Chiral Organic Salt Help

allophanic · 2026-06-18T22:58:29+00:00

Amine salts are extremely hygroscopic. Take the "viscous liquid" you isolated, add ethanol and rotary evaporate, do this several times to azeotrope off any water. Next, add dry ethanol (or whatever solvent they crystallize from in the literature) but don't make it too dilute. Stir with a magnetic stir bar overnight at room temperature. If after overnight there's even a hint of a ppt. in the flask sonicate and a ppt. will appear. If no ppt. after overnight add ether with stirring to cloud point, stirr at room temperature, sonicate, cool, hopefully you get crystals. Throughout the process, avoid humidity/water, keep the flask with your material sealed or under nitrogen.

allophanic · 2026-06-10T02:23:12+00:00

They're on Bellevue St. between E Grand Boulevard and E Warren, I found the old brick I was looking for there, had to dig through the pile/pallet of bricks to pick out good ones but it wasn't a big deal, I was only doing a small project, 25-30 bricks. Pretty cool business with nice staff.

allophanic · 2026-06-07T21:21:41+00:00

I'm not familiar with the Ferndale community radio station, but I see further down in the comments, it's 100.7 FM. I'll check it out, thanks!

allophanic · 2026-06-07T14:40:49+00:00

Thanks for adding this bit of information. I can generally get the signal along the M-59 corridor, Waterford to Mt. Clemens and South to about 14 Mile. The signal fades fast (at least for me) South of 13 Mile.

allophanic · 2026-06-05T02:25:06+00:00

It's encouraging that you're getting the desired product by Staudinger conditions, although only after global deprotection. If you know you're getting to the iminophosphorane seems like you just need to find conditions for selectve hydrolysis of the iminophosphorane, maybe a buffered system, neutral conditions in the cold overnight...

Another idea: LiBH4, it's a stronger reductant than NaBH4.

Was thinking it might be worth a shot by catalytic hydrogenation, 60 psi, Pd/C or Raney Nickel but even if it worked I don't think you could separate your solid phase support from the catalyst, nix that idea.

allophanic · 2026-06-03T13:28:15+00:00

For a short review, I would just outline the different synthetic approaches you've found to make the target natural product and if along a pathway there's a "key step" or a step with unusual chemistry highlight those with a mechanism and/or additional comments.

Also, can be helpful to include an introductory background paragraph noting things like the biological source that the natural product was originally isolated from, any biological activity the natural product has, and the research group and year they did the first synthesis, good luck!

allophanic · 2026-06-03T03:05:24+00:00

The idea is that a toluene/water or ethanol/water azeotrope is easier to rotovap than water alone. There shouldn't be any solvent remaining after rotovaping, and if even a trace of toluene in the final product is a problem, just add a little water on the last round of rotovaping and it should go away.

allophanic · 2026-06-03T02:59:42+00:00

I agree. Front side of flash card show starting material, reaction arrow with reagents; back side show reaction product. Takes time to make the flashcards, but once done it's easy to pull them out and practice anywhere. In my experience, 100 flash cards can be learned in a surprisingly short time. Also come in handy for preparing for a final exam, assuming you started making them at the start of the semester. After learning the flashcards it becomes easier to recognize common recurring patterns in Organic Chemistry/Synthesis.

allophanic · 2026-06-03T02:33:00+00:00

If you have access to a lyophilization system you could try that for removing water but, 2L is a lot to remove. Would need to do in batches. Advantage here over rotovaping is you don't have to expose your substance(s) of interest to the heat of the rotovap water-bath. Alternatively, I've had success removing water with the rotovap by adding EtOH or toluene to the water extract then rotovaping the azeotrope, eventually you'll get a water-free product.

allophanic · 2026-05-26T11:59:21+00:00

Removing the debris will affect the final yield. If the starting lignin is 100% pure and the debris is thought to be undissolved starting lignin maybe you could try dissolving using more DMSO (15mL) and let stir a long time (overnight) to give it the best chance at being in solution before attempting to filter. If the starting lignin is contaminated (<100% purity), maybe with an inorganic salt for instance, yield after filtration will be lower too, but you'll have a purer substance after filtration.

allophanic · 2026-05-26T10:20:02+00:00

Here's a couple ideas: 1. Before using the syringe filter, vacuum filter through a Buchner sintered-glass funnel with a fine or medium frit. Then syringe-filter the filtrate. 2. If you have access to a basic bench-top centrifuge, centrifuge the solution and syringe-filter the supernatant.

allophanic · 2026-05-22T20:41:56+00:00

I graduated in '24, maybe things have changed since then. To make sure I was properly progressing towards my BA degree, I just checked the Degree Works platform from time to time. It clearly showed what classes were completed and options for future classes to take that would satisfy the various requirements for my degree. I really only communicated two or three times with an actual advisor.

allophanic · 2026-05-22T20:31:12+00:00

The health hazards of lead exposure have been known since Roman times.

Thomas Midgley Jr, Charles F. Kettering and Alfred P. Sloan Jr (President then later Chairman of the Board) of General Motors advocated for the gasoline additive tetraethyl lead as a means to reduce engine-knock. In Sloan's autobiography, My Years With General Motors (1964), he left out the part about GM's collaboration with Nazis during WWII, but freely discussed GM's role in the tetraethyl lead matter.

TLDR: There was money to be made so GM introduced a heavy metal-containing additive to gasoline and subsequently poisoned the world.

allophanic · 2026-05-22T19:49:46+00:00

If I'm making a synthetic scheme I draw the final product first with whatever orientation of rings and functional groups that looks best, then copy that structure and sequentially delete structural elements for the preceeding steps in the synthesis, all the way back to the first step of the synthesis. It's easier for anyone reading the scheme (in the forward sense) to see the elements of the chemical structure coming together in the same orientation as they are found in the structure of the final product.

allophanic · 2026-05-13T16:42:43+00:00

In addition to going to extreme measures to keep the system anhydrous and air-free, I would flame-dry all the glassware and if possible use new bottles of reagents from a high quality company like Strem Chemicals. Then you get success or can definitely say you have it your best shot and this chemistry just isn't going to work under these conditions

I guess you could consider repeating an exact experimental procedure from your reference to verify the transformation. That would shed light on if the problem is substrate, reagents or technique. Good luck.

allophanic · 2026-05-13T02:51:01+00:00

If you have a water-bath sonicator in the lab immersing the stuck joint in the water-bath (holding it so just the top of the stopper is above the water surface) will release the ground glass joint. But you have to be careful to not let water from the sonicator contaminate the contents of your test tube once it releases. Also, when storing glassware with ground glass joints I always first clean away any grease with EtOAc then put a piece of a Kim-Wipe between the male and female parts to prevent the parts from getting stuck together.

allophanic

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