RESUMO
A novel synthetic approach to nemtabrutinib (MK-1026) was recently developed in our laboratories. The chemistry goes through a cyrene amine intermediate which does not contain any chromophore. As a result, analysis of this key chiral intermediate by HPLC-UV is not feasible. Initial attempts to develop a HPLC-CAD method were unfruitful; therefore, a gas chromatography method was developed and optimized to effectively monitor the cyrene amine free base and related impurities generated during the process. As the synthetic process continued to be optimized, the toluene sulfonic acid salt (p-TsOH) of the cyrene amine intermediate was later identified by our process chemistry group to be beneficial in terms of ease of isolation and purity upgrade. However, repeated injections of the cyrene amine p-TsOH intermediate resulted in rapid GC column deterioration. After identifying p-TsOH as the main cause of the issue, we developed a straightforward and practical procedure that involves using a resin to remove the p-TsOH counterion in-situ, which converts cyrene amine salt to its neutral form in sample solutions. This protocol was successfully demonstrated and proven to be an efficient solution. This methodology may find applications with other analytes containing counterions that need to be neutralized prior to analysis.
Assuntos
Cloreto de Sódio , Tolueno , Cromatografia Líquida de Alta Pressão/métodos , AminasRESUMO
An efficient multicomponent orthogonal protocol was developed for post-synthetic oligonucleotide modification using commercially available 2'- O-methyl ester and 2'- O-propargyl nucleoside scaffolds. Amidation of methyl esters with primary amines was achieved in the presence of 2'-propargyl groups which were utilized for subsequent copper catalyzed cycloaddition with GalNAc-azide. The methodology was applied to generate siRNA composed of multiple amide and triazole conjugates. Computational methods were used to illustrate the impact of substitution at the 2'-position. This a powerful post-oligomerization technique for rapidly introducing diversity to oligonucleotide design.
Assuntos
Acetilgalactosamina/química , Amidas/química , Azidas/química , Cobre/química , Reação de Cicloadição/métodos , Oligonucleotídeos/química , RNA Interferente Pequeno/química , Acetilgalactosamina/síntese química , Amidas/síntese química , Azidas/síntese química , Catálise , Química Click/métodos , Esterificação , Células HeLa , Humanos , Modelos Moleculares , Oligonucleotídeos/síntese química , RNA Interferente Pequeno/síntese química , Triazóis/síntese química , Triazóis/químicaRESUMO
Volatile amines are among the most frequently used chemicals in organic and pharmaceutical chemistry. Synthetic route optimization often involves the evaluation of several different amines requiring the development and validation of analytical methods for quantitation of residual amine levels. Herein, a simple and fast generic GC-FID method on an Agilent J&W CP-Volamine capillary column (using either He or H2 as the carrier gas) capable of separating over 25 volatile amines and other basic polar species commonly used in pharmaceutical chemistry workflows is described. This 16min method is successfully applied to the analysis and quantitation of volatile amines in a variety of pharmaceutically-related drugs and synthetic intermediates. Method validation experiments showed excellent analytical performance in linearity, recovery, repeatability, and limit of quantitation and detection. In addition, diverse examples for the application of this method to the simultaneous determination of other amine-related chemicals in reaction mixtures are illustrated, thereby indicating that these GC-FID method conditions can be effectively used as starting point during method development for the analysis of other basic polar species beyond the validated list of amines described in this study.
Assuntos
Aminas/análise , Química Farmacêutica/métodos , Cromatografia Gasosa , Ionização de Chama , Preparações Farmacêuticas/químicaRESUMO
Single-stranded silencing RNAs (ss siRNA), while not as potent as duplex RNAs, have the potential to become a novel platform technology in RNA interference based gene silencing by virtue of their simplicity and plausibly favorable characteristics in pharmacokinetics and biodistribution. Like other therapeutic pharmaceutical agents, ss siRNA can be optimized to achieve higher potency through a structure-activity based approach. Systematic chemical modification at each position of a 21-mer oligonucleotide identified 2',5'-linked 3'-deoxythymidine (3dT) at position 1 and locked nucleic acids (LNAs) at the seed region as key components to afford significant enhancement in knockdown activity both in vitro and in vivo. Further optimization by additional chemical modifications should enable ss siRNA as an alternative gene silencing modality.
Assuntos
Inativação Gênica , RNA Mensageiro/genética , RNA Interferente Pequeno/genética , beta Catenina/genética , Células HEK293 , HumanosRESUMO
Chemical modification of siRNA is achieved in a high-throughput manner (96-well plate format) by copper catalyzed azide-alkyne cycloadditions. This transformation can be performed in one synthetic operation at up to four positions with complete specificity, good yield, and acceptable purity. As demonstrated here, this approach extends the current synthetic options for oligonucleotide modifications and simultaneously facilitates the systematic, rapid biological evaluation of modified siRNA.
Assuntos
Ensaios de Triagem em Larga Escala/métodos , Oligonucleotídeos/química , Oligonucleotídeos/farmacologia , Relação Estrutura-Atividade , Alcinos/química , Azidas/química , Catálise , Cromatografia Líquida de Alta Pressão/métodos , Química Click , Cobre/química , Reação de Cicloadição , Técnicas de Silenciamento de Genes , Células HeLa , Humanos , RNA Interferente Pequeno/química , RNA Interferente Pequeno/farmacologia , Técnicas de Síntese em Fase SólidaRESUMO
New mixed-mode columns consisting of reversed-phase and ion-exchange separation modes were evaluated for the analysis of short RNA oligonucleotides (â¼20mers). Conventional analysis for these samples typically involves using two complementary methods: strong anion-exchange liquid chromatography (SAX-LC) for separation based on charge, and ion-pair reversed-phase liquid chromatography (IP-RPLC) for separation based on hydrophobicity. Recently introduced mixed-mode high performance liquid chromatography (HPLC) columns combine both reversed-phase and ion-exchange modes, potentially offering a simpler analysis by combining the benefits of both separation modes into a single method. Analysis of a variety of RNA oligonucleotide samples using three different mixed-mode stationary phases showed some distinct benefits for oligonucleotide separation and analysis. When using these mixed-mode columns with typical IP-RPLC mobile phase conditions, such as ammonium acetate or triethylammonium acetate as the primary ion-pair reagent, the separation was mainly based on the IP-RPLC mode. However, when changing the mobile phase conditions to those more typical for SAX-LC, such as salt gradients with NaCl or NaBr, very different separation patterns were observed due to mixed-mode interactions. In addition, the Scherzo SW-C18 and SM-C18 columns with sodium chloride or sodium bromide salt gradients also showed significant improvements in peak shape.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Cromatografia de Fase Reversa/métodos , Oligonucleotídeos/isolamento & purificação , Sequência de Bases , Cromatografia por Troca Iônica/métodos , Oligonucleotídeos/químicaRESUMO
This unit describes two protocols for the deprotection of 2'-O-TBS groups in oligoribonucleotides under mild conditions. Desilylation using ammonium fluoride is applicable to fully protected "RNA only" substrates and desilylation using potassium fluoride is applicable to "mixed RNA/non-RNA" substrates. Characterization of products is accomplished using LC/MS, RP HPLC and SAX HPLC.
Assuntos
Sondas de Oligonucleotídeos/síntese química , Compostos de Organossilício/química , RNA/síntese química , Compostos de Amônio , Cromatografia Líquida de Alta Pressão , Fluoretos/química , Compostos de Amônio Quaternário/químicaRESUMO
Development of a practical synthesis of MK-7009, a 20-membered [corrected] macrocycle, is described. A variety of ring-closing strategies were evaluated, including ring-closing metathesis, intermolecular palladium-catalyzed cross-couplings, and macrolactamization. Ring closure via macrolactamization was found to give the highest yields under relatively high reaction concentrations. Optimization of the ring formation step and the synthesis of key intermediates en route to MK-7009 are reported.
Assuntos
Técnicas de Química Sintética/métodos , Indóis/química , Indóis/síntese química , Lactamas/química , Compostos Macrocíclicos/química , Catálise , Ciclização , Ciclopropanos , Hidrogenação , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Paládio/química , Prolina/análogos & derivados , SulfonamidasRESUMO
We report a practical global deprotection of RNA 2'-O-tert-butyldimethylsilyl (TBS) ethers using commercially available aqueous NH(4)F. The procedure is applicable to both 96-well plate format and large-scale production of RNA. This improved procedure provides a safe, mild, and cost-effective alternative to highly hazardous Et(3)N x 3 HF, a reagent commonly used in the routine synthesis of RNA.
Assuntos
Oligorribonucleotídeos/química , Compostos de Amônio , Cromatografia Líquida de Alta Pressão , Fluoretos/química , Compostos de Amônio Quaternário/química , Espectrometria de Massas por Ionização por Electrospray , Espectrofotometria UltravioletaRESUMO
A short and practical synthesis of glucokinase activator 1 was achieved utilizing a convergent strategy involving S(N)Ar coupling of activated aryl fluoride 11 with hydroxypyridine 9. The key to the success of the synthesis was the development of a novel method for enantioselective formation of alpha-arylpyrrolidines during the course of the project. In this method, (-)-sparteine-mediated enantioselective lithiation of N-Boc-pyrrolidine was followed by in situ transmetalation to zinc and Pd-catalyzed coupling with aryl bromide 3, proceeding in 92% ee. This transformation allowed the preparation of compound 1 in a 31% overall yield over six steps.
Assuntos
Ativadores de Enzimas/síntese química , Glucoquinase/metabolismo , Paládio/química , Pirrolidinas/química , Estrutura MolecularRESUMO
The cycloacylation of aniline derivatives to 4-quinolones in the presence of Eaton's reagent is described. This high-yielding methodology is applicable to a wide variety of functionalized anilines and requires milder conditions than those traditionally employed. This cyclization protocol is used to prepare a host of heterocycles and bis-quinolones and is characterized by relatively low reaction temperature and ease of product isolation.
Assuntos
Compostos Heterocíclicos/síntese química , Quinolonas/síntese química , Catálise , Ciclização , Estrutura MolecularRESUMO
Compound 1 is a p38 MAP kinase inhibitor potentially useful for the treatment of rheumatoid arthritis and psoriasis. A novel six-step synthesis suitable for large-scale preparation was developed in support of a drug development program at Merck Research Laboratories. The key steps include a tandem Heck-lactamization, N-oxidation, and a highly chemoselective Grignard addition of 4-(N-tert-butylpiperidinyl)magnesium chloride to a naphthyridone N-oxide. The N-oxide exerted complete chemoselectivity via chelation in directing the Grignard addition to the alpha position as opposed to 1,4-addition on the ene-lactam. The dihydropyridyl adduct was in situ aromatized with isobutylchloroformate followed by heating in pyridine. Syntheses of Grignard precursor, N-tert-butyl-4-chloro-piperidine, were accomplished via transamination with a quaternary ammonium piperidone or via addition of methylmagnesium chloride to an iminium ion. Utilizing this chemistry, multi-kilogram preparation of compound 1 was successfully demonstrated.
Assuntos
Inibidores Enzimáticos/síntese química , Naftiridinas/química , Naftiridinas/síntese química , Proteínas Quinases p38 Ativadas por Mitógeno/antagonistas & inibidores , Óxidos N-Cíclicos/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Estrutura Molecular , Naftiridinas/farmacologiaRESUMO
[reaction: see text] A practical, ligand-free cyanation of aryl bromides that utilizes as little as 0.1 mol % Pd(OAc)(2) in combination with a nontoxic cyanide source, M(4)[Fe(CN)(6)] (M = K, Na), is described. The reactions are performed in DMAC at 120 degrees C and provide the corresponding aryl nitrile in 83-96% yield, typically in less than 5 h. TON values of up to 7100 were attained.
RESUMO
The preparation of 3-(5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl)propan-1-amine 2a and 3-[(7R)-7-methyl-5,6,7,8-tetrahydro-1,8-naphthyridin-2-yl]propan-1-amine 2b, key intermediates in the synthesis of alpha(V)beta(3) antagonists, is described. The syntheses rely on the efficient double Sonogashira reactions of 2,5-dibromopyridine 3 with acetylenic alcohols 4a/4b and protected propargylamines 10a-e followed by Chichibabin cyclizations of 3,3'-pyridine-2,5-diyldipropan-1-amines 9a/9b.
Assuntos
Integrina alfaVbeta3/antagonistas & inibidores , Naftiridinas/síntese química , Propano/análogos & derivados , Propano/síntese química , Estrutura MolecularRESUMO
An efficient asymmetric synthesis of a selective estrogen receptor modulator (SERM) that has a dihydrobenzoxathiin core structure bearing two stereogenic centers is reported. The stereogenic centers were established by an unprecedented chiral sulfoxide-directed stereospecific reduction of an alpha,beta-unsaturated sulfoxide to the saturated sulfide in one step. Studies to elucidate the mechanism for this reduction are reported. Highly efficient Cu(I)-mediated ether formation was used to install the ether side chain, and selective debenzylation conditions were developed to remove the benzyl protecting groups on the phenols.