On the Mechanism, Substituent Effects, and Intramolecular Catalysis in Schiff Base Hydrolysis

Reeves, Richard L.

doi:10.1021/jo01020a061

Cited by 43 publications

(29 citation statements)

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“…Regarding the X substitutes, from the results, the kinetic constant decreased when X was an electron‐withdrawing substituent; this is in agreement with the conclusions of Reeves and Cordes and Jencks about the substituted aromatic Schiff bases.…”

Section: Resultssupporting

confidence: 89%

“…becomes Eq. , where the hydrolysis reaction is simultaneously specific acid and base‐catalyzed:

k_{obs} = \frac{k_{1} [{normalH}^{+}] + K_{e} k_{2}}{([{normalH}^{+}] + K_{{SH}^{+}})}

The basic plateau P appeared from pH 8–13, and in this domain Reeves demonstrated that the rate‐limiting step corresponded to the nucleophile attack of hydroxide anion on the protonated imine. The hydrolysis constant is then given by Eq.…”

Section: Resultsmentioning

confidence: 99%

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Hydrolysis Kinetic Studies of Schiff Bases Derived from Pyrrolic Aldehydes in Buffered Aqueous Ethanol and Sulfuric Acid Solutions: Structural Effects of Substitutes

Bengharez

Bahri

Mesli

2013

Int J of Chemical Kinetics

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Two series of substituted N‐pyrrolyl‐2‐methylene‐aniline were synthesized and characterized to study their stability in a large domain of pH (0–14) and especially in the H0 domain (–4 to 0). The hydrolysis kinetics of the azomethine group was established in homogeneous media using a thermostated UV–vis spectrophotometer. The hydrolysis mechanism was investigated, and the experimental kinetic constants were calculated. Then, the pH–rate diagram profile was determined and the structural effect of substitutes on the kinetic constants was clarified and discussed.

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Section: Resultssupporting

confidence: 89%

“…becomes Eq. , where the hydrolysis reaction is simultaneously specific acid and base‐catalyzed:

k_{obs} = \frac{k_{1} [{normalH}^{+}] + K_{e} k_{2}}{([{normalH}^{+}] + K_{{SH}^{+}})}

Section: Resultsmentioning

confidence: 99%

Hydrolysis Kinetic Studies of Schiff Bases Derived from Pyrrolic Aldehydes in Buffered Aqueous Ethanol and Sulfuric Acid Solutions: Structural Effects of Substitutes

Bengharez

Bahri

Mesli

2013

Int J of Chemical Kinetics

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“…The UV–vis spectrum for each compound revealed that only 5 underwent decomposition (data not shown). Indeed, imines derived from salicylidene aldehydes, like 5 , are known to be easily hydrolyzed in aqueous medium (26). A six‐membered conformer is established between the o‐ hydroxyl group and the nitrogen atom from C=N bond, which activates the addition of a nucleophile (e.g., H 2 O) to the carbon atom at C=N bond (26).…”

Section: Resultsmentioning

confidence: 99%

“…Indeed, imines derived from salicylidene aldehydes, like 5 , are known to be easily hydrolyzed in aqueous medium (26). A six‐membered conformer is established between the o‐ hydroxyl group and the nitrogen atom from C=N bond, which activates the addition of a nucleophile (e.g., H 2 O) to the carbon atom at C=N bond (26). Thus, the lack of activity for compounds 4 , 6, and 7 cannot be attributed to a possible decomposition in the medium.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Aryl Aldimines and Their Activity against Fungi of Clinical Interest

Silva

Martins

et al. 2011

Chem Biol Drug Des

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Aldimines are aldehyde-derived compounds that contain a C=N group. Besides its broad industrial applications, this class of non-naturally occurring compounds are found to possess antibacterial, antifungal, antimalarial, antiproliferative, anti-inflammatory, antiviral, and antipyretic properties. Based on this, six aryl aldimines were synthesized from the condensation of aromatic amines with benzaldehydes. The antifungal activities of synthesized compounds were evaluated against nineteen fungal strains that included Candida and Aspergillus species, Cryptococcus neoformans. The aryl aldimines 2-(benzylideneamino)phenol (3) and 4-(benzylideneamino)phenol (8) were the most active compounds against the fungi studied. Compounds 3 and 8 efficiently inhibited the metabolism of C. neoformans mature biofilm.

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“…In aqueous solutions, furthermore, the addition can involve either a water molecule or the hydroxide ion as the nucleophile. Probably due to this complexity, the equilibrium constants for additions of H 2 O or OH -to such Schiff bases have not been in most cases isolated [70][71][72][73][74] .…”

Section: Covalent Additions To Benzylidene Derivativesmentioning

confidence: 99%

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

Zuman¹

2002

Arkivoc

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In this review are discussed equilibria involved in nucleophilic additions of H 2 O, HO -, ROH, and RO -(where R is an alkyl) to compounds containing carbonyl and azomethine bonds. These reactions result in a formation of covalent bonds between the heteroatom of the nucleophile and the carbon of the carbonyl double bond. After a brief summary of reactions resulting in additions to aliphatic carbonyl compounds, attention is paid to additions to benzaldehydes and formyl aromatic heterocycles. Equilibria involving additions to pyridoxal and some related compounds are dealt with in some detail. Discussion of additions of stated nucleophiles to azomethine bonds is practically restricted to additions to C=N bonds in heterocyclic rings. The reactivity of nucleophiles in such additions depends on the number of heteroatoms (in particular nitrogen) in the attacked ring, as well as on the number and position of substituents in such rings. In polynuclear compounds the reactivity depends on the number and kind of annelled rings, on the number and mutual position of heteroatoms and on the kind, number and position of substituents. In particular additions to pyrimidines, quinazolines, 1,2,4-and 1,3,5-triazines, pteridines and other heterocycles with four nitrogens, as well as 8-azapurines are mentioned.

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On the Mechanism, Substituent Effects, and Intramolecular Catalysis in Schiff Base Hydrolysis

Cited by 43 publications

References 0 publications

Hydrolysis Kinetic Studies of Schiff Bases Derived from Pyrrolic Aldehydes in Buffered Aqueous Ethanol and Sulfuric Acid Solutions: Structural Effects of Substitutes

Hydrolysis Kinetic Studies of Schiff Bases Derived from Pyrrolic Aldehydes in Buffered Aqueous Ethanol and Sulfuric Acid Solutions: Structural Effects of Substitutes

Synthesis of Aryl Aldimines and Their Activity against Fungi of Clinical Interest

Additions of water, hydroxide ions, alcohols and alkoxide ions to carbonyl and azomethine bonds

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