) is reduced to form an aqueous acidic solution of the compound of formula (3), wherein: the treating of step (b) is carried out at one or more temperatures greater than ambient in the presence of a hydrogenation catalyst and hydrogen gas; and wherein for the compounds of formulae (1), (2) and (3): i) R1 is -OH, R2 is-OH and R3-H; or ii) R1 is -OCH3, R2 is -H and R3 -CH3; or iii) R1 is-OH, R2 is-H and R3-CH3; or iv) R1, is -OCH3, R2 is -H and R3 -H; or v) R1, is -OH, R2is-H and R3-H; or vi) R1, is -OCH3, R2 is -OH and R3 -H.

The present invention is directed to an improved process to convert morphine into noroxymorphone comprising the step of reacting a compound of formula (Va) or (Vb) to a compound of formula (VIa) or (VIb), respectively characterized in that the reaction is carried out with hydrogen peroxide and an organic acid, wherein the organic acid and the hydrogen peroxide are mixed and allowed to react for a defined induction time prior to addition to the compound of formula (Va) or (Vb).

The present invention is directed to an improved process to convert morphine into noroxymorphone comprising the step of reacting a compound of formula (Va) or (Vb) to a compound of formula (VIa) or (Vlb), respectively, characterized in that the reaction is carried out with hydrogen peroxide and an organic acid, wherein the organic acid and the hydrogen peroxide are mixed and allowed to react for a defined induction time prior to addition to the compound of formula (V).

A high-yielding method for the N-demethylation of oxycodone- and oxymorphone-N-oxides by the reaction of these compounds with cyclodehydration reagents has been performed. This method has been utilized to improve the synthesis of various morphine analogs, such as naltrexone, nalbuphone and naloxone.

N-Oxides derived from oxycodone and O-acyloxymorphone were treated with the Burgess reagent to provide the corresponding oxazolidines in excellent yields. Oxazolidines derived from Oacyloxymorphone were further hydrolyzed to noroxymorphone, whose alkylation furnished naltrexone, naloxone, and nalbuphone, which can be converted to nalbuphine, the mixed agonist-antagonist analgesic. The entire sequence from oxymorphone to the various antagonists was reduced to three one-pot operations, proceeding in excellent overall yields. In addition, quaternary salts of the oxazolidines with allyl or cyclopropylmethyl groups in fixed equatorial configurations were synthesized. Complete spectral and experimental data are provided for all compounds.

The present disclosure provides improved methods for N-dealkylation of tertiary amines, including methods for N-demethylation of alkaloids and opioids, in which the dealkylation reaction is carried out in a solvent comprising a tertiary alcohol. The present disclosure also provides improved processes for preparing semi-synthetic opioids that incorporate the disclosed methods for N-dealkylation of tertiary amines.

The present disclosure provides processes for the N-dealkylation of tertiary amines and the use of transition metal catalysts to prepare tertiary N-allyl amine derivatives and secondary amine derivatives thereof. The tertiary amines can be alkaloids and, more particularly, the tertiary amines can be opioids. In specific embodiments, the present disclosure provides methods for use in processes for the synthesis of naloxone and naltrexone from oripavine.

Under Polonovski-type conditions, ferrocene has been found to be a convenient and efficient catalyst for the N-demethylation of a number of N-methyl alkaloids such as opiates and tropanes. By judicious choice of solvent, good yields have been obtained for dextromethorphan, codeine methyl ether, and thebaine. The current methodology is also successful for the N-demethylation of morphine, oripavine, and tropane alkaloids, producing the corresponding N-nor compounds in reasonable yields. Key pharmaceutical intermediates such oxycodone and oxymorphone are also readily N-demethylated using this approach.

(Figure Presented) A mild and simple two-step Fe(0)-mediated N-demethylation of a number of tertiary N-methyl alkaloids is described. The tertiary N-methylamine is first oxidized to the corresponding N-oxide, which is isolated as the hydrochloride salt. Subsequent treatment of the N-oxide hydrochloride with iron powder readily provides the N-demethylated amine. Representative substrates include a number of opiate and tropane alkaloids. Key intermediates in the synthesis of semisynthetic 14-hydroxy pharmaceutical opiates such as oxycodone and oxymorphone are also readily N-demethylated using this method.

The present invention relates to an improved process for preparing morphinane analogues of formula (1) wherein the substituents R1, R2, R2a, R3, R4, R5 and Y have the meanings as defined in the specifications.

The present invention is directed to a method for demethylating 14-hydroxy substituted alkaloid derivatives, in particular of 14-hydroxy-17-methyl-4,5-epoxymorphinane-6-on-derivatives. This is achieved by reacting a starting compound with a compound of general formula R1OOC—N═N—COOR2 in a suitable solvent.

The invention relates to a method for purifying oxymorphone compounds of formula (II) or a mixture of compounds of formula (II), and said compounds of formula (II) or the mixture of compounds of formula (II) which contain at least one corresponding a,?-unsaturated compound as an impurity, wherein R1, R2 and R3 independently represent hydrogen, optionally substituted (C1-C8) -alkyl, (C2-C4) -alkenyl or a leaving group which can be separated thereon. The invention is characterised in that the oxymorphone compounds of formula (II) or a mixture of compounds of formula (II), which contain at least one corresponding a,?-unsaturated compound is subjected to a hydrogen reaction. The purified noroxymorphone are processed in such a manner that naltrexone or naloxone or a salt of said compounds or a quaternary derivative of said compounds are formed. The invention also relates to pharmaceutical formulations which contain said compound.

The invention relates to a method for purifying plant extracts that are substantially composed of noroxymorphone compounds and that contain in the a,? position unsaturated noroxymorphones as contaminants. The method comprises the following steps: (a) reacting the plant extract or the product of a subsequent step in synthesis of a selected noroxymorphone compound in a reaction by which the hydroxyl groups present in the mixture are converted to leaving groups of the formula -OR2, wherein R2 represents the inserted group of the leaving group; (b) optionally removing the leaving groups; (c) subjecting the mixture thereby obtained to a selective hydration so that a saturated bond is formed in the α,? position of the unsaturated noroxymorphone compound and the remaining present leaving groups are each converted to a hydroxyl group; and then optionally (d) isolating the pure noroxymorphone compound. The invention also relates to the manufacture of the noroxymorphone so purified to naltrexone or naloxone or to a salt of these compounds or to a quaternary derivative of these compounds. The invention finally relates to the pharmaceutical compositions comprising the inventive compound.

L-Selectride was shown to be an efficient and general O-demethylating agent for the opium alkaloids and their derivatives and also an efficient reagent for the cleavage of methyl carbamates, thus offering a convenient method for the N-demethylation of opioids. Further, it was shown that by choice of reaction conditions it is possible to achieve both N- decarbomethoxylation and O-demethylation in one pot, or only render N- decarbomethoxylation in high yield without accompanying O-demethylation.

3,17-(diethoxycarbonyl)normorphine, which may be prepared by reaction of morphine with ethyl chloroformate, is converted to 3,17-(diethoxycarbonyl)normorphinone, a novel compound, by oxidation. The novel normorphinone derivative is converted to 3,17-(diethoxycarbonyl)normorphinone enol acetate, a second novel compound, by esterification with acetic anhydride or acetyl halide. A 14-hydroxy group is introduced into the novel dienol ester by oxidation with peracid. The resultant 14-hydroxy-3,17-(diethoxycarbonyl)normorphinone, a third novel compound, may be catalytically hydrogenated to produce 3,17-(diethoxycarbonyl)noroxymorphone. The latter intermediate may be converted to noroxymorphone by hydrolysis.

There is provided a novel, high yield, method of dealkylating N-alkylated 14-hydroxymorphinans and derivatives thereof including, inter alia, oxymorphone and oycodone. There are thus provided, inter alia, more efficient routes for the formation of naloxone, naltrexone, and nalbuphine. In the principal step of the process, the dealkylation using certain oxycarbonyl halides (or haloformates) is carried out on the N-alkyl-14-acyloxy-morphinan which it is desired to dealkylate.