Photocycloaddition of Four-Carbon-Tethered Pyridones. Intramolecular Hydrogen Bonding and Facilitated Amide Hydrolysis by a Proximal Secondary Alcohol<sup>1</sup>

Zhu, Man; Qiu, Zhilei; Hiel, Gary; Sieburth, Scott McN.

doi:10.1021/jo025565n

Cited by 16 publications

(12 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 H NMR (400 MHz, CDCl 3 ) δ : 8.18 (2H, m) 6.97 (1H, m); 13 C NMR (101 MHz, CDCl 3 ) δ : 161.9 (d, J = 260.0 Hz), 150.2 (d, J = 3.0 Hz), 147.2 (d, J = 13.0 Hz), 122.7 (d, J = 4.5 Hz), 76.0 (d, J = 43.5 Hz). The analytical data are in agreement with literature values …”

Section: Synthesis Route Isupporting

confidence: 90%

“…For this route, we synthesized the desired 3‐iodo‐2‐(methylamino)‐pyridine 8a , starting from the 2‐fluoropyridine 7 , in two steps . The internal alkyne was synthesized by the diastereoselective alkylation of the Schöllkopf chiral auxiliary 10 . The activation of the protected propargyl alcohol 11 toward the alkylation reaction with the Schöllkopf auxiliary was achieved using a variety of activating agents; however, the best results were obtained when diphenylphosphoranyl chloride was used.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

2015

View full text Add to dashboard Cite

Tryptophan has been taken as the basic scaffold for a chromophore whose indole residue can be further functionalized by the introduction of endocyclic nitrogen atoms or by N-methylation. When compared with exocyclic modifications, modifying tryptophan in an endocyclic fashion (through atomic substitution) should not perturb the steric profile of the amino acid side chain to such a large extent as that of an exocyclic modification, while simultaneously modulating the polarity, hydrogen-bonding ability, and spectral properties of the amino acid. Of particular interest is that the spectral properties can be tailored such that the chromophore can be monitored at wavelengths that exceed natural protein fluorescence. Ideally, the optimum excitation wavelength should be between 300 and 350 nm, and the emission wavelength should be ≥500 nm such that no cross-excitation/fluorescence occurs. Here, we report the synthesis of amino acid labels that exhibit large red shifts in their fluorescence profiles and their use in peptides.

show abstract

Section: Synthesis Route Isupporting

confidence: 90%

Section: Resultsmentioning

confidence: 99%

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

2015

View full text Add to dashboard Cite

show abstract

“…Thus, 2-fluoropyridine was converted into 2-fluoro-3-iodopyridine. 21 Then, the treatment with LDA at −78 °C gave the 4-lithio derivative which underwent basicity-gradient driven isomerization immediately to give more stable 2-fluoro-3-lithio-4-iodopyridine. 22 This was trapped with 2-methoxybenzaldehyde to afford α-(2′-methoxyphenyl)-2-fluoro-4-iodopyridine-3-methanol 5a, which was protected in the form of a sodium salt using NaH and then treated with tBuLi.…”

Section: Synthesismentioning

confidence: 99%

Nitrogen–boron coordination versus OH⋯N hydrogen bonding in pyridoxaboroles – aza analogues of benzoxaboroles

et al. 2015

View full text Add to dashboard Cite

Pyridoxaboroles - fused heterocyclic systems composed of pyridine and five-membered oxaborole rings - have been obtained for the first time from simple halopyridines. Thus, 6-butyl-2-(3'-bromo-4'-pyridyl)-(N-B)-1,3,6,2-dioxazaborocan obtained from 3-bromopyridine was converted into a lithio derivative by Br/Li exchange using nBuLi/THF at -85 °C. This intermediate was trapped with benzaldehydes to give the corresponding pyridoxaboroles after hydrolysis. The use of chlorodiphenylsilane as an electrophile gave rise to a related pyridosiloxaborole. The fluorinated pyridoxaborole was obtained by deprotonation of α-(2-methoxyphenyl)-2-fluoro-4-iodopyridylmethanol with NaH and consecutive iodine-lithium exchange/boronation followed by hydrolysis. Single-crystal X-ray analysis of pyridino[4,3-c]-1,3-dihydro-1-hydroxy-3-mesityl[2,1]oxaborole revealed the formation of a unique 1D coordination polymer based on N-B dative bonds between monomeric molecules. In contrast, the crystal structure of 2-fluoropyridino[4,3-c]-1,3-dihydro-1-hydroxy-3-(2'-methoxyphenyl)[2,1]oxaborole features an infinite H-bonded chain as the main structural motif. The presented considerations are quantified in terms of various computational methods (single molecule and dimer energy calculations, electron density topology, NBO analyses) providing a comprehensive picture of the structural properties of pyridoxaboroles.

show abstract

“…Kametani and col. have used -chloropyridine N-oxides as starting material for the synthesis of picolinic acids derivatives [59][60]. However, direct hydrolysis under acidic conditions (aqueous HCl, dioxane, reflux, 2h) provided the corresponding 2-pyridones in very high yields [62], and is being widely applied [63,64] (Scheme (6)). However, direct hydrolysis under acidic conditions (aqueous HCl, dioxane, reflux, 2h) provided the corresponding 2-pyridones in very high yields [62], and is being widely applied [63,64] (Scheme (6)).…”

Section: From Other Aromatic Heterocyclic Ringsmentioning

confidence: 99%

New Synthetic Methods to 2-Pyridone Rings

Torres¹,

Gil²,

Parra

2005

COC

202

View full text Add to dashboard Cite

The synthesis of a substituted 2-pyridone ring is a topical area of continuing interest due to the number of biologically active molecules containing this moiety. Over the last decade, natural compounds with this structure have emerged as potent antitumor antiviral and attention, because those compounds may be studied as a simple model for investigating mechanisms of some enzymatic reactions or for discerning the behavior of nucleic acids bases in connection with mutation due to base mispairing or other mistaken helices. Recent studies have shown the usefulness of 2-pyridones as intermolecular connectors between building blocks in material science. Thus, despite the large number of methods known for their synthesis, new procedures are continuously being developed. Two main synthetic approaches can be found in the literature: from other heterocycles systems or condensation of acyclic systems. The latter can be further classified depending on the bond formed in the cyclization step: by C-C or C-N bond generation. The latter can be subclassified depending on the first condensation step. This is a review of new or improved methods for constructing 2-pyridone rings. This article will be restricted to ring formation, which can be included in the total synthesis of several compounds with specific biological or material properties.The pursuit of these properties requires efficient synthetic routes that allow rapid assembly and variation of multiple pendant substituents on the heteroaromatic case, which permits rapid analogsynthesis (RAS) [1].

show abstract

Photocycloaddition of Four-Carbon-Tethered Pyridones. Intramolecular Hydrogen Bonding and Facilitated Amide Hydrolysis by a Proximal Secondary Alcohol¹

Cited by 16 publications

References 25 publications

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

Nitrogen–boron coordination versus OH⋯N hydrogen bonding in pyridoxaboroles – aza analogues of benzoxaboroles

New Synthetic Methods to 2-Pyridone Rings

Contact Info

Product

Resources

About

Photocycloaddition of Four-Carbon-Tethered Pyridones. Intramolecular Hydrogen Bonding and Facilitated Amide Hydrolysis by a Proximal Secondary Alcohol1

Cited by 16 publications

References 25 publications

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

Toward intrinsically colored peptides: Synthesis and investigation of the spectral properties of methylated azatryptophans in tryptophan‐cage mutants

Nitrogen–boron coordination versus OH⋯N hydrogen bonding in pyridoxaboroles – aza analogues of benzoxaboroles

New Synthetic Methods to 2-Pyridone Rings

Contact Info

Product

Resources

About

Photocycloaddition of Four-Carbon-Tethered Pyridones. Intramolecular Hydrogen Bonding and Facilitated Amide Hydrolysis by a Proximal Secondary Alcohol¹