- Direct Synthesis of Protoberberine Alkaloids by Rh-Catalyzed C-H Bond Activation as the Key Step
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A one-pot reaction of substituted benzaldehydes with alkyne-amines by a Rh-catalyzed C-H activation and annulation to afford various natural and unnatural protoberberine alkaloids is reported. This reaction provides a convenient route for the generation o
- Jayakumar, Jayachandran,Cheng, Chien-Hong
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- Overcoming inaccessibility of fluorinated imines-synthesis of functionalized amines from readily available fluoroacetamides
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Although imines are convenient substrates for the synthesis of functionalized amines, they may be hard to obtain, as in the case of fluorinated imines. To aid in overcoming this issue, we propose a protocol of corresponding amine synthesis from simple fluoroacetic acid-derived amides using Schwartz's reagent.
- Czerwiński, Pawe? J.,Furman, Bart?omiej
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supporting information
p. 9436 - 9439
(2019/08/15)
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- Efficient DBU accelerated synthesis of 18F-labelled trifluoroacetamides
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Nucleophilic 18F-fluorination of bromodifluoromethyl derivatives was performed using [18F]Bu4NF in the presence of DBU (1,8-diazabicyclo[5.4.0]undec-7-ene). This novel procedure provided a diverse set of [18F]trifluoroacetamides in good to excellent radiochemical conversions. A mechanism where DBU acts as organomediator in this transformation is proposed.
- Gómez, Antonio Bermejo,Cortés González, Miguel A.,Lübcke, Marvin,Johansson, Magnus J.,Halldin, Christer,Szabó, Kálmán J.,Schou, Magnus
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supporting information
p. 13963 - 13966
(2016/12/09)
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- Hexamethyldisilazane as an acylation generator for perfluorocarboxylic acids in quantitative derivatization of primary phenylalkyl amines confirmed by GC/MS and computations
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A novel, selective acylation of primary phenylalkyl amines (PPAAs) using hexamethyldisilazane (HMDS) and perfluorocarboxylic acids (PFCAs) is noted. Couples, like HMDS and trifluoroacetic acid, HMDS and pentafluoropropionic acid, or HMDS and heptafluorobutyric acid trigger PPAAs' quantitative acylation. Processes' selectivity was characterized by applying all couples to derivatize benzyl, 2-phenylethyl, 3-phenylpropyl, 4-phenylbutyl amines, and their relevant substituted versions. Aliphatic amines were unreactive. Identification, quantification, proportionality, and stoichiometry in derivatization processes were determined by gas chromatography/mass spectrometry. Reaction conditions were optimized depending on reagents' molar ratios, solvents, and temperatures applied. The new acylation method, in comparison to the traditional ones, obtained with trifluoroacetic anhydride, heptafluorobutyric anhydride, and N-methyl-bis(trifluoroacetamide), offers numerous advantages. Derivatives, provided by couples, can be directly injected onto the column, avoiding loss of species, saving time, work, and cost in the preparation process. Due to traditional reagents' excess evaporation by nitrogen drying, the loss of trifluoroacylated species proved to be 65% or less. Regarding heptafluorobutyryl species, their losses varied between 25% and 5%. Unified huge responses, obtained with the HMDS and PFCA couples are attributable to their direct injection onto the column and to fragments sourced from the molecular ions and from their self-chemical ionization ([M]?+, [M+147]+, i.e., [M+(CH3)2-Si=O-Si-(CH3)3]+). The reaction mechanism, due to the HMDS symmetrical structure, acting HMDS as acylation generator for PFCAs, was confirmed by density functional theory (DFT) computation.
- Molnr, Borbla,Csmpai, Antal,Molnr-Perl, Ibolya
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p. 848 - 852
(2015/02/19)
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- Quantitative Silylation Speciations of Primary Phenylalkyl Amines, Including Amphetamine and 3,4-Methylenedioxyamphetamine Prior to Their Analysis by GC/MS
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A novel, quantitative trimethylsilylation approach derivatizing 11 primary phenylalkyl amines (PPAAs), including amphetamine (A) and 3,4-methylenedioxyamphetamine (MDA), was noted. Triggering the fully derivatized ditrimethylsilyl (diTMS) species with the N-methyl-N-(trimethylsilyl)-trifluoroacetamide (MSTFA) reagent, a new principle was recognized followed by GC/MS. In the course of method optimization, the complementary impact of solvents (acetonitrile, ACN; ethyl acetate, ETAC; pyridine, PYR) and catalysts (trimethylchlorosilane, TMCS; trimethyliodosilane, TMIS) was studied: the role of solvent and catalyst proved to be equally crucial. Optimum, proportional, huge responses were obtained with the MSTFA/PYR = 2/1-9/1 (v/v) reagent applying catalysts; A and MDA needed the TMIS, while the rest of PPAAs provided the diTMS products also with TMCS. Similar to derivatives generated with hexamethyldisilazane and perfluorocarboxylic acid (HMDS and PFCA) (Molnár et al. Anal. Chem. 2015, 87, 848'852), the fully silylated PPAAs offer several advantages. Both of our methods save time and cost by allowing for direct injection of analytes into the column; this is in stark contrast with the requirement to evaporate acid anhydrides by nitrogen prior to their injection. Efficiences of the novel catalyzed trimethylsilylation (MSTFA) and our recently introduced (now, for A and MDA extended) acylation principle were contrasted. Catalyzed trimethylsilylation led to diTMS derivatives resulting in on average a 1.7 times larger response compared to the corresponding acylated species. Catalyzed trimethylsilylation of PPAAs, A, and MDA were characterized with retention, mass fragmentation, and analytical performance properties (R2, LOQ values). The practical utility of ditrimethylsilyation was shown by analyzing A in urine and mescaline (MSC) in cactus samples.
- Molnár, Borbála,Fodor, Blanka,Boldizsár, Imre,Molnár-Perl, Ibolya
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p. 10188 - 10192
(2015/11/09)
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- PROCESS FOR THE SYNTHESIS OF IVABRADINE AND ADDITION SALTS THEREOF WITH A PHARMACEUTICALLY ACCEPTABLE ACID
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Process for the synthesis of ivabradine of formula (I): and addition salts thereof with a pharmaceutically acceptable acid.
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Paragraph 0039; 0040; 0041; 0041
(2013/10/08)
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- Iridium-catalyzed asymmetric intramolecular allylic amidation: Enantioselective synthesis of chiral tetrahydroisoquinolines and saturated nitrogen heterocycles
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For the first time iridium catalysis has been used for the synthesis of chiral tetrahydroisoquinolines with excellent yields and high enantioselectivities (see scheme; cod=1,5-cyclooctadiene, DBU=1,8- diazabicyclo[5.4.0]undec-7-ene). These products are important chiral building blocks for the synthesis of biologically active compounds, in particular alkaloids. Copyright
- Teichert, Johannes F.,Fananas-Mastral, Martin,Feringa, Ben L.
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supporting information; experimental part
p. 688 - 691
(2011/04/18)
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- PHENETHYLAMIDE DERIVATIVES AND THEIR HETEROCYCLIC ANALOGUES
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The invention relates to novel phenethylamide derivatives and their heterocyclic analogues of formula (I), wherein A, B, R1, R2 and R3 are as described in the application, and to the use of such compounds, or of pharmaceut
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Page/Page column 127
(2010/04/30)
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- Asymmetric synthesis of 1-vinyltetrahydroisoquinoline through Pd-catalyzed intramolecular allylic amination
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Asymmetric synthesis of 6,7-dimethoxy-1-vinyltetrahydroisoquinolines through Pd-catalyzed intramolecular allylic amination of 3-(amidoethylphenyl)prop-2-enyl carbonates was studied, using a library of fine-tunable monodentate phosphoramidite ligands. Unde
- Shi, Ce,Ojima, Iwao
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p. 8563 - 8570
(2008/02/08)
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- Enantioselective synthesis of (+)-(S)-laudanosine and (-)-(S)-xylopinine
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The study presents a new pathway for the enantioselective synthesis of benzylisoquinoline alkaloids. The key steps of the synthesis of (+)-(S)-laudanosine (1) and (-)-(S)-xylopinine (2) are a Sonogashira coupling that builds up the C1-C8a bond of the benzylisoquinoline skeleton, an intramolecular Ti-catalyzed hydroamination of an alkyne, and a subsequent enantioselective imine reduction according to Noyori's protocol.
- Mujahidin, Didin,Doye, Sven
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p. 2689 - 2693
(2007/10/03)
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- Asymmetric Intramolecular Allylic Amination: Straightforward Approach to Chiral C1-Substituted Tetrahydroisoquinolines
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Newly introduced Pd-catalyzed asymmetric intramolecular allylic amination provides an easy access to pharmaceutically important 1-substituted tetrahydroisoquinolines. With this amination as the key step, (R)-carnegine was synthesized in an enantioselectiv
- Ito, Katsuji,Akashi, Suemi,Saito, Bunnai,Katsuki, Tsutomu
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p. 1809 - 1812
(2007/10/03)
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- Regioselective synthesis of 6-fluorodopamine, 6-fluoro-m-tyramine and 4-fluoro-m-tyramine using elemental fluorine, oxygen difluoride and acetyl hypofluorite
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6-Fluorodopamine was regioselectively synthesized in good yields from N-(trifluoroacetyl)-3,4-di-t-butoxycarbonyloxy-6-(trimethylstannyl)phenylethylamine (6) via a fluorodestannylation reaction using F2, OF2 or CH3COOF followed by acid hydrolysis.Similarly, 6-fluoro-m-tyramine (14) and 4-fluoro-m-tyramine (20) were prepared from their corresponding trimethylstannyl derivatives.All precursors and products were fully characterized by multinuclear NMR spectroscopy and high resolution mass spectrometry. - Keywords: Dopamine neurotransmission; Norepinephrine synthesis; Dopamine agonist; 6-fluorodopamine; Fluorodestannylation
- Namavari, Mohammad,Satyamurthy, N.,Barrio, Jorge R.
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p. 113 - 122
(2007/10/03)
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- Deuterated analogs of verapamil and nifedipine. Synthesis of and biological activity
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The preparations of various deuterium analogs of verapamil and nifedipine have been described. Deuterium is incorporated at specific positions in the molecules in 97% isotopic purity. The deuterated analogs 1d of verapamil and 2d of nifedipine lowered blo
- Rampe,Hake,Borretzen,Holm,Skattebol
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p. 259 - 263
(2007/10/02)
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- Novel N-[4-(aminosubstituted)phenyl]methanesulfonamides and their use as cardiovascular agents
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Novel N-[4-(aminosubstituted)phenyl]methanesulfonamides and their use as cardiovascular agents, especially as antiarrhythmic agents are described. Pharmaceutical formulations containing such compounds are also discussed.
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- N-Acylcatecholamines and 3,4-Dihydro-6,7-isoquinolinediols from N-Acyl-3,4-dimethoxyphenethylamines
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The N-acetamides 2a and 2e are cleaved with boron tribromide to yield as expected the catechols 3a and 3e whereas, under the same conditions, mixtures of the catechols 3b, 3c, 3f, or 3g and 1-(haloalkyl)dihydroisoquinolines 4
- Niederstein, Yvonne,Peter, Martin G.
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p. 1189 - 1194
(2007/10/02)
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- Friedel-Crafts Acylation with N-(Trifluoroacetyl)-α-amino Acid Chlorides. Application to the Preparation of β-Arylalkylamines and 3-Substituted 1,2,3,4-Tetrahydroisoquinolines
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Several N-(trifluoroacetyl)-α-amino acid chlorides have been reacted with benzene, anisole, and veratrole in the presence of AlCl3 or SnCl4 to produce the corresponding aromatic ketones in fair to high yields.The products are reductible under neutral or acidic conditions to the corresponding N-(trifluoroacetyl)-β-hydroxy-β-arylakylamines or N-(trifluoroacetyl)-β-arylalkylamines.The latter can be readily detrifluoroacetylated by mild basic hydrolysis and thence converted to the corresponding 3-substituted 1,2,3,4-tetrahydroisoquinolines by condensation with formaldehyde.
- Nordlander, Eric J.,Payne, Mark J.,Njoroge, George F.,Balk, Michael A.,Laikos George D.,Vishwanath, Vasanth M.
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p. 4107 - 4111
(2007/10/02)
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- NOVEL CONDENSING AGENTS FOR BISCHLER-NAPIERALSKI TYPE CYCLODEHYDRATION
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Trifluoroacetic anhydride and trifluoromethyl sulfonyl anhydride are used in Bischler-Napieralski type cyclization.Starting from the appropriate amides, the dihydroisoquinolines are formed in excellent yields.
- Nagubandi, Sreeramulu,Fodor, G.
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p. 165 - 177
(2007/10/02)
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- Preparation and biological actions of N-2,2,2-trifluoroethyl-2-(3,4-dihydroxyphenyl)ethylamine
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N-2,2,2-Trifluoroethyl-2-(3,4-dihydroxyphenyl)ethylamine was synthesized and compared to N-ethyl-2-(3,4-dihydroxyphenyl)-ethylamine and dopamine for activity on adenylate cyclase in the rat striatum. Both dopamine and N-ethyl-2-(3,4-dihydroxyphenyl)ethyl-amine stimulated adenylate cyclase activity in a dose-dependent fashion. The N-trifluorethyldopamine analog at 1 x 10-4 M induced a weak effect. The compounds were evaluated further by studying their relaxant effects in isolated rabbit renal and ear arteries. Both the N-ethyl- and N-trifluoroethyldopamine analogs produced a relaxant effect but demonstrated no selectivity for dopamine receptors.
- O'Donnell,Azzaro,Urquilla
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p. 149 - 152
(2007/10/02)
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- 30. Eine neue Synthese von 8-Hydroxy-2-methyl-1,2,3,4-tetrahydroisochinolin
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Vilsmeier formylation of N--trifluoroacetamide (5) yielded the aldehyde 6, which under mild basic conditions was hydrolyzed to 7 and cyclized to 6,8-dimethoxy-3,4-dihydroisoquinoline (3).Methylation of 3 and reduction of the
- Gray, Robert W.,Dreiding, Andre S.
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p. 315 - 319
(2007/10/02)
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