The Synaptic Leap

I've been working on the sulfur melt reaction, trying to optimize the reaction yield of the singly dehydrogenated product (DHP below).  Many studies have been conducted, and here I'll discuss some of what I've found out.
 

Recent work has been towards developing a GC assay to quickly monitor the sulfur melt reactions.
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In order to optimize the sulfur melt reaction, we've been trying to develop a solid set of GC conditions that'll let us quantitate the reaction progress quickly and accurately (which precludes running a column every time I try the reaction with different conditions).  Initially, PZQ and the dehydrogenated product were found to come off the column at different times, although high temperatures around 320ºC are needed.  A small blip in the PZQ-only sample's chromatogram unfortunately lines up with the product peak.
 

InChI is great and all, but today while exploring, I found two issues that bugged me.  The first arose from my simple double-checking exercise: I drew praziquantel at http://pubchem.ncbi.nlm.nih.gov/edit/ then took the InChI returned and plugged it into chemspider.com to see if it would bring up the appropriate page for PZQ (which I already knew existed).  I made the mistake of leaving one of the amide nitrogens as a carbon, so my search on chemspider returned that there were no hits at all.  Now, in this case that's fine, cause I messed up and I could ammend my structure, get the appropriate InChI, and have chemspider return the proper page, but it made me think about the fact that I don't know if anyone has a search which also returns similar structures in

The sulfur melt dehydrogenation,

was carried out, with 9.5% isolated yield of the desired product and 69.3% recovered starting material.  Other products (observed by TLC) were not found after the column.
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Trying to dehydrogenate PZQ using elemental sulfur.

Total yields including second batch of recrystallization are 86.4%, 74.34% (no second batch), 78.7%, and 80.1%, respective to 0x, 0.5x, 1x, and 2.5x hexanes volume to ethanol volume.
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V(hexanes) = 0.5*V(EtOH) resulted in the highest recrystallization yield at 74.34%.
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Of the four experiments where 50ºC hexanes was added to the saturated 50ºC EtOH solutions (where the volume of hexanes was 0x, 0.5x, 1x, and 2.5x the volume of EtOH needed to solvate the PZQ completely), the recovery percentages were, respectively: 73.53%, 74.34%, 70.90%, and 68.16%.  The motherliquors were chilled to 5ºC try to collect a second crop, but, likely due to the additional volume of solvent used to wash the first crop, no precipitate formed.  I plan to concentrate these, then go for a second crop.
 

EtOH with hexanes had wispy crystals; recovery was 43.98%; pure by NMR; Tm = 138.2-138.8ºC.  No crystals had formed from benzene sl'n nor toluene, so hexanes were added, and vials left at 5ºC.  Began EtOH with varying amounts of hexanes recrystallizations.
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1 mL hexanes was added to the solution of benzene (1.4 mL), and 2 mL hexanes were added to the toluene solution (3 mL).  After a few hours at 5ºC, crystals have begun to form.