113-45-1

Resolution of (±)-threo-methylphenidate (1) with 0.5 M equiv of (R)-(-)-binaphthyl-2,2′-diyl hydrogen phosphate (4) is described. Use of 0.5 M equiv of 4 was found to be better than 1 M equiv for the resolution of (±)-threo-methylphenidate (1) under diffe

The rhodium(II)-catalyzed intermolecular C-H insertion of methyl aryldiazoacetates with either N-Boc-piperidine or N-Boc-pyrrolidine followed by deprotection with trifluoroacetic acid is a very direct method for the synthesis of methylphenidate analogues. By using either dirhodium tetraacetate or dirhodium tetraprolinate derivatives as catalyst, either the racemic or enantioenriched methylphenidate analogues can be prepared. The binding affinities of the methylphenidate analogues to both the dopamine and the serotonin transporters are described. The most notable compounds are the erythro-(2-naphthyl) analogues which display high binding affinity and selectivity for the serotonin transporter.

Enolizable cyclic imines, obtained in situ from their corresponding lithium amides by oxidation with simple ketone oxidants, are readily alkylated with a range of enolates to provide mono- and polycyclic β-aminoketones in a single operation, including the natural product (±)-myrtine. Nitrile anions also serve as competent nucleophiles in these transformations, which are promoted by BF3 etherate. β-Aminoesters derived from ester enolates can be converted to the corresponding β-lactams.

The invention discloses preparation methods of methylphenidate and dexmethylphenidate, intermediates and preparation methods of the intermediates. The invention provides the preparation method of the methylphenidate, wherein the preparation method is any one of the following methods: a first method comprises the following steps of in a solvent, carrying out an amino protecting group removal reaction of a compound 4 with an amino de-protection reagent, and thus obtaining the methylphenidate 5; a second method comprises the following steps of under the action of an alkali, carrying out an intramolecular nucleophilic substitution reaction of a compound 11 to obtain the methylphenidate 5; and a third method comprises the following steps of in a closed system, in a solvent, under a palladium on carbon or palladium carbon hydroxide catalytic condition, carrying out a reaction of a compound 9 with hydrogen, to obtain the methylphenidate 5. The synthesis method has the advantages of short steps, cheap and easily obtained raw materials, high product yield, good chiral purity, low production cost, and good atomic economy, and is suitable for industrialized production.

Disclosed herein a process for the preparation of highly pure dexmethylphenidate hydrochloride (Formula-I) which comprises the steps of neutralization of dl- threomethylphenidate hydrochloride to dl-threo methylphenidate; subsequent resolution of dl-threo methylphenidate using amino acid or its derivatives as chiral resolution agent to yield dexmethylphenidate salt; hydrolysis of the salt and further conversion of dexmethylphenidate into its hydrochloride salt.

Chlorine radical, which is classically generated by the homolysis of Cl2 under UV irradiation, can abstract a hydrogen atom from an unactivated C(sp3)?H bond. We herein demonstrate the use of HCl as an effective hydrogen-atom-transfer catalyst precursor activated by an organic acridinium photoredox catalyst under visible-light irradiation for C?H alkylation and allylation. The key to success relied on the utilization of microtubing reactors to maintain the volatile HCl catalyst. This photomediated chlorine-based C?H activation protocol is effective for a variety of unactivated C(sp3)?H bond patterns, even with primary C(sp3)?H bonds, as in ethane. The merit of this strategy is illustrated by rapid access to several pharmaceutical drugs from abundant unfunctionalized alkane feedstocks.

In this communication, we developed a new procedure for the direct carbonylative transformation of benzyl amines. Using dimethyl carbonate as the solvent, methyl 2-arylacetates can be produced in good to excellent yields from the corresponding primary, secondary, and tertiary benzyl amines with palladium as the catalyst. Notably, no base or any other additive is required here. In addition, our procedure can also be applied in the preparation of methylphenidate, which is a marketing drug and used in the treatment of attention deficit hyperactivity disorder (ADHD) and narcolepsy.

The invention provides novel antibodies which specifically bind to the methylphenidate metabolite ritalinic acid, enabling an immunoassay that can detect methyphenidate in biological samples for an extended period following its ingestion. The invention also describes novel conjugates and kits incorporating the antibodies.

A pharmaceutical composition comprising a drug substance consisting essentially of a pharmaceutically acceptable organic acid addition salt of an amine containing pharmaceutically active compound wherein the amine containing pharmaceutical active compound is selected from the group consisting of racemic or single isomer ritalinic acid or phenethylamine derivatives and the drug substance has a physical form selected from amorphous and polymorphic.

Mannich reactions with chiral silicon Lewis acid activated acylhydrazones and α-aryl silyl ketene acetals and α-aryl,α-alkyl silyl ketene imines proceed efficiently and with good to excellent levels of both diastereoselectivity and enantioselectivity. The reactions provide access to α-aryl,β-hydrazido esters and α-aryl,α-alkyl,β- hydrazido nitriles, which are valuable analogs of β-amino acids.

The conditions of the Eschenmoser coupling reaction were studied. The formation of the α-thioiminium ion was achieved faster in the presence of an additive (NaI) and dry chloroform as the preferred solvent. The developed conditions were used for the second part of the reaction (the sulfur extrusion itself). The present protocol avoids the formation of byproducts, which were previously described as a major drawback to be overcome. Electrospray ionization tandem mass spectrometry was used to characterize some aspects (intermediates) of the first step of the reaction mechanism. Some reduction conditions were properly tested and the selected conditions were applied to the synthesis of the natural alkaloid Norallosedamine and other derivatives.

The present invention discloses selective and complete reduction of pyridine ring in a biaryl system comprising α-substituted or non-substituted benzene ringand relates more specifically, not exclusively, for the manufacture of methylphenidate, which is used for treatment of Attention Deficit Hyperactive Disorder (ADHD) and also acts as central nervous system stimulant, by using palladium/C in a solvent such as C1-C4 alcohols in presence of molar quantities of organic and/or inorganic acids.

The present invention discloses selective and complete reduction of pyridine ring in a biaryl system comprising ∝-substituted or nonsubstituted benzene ring and relates more specifically, not exclusively, for the manufacture of methylphenidate, which is used for treatment of Attention Deficit Hyperactive Disorder (ADHD) and also acts as central nervous system stimulant, by using palladium/C in a solvent such as C1-C4 alcohols in presence of molar quantities of organic and/or inorganic acids.

The present invention provides a process for the preparation of threo-methylphenidate hydrochloride. According to a preferred embodiment, the process comprises the following steps: (a) contacting 1-(phenylglyoxylyl)piperidine arenesulfonylhydrazone of the formula wherein Ar denotes an aryl group, where the aryl group may be substituted by a C1-C6 alkyl, halo or nitro group; with an inorganic base in the presence of a water immiscible organic solvent and a phase transfer catalyst to obtain (R*,R*)-enriched 7-phenyl-1-azabicyclo[4.2.0]octan-8-one of the formula: (b) reacting the (R*,R*)-enriched 7-phenyl-1-azabicyclo[4.2.0]octan-8-one prepared in step (a) with a solution of hydrogen chloride in methanol to obtain threo-enriched methylphenidate hydrochloride; (c) crystallizing the threo-enriched methylphenidate hydrochloride prepared in step (b) to give the desired threo-methylphenidate hydrochloride. Preferably, the threo-methylphenidate hydrochloride produced by the process of the present invention contains no more than 1% of the erythro-isomer.

The present invention provides a new and efficient process for the preparation of the dexmethylphenidate hydrochloride with high optical purity, the process comprising: (a) reacting a solution of threo-N-Boc-ritalinic acid with (S)-1-phenylethylamine, separating precipitated solid salt of (R,R)-enriched N-Boc-ritalinic acid with (S)-1-phenylethylamnine from the reaction mixture and recrystallizing, reslurring and/or trituring of said salt; (b) mixing the solid salt of (R,R)-N-Boc-ritalinic acid and (S)-1-phenylethylamine obtained in step (a) with aqueous acid and separating (R,R)-N-Boc-ritalinic acid from the mixture; and (c) reacting the (R,R)-N-Boc-ritalinic acid prepared in step (b) with hydrogen chloride and methanol to give dexmethylphenidate hydrochloride with optical purity of at least 99% ee. The present invention further provides salt of (R,R)-N-Boc-ritalinic acid with (S)-1-phenylethylamine as new intermediate in the preparation of dexmethylphenidate hydrochloride.

A concise and stereoselective synthesis of racemic erythro-methylphenidate (1) is described. The coupling reaction between piperidine-2-thione (3) and 2-bromo-2-phenylmethylacetate (4) afforded the β-enaminocarbonyl compound 2 in 60% yield by a modified Eschenmoser sulfide contraction reaction. In most cases the bicyclic thiazolidinone 5 was produced. Diastereoselective reduction of 2 in the presence of borohydrydes furnished the (+/-)-erythro-methylphenidate in good yields with dr >95%.

The products derived from C-H activation of secondary sites by rhodium-carbenoids exist in a well-defined conformation. Consequently, their stereochemical assignment can be readily determined on the basis of chemical shift arguments.

In order to make new analogs of the dopamine (DA) uptake inhibitor methylphenidate, a synthetic methodology based on the Blaise reaction was developed. The reaction between α-bromophenylacetic acid esters, zinc and α-cyano-ω-mesylates gave stable primary enamines. After reduction of the enamines with cyanoborohydride, the amines could be cyclized to methylphenidate analogs in which the amine ring size and aromatic ring were varied. These compounds were tested for inhibitory potency against [3H]WIN 35,428 binding to the cocaine recognition site and [3H]DA uptake using rat striatal tissue. When the heterocyclic ring size was varied, the six-membered ring of methylphenidate appeared to be the optimum ring size. When the aryl ring was varied the 4-trifluoromethylphenyl analog was less potent than methylphenidate, the β-naphthyl congener was considerably more potent, whereas the α-naphthyl congener was less potent. Most of the compounds tested had ratios of uptake to binding inhibition (discrimination ratio) that were similar to cocaine and were therefore not lead compounds for the development of cocaine antagonists.

A process for preparing the d-threo isomer of methylphenidate hydrochloride comprising resolving the racemic mixture of threo methylphenidate hydrochloride with dibenzoyl-D-tartaric acid to obtain a dibenzoyl-D-tartrate salt enriched with the d-threo isomer of methylphenidate in a first step, basifying the tartrate salt to obtain the free base form of the d-threo isomer of methylphenidate in a second step, converting the free base to the hydrochloride salt form of the d-threo isomer of methylphenidate in high optical purity in a third step, and recrystallizing the hydrochloride salt form to obtain the desired d-threo isomer in a higher optical purity.

A short method for the preparation of racemic threo- and erythromethylphenidate derivatives is described. Condensation between α- ethoxy carbamate 1 and silyl ketene acetals 2a-b in the presence of TESOTf (20 mol%) afforded a 1.5:1 mixture of carbamates 3a-b/4a-b. Hydrogenolysis in EtOH followed by treatment with 3N HCl/MeOH afforded the corresponding hydrochlorides 7a-b/8a-b in good yields.

(equation presented) This report describes a new method to prepare optically active methylphenidate starting from piperidine. The method consists of a transformation of N-methoxycarbonylpiperidine to the corresponding α-methoxylated carbamate I by utilizing electrochemical oxidation followed by the coupling reaction with optically active Evans imides II to produce optically active methylphenidate derivatives III with high stereoselectivities. threo-(2R,2′R)-Methylphenidate (IV; Ar=Ph; Ritalin) was easily prepared from III in three steps.

As part of a program, to develop medications which can block the binding of cocaine to the dopamine transporter, yet spare dopamine uptake, a series of aromatic ring-substituted methylphenidate derivatives was synthesized and tested for inhibitory potency in [3H]WIN 35,428 binding and [3H]dopamine uptake assays using rat striatal tissue. Synthesis was accomplished by alkylation of 2-bromopyridine with anions derived from various substituted phenylacetonitriles. In most cases, erythro compounds were markedly less potent than the corresponding (±)-threo-methylphenidate (TMP; Ritalin) derivatives. The ortho-substituted compounds were much less potent than the corresponding meta- and/or para-substituted derivatives. The most potent compound against [3H]WIN 35,428 binding, m-bromo-TMP, was 20-fold more potent than the parent compound, whereas the most potent compound against [3H]dopamine uptake, m,p-dichloro-TMP, was 32-fold more potent. Threo derivatives with m-or p-halo substituents were more potent than TMP, while electron-donating substituants caused little change or a small loss of potency. All of the derivatives had Hill coefficients approaching unity, except m,p-dichloro-TMP, which had an nH of 2.0. Although the potency of the (±)-methylphenidate derivatives in the two assays was highly correlated (R2 = 0.986), the compounds m-chloro-, m-methyl-, and p-iodo-TMP were 4-5-fold more potent at inhibiting [3H]-WIN 35,428 binding than [3H]dopamine uptake (cocaine has a ratio of 2.3). These and other compounds may be promising candidates for further testing as potential partial agonists or antagonists of cocaine.

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A process for alleviating proliferative skin diseases such as psoriasis, atopic dermatitis, etc. comprising administering to humans, or domesticated animals, topically and/or systemically a composition comprising a pharmaceutical carrier and at least one active compound selected from the groups, substituted alkyl zanthines, tricyclic antidepressants, organic nitrates, antihypertensives, anti-asthma agents and central nervous system depressants and combinations of certain compounds from specifically named groups of compounds.

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