24324-17-2Relevant articles and documents
Formation and verification of the structure of the 1-fluorenylmethyl chloroformative derivative of sulfamethazine
Liang,Zhang,Baker,Cross
, p. 86 - 92 (1996)
Sulfamethazine (SMZ) is derivatized with 1-fluorenylmethyl chloroformate (FMOC) to form the fluorescent adduct SMZ-FMOC. Conditions for formation are optimized with respect to pH, reagent concentration, and reagent ratio. Reagent and product profiles (including the hydrolysis byproduct FMOC-OH) versus time are followed by reversed phase HPLC with UV absorbance detection. FMOC-SMZ has been crystallized, its composition confirmed by microanalysis, and its structure corroborated by IR and NMR spectroscopy. From 10 down to 1 ppm, there is clear gentle curvature in the fluorescence intensity of SMZ-FMOC. The linear response range extends from above 100 ppb down to about 100 ppt, and an increase in sensitivity for the fluorescent detection of FMOC-SMZ (over the usual UV absorbance detection of SMZ) is calculated to be better than 3 orders of magnitude.
-
Brown,Bluestein
, (1943)
-
Method for high-selectivity synthesis of 9-fluorenylcarbinol
-
Paragraph 0025-0080, (2021/06/06)
The invention discloses a method for high-selectivity synthesis of 9-fluorenylcarbinol. The method comprises the following steps: heating and dissolving fluorene in a DMSO solvent system at 50-55 DEG C in the presence of a sodium ethoxide ethanol solution alkali catalyst, adding an acylation reagent ethyl formate, carrying out acylation reaction at the same temperature to prepare 9-fluorenylformaldehyde, adding a soluble metal inorganic salt auxiliary agent, then using NaBH4 for a reduction reaction, adjusting the pH value of reaction liquid to be neutral, and separating out 9-fluorene methanol solid sediment. According to the method disclosed by the invention, fluorene is completely converted by utilizing a section of temperature, the 9-fluorene methanol can be obtained through high-selectivity reduction without solvent conversion by adding the soluble metal inorganic salt auxiliary agent, and the yield of the 9-fluorene methanol is improved on the premise of shortening the reaction time.
Preparation method of 9-hydroxymethyl-fluorene diacid
-
Paragraph 0039-0045; 0062-0063; 0068-0069; 0074-0075, (2020/12/10)
The invention provides a method for preparing 9-hydroxymethyl-fluorene diacid. The method comprises the following steps: (1) subjecting fluorene to reacting with paraformaldehyde to generate 9-hydroxymethylfluorene; (2) enabling the 9-hydroxymethylfluorene to react with acetyl chloride to generate (2,7-diacetyl-9H-fluoren-9-yl)methyl acetate; (3) enabling the (2,7-diacetyl-9H-fluoren-9-yl)methyl acetate to react with bromine to generate (2,7-bis(2,2-dibromoacetyl)-9H-fluoren-9-yl)methyl acetate; (4) enabling the(2,7-bis(2,2-dibromoacetyl)-9H-fluoren-9-yl)methyl acetate to react with bromine and sodium carbonate to generate 9-(acetoxymethyl)-9H-fluorene-2,7-dicarboxylic acid; and (5) subjecting 9-(acetoxymethyl)-9H-fluorene-2,7-dicarboxylic acid to reacting with an acidic solution to generate 9-hydroxymethyl-fluorene diacid. The method has the advantages of simple preparation process, accessible raw materials and high yield, and lowers the production cost of 9-hydroxymethyl-fluorene diacid.
Additive-free cobalt-catalysed hydrogenation of carbonates to methanol and alcohols
Ferretti, Francesco,Scharnagl, Florian Korbinian,Dall'Anese, Anna,Jackstell, Ralf,Dastgir, Sarim,Beller, Matthias
, p. 3548 - 3553 (2019/07/10)
Reduction of various organic carbonates to methanol and alcohols can be achieved in the presence of a molecularly-defined homogeneous cobalt catalyst. Specifically, the use of Co(BF4)2 in combination with either commercial or tailor-made tridentate phosphine ligands allows for additive-free hydrogenations of carbonates. Optimal results are obtained at relatively mild conditions (120 °C, 50 bar hydrogen pressure) in the presence of xylyl-Triphos L4.