6740-85-8

The invention discloses a preparation method of a high-purity esketamine hydrochloride ketone body. The structure of the esketamine hydrochloride ketone body is shown as a formula (I). The preparationmethod comprises the following steps of: by taking cyclopentanoic acid and o-chlorobromobenzene as starting materials, carrying out acylating chlorination reaction, metallization reaction and Grignard reaction to synthesize the esketamine hydrochloride ketone body. The esketamine hydrochloride ketone body obtained by the method has the characteristics of high purity, high yield, capability of being applied to preparation of esketamine hydrochloride bulk drugs and the like.

The dissociative-hypnotic compound ketamine is being used in an increasingly wide range of therapeutic contexts, including anesthesia, adjunctive analgesia, treatment-resistant depression, but it also continues to be a notable substance of abuse. No specific antidotes exist for ketamine intoxication or overdose. Immunopharmacotherapy has demonstrated the ability to offer overdose protection through production of highly specific antibodies that prevent psychoactive drug penetration across the blood-brain barrier, although antiketamine antibodies have not yet been assessed or optimized for use in this approach. Moreover, generation of specific antibodies also provides an opportunity to address the role of 6-hydroxynorketamine metabolites in ketamine's rapid-acting antidepressant effect through selective restriction of metabolite access to the central nervous system. Hapten design is a critical element for tuning immune recognition of small molecules, as it affects the presentation of the target antigen and thus the quality and selectivity of the response. Here, we report the synthesis and optimization of carrier protein and conjugation conditions for an initial hapten, norketamine-N-COOH (NK-N-COOH), to optimize vaccination conditions and assess the functional consequences of such vaccination on ketamine-induced behavioral alterations occurring at dissociative-like (50 mg/kg) doses. Iterating from this initial approach, two additional haptens, ketamine-N-COOH (KET-N-COOH) and 6-hydroxynorketamine-N-COOH (HNK-N-COOH), were synthesized to target either ketamine or 6-hydroxynorketamine with greater selectivity. The ability of these haptens to generate antiketamine, antinorketamine, and anti-6-hydroxynorketamine immune responses in mice was then assessed using enzyme-linked immunosorbent assay (ELISA) and competitive surface plasmon resonance (SPR) methods. All three haptens provoked immune responses in vivo, although the KET-N-COOH and 6-HNK-N-COOH haptens yielded antibodies with 5- to 10-fold improvements in affinity for ketamine and/or 6-hydroxynorketamine, as compared to NK-N-COOH. Regarding selectivity, vaccines bearing a KET-N-COOH hapten yielded an antibody response with approximately equivalent Kd values against ketamine (86.4 ± 3.2 nM) and 6-hydroxynorketamine (74.1 ± 7.8 nM) and a 90-fold weaker Kd against norketamine. Contrastingly, 6-HNK-N-COOH generated the highest affinity and most selective antibody profile, with a 38.3 ± 4.7 nM IC50 against 6-hydroxynorketamine; Kd values for ketamine and norketamine were 33- to 105-fold weaker, at 1290 ± 281.5 and 3971 ± 2175 nM, respectively. Overall, these findings support the use of rational hapten design to generate antibodies capable of distinguishing between structurally related, yet mechanistically distinct, compounds arising from the same precursor molecule. As applied to the production of the first-reported anti-6-hydroxynorketamine antibodies to date, this approach demonstrates a promising path forward for identifying the individual and combinatorial roles of ketamine and its metabolites in supporting rewarding effects and/or rapid-acting antidepressant activity.

An improved synthesis of (S)-ketamine (esketamine) has been developed, which was cost-effective, and the undesired isomer could be recovered by racemization. Critical process parameters of each step were identified as well as the process-related impurities. The formation mechanisms and control strategies of most impurities were first discussed. Moreover, the (S)-ketamine tartrate is a dihydrate, which was disclosed for the first time. The practicable racemization catalyzed by aluminum chloride was carried out in quantitative yield with 99% purity. The ICH-grade quality (S)-ketamine hydrochloride was obtained in 51.1% overall yield (14.0% without racemization) by chiral resolution with three times recycling of the mother liquors. The robust process of esketamine could be industrially scalable.

A highly enantioselective acyloin rearrangement of cyclic α-ketols has been developed with a chiral Al(III)-N,N′-dioxide complex as catalyst. This strategy provided an array of optically active 2-acyl-2-hydroxy cyclohexanones in moderate to good yields with high enantioselectivities. The asymmetric isomerizations of acyclic α-hydroxy aldehydes and α-iminols were achieved as well under modified conditions, affording the corresponding chiral α-hydroxy ketones and α-amino ketones in moderate results. Moreover, further transformations of product to enantioenriched diols were carried out.

The invention relates to the compounds or its pharmaceutical acceptable polymorphs, solvates, enantiomers, stereoisomers and hydrates thereof. The pharmaceutical compositions comprising an effective amount of compounds of formula I, formula II and formula III and the methods for the treatment of neurological diseases may be formulated for oral, buccal, rectal, topical, transdermal, transmucosal, lozenge, spray, intravenous, oral solution, nasal spray, oral solution, suspension, oral spray, buccal mucosal layer tablet, parenteral administration, syrup, or injection. Such compositions may be used to treatment of neurological diseases.

The invention relates to a method for synthesizing chiral alcohol (formula I) through deracemization. The preparation method provided by the invention is one-pot asymmetric cascade reaction, and comprises the following steps: 1), with racemic alcohol (formula II) as a raw material and dipropylene glycol dimethyl ether as a solvent, reacting at 120 DEG C for 12 hours, and performing a dehydrogenation reaction to produce intermediate ketone (formula III); and 2), directly adding 2.5mol% of a chiral diamine metal ruthenium complex as a catalyst into a reaction system, with 5 equivalents of sodiumformate as a hydrogen source and a mixed solution of methanol and water as a solvent, reacting at 50 DEG C for 12 hours under the protection of nitrogen, and performing asymmetric transfer hydrogenation to obtain the chiral alcohol (formula I). The method has the advantages of environment-friendly synthesis such as a simple and mild reaction condition, step economy and atomic economy; and in addition, a substrate has a wide application range, the enantioselectivity is high, and the method has a broad application prospect in synthesis of chiral alcohol pharmaceutical intermediates and fine chemical raw materials.

The disclosure provides a method for synthesizing free base forms of (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-hydroxynorketamine. In an embodiment synthesis of (2R,6R)-hydroxynorketamine (HNK) includes preparation of (R)-norketamine via chiral resolution from racemic norketamine via a chiral resolution with L-pyroglutamic acid. The disclosure also provided crystal forms of the corresponding (2R,6R)-hydroxynorketamine (HNK) and (2S,6S)-hydroxynorketamine hydrochloride salts.

The invention provides a method for synthesizing a compound of formula (I) wherein each R independently represents an optionally substituted aryl, heteroaryl, alkyl, perfluoroalkyl, cycloalkyl, alkoxy, aryloxy, acyl, carboxyl, hydroxyl, halogen, amino, nitro, cyano, sulfo or sulfhydryl group, in ortho, meta or para position to the cycloalkylamine moiety; R1 and R2 each independently represents a hydrogen atom, a lower alkyl group or a cycloalkyl group; R3 represents a hydrogen group, substituted aryl, heteroaryl, alkyl, perfluoroalkyl, cycloalkyl, alkoxy, aryloxy group; Y represents an oxygen atom, a sulfur atom, a NH group, a NR4 group or a CH2 group; R4 represents a hydrogen atom or an alkyl, aryl or a heteroaryl group; and n and m each independently represents an integer from 1 to 5; or a pharmaceutically acceptable salt thereof; or a precursor thereof; wherein the method comprises one or more of the following steps: (a) reacting a compound of formula (II): (II) wherein R, R3, Y, n and m are as defined above in relation to the compound of formula (I) with an oxygenating agent, a first additive and a second additive in a solvent in a fluidic network or in a batch process under thermal and/or photochemical conditions to form a compound of formula (III): (III) wherein R, R3, Y, n and m are as defined above in relation to the compound of formula (I), (b) reacting a compound of formula (III) with a nitrogen containing nucleophile in the presence of a third additive and/or a solvent in the fluidic network or in a batch process under thermal conditions to form a compound of formula (IV): (IV) wherein R, R1, R2, R3, Y, n and m are as defined above in relation to the compound of formula (I); and/or (c) reacting a compound of formula (IV) in a fluidic network or in a batch process, optionally in the presence of a fourth 20 additive, under thermal conditions to form a compound of formula (I); wherein one or more of steps (a), (b) and/or (c) is carried out in a fluidic network that comprises micro- and/or meso-channels having an internal dimension of from 100 μm to 2000 μm.

A robust three-step continuous flow procedure is presented for the efficient and sustainable preparation of active pharmaceutical ingredient ketamine. The procedure relies on the main assets of continuous flow processing, starts from commercially available chemicals, utilizes low toxicity reagents and a FDA class 3 solvent under intensified conditions. The procedure features a unique hydroxylation step with molecular oxygen, a fast imination relying on triisopropyl borate and a thermolysis employing Montmorillonite K10 as a heterogeneous catalyst, all three steps being performed in ethanol. The three individual steps can be run independently or can be concatenated, thus providing a compact yet efficient setup for the production of ketamine. The scalability of the critical hydroxylation step was assessed in a commercial pilot continuous flow reactor. The process can also be adapted for the preparation of ketamine analogs. A thorough computational study on the backbone rearrangement of the cyclopentylphenylketone scaffold under thermal stress rationalizes the experimental selectivity and the various experimental observations reported herein.

Ketamine is primarily metabolized to norketamine by hepatic CYP2B6 and CYP3A4-mediated N-demethylation. However, the relative contribution from each enzyme remains controversial. The CYP2B6*6 allele is associated with reduced enzyme expression and activity that may lead to interindividual variability in ketamine metabolism. We examined the N-demethylation of individual ketamine enantiomers using human liver microsomes (HLMs) genotyped for the CYP2B6*6 allele, insect cell-expressed recombinant CYP2B6 and CYP3A4 enzymes, and COS-1 cell-expressed recombinant CYP2B6.1 and CYP2B6.6 protein variant. Effects of CYP-selective inhibitors on norketamine formation were also determined in HLMs. The two-enzyme Michaelis-Menten model best fitted the HLM kinetic data. The Michaelis-Menten constants (Km) for the highaffinity enzyme and the low-affinity enzyme were similar to those for the expressed CYP2B6 and CYP3A4, respectively. The intrinsic clearance for both ketamine enantiomers by the high-affinity enzyme in HLMs with CYP2B6 *1/*1 genotype were at least 2-fold and 6-fold higher, respectively, than those for CYP2B6*1/ *6 genotype and CYP2B6*6/*6 genotype. The Vmax and Km values for CYP2B6.1 were approximately 160 and 70% of those for CYP2B6.6, respectively. N,N9N9-triethylenethiophosphoramide (thioTEPA) (CYP2B6 inhibitor, 25 μM) and the monoclonal antibody against CYP2B6 but not troleandomycin (CYP3A4 inhibitor, 25 μM) or the monoclonal antibody against CYP3A4 inhibited ketamine N-demethylation at clinically relevant concentrations. The degree of inhibition was significantly reduced in HLMs with the CYP2B6*6 allele (genedose P *6 allele on enzyme-ketamine binding and catalytic activity. Copyright

-