A New Synthetic Route to Benzoxazole Polymer via Tandem Claisen Rearrangement

Yang, Gang; Matsuzono, Shin‐Ichiro; Koyama, Emiko; Tokuhisa, Hideo; Hiratani, Kazuhisa

doi:10.1021/ma010721y

Cited by 25 publications

(9 citation statements)

References 22 publications

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“…When the temperature is above 225 °C, the newly appeared bands at 1616 cm −1 (CN stretch) and 1006 cm −1 (C−O stretch) indicate the formation of the oxazole ring. 41,42 This matches well with the decreased NH absorption at 3421 cm −1 upon heating as shown in Figure 2(b) since the NH group must be consumed for the benzoxazole formation according to the proposed mechanism.…”

Section: Resultssupporting

confidence: 82%

Enhanced Thermal Property and Flame Retardancy via Intramolecular 5-Membered Ring Hydrogen Bond-Forming Amide Functional Benzoxazine Resins

Liu

Safronava²,

Lyon

et al. 2018

Macromolecules

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Polybenzoxazines containing an ortho-amide group in the backbone with a significant degree of aromaticity have been synthesized and characterized in this study. This class of materials makes use of smart chemistry to be able to readily process the monomer and later transform from polybenzoxazine into polybenzoxazole. All the benzoxazine monomers studied contain amide groups that form 5-membered intramolecular hydrogen bonds with the oxazine rings. Systematic manipulation of the diamine structure has allowed the structure–property relationship of polybenzoxazines to be examined. Polymerization behavior of monomers is studied by differential scanning calorimetry (DSC) and in situ Fourier transform infrared spectroscopy (FT-IR). Thermal stability and flammability are characterized by thermogravimetric analysis (TGA) and microscale combustion calorimetry (MCC), respectively. The experimental results are fitted to the major thermal decomposition processes contributing to the specific heat release rate histories Q′(T). This family of materials show one of the lowest heat release capacity values of all polymers indicating the excellent flame retardancy.

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Section: Resultssupporting

confidence: 82%

Enhanced Thermal Property and Flame Retardancy via Intramolecular 5-Membered Ring Hydrogen Bond-Forming Amide Functional Benzoxazine Resins

Liu

Safronava²,

Lyon

et al. 2018

Macromolecules

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“…The C=N stretching vibrations [33][34][35][36] are observed in the range 1672-1566 cm −1 . Varsanyi [37] has suggested that an IR band at 1626 cm −1 for C=N stretching and Raman frequency is assigned to the C=N stretching vibration of benzothizaole [38].…”

Section: C=n Vibrationsmentioning

confidence: 99%

Molecular Modeling and Spectroscopic Studies of Benzothiazole

Sathyanarayanmoorthi¹,

Karunathan²,

Kannappan³

2013

Journal of Chemistry

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The Fourier Transform (FT) infrared and FT-Raman spectra of benzothiazole (BT) have been recorded and analyzed. The equilibrium geometry, bonding features, and harmonic vibrational frequencies have been investigated by ab initio and density functional theory (DFT) methods. The assignments of the vibrational spectra have been carried out. The computed optimized geometric bond lengths and bond angles show good agreement with experimental data of the title compound. The calculated HOMO and LUMO energies indicate that charge transfer occurs within the molecule. Stability of the molecule due to conjugative interactions arising from charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The results show that the electron density (ED) in the * and * antibonding orbital and second-order delocalization energies (2) confirm the occurrence of intramolecular charge transfer (ICT). The calculated results were applied to simulate infrared and Raman spectra BT which show good agreement with recorded spectra.

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“…5 Compounds 4 were highly fluorescent 9 and they could be incorporated into polymers by performing the tandem Claisen rearrangement with polyamides using compounds such as 3 as a monomeric diamine in the preparation of the polymers. 10…”

Section: The Tandem Claisen Rearrangementmentioning

confidence: 99%

The tandem Claisen rearrangement in the construction of building blocks for supramolecular chemistry

Hiratani

Albrecht

2008

Chem. Soc. Rev.

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The tandem Claisen rearrangement is a simple but highly efficient reaction to synthesize useful building blocks for supramolecular chemistry. It provides in one step two new C-C bonds in very high yield. The scope and limits of this reaction will be discussed in this review and it will be shown, how macrocyclic compounds as well as rotaxanes or helicates can be formed by use of butenylidene bridged aromatic compounds obtained after the rearrangement reaction. Special aspects will cover the search for new receptors and sensors or for energy transfer properties. The contents of this tutorial review are within the field of preparative organic synthesis but in addition cover aspects of inorganic and supramolecular chemistry.

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A New Synthetic Route to Benzoxazole Polymer via Tandem Claisen Rearrangement

Cited by 25 publications

References 22 publications

Enhanced Thermal Property and Flame Retardancy via Intramolecular 5-Membered Ring Hydrogen Bond-Forming Amide Functional Benzoxazine Resins

Enhanced Thermal Property and Flame Retardancy via Intramolecular 5-Membered Ring Hydrogen Bond-Forming Amide Functional Benzoxazine Resins

Molecular Modeling and Spectroscopic Studies of Benzothiazole

The tandem Claisen rearrangement in the construction of building blocks for supramolecular chemistry

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