91-60-1Relevant articles and documents
Integration of a Four-Step Reaction into One-Pot under the Coexistence of Silica-Gel-Supported Acid and Base Reagents: Synthesis of Benzo- and Naphthothiophenes Using NaHSO 4 /SiO 2 and Na 2 CO 3 /SiO 2
Aoyama, Tadashi,Hayakawa, Mamiko,Kosuge, Masayuki,Nakaoka, Kyohei,Ouchi, Akihiko
, p. 2572 - 2578 (2019/06/08)
A four-step synthesis of benzo- and naphthothiophenes that have biological importance and application in material science was integrated into a one-pot reaction by using silica gel-supported acid and base reagents, NaHSO 4 /SiO 2 and Na 2 CO 3 /SiO 2. The supported reagents provided acid and base environments on the surface of the supports without neutralization and worked separately in the same medium. The four-step reaction comprises (i) deacetylation of 3-halo-2,4-pentanediones to α-halo ketones, (ii) deacetylation of S -aryl thioacetates to arenethiols, (iii) coupling of α-halo ketones and arenethiols to give α-sulfanyl ketones, and (iv) cyclization of sulfanyl ketones to benzo- and naphthothiophenes. The steps (i) and (iii) proceeded by Na 2 CO 3 /SiO 2, and (ii) and (iv) by NaHSO 4 /SiO 2. The four-step reaction proceeded efficiently by introduction of starting materials and reagents in a single reaction vessel. The starting materials were very easy to handle and unpleasant smell of aryl thiols that were used in conventional methods could be avoided. Novel thirty-nine benzo- and naphthothiophenes were synthesized by this method in excellent to fair yields.
SINGLE-STEP SYNTHESIS METHOD OF ARYL THIOL AND APPLICATION THEREOF
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Paragraph 0032; 0033; 0063; 0067; 0068; 0070, (2017/09/02)
The present invention relates to a single-step synthesis method of aryl thiol, and more specifically, to a method of synthesizing aryl thiol in a single-step by making aryl halide react with alkane dithiol in the presence of a transition metal catalyst. According to the present invention, a single-step synthesis method using the transition metal catalyst, the synthesis method which is capable of synthesizing aryl thiol from aryl halide at a high yield, can be provided. Various aryl halides may be applied to the synthesis method. Further, the synthesis method has advantages that an easily usable reagent may be used, operations are simple, and reactions can be performed under mild conditions. In addition, the synthesized aryl thiol may be used in the synthesis of advanced molecules such as diaryl sulfides and benzothiophenes.COPYRIGHT KIPO 2017
Structural characterization and function determination of a nonspecific carboxylate esterase from the amidohydrolase superfamily with a promiscuous ability to hydrolyze methylphosphonate esters
Xiang, Dao Feng,Kumaran, Desigan,Swaminathan, Subramanyam,Raushel, Frank M.
, p. 3476 - 3485 (2014/06/23)
The uncharacterized protein Rsp3690 from Rhodobacter sphaeroides is a member of the amidohydrolase superfamily of enzymes. In this investigation the gene for Rsp3690 was expressed in Escherichia coli and purified to homogeneity, and the three-dimensional structure was determined to a resolution of 1.8 ? The protein folds as a distorted (β/α)8-barrel, and the subunits associate as a homotetramer. The active site is localized to the C-terminal end of the β-barrel and is highlighted by the formation of a binuclear metal center with two manganese ions that are bridged by Glu-175 and hydroxide. The remaining ligands to the metal center include His-32, His-34, His-207, His-236, and Asp-302. Rsp3690 was shown to catalyze the hydrolysis of a wide variety of carboxylate esters, in addition to organophosphate and organophosphonate esters. The best carboxylate ester substrates identified for Rsp3690 included 2-naphthyl acetate (kcat/Km = 1.0 × 105 M-1 s-1), 2-naphthyl propionate (k cat/Km = 1.5 × 105 M-1 s -1), 1-naphthyl acetate (kcat/Km = 7.5 × 103 M-1 s-1), 4-methylumbelliferyl acetate (kcat/Km = 2.7 × 103 M-1 s-1), 4-nitrophenyl acetate (kcat/Km = 2.3 × 105 M-1 s-1), and 4-nitrophenyl butyrate (kcat/Km = 8.8 × 105 M -1 s-1). The best organophosphonate ester substrates included ethyl 4-nitrophenyl methylphosphonate (kcat/Km = 3.8 × 105 M-1 s-1) and isobutyl 4-nitrophenyl methylphosphonate (kcat/Km = 1.1 × 104 M-1 s-1). The (SP)-enantiomer of isobutyl 4-nitrophenyl methylphosphonate was hydrolyzed 10 times faster than the less toxic (RP)-enantiomer. The high inherent catalytic activity of Rsp3690 for the hydrolysis of the toxic enantiomer of methylphosphonate esters make this enzyme an attractive target for directed evolution investigations.