• Title/Summary/Keyword: 2-Aryl esters

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Synthesis of N-Aryl Phenylglycine Ο-Alkyl Esters and Its Substitution of Ester Moiety (N-Aryl Phenylglycine Ο-Alkyl Esters의 간편한 합성 및 에스테르 치환반응)

  • 박명숙;박해선
    • YAKHAK HOEJI
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    • v.47 no.5
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    • pp.276-282
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    • 2003
  • For the development of new synthetic method for unnatural amino acid esters, N-aryl phenylglycine Ο-alkyl esters 4a∼i were synthesized through esterification, bromination, C-N bond formation from commercially available phenylacetic acids. An efficient and practical reaction condition for esters 2a∼c was that the starting materials 1a∼c were refluxed in absolute methanol for 3 hours with catalytic concentrated hydrosulfuric acid. In addition, bromines 3a∼c were formated for 3h in dichloromethane at rt with N-bromosuccinimide. Bromines 3a∼c were also converted to 4a∼i through substitution of arylamines during refluxing for 24 hours in ethanol with triethylamine. Interestingly, ethyl esters 5a∼c were formed via transesterification reaction when the p-sulfamylanilino group was used as a nucleophile in ethanol solvent.

Synthesis of ($\pm$)-Methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-amines

  • Jang, Jin-Hee;Sin, Kwan-Seog;Park, Hae-Il
    • Archives of Pharmacal Research
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    • v.24 no.6
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    • pp.503-507
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    • 2001
  • trans-Metanicotine, a subtype (${\alpha}_4{\beta}_2$)-selective ligand for neuronal nicotinic acetylcholine receptor, is under clinical phase for Alzheimer's disease. An efficient synthetic route for ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-am ices, derivatives of tracts-metanicotine, was explored. Allylation reaction of aryl aldimines with allylmagnesium bromide in THF gave ($\pm$)-methyl-(1-aryl-but-3-enyl)-amines. Protection of the amines with the Boc group and following Heck reaction of the N-Boc amines with 3-bromopyridine gave ($\pm$)-methyl-(1-aryl-4-pyridin-3-yl-but-3-enyl)-carbamic acid tert-butyl esters. Deprotection of the N-Boc group in aqueous 1 N-HCI solution gave the titled amines in good yields. Thus, trans-metanicotine analogues modified at the ${\alpha}-position$ of the methylamino group with amyl groups were obtained in 5 steps.

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Synthesis and Antifungal Activities of Some Aryl (3-Methyl-Benzofuran-2-yl) Ketoximes

  • Benkli, Kadriye;Gundogdu-Karaburun, Nalan;Karaburun, Ahmet-Cagrl;Ucucu, Umit;Demirayak, Seref;Kiraz, Nuri
    • Archives of Pharmacal Research
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    • v.26 no.3
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    • pp.202-206
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    • 2003
  • In this study, some aryl (3-methyl-benzofuran-2-yl) ketoximes and their ethers and esters were synthesised. The structure elucidation of the compounds was performed by IR, $^1H-NMR$, MASS spectroscopy and elemental analyses. Antifungal activities of the compounds were examined and moderate activity was obtained.

An NMR Study on Complexation of Ethylammonium Ion by Alkyl p-tert-Butylcalix[6]aryl Ester Derivatives

  • 안상두;문철순;정기주;이조웅;오원석;장석규
    • Bulletin of the Korean Chemical Society
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    • v.19 no.1
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    • pp.68-74
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    • 1998
  • The complexation of ethylammonium ion by alkyl p-tert-butylcalix[6]aryl ester derivatives was studied via measurements of proton and carbon spin-lattice relaxation times $(T_1)$ and chemical shift changes in solution state $(CDCl_3)$. The results indicate that the endo-type complexes are formed and that the overall tumbling rates of these complexes are more rapid than those of the corresponding free hosts. The association constants for these complexes in $THF-d_8$ were determined by $^1H$ NMR titration at several different temperatures to estimate the relevant thermodynamic parameters. The logK's for ethylammonium complexes of methyl, ethyl, and propyl esters at 313 K, for example, were found to be 1.56, 3.41, and 3.08, respectively. The complexes formed may be thought of as being kinetically stable in view of their $^1H$ NMR behavior in 2 : 1 host/guest solution.

Reactions of Pyrimidinonethione Derivatives;Synthesis of 2-Hydrazinopyrimidin-4-one, Pyrimido[1,2-a]-1,2,4-triazine, Triazolo-[1,2-a]pyrimidine, 2-(1-pyrazolo)Pyrimidine and 2-Arylhydrazonopyrimidine Derivatives

  • Attaby, Fawzy-A.;Eldin, Sanaa-M.;Hanafi, Eman-A.Z.
    • Archives of Pharmacal Research
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    • v.20 no.6
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    • pp.620-628
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    • 1997
  • 6-Aryl-5-cyano-4-pyrimidinon-2-thione derivatives 1a-c reacted with ethyl iodide to give the corresponded 2-S-ethylpyrimidin-4-one-derivatives 2a-c. Compounds 2a-c was, in turn, reacted with hydrazine hydrate to give the sulfur free reaction products, 3a-c. These reaction products were taken as the starting materials for the synthesis of several newly synthesized heterocyclic derivatives. Reactions with several halogenated ketones, esters, chloroacetic acid and chloroacetamide give pyrimidotriazines 8,12 and 15 while their reactions with formic acid, acetic acid and carbon disulfide gave the corresponded triazolopyrimidines 17 and 21. The reaction with both acetyl acetone and ethylacetoacetate gave the corresponded 2-$(3^{I},5^{I}-dimethyl-1^{I}-pyrazoly$pyrimidine derivatives 20a-c and 24a-c respectively while the reaction with cinnamonitriles 25a-h afforded the corresponded aryl hydrazopyrimidines 27a-f. The structure of these reaction products were eatablished based on both elemental anlayses and spectral data studies.

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Ab Initio Study of Complexation of Alkali Metal Ions with Alkyl Esters of p-tert-Butylcalix[4]arene

  • Choe, Jong-In;Oh, Dong-Suk
    • Bulletin of the Korean Chemical Society
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    • v.25 no.6
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    • pp.847-851
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    • 2004
  • The complexation characteristics of tetramethyl (1) and tetraethyl esters (2) of p-tert-butylcalix[4]arene with alkali metal cations have been investigated by ab initio calculation. The structures of endo- or exocomplexation of the hosts in cone conformation with alkali metal ions have been optimized using HF/6-31G method followed by B3LYP/6-31G(d) single point calculation. B3LYP/6-31G(d) calculations suggest that exo-complexation efficiencies of sodium ion to the cavity of lower rim of hosts 1 and 2 are 27.1 and 25.8 kcal/mol better than that of potassium ion, respectively. The exo-complexation efficiencies of potassium ion to the cavity of lower rim of hosts 1 and 2 are 33.3 and 31.5 kcal/mol better than the endo-complexation inside the upper rim (four aromatic rings) as expected from the experimental results. B3LYP/6-31G(d) calculation of the ethyl ester 2 shows 29.5 and 30.8 kcal/mol better exo-complexation efficiency for both sodium and potassium ions than the methyl ester 1.

Synthesis and Biological Activities of Some New 3,6-Disubstituted 1,2,4-Triazolo[3,4-b]1,3,4-thiadiazole Derivatives

  • Rafiq, Muhammad;Saleem, Muhammad;Hanif, Muhammad;Maqsood, Muhammad Rizwan;Rama, Nasim Hasan;Lee, Ki-Hwan;Seo, Sung-Yum
    • Bulletin of the Korean Chemical Society
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    • v.33 no.12
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    • pp.3943-3949
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    • 2012
  • A series of aromatic hydrazides 3a-j were prepared by refluxing esters 2a-j with hydrazine hydrate in methanol, which were prepared by the esterification of 1a-j. Acetohydrazides 3a-j upon treatment with carbon disulfide and methanolic potassium hydroxide yielded potassium dithiocarbazate salts 4a-j, which on refluxing with hydrazine hydrate yielded substituted 4-amino-5-aryl-3H-1,2,4-triazole-3-thiones 5a-j. The target compounds 6a-j were synthesized by condensing furan-3-carboxylic acid in the presence of polyphosphoric acid under reflux. The structures of newly synthesized compounds were characterized by IR, $^1H$ NMR, $^{13}C$ NMR, elemental analysis and mass spectrometric studies. All the synthesized compounds were screened for their urease, acetylcholine esterase inhibition, antioxidant and alkaline phosphatase inhibition activity. Almost all of the compounds 6a-j showed good to excellent activities against urease and acetylcholine esterase more than the reference drugs. Compounds 6f and 6g were more potent scavenger of free radicals than the reference n-propyl gallate. Compound 6b and 6h showed excellent activities of alkaline phosphatase as compare to the reference $KH_2PO_4$.