Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer

Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer

Osako, T.; Toriia, K.; Uozumi, Y.; Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer; RSC Adv.; 2015; 5; 2647-2654

link to article

http://pubs.rsc.org/en/content/articlelanding/2015/ra/c4ra14947e#!divAbstract

We have developed a technique for the aqueous aerobic flow oxidation of alcohols in a continuous-flow reactor containing platinum nanoparticles dispersed on an amphiphilic polystyrene–poly(ethylene glycol) resin (ARP-Pt). Various primary and secondary alcohols including aliphatic, aromatic and heteroaromatic alcohols were efficiently oxidized within 73 seconds in a flowing aqueous system at 100–120 °C under 40–70 bar of the system pressure to give the corresponding carboxylic acids and ketones, respectively, in up to 99% yield. Benzaldehydes could be also prepared selectively from benzyl alcohols by conducting the flow oxidation under the standard conditions in the presence of triethylamine. Moreover, a practical gram-scale synthesis of surfactants was realized in the aqueous aerobic continuous flow oxidation for 36–116 hours. This aerobic flow oxidation system provides a safe, clean, green, rapid and efficient practical method for oxidizing alcohols.

Paper

Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer

Takao Osako,^a   Kaoru Torii^a and   Yasuhiro Uozumi*^ab  

*

Corresponding authors

^a

Institute for Molecular Science (IMS) Myodaiji, Okazaki, Japan
E-mail: uo@ims.ac.jp

^b

RIKEN, Wako, Japan

RSC Adv., 2015,5, 2647-2654

DOI: 10.1039/C4RA14947E
Yasuhiro Uozumi

D.Pharm.

Okazaki, Japan

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Novel 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine bearing substituted phenylquinolin-2-one moiety

Figure 1.

General structure of final synthesized derivatives.

Scheme 1. 

Synthetic Scheme for 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine bearing substituted phenylquinolin-2-one (4a–4t). Where R = H, 2-Br, 3-Br, 4-Br, 2-Cl, 3-Cl, 4-Cl, 2-F, 3-F, 4-F, 2-NO₂, 3-NO₂, 4-NO₂, 2-CH₃, 3-CH₃, 4-CH₃, 2-OCH₃, 3-OCH₃, 4-OCH₃, 3,4,5-t-OCH₃. Reagents and conditions: (a) C₂H₅OH, Nitrobenzene, Con. H₂SO₄, reflux, 80 °C, 4 h; (b) chloroacetic acid, NaHCO₃, water, CuO, reflux, 80 °C, 5 h; (c) thiocarbohydrazide, Δ, 2 h; (d) phenacyl bromide, anhydrous ethanol, NH₄OH, 50 °C, 6 h.

 In the present work twenty derivatives of phenylquinoline-1,2,4-triazolothiadiazines were synthesized. The structures of the synthesized compounds were established by spectral data. According to IR spectroscopic data compounds (4a–4t) showed peaks at 1306–1330 cm⁻¹, 650–682 cm⁻¹ due to -NC and CSC stretching vibrations respectively and no absorption peaks at 3140–3280 cm⁻¹, 3050–3090 cm⁻¹ due to -NH₂ and -SH groups respectively indicated smooth cyclization of triazoles leading to the formation of thiadiazine ring. Further, ¹H NMR spectra of the synthesized compounds were confirmed by the appearance of SCH₂ proton of 1,3,4-thiadiazine ring at 4.40–4.54 ppm and CH₂ proton at 5.97–6.20 ppm as broad singlet. All other aromatic protons were observed at expected region. Mass spectra (ESI-MS) of all the synthesized compounds showed molecular ion [M + H]⁺ peak in agreement with their molecular formula. Physical and elemental analyses are listed in Table 1.

2.6.20. 6,7,8-Trimethoxy-4-phenyl-1-({6-phenyl-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-3-yl}methyl)-1,2-dihydroquinolin-2-one (4t)

White needle Crystal; IR (KBr, cm⁻¹): 3023 (Ar CH str), 2901 (Aliphatic CH str),1706 (CO str), 1620 (CN str), 1564 (CC str), 1330 (Ar CN str), 683 (CSC); ¹H NMR (CDCl₃, 300 MHz): δ (ppm): 3.84 (s, 9H, 3xOCH₃), 4.51 (s, 2H, SCH₂), 5.98 (s, 2H, CH₂), 6.85 (s, 1H, CH), 7.45(d, 2H, J = 8.5 Hz, ArH), 7.48(m,5H, ArH), 7.74 (q, 4H, ArH). ESI-MS (m/z) calcd. is 539.6, found 540.7 [M + H]⁺; anal. calcd. for C₂₉H₂₅N₅O₄S (539.60): C 64.55, H 4.67, N 12.98; found: C 64.54, H 4.63, N 12.95.

 Arabian Journal of Chemistry
 

Available online 11 July 2015

In Press, Corrected Proof — Note to users

ORIGINAL ARTICLE

Synthesis, characterization and antimicrobial evaluation of some novel 1,2,4-triazolo[3,4-b][1,3,4]thiadiazine bearing substituted phenylquinolin-2-one moiety

• Swagatika Ghosh^a, ,
• Amita Verma^{a, ,} ,
• Alok Mukerjee^b,
• Milan Kumar Mandal^a

• ^a Department of Pharmaceutical Sciences, Faculty of Health Sciences, Allahabad, Uttar Pradesh 211007, India
• ^b Department of Pharmaceutical Chemistry, United Institute of Pharmacy, UPSIDC, Naini, Allahabad, Uttar Pradesh 211010, India

Received 3 April 2014, Accepted 7 July 2015, Available online 11 July 2015

Open Access funded by King Saud University

Under a Creative Commons license

http://www.sciencedirect.com/science/article/pii/S187853521500218X

doi:10.1016/j.arabjc.2015.07.003

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