30964-00-2Relevant academic research and scientific papers
Synthesis and Properties of Aromatic-Terminated Diacetylene Organogelators and Their Application to Photopatterning of Polydiacetylenes
Aoki, Ken'Ichi,Horitsugu, Kousuke,Narazaki, Kenta,Seki, Atsushi,Takahashi, Daiki,Tamaoki, Nobuyuki
, p. 13160 - 13169 (2021/11/16)
A series of simply structured diacetylene-diamide-based gelators (DAGs) with aromatic terminals were synthesized, and their gelation and subsequent photopolymerization abilities were analyzed. DAGs with an adequate spacer length (n) and tolyl terminals (DA-Tn) interacted with aromatic solvents, such as benzene and xylenes, at elevated temperatures. During the subsequent cooling process, the DAGs interacted with each other through CH-πinteractions at their terminal positions. They also formed one-dimensional hydrogen bonding arrays through secondary amides, leading to stable organogels. These gels polymerized into π-conjugated polydiacetylenes (PDAs) under ultraviolet irradiation. In the p-xylene gels of DA-Tn, the spacer length exerted characteristic odd-even effects on the photopolymerization rates over a certain range (n = 3-6), which can be explained by periodic changes in the uniformity of the molecular packing modes. When the gelling solvent was changed to cyclohexane, the gelation and photopolymerization abilities were greatly improved because the DA-Tn gel networks became highly crystallized and transparent to ultraviolet light (254 nm). The ultimate conversion to PDA from DA-T8/cyclohexane gels was 45.2 wt %. Applying photolithographic techniques to the DAG with excellent photopolymerizability in the film state, we successfully fabricated microscale photopatterns of PDA. We also established a convenient removal process (development process) of DA monomers in unexposed areas. The resulting PDA patterns were quite stable to ambient light stimuli.
Diazophosphonates: Effective Surrogates for Diazoalkanes in Pyrazole Synthesis
Ruffell, Katie,Smith, Frances R.,Green, Michael T.,Nicolle, Simon M.,Inman, Martyn,Lewis, William,Hayes, Christopher J.,Moody, Christopher J.
, p. 13703 - 13708 (2021/09/09)
Diazophosphonates, readily prepared from α-ketophosphonates by oxidation of the corresponding hydrazones in batch or in flow, are useful partners in 1,3-dipolar cycloaddition reactions to alkynes to give N-H pyrazoles, including the first intramolecular examples of such a process. The phosphoryl group imbues a number of desirable properties into the diazo 1,3-dipole. The electron-withdrawing nature of the phosphoryl stabilizes the diazo compound making it easier to handle, whilst the ability of the phosphoryl group to migrate readily in a [1,5]-sigmatropic rearrangement enables its transfer from C to N to aromatize the initial cycloadduct, and hence its facile removal from the final pyrazole product. Overall, the diazophosphonate acts as a surrogate for the much less stable diazoalkane in cycloadditions, with the phosphoryl group playing a vital, but traceless, role. The cycloaddition proceeds more readily with alkynes bearing electron-withdrawing groups, and is regiospecific with asymmetrical alkynes. The potential of diazophosphonates for use in bioorthogonal cycloadditions is demonstrated by their facile addition to strained alkynes.
Reversible Stereoselective Folding/Unfolding Fueled by the Interplay of Photoisomerism and Hydrogen Bonding
Opie, Christopher R.,Kumagai, Naoya,Shibasaki, Masakatsu
supporting information, p. 3349 - 3353 (2017/03/17)
A linear molecular architecture equipped with complementary three-fold hydrogen-bonding units embedded with a photoswitchable trans-tetrafluoroazobenzene moiety was synthesized. The transto cis photoisomerism of the azobenzene unit induced drastic changes
Self-assembly and solid-state polymerization of butadiyne derivatives with amide and trialkoxyphenyl groups
Kikuchi, Kohei,Tatewaki, Yoko,Okada, Shuji
supporting information, p. 298 - 305 (2017/05/10)
Three butadiyne derivatives with amide and tri(dodecyloxy)-phenyl (TDP) groups were synthesized, and four solidification methods were applied to obtain their self-assembling states in various conditions. The solids obtained were characterized by the solid-state polymerization behaviors, stretching vibration wavenumbers of N-H bonds of amide groups, powder X-ray diffraction, the thermal behaviors, and scanning electron microscope (SEM) observations. We found that all compounds had at least two polymorphs. Property differences between two polymorphs depended on the compounds. Two compounds showed clear differences in UV-vis spectra of the photo-polymerized solids, i.e., the polydiacetylene (PDA) structure, and irregularly polymerized form, or two PDA structures. The remaining compound showed the same PDA absorption but the monomer melting points were different. All compounds gave the gels in various organic solvents because of the molecular design with amide and TDP groups. SEM observation clarified the relationship between gel appearance and the nanostructures.
Additional nucleophile-free FeCl3-catalyzed green deprotection of 2,4-dimethoxyphenylmethyl-protected alcohols and carboxylic acids
Sawama, Yoshinari,Masuda, Masahiro,Honda, Akie,Yokoyama, Hiroki,Park, Kwihwan,Yasukawa, Naoki,Monguchi, Yasunari,Sajiki, Hironao
, p. 778 - 784 (2016/07/16)
The deprotection of the methoxyphenylmethyl (MPM) ether and ester derivatives can be generally achieved by the combinatorial use of a catalytic Lewis acid and stoichiometric nucleophile. The deprotections of 2,4-dimethoxyphenylmethyl (DMPM)-protected alcohols and carboxylic acids were found to be effectively catalyzed by iron(III) chloride without any additional nucleophile to form the deprotected mother alcohols and carboxylic acids in excellent yields. Since the present deprotection proceeds via the self-assembling mechanism of the 2,4-DMPM protective group itself to give the hardly-soluble resorcinarene derivative as a precipitate, the rigorous purification process by silica-gel column chromatography was unnecessary and the sufficiently-pure alcohols and carboxylic acids were easily obtained in satisfactory yields after simple filtration.
Reversible color changes in lamella hybrids of poly(diacetylenecarboxylates) incorporated in layered double hydroxide nanosheets
Itoh, Toshio,Shlchi, Tetsuya,Yui, Tatsuto,Takahashi, Hiroki,Inui, Yoshihisa,Takagi, Katsuhiko
, p. 3199 - 3206 (2008/03/14)
The present study is an investigation of a reversible thermal color change induced in lamella hybrids of poly(diacetylenecarboxylates) incorporated in layered double hydroxide (LDH) nanosheets. These poly-[m,n]/ LDH hybrids prepared by the photo- or ?3-ray-induced polymerization of diacetylenecarboxylates, i.e., CH3-(CH2) m-1Ca??C-Ca??C(CH2)n-1CO 2- (mono-[m,n]), and intercalated in LDH lamella sheets, were observed to develop colors ranging from yellow to blue. The change in color was found to depend greatly on the alkyl carbon numbers of the mono-[m,n] (m,n = 10,11; 5,11; 10,5; 16,1) values. Moreover, the conformational alignment of the mono-[m,n] within the LDH was observed to be a crucial factor in color development, which was greatly affected by the intercalation degrees and extent of poly(ene-yne) linkage elongation of the polymers. For the poly-[m,n]/LDH hybrids investigated, a reversible color change was found to occur repeatedly and remarkably for the poly-[10,11]/LDH hybrid. This color change occurred at temperatures between ca. 20 and 80?°C back and forth from purple red to bright orange, in stark contrast to the irreversible color change for poly-[10,11] without LDH. Moreover, DSC and Raman spectroscopic studies of the LDH hybrids showed that the thermochromic temperature corresponded to the phase transition temperature of 80?°C. XRD analysis also indicated that the poly-[m,n]/LDH hybrid could retain its lamella structure during such thermochromic color changes, enabling conformational recovery in the polymer chains by a cooling down of the hybrids to temperatures lower than the transition temperature, while the nonhybrid poly-[10,11] powders exhibited an irreversible color change at 60?°C, above which the polymer powder turned amorphous. ? 2005 American Chemical Society.
Preparation of large ring acetylenic lactones by iodo lactonisation
Rousseau, Gérard,Strzalko, Tekla,Roux, Marie-Claude
, p. 4503 - 4505 (2007/10/03)
Reaction of ω-ene-7-yne carboxylic acids with (biscollidine)iodine(I) hexafluorophosphate led to large ring acetylenic lactones. In the case of 5- or 6-yne carboxylic acids, iodo enol lactones were preferentially obtained.
Nitrone dipolar cycloaddition routes to piperidines and indolizidines. Part 9. Formal synthesis of (-)-pinidine and total synthesis of (-)-histrionicotoxin, (+)-histrionicotoxin and (-)-histrionicotoxin 235A
Davison, Edwin C.,Fox, Martin E.,Holmes, Andrew B.,Roughley, Stephen D.,Smith, Catherine J.,Williams, Geoffrey M.,Davies, John E.,Raithby, Paul R.,Adams, Joseph P.,Forbes, Ian T.,Press, Neil J.,Thompson, Mervyn J.
, p. 1494 - 1514 (2007/10/03)
An intramolecular hydroxylamine-alkyne cyclisation is used for the enantioselective synthesis of the cyclic nitrones 36 and 44. We have demonstrated the use of a novel nitrone protection strategy by cycloaddition of styrene to the cyclic nitrone 44 in the synthesis of the spirocyclic core of the histrionicotoxin family of alkaloids. Deprotection by dipolar cycloreversion of the styrene adduct (the bicyclic isoxazolidine 39) and in situ intramolecular dipolar cycloaddition of a pendant (Z)-α,β-unsaturated nitrile to the intermediate nitrone 50 gave the isoxazolidine 51 in high yield with a surprising degree of regioselectivity compared with the corresponding (Z)-enyne 36. The method is amenable to the synthesis of both enantiomers 51 and 62 of the tricyclic core structure which can be converted by way of the common intermediates (e.g. 53 and ent-53) respectively into the natural configuration of alkaloids (-)-histrionicotoxin 1 and (-)-histrionicotoxin 235A 65 as well as the unnatural (+)-histrionicotoxin 63.
Synthesis of ω-and (ω - 1)-acetylenic acids from five-, six-, or seven-membered cycloalkanones
Starostin,Ignatenko,Lapitskaya,Pivnitsky,Nikishin
, p. 833 - 837 (2007/10/03)
A convenient method for the synthesis of ω-and (ω - 1)-acetylenic acids involves free-radical oxidative scission of cycloalkanones containing five-, six, or seven-membered cycles to give the corresponding ω-olefinic acids followed by bromination of the latter and subsequent dehydrobromination under the action of alkalis.
The total synthesis of 20-hydroxyhepoxilins A3, new metabolites of the hepoxilin family of eicosanoids
Demin,Kochev,Manukina,Pace-Asciak,Pivnitsky
, p. 692 - 699 (2007/10/03)
An enantiodirected total synthesis of 20-hydroxyhepoxilins A3, new eicosanoids of the lipoxygenase metabolism of arachidonic acid, was perfomed. The synthetic samples were found to be identical to the major metabolite formed upon incubation of (85)-hepoxilin A3 with human neutrophiles, which demonstrated that it has the structure of (8S)-20-hydroxy-HxA3.
