Flow microreactor synthesis of tricyclic sulfonamides via N-tosylaziridinyllithiums

Tricyclic sulfonamides were synthesized by the generation of aziridinyllithiums from N-tosylaziridines followed by an intramolecular nucleophilic reaction and the subsequent reaction with electrophiles using a flow microreactor system. The reactions could be carried out at 0 °C, although much lower temperatures such as ?78 °C are needed for batch macro reactors.     

Drying dissipative structures of thermo-sensitive gel spheres of poly(<Emphasis Type="Italic">N</Emphasis>-isopropylacrylamide)

Drying dissipative patterns were observed at 25 °C, 33 °C, and 45 °C on a cover glass, a watch glass, and a Petri glass dish during the course of dryness of colloidal crystals of the thermo-sensitive gels of poly(N-isopropylacrylamide) (PNIPA). Two kinds of broad rings, i.e., transparent ring at the outside edge and the ring in the inner area from the edge, were observed. Sizes of the former were the same as those of the initial liquids irrespective of gel concentration, whereas sizes of the latter decreased as gel concentration decreased. These broad rings were composed mainly of the monomeric and the agglomerated gel particles, respectively. Formation of the monodispersed agglomerated particles and their ordered arrays in the inner area of the dried film were observed especially on a Petri glass dish and a watch glass. The important role of the electrical double layers formed around the agglomerated particles is supported for the ordering of the agglomerated particles. The essential differences in the drying patterns between PNIPA gel spheres and the typical colloidal particles did not appear.     

Synthesis of poly(hydroxyurethane) from 5-membered cyclic carbonate under mild conditions in the presence of bicyclic guanidine and their reaction process

A series of amines are applied as catalysts in the aminolysis reactions of five-membered cyclic carbonate (5CC). Kinetic results display that TBD, which has a guanidine structure, exhibits the best catalytic efficacy and the reaction rate constant is about 100 times higher than the blank system without catalyst. The reaction medium, NMP is found to be as both solvent and promoter in the aminolysis of 5CC. Finally, with TBD and NMP as catalyst and solvent, respectively, the polymerization of bis-functional 5CC (B5CC) and 1, 6-diaminohexane can proceed almost 100% at room temperature in less than 4 h to obtain poly(hydroxyurethane)s (PHUs) with moderate molecular weight.     

Preparation of perfluoro‐1,3‐propanedisulfonic acid/Nafion/silica hybrid nanoparticles—thermally stable Nafion in these silica hybrid nanoparticles even after calcination at 800 °C

Perfluoro‐1,3‐propanedisulfonic acid (PFPS)/Nafion/silica hybrid particles were prepared by the sol–gel reactions of PFPS with tetraethoxysilane and silica nanoparticles in the presence of Nafion under alkaline conditions. These obtained composites exhibited a good dispersibility and stability in not only water but also traditional organic media such as methanol, ethanol, 1,2‐dichloroethane, tetrahydrofuran, and dimethyl sulfoxide. Dynamic light scattering measurements and field‐emission scanning electron microscopy show that these hybrid particles are nanometer size‐controlled fine particles before and even after calcination at 800 °C. Nafion/silica hybrid nanoparticles were also prepared in the absence of PFPS under similar conditions. The weight of original Nafion markedly dropped around 350 °C and decomposed gradually, reaching 0% around 450 °C, and Nafion in the Nafion/silica nanocomposites exhibited a similar weight loss behavior to that of the original one. However, Nafion/PFPS/silica hybrid nanoparticles were found to exhibit no weight loss corresponding to the contents of Nafion and PFPS in the silica gel matrices even after calcination at 800 °C. It was demonstrated that the pH value (3.77 at 25 °C) of Nafion/PFPS/silica hybrid nanoparticles after calcination is smaller than that (5.66 at 25 °C) before calcination, and this hybrid nanoparticles exhibited a higher proton conductivity (5.8 × 10^?3 S/cm at 85 °C) than that (4.1 × 10^?3 S/cm at 85 °C) before calcination. In addition, Nafion/PFPS/silica hybrid nanoparticles after calcination at 800 °C were applied to the Friedel‐Crafts acylation of thiophene with acetic anhydride to give the expected 2‐acetylthiophene, of whose yield was similar to that before calcination under similar conditions. These findings suggest that Nafion in PFPS/silica hybrid nanoparticle cores should exhibit a nonflammable characteristic even after calcination at 800 °C to act as an effective acid catalyst. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1869–1877     

Formation of H3O+ from alcohols and ethers induced by intense laser fields

The processes of H₃O⁺ production from alcohols (ethanol, 2‐propanol, 1‐propanol, 2‐butanol) and ethers (diethyl ether and ethyl methyl ether), and their deuterium‐substituted species, by intense laser fields (800 nm, 100 fs, ～1 × 10¹⁴ W/cm) were investigated through time‐of‐flight (TOF) mass spectrometry. H₃O⁺ formation was observed for all these compounds except for ethyl methyl ether. From the analysis of TOF signals of H_(3?n)D_nO⁺ (n = 0, 1, 2, and 3) that have expanding tails with increasing flight time, it has been confirmed that the reaction proceeds through metastable dissociation from the intermediate species C₂H_(5?m)D_mO⁺(m = 0–5). The common shape of the H_(3?n)D_nO⁺ signal profiles contains two major distributions in the time constant, i.e., fast and slow components of <50 ns and ～500 ns, respectively. The H_(3?n)D_nO⁺ branching ratio is interpreted to be the result of complete scrambling of four hydrogen atoms at the C? C site in C₂H₄‐OH⁺, and partial exchange (18–38%) of a hydrogen atom in the OH group with four other hydrogen atoms within 1 ns prior to H_(3?n)D_nO⁺ production. Ab initio calculations for the isomers and transition states of C₂H₅O⁺ were also performed, and the observed H_(3?n)D_nO⁺ production mechanism has been discussed. In addition, a stable isomer having a complex structure and two isomerization pathways were discovered to contribute to the H₃O⁺ formation process. Copyright © 2010 John Wiley & Sons, Ltd.     

Rigid diol bearing 6‐6‐6 fused ring system derived from naturally occurring myo‐inositol and its polyaddition with diisocyanates

Naturally occurring myo‐inositol was developed into a highly rigid diol by converting its 3,4‐ and 1,6‐vicinal diols in trans configuration into the corresponding butane‐2,3‐diacetals. The resulting diol bearing 6‐6‐6 fused ring system, in which conformational change is strictly suppressed, was combined with diisocyanates to perform polyadditions. The resulting polyurethanes were analyzed by differential scanning calorimetry, and it was found that their glass transition temperatures were much higher than those of the previously reported myo‐inositol‐derived polyurethanes, which were synthesized from a myo‐inositol‐derived diol bearing 5‐6‐5 fused ring system. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3798–3803     

Synthesis of poly(1‐chloro‐2‐arylacetylene)s with high cis‐content and examination of their absorption/emission properties

A series of 1‐chloro‐2‐arylacetylenes [Cl‐C?C‐Ar, Ar = C₆H₅ ( 1 ), C₆H₄‐p‐i Pr ( 2 ), C₆H₄‐p‐Oi Pr ( 3 ), C₆H₄‐p‐NHC(O)Ot Bu ( 4 ), and C₆H₄‐o‐i Pr ( 5 )] were polymerized using (tBu₃P)PdMeCl/silver trifluoromethanesulfonate (AgOTf) and MoCl₅/SnBu₄ catalysts. The corresponding polymers [poly( 1 )–poly( 5 )] with weight‐average molecular weights of 6,500–690,000 were obtained in 10–91% yields. THF‐insoluble parts, presumably high‐molecular weight polymers, were formed together with THF‐soluble polymers by the Pd‐catalyzed polymerization. The Pd catalyst polymerized nonpolar monomers 1 and 2 to give the polymers in yields lower than the Mo catalyst, while the Pd catalyst polymerized polar monomers 3 and 4 to give the corresponding polymers in higher yields. The ¹H NMR and UV–vis absorption spectra of the polymers indicated that the cis‐contents of the Pd‐based polymers were higher than those of the Mo‐based polymers, and the conjugation length of the Pd‐based polymers was shorter than that of the Mo‐based polymers. Pd‐based poly( 5 ) emitted fluorescence most strongly among poly( 1 )–poly( 5 ). © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55 , 382–388