Equilibrium additions of carbon-nitrogen double bonds in nonaqueous solutions. Addition of alcohols to substituted benzylideneanilines

Ogata, Yoshiro; Kawasaki, Atsushi

doi:10.1021/jo00922a009

Cited by 13 publications

(5 citation statements)

References 16 publications

(20 reference statements)

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“…The equilibrium constants were determined with a range of 0.24–9.45 M –1 . Albeit small, these equilibrium constants are significantly higher than the data reported for the reaction of N -( p -nitrobenzylidene)- m -nitroaniline and methanol even in 9:1 methanol/acetonitrile (0.065 M –1 ), thereby further validating the power of our strategy of in situ dynamic multicomponent covalent assembly.…”

Section: Resultssupporting

confidence: 66%

Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry

Zhou

et al. 2015

J. Am. Chem. Soc.

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Dynamic covalent chemistry (DCC) has become a powerful tool for the creation of molecular assemblies and complex systems in chemistry and materials science. Herein we developed for the first time quantitative reactivity scales capable of correlation and prediction of the equilibrium of dynamic covalent reactions (DCRs). The reference reactions are based upon universal DCRs between imines, one of the most utilized structural motifs in DCC, and a series of O-, N-, and S- mononucleophiles. Aromatic imines derived from pyridine-2-carboxyaldehyde exhibit capability for controlling the equilibrium through distinct substituent effects. Electron-donating groups (EDGs) stabilize the imine through quinoidal resonance, while electron-withdrawing groups (EWGs) stabilize the adduct by enhancing intramolecular hydrogen bonding, resulting in curvature in Hammett analysis. Notably, unique nonlinearity induced by both EDGs and EWGs emerged in Hammett plot when cyclic secondary amines were used. This is the first time such a behavior is observed in a thermodynamically controlled system, to the best of our knowledge. Unified quantitative reactivity scales were proposed for DCC and defined by the correlation log K = S(N) (R(N) + R(E)). Nucleophilicity parameters (R(N) and S(N)) and electrophilicity parameters (R(E)) were then developed from DCRs discovered. Furthermore, the predictive power of those parameters was verified by successful correlation of other DCRs, validating our reactivity scales as a general and useful tool for the evaluation and modeling of DCRs. The reactivity parameters proposed here should be complementary to well-established kinetics based parameters and find applications in many aspects, such as DCR discovery, bioconjugation, and catalysis.

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Section: Resultssupporting

confidence: 66%

Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry

Zhou

et al. 2015

J. Am. Chem. Soc.

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“…o + constants, shown in Figure 5, gave two lines broken at o+ = 0. With electron-attracting groups except for p-chloro, a fairly good straight line with a p+ value of -4.35 (r = 0.987) and with electron-releasing groups except forp-dimethylamino group (18) a straight line with a p + value of 1.01 (r = 0.998) were obtained.…”

Section: Resultsmentioning

confidence: 89%

Effect of substituents on the 13C chemical shifts of the azomethine carbon atom of N-benzylideneanilines and 2-N-arylimino-2-p-nitrophenylethanenitriles

Kawasaki¹

1990

J. Chem. Soc., Perkin Trans. 2

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The 13C chemical shifts of the azomethine carbon atoms have been determined for a series of metaand para-substituted benzylideneanilines PhCH=NC6H4R3 (1 )-( 8), p-No2C6H4CH=Nc6H,R3 (9)-(17), R1C6H,CH=NPh (18)-(26), and p-N0,C6H4C(CN)=NC6H,R3 (27)-(32) in CDCI, solution. For the compounds (1)-(17), good p + a + correlations are observed; the p+ values are 2.73 for compounds (1)-(8) and 3.52 for the compounds (9)-( 17). However, the shifts with m-and p-nitro substituents show small but appreciable lower-field deviations. For the compounds (1 8)-(26) plots of chemical shifts vs. a+ constants give t w o lines intersecting at 0 ' = 0, explicable by the overlapping effects. For the nitriles (27)-(32) the plots give two lines which do not intersect, but plots of chemical shifts vs. the reciprocals of the h,,, of the K band of the electronic spectra are found to be a straight line. This is explicable in terms of unusually strong resonance electron donation from the phenylimino system.Reaction constants (p') changed from 2.49 for (1)-(3) through 3.28 for (9)-(11) t o 9.39 for (27)-(29). Apart from the dihedral angle, the sensitivities of chemical shifts t o the electronic effects of the substituents in the aniline ring are affected strongly by the degree of electron demand of the carbon atom of the C=N moiety.N-Benzylideneanilines are generally accepted to adopt E-nonplanar or E-dihedral structures on the basis of their dipole moment studies,'** UV spectra,2-6 X-ray ~rystallography,'.~ ' 3C N M R spectra,' and molecular-orbital st~dies.~.' Since the geometry in the solid state depends on molecular packing," it is not always the same as that irr solutions nor in the vapour state. Because of these peculiar conformations studies of electronic substituent effects have been extensive with regard to physical and chemical properties such as IR vmaX,l ' polarographic halfwave potential,12 reaction rates of N-alkylation l 3 and of cis-trans is~merisation,'~ base strength,' rate and equilibrium constants for addition reaction^,'^-'^ and azomethine ' 3C chemical shifts.' While the effects on reaction rates depend on the reaction mechani~rns,'~-'~ p +o+ correlations have been observed for the equilibrium constants " p l ' Paper 8/03034K

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“…From the difference in these two concentrations it is possible to obtain the concentration changes of the carbinolamine intermediate. (Table 17) is increased by electron-withdrawing substituents in both the aniline and benzylidene ring 77 . These The polar effect of substituents (∆ * = -8.2) is stronger than the steric one ( * = 0.48).…”

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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Equilibrium additions of carbon-nitrogen double bonds in nonaqueous solutions. Addition of alcohols to substituted benzylideneanilines

Cited by 13 publications

References 16 publications

Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry

Quantitative Reactivity Scales for Dynamic Covalent and Systems Chemistry

Effect of substituents on the 13C chemical shifts of the azomethine carbon atom of N-benzylideneanilines and 2-N-arylimino-2-p-nitrophenylethanenitriles

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

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