User:Andrew W Long/Notebook/Synthesis of Lipid Modulators/2015/10/02

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Purification of Product of Rxn Between MTT and CNP, and Large-Scale Reaction Setup

Note that MTT refers to 5-(methylthio)-1,3,4-thiadiazole-2-thiol, and that CNP refers to 2-chloro-3-nitropyridine. Structures shown here


Goals:

  • To purify the products of my second reaction (Ross carried it out with the modified procedure).
  • To set up a large-scale version of the previous small-scale reaction. Target compound must be synthesized and purified by Wednesday (10/07/15)

Procedure for purification:

  1. The product was shown to be slightly soluble in ethyl acetate (which is more polar than dichloromethane). The insoluble impurity could be the result of residual triethylamine. A "dirty column" was run in an attempt to remove the impurity.
    1. The column was a Büchner funnel containing powdered silica, which sat in a vacuum flask.
    2. The powdered silica was then made into a slurry with hexane.
    3. The compound, once redissolved in methanol, was run through the column. It was hoped that the triethylamine would remain in the silica.
    4. After the fraction collected with ethyl acetate was obtained, another flask was used to collect a methanol fraction.
  2. Mass spectrometry was used to examine the two fractions. The result is shown below:

XXX

Procedure for large-scale rxn:

  1. Calculations:
    1. Start with mass of CNP and get moles of CNP: Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle \frac{250mg}{1}|\frac{1g}{1000mg}|\frac{1mol}{158.54g}=0.00158mol}
    2. Get mass of MTT using moles of CNP (use 5% extra MTT since it is less valuable): Failed to parse (MathML with SVG or PNG fallback (recommended for modern browsers and accessibility tools): Invalid response ("Math extension cannot connect to Restbase.") from server "https://api.formulasearchengine.com/v1/":): {\displaystyle \frac{Xg}{1}|\frac{1mol}{164.27g}=1.05*0.00158mol=0.001659mol => X = 272.5mg}
  2. Dump solids (CNP & MTT) into round bottom with stir bar.
  3. Evacuate the flask with nitrogen gas (put a septum on the opening, wrap in parafilm, stick two needles through the septum, connect one of the needles to the nitrogen tank output, wait ~2min, disconnect the nitrogen tank and shut it off)
  4. Put enough DMF to dissolve the solid into flask through one of the needle ports
  5. Once dissolved, put 100-200mL triethylamine (TEA) into the reaction flask.
  6. Allow to spin in mineral oil bath overnight on heat.