Spectrophotometrically Determined Ionization Constants of Derivatives of Symmetric Triazine.

Hirt, R. C.; Schmitt, R. G.; Strauss, H. A.; Koren, J. G.

doi:10.1021/je60011a040

Cited by 35 publications

(18 citation statements)

References 15 publications

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“…According to the molecular structure of mb, a four-site protonation model was used to determine the proton binding constants (log K 1-4 ) for mb in a first step. The value of log K 1 representing the protonation of the tyrosine group was derived from the pHdependent UV-vis absorption spectra according to Hirt et al [26]. The curve was fitted with a sigmoidal equation (Eq.…”

Section: Data Analysis and Modeling Of Conditional Stability Constantsmentioning

confidence: 99%

Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

Pesch

Christl

Hoffmann

et al. 2012

Journal of Inorganic Biochemistry

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Section: Data Analysis and Modeling Of Conditional Stability Constantsmentioning

confidence: 99%

Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

Pesch

Christl

Hoffmann

et al. 2012

Journal of Inorganic Biochemistry

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“…On the other hand, aza-arylamines are stronger bases than 4, with ring nitrogen acting as site of protonation [42]. Still, the basicity is not marked, and we assumed that the presence of bulky groups in positions 4/6 would prevent the endocyclic nitrogen from acting as Brønsted base.…”

Section: Resultsmentioning

confidence: 99%

“…Ref. [42] 2-Amino-1,3,5-triazine chemistry: Hydrogen-bond networks, Takemoto thiourea catalyst analogs,… 1533 forming hydrogen-bonded dimers. Surprisingly, the lonepair of the basic dimethylamino unit is not involved in any hydrogen-bonding interaction or close contact.…”

Section: Resultsmentioning

confidence: 99%

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

2015

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The chemistry of 4,6-dialkyl-2-amino-1,3,5-triazines with bulky alkyl substituents was investigated and their use as building blocks for preparing chiral thiourea organocatalysts explored. Reaction of ammonia with 4,6-di-tert-butyl-2-chloro-1,3,5-triazine gave 4,6-di-tert-butyl-1,3,5-triazin-2-amine which formed extended hydrogenbond networks in the solid state according to X-ray crystallography. Selected heterocyclic amines were converted to isothiocyanates, and the latter reacted with (S,S)-2-(dimethylamino)cyclohexylamine to give enantiopure 1-hetaryl-3-[2-(dimethylamino)cyclohexyl]thioureas, with hetaryl representing either 4,6-dimethyl-1,3-diazin-2-yl, 4,6-diisopropyl-1,3,5-triazin-2-yl, or 4,6-di-tert-butyl-1,3, 5-triazin-2-yl groups. These compounds are structural analogs of Takemotos's chiral thiourea organocatalysts (1-[3,5-bis(trifluoromethyl)phenyl]-3-[(1S,2S)-2-(dimethylamino)cyclohexyl]thiourea) with an aza-aryl instead of the 3,5-bis(trifluoromethyl)phenyl group. They feature a strong intramolecular N-H to N-1 hydrogen bond, as shown by X-ray crystallography of 1-(4,6-di-tert-butyl-1,3,5-triazin-2-yl)-3-[2-(dimethylamino)cyclohexyl]thiourea in the solid state and by 1 H NMR spectroscopy of all derivatives in CDCl 3 solution, which prevents them from acting as bifunctional organocatalyst. In the reaction of 4,6-di-tertbutyl-2-chloro-1,3,5-triazine with ammonia, 4,6-di-tertbutyl-2-ethoxy-1,3,5-triazine was identified as side-product displaying a mildly sweet, floral odor that is unusual for a 1,3,5-triazine. Analogs ([35) of 4,6-di-tert-butyl-2-ethoxy-1,3,5-triazine were prepared to define the important structural factors of the olfactophore. Graphical abstract N N N H N tBu tBu N S H Me 2 N N N N NH 2 tBu tBu

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“…Alternatively, AMMT and AHMT triazines could be formed in the interlayer and remain adsorbed therein as the protonated species. Triazine, with electron-releasing substituents in the ring, is a weak base, e.g., AHMT has a pKa value of 3.1 (Hirt et al, 1961). Therefore, the greater acidity of hydrated Fe > ions, compared with AP +, may favor adsorption in the interlayer by protonation.…”

Section: Discussionmentioning

confidence: 99%

Adsorption and Degradation of Triasulfuron on Homoionic Montmorillonites

Pusino

2000

Clays and clay miner.

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Abstract--The adsorption and degradation of the herbicide triasulfuron [2-(2-chloroethoxy)-N- [[(4-methoxy-6-methyl-l,3,5-triazin-2-yl)(CMMT) on homoionic Fe 3 § AP +-, Ca 2+-, or Na+-exchanged montmorillonite in aqueous medium were studied. Ca-and Na-exchanged montmorillonite were ineffective in the adsorption and degradation of triasulfuron. The adsorption on Feand Al-exchanged montmorillonite was rapid, and equilibrium was attained after 5 min. Degradation of the herbicide was slow and the type of the degradation products depended on the nature of the exchangeable cations. In the presence of Fe3+-rich montmorillonite, the metabolites 2-(2-chloroethoxy)benzenesulfonamide (CBSA), 2-(2-chloroethoxy)-N-[[(4-hydroxy-6-methyl-l,3,5-triazin-2-yl)amino]carbonyl]benzenesulfonamide (CHMT), and l-[2-(2-chloroethoxy)benzene-l-sulfonyl]-7-acetyltriuret (CBAT) were the only identified products, whereas 2-amino-4-methoxy-6-methyltriazine (AMMT), CBSA, CHMT, and CBAT were the primary metabolites for the AP+-rich montmorillonite. A Fourier transform infrared (FT-IR) study of montmorillonite samples after the interaction with triasulfuron in organic solution suggests that the hydrolysis mechanism involves the adsorption of the herbicide on the 2:1 layers.

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Spectrophotometrically Determined Ionization Constants of Derivatives of Symmetric Triazine.

Cited by 35 publications

References 15 publications

Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

Copper complexation of methanobactin isolated from Methylosinus trichosporium OB3b: pH-dependent speciation and modeling

2-Amino-1,3,5-triazine chemistry: hydrogen-bond networks, Takemoto thiourea catalyst analogs, and olfactory mapping of a sweet-smelling triazine

Adsorption and Degradation of Triasulfuron on Homoionic Montmorillonites

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