Cleavage And Rearrangement Of Sulfonamides

Searles, Scott; Nukina, Shogo

doi:10.1021/cr50030a004

Cited by 112 publications

(44 citation statements)

References 48 publications

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“…Finally, the protecting groups were removed under drastic conditions by reductive hydrogenolysis under basic or acidic conditions and by acidic hydrolysis. 29 The method for the cleavage depended on the stability of the substituent X under the reaction conditions. The diaza[n]paracyclophanes were isolated as their dihydrochlorides to prevent oxidation by air and were obtained in yields of up to 20%.…”

Section: Resultsmentioning

confidence: 99%

Synthesis, resolution, and investigation of the rotational interconversion process of atropisomeric 1,n‐diaza[n]paracyclophanes using cyclodextrin‐mediated capillary zone electrophoresis

et al. 2001

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A number of variously monosubstituted 1,n-diaza[n]paracyclophanes (n = 10-12), which show planar chirality and atropisomerism due to hindered rotation about single bonds, were synthesized via a classical route to analyze their stereodynamic properties. Racemic analytes with 10- and 11-membered bridges were resolved by capillary zone electrophoresis (CZE) in acidic phosphate buffers (pH 2.5-4.5) employing permethylated beta- and gamma-cyclodextrin as chiral additives. Moreover, cyclodextrin mediated CZE was used in a discontinuously driven mode for investigations of the rotational interconversion process of conformationally labile homologues (n = 11). In stopped-flow experiments, after baseline separation enantiomers were partially enantiomerized in situ inside the capillary by heating. The rate constants (k(enan) = 1/2 k(rac)) and rotational energy barriers (Delta G(++)) were determined from the resulting enantiomeric ratios. Energy barriers between 113-126 kJ/mol were found depending on the substituent of the benzene ring and the degree of ionization of the amino groups in bridgehead positions. The energy barriers increased in order of the substituents: NO(2) >> CF(3) > Br > Cl > CH(3) approximately F. In addition, the rotational energy barriers were decreased by approximately 6-8 kJ/mol in the presence of the chiral selector.

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Section: Resultsmentioning

confidence: 99%

Synthesis, resolution, and investigation of the rotational interconversion process of atropisomeric 1,n‐diaza[n]paracyclophanes using cyclodextrin‐mediated capillary zone electrophoresis

et al. 2001

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“…Yet such cleavages were often not observed with ortho substituents. [19,20] Except for compound 4 d, all of the crude aminophenol derivatives obtained were pure enough to be directly used in the biotransformations. Nevertheless, all of the compounds were purified by flash chromatography to rule out any external artefacts in the subsequent reactions with laccases.…”

Section: Resultsmentioning

confidence: 99%

Laccase‐Mediated Synthesis of Novel Substituted Phenoxazine Chromophores Featuring Tuneable Water Solubility

Bruyneel

Payen

Rescigno

et al. 2009

Chemistry A European J

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Laccases are members of the blue copper oxidases family found in nature. They commonly oxidise a wide range of phenol and aniline derivatives, which in turn are involved in oxidative coupling reactions. Yet, laccases remain rarely described as biocatalysts in organic synthesis. This paper describes the chemical preparation of original sulfonated aminophenol substrates and their enzyme-mediated dimerisation into phenoxazine chromophores that feature tuneable water solubility as a function of the sulfonyl substituent. The scope and limitations of the biocatalysed synthetic process are outlined. Kinetic data were collected to evaluate the influence of physicochemical parameters. The structure of the novel phenoxazine dyes ("head-to-head" or "head-to-tail" dimer) was assessed by NMR spectroscopic analysis. Two crystalline compounds were analysed by X-ray diffraction. Such laccase-mediated synthesis (a green chemistry process) was proven to be more efficient than the chemical oxidation of o-aminophenols with silver oxide.

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“…The solvent was evaporated, the residue recrystallized from water, and the product was further purified by ion-exchange resin (Dowex 50X8-400). Recrystallization from E1OH (80%) afforded pale, yellow needles ot 15 ( 3,4-Dicyano-trf,lV-diphenylbenzenesulfonamide (16) To a solution of 9 (1.80 g, 3 l-(3,4-Dicyanophenylsulfonyl)pyrrole (17) In a manner identical to that of 16 l-(3,4-Dicyanophenylsulfonyl)indole (18) As for 16 9,L0,16,11,23,24-Hexakis-(1 -heptyl)-2-(lpyrrolylsulfonyl)phthalocyanine (26) Excess 4,S-diheptylphthalonitrile (25) (29), prepared by our previously described method (32), (200 mg, 0.69 mmol) and 17 (20 mg. 0.078 mmol) were dissolved in DMAE (3 mL). As ammonia gas was brlbbled through, the reaction mixture was heated to I 00-1 lO'C (sand bath).…”

Section: -(34-dibromophenylsulphonyl)-35-dimethylpyrazole (R2)mentioning

confidence: 99%

Heterocyclic aromatic amide protecting groups for aryl and phthalocyaninesulfonic acids

Li¹,

Lier²,

Leznoff³

1999

Can. J. Chem.

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Pyroles, indole, imidazole, and a pyrazole were treated with 3,4-dibromobenzenesulfonyl chloride to form 3,4-dibromobenzenesulfonamides. The l-(3,4-dibromophenylsulfonyl)pyrrole and I -(3,4-dibromophenylsullonyl)indole were stable to CUCN iu DMF to produce l{3,4-dioyanophenylsulfonyl)pynole and l-(3.4-dicyanophenylsulfbnyl)indole, which upon treatment rvith ammonia in 2-N,,V-dimethylaminoethanol gave the protected phthalocyanine-2,9,16,23-tetrasulfonamides. Base cleavage of these sulfonamides yielded the free acids. A mixed conclensation of 4,5-diheptylphthalonitrile and 1-(3,4-dicyanophenylsulfonyl)pynole gave 9,10,16.17,23,24-hexakis(1-heptyl)-2-(lpyrrolylsulfonyl)phthalocyanine. Cleavage of the latter yielded the lithium salt of the monosulfonic acid.Ke"v words: sulfonic acid blocking groups, phthalocyanine sulfonic acids, l-(3,4-dicyanophenylsulfonyl)pynole, I -(3,4-dicyanophenyl sulfonyl)indole. 2). Although phthalocyanine -2,9,1 6,23 -tetr asulfonic acid is commercially available as a mixtufe of isomers, it has been shown that phthalocyanine-2-sulfonic acid ard plrthalocyanine-2,9-disulfonic acid are more effective for direct cell kill (3)(4)(5)(6)(7)(8)(9)

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Cleavage And Rearrangement Of Sulfonamides

Cited by 112 publications

References 48 publications

Synthesis, resolution, and investigation of the rotational interconversion process of atropisomeric 1,n‐diaza[n]paracyclophanes using cyclodextrin‐mediated capillary zone electrophoresis

Synthesis, resolution, and investigation of the rotational interconversion process of atropisomeric 1,n‐diaza[n]paracyclophanes using cyclodextrin‐mediated capillary zone electrophoresis

Laccase‐Mediated Synthesis of Novel Substituted Phenoxazine Chromophores Featuring Tuneable Water Solubility

Heterocyclic aromatic amide protecting groups for aryl and phthalocyaninesulfonic acids

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