71897-63-7Relevant academic research and scientific papers
α-Heteroarylation of Thioethers via Photoredox and Weak Br?nsted Base Catalysis
Alfonzo, Edwin,Hande, Sudhir M.
supporting information, p. 6115 - 6120 (2021/08/16)
We report the C-H activation of thioethers to α-thio alkyl radicals and their addition to N-methoxyheteroarenium salts for the redox-neutral synthesis of α-heteroaromatic thioethers. Studies are consistent with a two-step activation mechanism, where oxidation of thioethers to sulfide radical cations by a photoredox catalyst is followed by α-C-H deprotonation by a weak Br?nsted base catalyst to afford α-thio alkyl radicals. Further, N-methoxyheteroarenium salts play additional roles as a source of methoxyl radical that contributes to α-thio alkyl radical generation and a sacrificial oxidant that regenerates the photoredox catalytic cycle.
Transition-metal-free decarboxylative thiolation of stable aliphatic carboxylates
Xing, Wei-Long,Liu, De-Guang,Fu, Ming-Chen
, p. 4593 - 4597 (2021/02/03)
A transition-metal-free decarboxylative thiolation protocol is reported in which primary, secondary, tertiary (hetero)aryl acetates and α-CN substituted acetates undergo the decarboxylative thiolation smoothly, to deliver a variety of functionalized aryl alkyl sulfides in moderate to excellent yields. Aryl diselenides are also amenable substrates for construction of C-Se bonds under the simple and mild reaction conditions. Moreover, the protocol is successfully applied to the late-stage modification of pharmaceutical carboxylates with satisfactory chemoselectivity and functional-group compatibility. This journal is
Regioselective Synthesis of 1-Sulfanyl- and 1-Selanylindolizines
Penteado, Filipe,Gomes, Caroline S.,Perin, Gelson,Garcia, Cleisson S.,Bortolatto, Cristiani F.,Brüning, César A.,Lenard?o, Eder J.
, p. 7189 - 7198 (2019/06/14)
We describe herein a new approach to prepare unprecedented bioactive indolizine motifs decorated with organosulfur and organoselenium groups. A total of 12 1-sulfanylindolizines and 2 1-selanylindolizines were prepared in excellent yields by an intramolecular annulation of easily prepared chalcogen-containing pyridinium salts. The reaction is fast (1 h at 70 °C or 5 min under sonication) and transition-metal-free, using glycerol as a green solvent.
Substitution of aqua ligands from cis-platinum(II) complexes bearing 2-(phenylthiomethyl)pyridine spectator ligands
Mthiyane, Wakhiwe M.,Mambanda, Allen,Jaganyi, Deogratius
, p. 739 - 751 (2017/09/25)
Cis-Pt(II) complexes, namely [Pt{2-(phenylthiomethyl)pyridine}(H2O)2](CF3SO3)2Pt(pySPh), [Pt{2-(4-tert-butylphenylthiomethyl)pyridine}(H2O)2](CF3SO3/s
SUBSTITUTED METHYL AMINES, SEROTONIN 5-HT6 RECEPTOR ANTAGONISTS, METHODS FOR PRODUCTION AND USE THEREOF
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Paragraph 0176, (2013/10/22)
The present invention relates to novel substituted methyl-amines, serotonin 5-HT6 receptor antagonists, to active components, pharmaceutical compositions, method for prophylaxis and treatment of CNS diseases and “molecular tools”, in which novel substituted methyl-amines represent compounds of the general formula 1 and their crystalline forms and pharmaceutically acceptable salts, wherein: W represents benzene, naphthalene, indolizine, quinoline or oxazole cycle; R1=H, F, Cl; R2 represents hydrogen, fluoro, methyl, phenyl, thienyl, furan-2-yl, pyridyl, piperazin-1-yl or 4-methylpiperazin-1-yl; R3 represents cyclopropyl or optionally substituted methyl; with the exception of the compounds in which W simultaneously represents oxazole cycle and R2=phenyl or pyridyl.
Half sandwich complexes of chalcogenated pyridine based bi-(N, S/Se) and terdentate (N, S/Se, N) ligands with (η6-benzene)ruthenium(ii): Synthesis, structure and catalysis of transfer hydrogenation of ketones and oxidation of alcohols
Prakash, Om,Sharma, Kamal Nayan,Joshi, Hemant,Gupta, Pancham Lal,Singh, Ajai K.
, p. 8736 - 8747 (2013/07/27)
The half sandwich complexes [(η6-C6H 6)Ru(L)Cl][PF6] (1-5) have been synthesized by the reactions of (2-arylchalcogenomethyl)pyridine [L = L1-L3] and bis(2-pyridylmethyl)chalcogenide [L = L4-L5] (chalcogen = S, Se; Ar = Ph/2-pyridyl for S, Ph for Se) with [(η6-C6H 6)RuCl2]2, at room temperature followed by treatment with NH4PF6. Their HR-MS, 1H, 13C{1H} and 77Se{1H} NMR spectra have been found characteristic. The single crystal structures of 1-5 have been established by X-ray crystallography. The Ru has pseudo-octahedral half sandwich "piano-stool" geometry. The complexes 1-5 have been found efficient for catalytic oxidation of alcohols with N-methylmorpholine-N-oxide (NMO) and transfer hydrogenation of ketones with 2-propanol (at moderate temperature 80 °C) as TON values are up to 9.9 × 103 and 9.8 × 103 respectively for the two catalytic reactions. On comparing the required catalyst loading for good conversions and reaction time for the present complexes with those reported in literature for other transfer hydrogenation/oxidation catalysts, it becomes apparent that 1-5 have good promise. The complexes of Se ligands have been found more efficient than their sulphur analogues. The complexes of bidentate ligands are more efficient than those of terdentate, due to difficult bond cleavage in the case of latter. These orders of efficiency are supported by DFT calculations. The calculated bond lengths/angles by DFT are generally consistent with the experimental ones.
Synthesis and structure of dichloropalladium(II) complexes of heteroleptic N,S- and N,Se-donor ligands based on the 2-organochalcogenomethylpyridine motif, and Mizoroki-Heck catalysis mediated by complexes of N,S-donor ligands
Jones, Roderick C.,Canty, Allan J.,Gardiner, Michael G.,Skelton, Brian W.,Tolhurst, Vicki-Anne,White, Allan H.
scheme or table, p. 77 - 87 (2010/04/01)
Ligands containing the 2-organochalcogenomethylpyridine motif with substituents in the 4- or 6-position of the pyridyl ring, R4,R6-pyCH2ER1 [R4 = R6 = H, ER1 = SMe (1), SeMe (2), SPh (6), SePh (7); R4 = Me, R6 = H, ER1 = SMe (3), SPh (8), SePh (9); R4 = H, R6 = Me, ER1 = SMe (4), SPh (10), SePh (11); R4 = H, R6 = Ph, ER1 = SMe (5), SPh (12), SePh (13)] are obtained on the reaction of R4,R6-pyMe with LiBun followed by R1EER1. On reaction with PdCl2(NCMe)2, the ligands with a 6-phenyl substituent form cyclopalladated species PdCl{6-(o-C6H4)pyCH2ER1-C,N,E} (5a, 12a, 13a) with the structure of 13a (ER1 = SePh) confirmed by X-ray crystallography; other ligands form complexes of stoichiometry PdCl2(R4,R6-pyCH2ER1). Complexes with R6 = H are monomeric with N,E-bidentate configurations, confirmed by structural analysis for 3a (R4 = Me, ER1 = SMe), 7a (R4 = H, ER1 = SePh) and 9a (R4 = Me, ER1 = SePh). Two of the 6-methyl substituted complexes examined by X-ray crystallography are oligomeric with trans-PdCl2(N,E) motifs and bridging ligands, trimeric [PdCl2(μ-6-MepyCH2SPh-N,S)]3 (10a) and dimeric [PdCl2(μ-6-MepyCH2SePh-N,Se)]2 (11a). This behaviour is attributed to avoidance of the Me···Cl interaction that would occur in the cis-bidentate configuration if the pyridyl plane had the same orientation with respect to the coordination plane as observed for 3a, 7a and 9a [dihedral angles 8.0(2)-16.8(2)°]. When examined as precatalysts for the Mizoroki-Heck reaction of n-butyl acrylate with aryl halides in N,N-dimethylacetamide at 120 °C, the complexes exhibit the anticipated trends in yield (ArI > ArBr > ArCl, higher yield for electron withdrawing substituents in 4-RC6H4Br and 4-RC6H4Cl). The most active precatalysts are PdCl2(R4-pyCH2SMe-N,S) (R = H (1a), Me (3a)); complexes of the selenium containing ligands exhibit very low activity. For closely related ligands, the changes SMe to SPh, 6-H to 6-Me, and 6-H to 6-Ph lead to lower activity, consistent with involvement of both the pyridyl and chalcogen donors in reactions involving aryl bromides. The precatalyst PdCl2(pyCH2SMe-N,S) (1a) exhibits higher activity for the reaction of aryl chlorides in Bun4NCl at 120 °C as a solvent under non-aqueous ionic liquid (NAIL) conditions. Crown Copyright
Inhibition of human O6-alkylguanine-DNA alkyltransferase and potentiation of the cytotoxicity of chloroethylnitrosourea by 4(6)- (benzyloxy)-2,6(4)-diamino-5-(nitro or nitroso)pyrimidine derivatives and analogues
Terashima, Isamu,Kohda, Kohfuku
, p. 503 - 508 (2007/10/03)
A series of 4(6)-(benzyloxy)-2,6(4)-diamino-5-(nitro or nitroso)pyrimidine derivatives and analogues of which 4(6)-benzyloxy groups were replaced with a (2-, 3-, or 4-fluorobenzyl)oxy or (2-, 3-, or 4- pyridylmethyl)oxy group, was synthesized. The abilities of these compounds to inhibit human O6-alkylguanine-DNA alkyltransferase (AGAT) in vitro and to potentiate the cytotoxicity of 1-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-3- (2-chloroethyl)-3-nitrosourea (ACNU) toward HeLa S3 cells were evaluated. 2,4-Diamino-6-[(2-fluorobenzyl)oxy]-5-nitropyrimidine (3) and 2,4-diamino-5- nitro-6-(2-pyridylmethoxy)pyrimidine (6), whose ortho positions of the 6- substituent are modified, were much weaker in terms of these abilities than the corresponding meta- or para-modified compounds. These results are consistent with those of our previous study using a series of O6- benzylguanine derivatives. All 5-nitrosopyrimidine derivatives examined exerted both stronger AGAT-inhibition and ACNU-enhancement abilities than the corresponding 5-nitro derivatives. Among a variety of compounds that we have examined to date, 2,4-diamino-6-[(4-fluorobenzyl)oxy]-5-nitrosopyrimidine (10) exhibited the strongest ability to inhibit AGAT, and its magnitude was 2.5 and 50 times those of 4-(benzyloxy)-2,6-diamino-5-nitrosopyrimidine (9) and O6-benzylguanine (1), respectively. A strong positive correlation was observed between the ability to inhibit AGAT and to potentiate the cytotoxicity of ACNU. This strongly indicates that 4(6)-(benzyloxy)pyrimidine derivatives and their analogues potentiate ACNU cytotoxicity by inhibiting AGAT activity. To characterize the reactivity of test compounds, alkyl- transfer reactions were also carried out using the biomimetic alkyl-transfer system.
Potentiation of the cytotoxicity of chloroethylnitrosourea by O6-arylmethylguanines
Kohda,Terashima,Koyama,Watanabe,Mineura
, p. 424 - 430 (2007/10/03)
It was reported recently that monomeric O6-benzylguanine (1) acts as an alternative substrate for a DNA repair enzyme, O6-alkylguanine-DNA alkyltransferase (AGT), and that therefore pretreatment of cells with 1 induces depletion of AGT resulting in an enhanced cytotoxic response to alkylating antitumor agents. In order to study the interaction of O6-benzylguanine derivatives with AGT and to obtain greater AGT depletion, me synthesized the following O6-arylmethylguanine derivatives and related compounds: O6-(4-, 3- and 2-fluorobenzyl)guanines (2, 3, 4), O6-(4-,3- and 2-trifluoromethylbenzyl)guanines (5, 6, 7), O6-(4-, 3- and 2-pyridylmethyl)guanines (8, 9, 10), O6-(2- and 1-naphthylmethyl)guanines (11, 12), O6-biphenylmethylguanine (13), S and Se analogues of O6-benzylguanine (14, 15) and O6-phenylguanine (16). Ten of these are new compounds. All these compounds were tested for their potentiation of N'-[(4-amino-2-methyl-5-pyrimidinyl)methyl] (ACNU) cytotoxicity using HeLa S3 and C6-1 cells. Compounds 2, 3, 5, 8, 9, 11 and 13 were active, as was 1. Compounds 7 and 12, with a substituent at the a position of the benzyl group, and compound 10, the a-nitrogen analogue of 1, were almost completely devoid of potentiating activity. These results suggest that the a-position of the O6-benzyl group plays an important role in the interaction of O6-benzylguanines with AGT. Of the other compounds, 4 and 6 exhibited very weak activity and 14, 15 and 16 were inactive. Possible reasons for these differences in activity are discussed in relation to the biomimetic dealkylation rates of O6-benzylguanine derivatives and the chemical characteristics of their substituents.
Solvation and metal ion effects on structure and reactivity of phosphoryl compounds. Part 4. Dealkylation of phosphate esters by thiophenoxide ion in methanol
Mentz,Modro,Modro
, p. 1933 - 1960 (2007/10/02)
Second-order rate constants for the demethylation of three phosphate esters by thiophenoxide salts, PhS-M+ (M+ = Me4N+, K+, Na+Li+) in methanol-d4 at 25°C have been measured. In contrast to the demethylation by iodide salts, metallic counterions do not exhibit any catalytic effects on the demethylation rate. The absence of the catalysis indicates that the salts react exclusively as ion pairs, in which an alkali metal ion is not available for the interactions with the phosphoryl group in the transition state.
