Hydride mobility in pyridinium salt-dihydropyridine mixtures. A Biomimetic pyridine nucleotide transhydrogenation

Vanbergen, Tj; Mulder, Titia; Kellogg, R. M.

doi:10.1021/ja00423a052

Cited by 19 publications

(3 citation statements)

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“…Sundberg demonstrated that heating a mixture of an indoleacrylate and a 1,2-dihydropyridine yielded an adduct 184 that was eventually converted to the catharanthine-like alkaloid 185. 131 Wender has S02Ph CO2C2H5 used the Diels-Alder reaction between acrolein and W-carbomethoxy-1,2-dihydropyridine to form cishydroisoquinolines 187 via the bicyclic adducts 186.132 The tetrahydropyridine baikiain (188) has been used with sodium hypochlorite to produce 2,5-dihydro- The two isomeric dihydropyridines then combine to afford the natural product anatabine (190).133 A model reaction utilizing a dihydropyridine was used to develop the synthetic strategy for preparing the alkaloid elaeocarpine (191) in two steps. Thus, lithium aluminum hydride reduction of iV-methylpyridinium iodide (192) followed by the addition of 6-methylsalicylaldehyde furnished condensation product 193.…”

Section: Photochemical Reactionsmentioning

confidence: 99%

“…Polymer-bound dihydropyridines have been found to reduce dyes and the central iron of ferriporphorins.185 Dihydropyridines have also been used for the nucleophilic displacement of sulfonium salts (231) from sp3-hybridized carbon by a (formal) hydride.186 Nitro the 1-alkyl compounds gave only the 1,6-isomers 236.190 In the presence of pyridinium salts, 1,4-dihydropyridines irreversibly isomerize to 1,2-dihydropyridines. 191 In view of these findings, a 1,2-dihydropyridine must not be involved in NADH equilibria since NADH is regenerated when NAD+ is allowed to equilibrate with simple 1,4-dihydronicotinamides.192 VII. Pharmacology Dihydropyridines have had a unique evolutionary history over this past century.…”

Section: E Miscellaneousmentioning

confidence: 99%

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Recent advances in the chemistry of dihydropyridines

Stout¹,

Meyers²

1982

Chem. Rev.

896

266

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Section: Photochemical Reactionsmentioning

confidence: 99%

Section: E Miscellaneousmentioning

confidence: 99%

Recent advances in the chemistry of dihydropyridines

Stout¹,

Meyers²

1982

Chem. Rev.

896

266

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“…This choice was based on several considerations. It is experimentally much simpler than the more extensively studied dihydronicotinamides, which are chemically more labile and in which there is a possibility of concurrent scrambling of deuterium between the 2-, 4-, and 6-positions (11). More importantly, both the lower ionization potential of 1 (below) and the smaller gain in resonance energy accompanying loss of hydride (compared to the dihydropyridines) (12) was expected to increase the lifetime of a radical ion pair intermediate.…”

mentioning

confidence: 99%

Hydride transfer reactions. Oxidation of N-methylacridan by π acceptors

Colter¹,

Saito²,

Sharom³

1977

Can. J. Chem.

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The oxidation of N-methylacridan (1) to N-methylacridinium ion (2) by the π acceptors p-benzoquinone (BQ), 7,7,8,8-tetracyanoquinodimethane (TCNQ), p-chloranil (CA), tetracyanoethylene (TCNE), and 2,3-dicyano-1,4-benzoquinone (DCBQ) has been investigated. Second-order rate constants in acetonitrile (AN) vary by a factor of more than 107 for this series. The rate of reaction of 1 with BQ increases 45-fold as the solvent composition is varied from AN to 50% (v/v) AN–water, but is insensitive to changes in buffer ratio or concentration in 75% AN. Spectroscopic evidence for charge-transfer complexing between the reactants was obtained with BQ and CA, and kinetic evidence for complexing was obtained with BQ in 75% AN. The primary isotope effect, p, calculated from the rates of oxidation of 1, 1-9-d, and 1-9,9-d2 (1(HH), 1(HD), and 1(DD)) in AN varied from 4.5 (TCNE) to 13 (BQ), while the secondary isotope effect, s, was approximately constant (∼1.1). Values of the isotope partitioning ratio, ipr (the ratio of 2(D) to 2(H) formed in reaction of 1(HD)) were determined for BQ in three AN-water mixtures and for CA, TCNE, and DCBQ in AN. For all systems studied, except BQ in 90% AN, where determination of the ipr is complicated by isotopic exchange between unreacted 1 and product (2), the ipr agrees with p/s from the kinetic measurements. These results are discussed in terms of mechanism and compared with those of other hydride transfer reactions involving dihydronicotinamide donors.

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Transition Metal Complexes Coordinated by an NAD(P)H Model Compound and their Enhanced Hydride‐Donating Abilities in the Presence of a Base

Kobayashi

Konno

Sakamoto

et al. 2005

Chemistry A European J

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The ruthenium(II) and rhenium(I) complexes containing an NAD(P)H model compound, 1-benzyl-1,4-dihydronicotinamide (BNAH), as ligand, [Ru(tpy)(bpy)(BNAH)]2+ (1 a) and [Re(bpy)(CO)3(BNAH)]+ (1 b), were quantitatively produced by the reaction of the corresponding metal hydrido complexes with BNA(+) (1-benzylnicotinamidium cation). In the presence of base with pK(a) = 8.9, 1 a and 1 b have much greater reducing power than "free" BNAH. The oxidation potentials of 1 a in the absence and the presence of triethylamine were 0.55 V and -0.04 V, respectively, versus Ag/AgNO(3), whereas that of "free" BNAH was 0.30 V. Spectroscopic results clearly showed that the base extracts a proton from the carbamoyl group on 1 a and 1 b to give the deprotonated BNAH coordinating to the transition-metal complexes [Ru(tpy)(bpy)(BNAH-H+)]+ (3 a) and [Re(bpy)(CO)3(BNAH-H+)] (3 b); this deprotonation underlies the enhancement in reducing ability. The deprotonated forms 3 a and 3 b can efficiently reduce other NAD(P) models to give the corresponding 1,4-dihydro form, resulting in the deprotonated BNA+ being coordinated to the metal complexes [Ru(tpy)(bpy)(BNA(+)-H+)]2+ (2 a) and [Re(bpy)(CO)3(BNA+-H+)]+ (2 b); "free" BNAH and the protonated adducts 1 a and 1 b cannot act in this way. X-ray crystallography was performed on the PF6- salt of 2 a, and showed that the deprotonated nitrogen atom on the carbamoyl group coordinates to the ruthenium(II) metal center with a bond length of 2.086(3) Angstroms. Infrared spectral data suggested that the deprotonated carbamoyl group on the reduced forms 3 a and 3 b is converted to the imido group, and that the oxygen atom coordinates to the metal center.

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Hydride mobility in pyridinium salt-dihydropyridine mixtures. A Biomimetic pyridine nucleotide transhydrogenation

Cited by 19 publications

References 0 publications

Recent advances in the chemistry of dihydropyridines

Recent advances in the chemistry of dihydropyridines

Hydride transfer reactions. Oxidation of N-methylacridan by π acceptors

Transition Metal Complexes Coordinated by an NAD(P)H Model Compound and their Enhanced Hydride‐Donating Abilities in the Presence of a Base

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