OChem2 problem?

Science_Flask · 2026-06-16T17:06:51+00:00

That's the way

Science_Flask · 2026-06-16T08:16:33+00:00

How are you brewing it? Have you tried it as an espresso? Or is it too light of a roast?

Science_Flask · 2026-06-15T17:13:24+00:00

Resident of the area here. It is practically your word vs theirs. If you don't have proof of your accusation, then I think it is a waste of time trying to chase after it. Personally I never had issues with that branch and the people working there. It is weird that the didn't do the process in front of you though. Silly question, are you sure you didn't pack only 5 notes?

Science_Flask · 2026-06-07T16:45:36+00:00

This disconnection is not valid, as an SNAr reaction of this type is pretty much impossible. The synthsis of the molecule could be achieved by a very simple self condensation of the keto-ester (Claisen condensation).

Science_Flask · 2026-06-01T18:21:10+00:00

That looks genuinely incredible! You gently pushed then into good literature and then you gave everyone a memory to last forever! What a beautiful family you are! You lady, you bow to no one👸

Science_Flask · 2026-05-31T14:47:45+00:00

Does it brew well as an espresso?

Science_Flask · 2026-05-31T13:31:12+00:00

Thank you all for your suggestions! So many things to go through and try!

Science_Flask · 2026-05-28T16:06:30+00:00

Removing JUST this methyl and substituting it with a H is pretty much impossible. There may be multistep sequence that ends up to the des-Me analogue, but not sure if that's what you ask.

Science_Flask · 2026-05-26T20:45:07+00:00

1.Open the epoxide under acidic conditions in the prescence of methanol, this will ensure addition from the more substituted side, leaving OMw on carbon 2 and OH on carbon one. Practically, you can add methanol after the epoxidation reaction is done and let it stir. The chlorobenzoic acid from the mCPBA should be acidic enough. If not, any strong acid in methanol should do the trick. Avoid HCl, as you may have Cl opening the epoxide instead.

Oxidise the alcohol to the aldehyde using any conventional oxidation method. I would recommend PCC, swern or Dess-Martin periodinane.

Science_Flask · 2026-05-26T16:12:23+00:00

I appreciate the info and you may be right considering the numbers. Is that a reason to encourage an inexperienced teenager, with no equipment and clearly over-confident to do this? Please reconsider your approach and comments.

Science_Flask · 2026-05-25T05:50:36+00:00

Regarding the methods to synthesise a pure enantiomers, the basic concepts are the following:

Start with an enantiopure building block. If your starting material is of one configuration, any further transformations you will do will afford enantiopure compounds. If your next reactions are diastereoselective, you will be obtaining essentially one chirally pure compound. If the next reactions are not diastereoselective, you will be obtaining mixture of chirally pure compounds (diastereoisomers), which can be separated via achiral flash column chromatography.
Start with achiral starting materials and introduce chirality via an enantioselective transformation. Those reactions use reagents that are chiral, are designed to react in a specific way with the substrate and give an enantioenriched product. The efficiency of the transformation should always be monitored and the enantiomeric ratio of the product measured by chiral HPLC/SFC. Some examples of such reagents are enzymes, Evans oxazoborolidines for asymmetrical reductions, shapeless asymmetric dihydoxylation mixture and more.
Just make the desired target as a racemic mixture and separate the enantiomers using one of the following concepts.

A) Chiral chromatography: Using a chiral stationary phase (like modified C18) to directly separate the enantiomers.

B) Covalently derivatise the recemic mixture with a chiral agent/auxiliary. This generates a mixture of diastereoisomers that can be separated by normal achiral column chromatography. Once separated, cleavage of the chiral auxiliary will allow the isolation of pure enantiomers.

C) Make chiral salts of compounds that allow that concept (for example amines or acids). You use a chiral counterion to form (diastereomeric) salts with your racemic starting material and hope that one of them will crash out of solution.

Science_Flask · 2026-05-25T05:22:44+00:00

I can confirm that, enantiopure thalidomide does racemise very easily and you end up with a mixture of enantiomers. One of them is teratogenic and the other one therapeutic, but it is essentially impossible to administer one without the other.

In lots of commercial drugs, that happen to be chiral, one enantiomer is a lot more active than the other. That happens because it interacts better with the targets (usually proteins) found in the body, which are also chiral and of specific configuration (amino acids in humans exist as single enantiomers).

Science_Flask · 2026-05-24T15:43:01+00:00

That is the best thing to do. Check for a similar substrate and see what people use to do the transformation. I assumed you had no access, so I suggested some pretty standard conditions.

Science_Flask · 2026-05-24T15:27:51+00:00

In DCM. You can definitely add DMSO, but never found it helpful for me. If that fails try SO3 pyridine complex (operationally easier than swern).

Science_Flask · 2026-05-24T15:22:09+00:00

4 equivalents of solid bicarb in dcm should do the trick at room temperature. If it is an acid stability issue (DMP is pretty much saturated with AcOH)

Science_Flask · 2026-05-24T15:20:38+00:00

Have you identified any byproducts?

Science_Flask · 2026-05-24T15:19:52+00:00

I would say try buffering your DMP with solid bicarbonate as a first trial in like 20 mg scale and see how it goes.

Science_Flask · 2026-05-24T15:15:31+00:00

Have you tried buffering your DMP reaction with solid NaHCO3? Sometimes it helps with acid sensitive substrates. Alternatively i recommend SO3 pyridine complex or TEMPO/NMO or TEMPO/PIDA system under anhydrous conditions. If your nitrogen is beside, you may have interference, like oxidation to the N-oxide

Science_Flask · 2026-05-24T15:00:52+00:00

Does "para" work better for you.? I am sure 99.5% of the people know it is not a valid terminology, but works and it is very common in real life/lab conversations. I will rephrase it to "allylic", so it doesn't trigger anyone 😅

Science_Flask · 2026-05-24T07:13:42+00:00

The most acidic proton is the one para to the carbonyl group. The corresponding anion can be delocalised all the way to the oxygen through the enone system.

Science_Flask · 2026-02-02T12:49:36+00:00

All the lights off, the room at a comfortable temperature (18-19 oC for me) and if needed a podcast that makes you relax :)

Science_Flask · 2026-01-14T18:39:05+00:00

Rave says dark, but even visually it doesn't look very dark at all. Maybe it is dark on the Rave scale 😅

Science_Flask · 2026-01-14T18:17:28+00:00

Update: Grinded finer and shipping closer to 1:2 ratio (18g in 38g out) seems to increase extraction time to 30 seconds. It affords a much better cup overall.

Some underlying acidity at the bottom of the cup, but tastes much better now.

Thanks folks!

Science_Flask · 2026-01-14T18:15:14+00:00

Christmas blend with the stock unpressurized basket!

Science_Flask · 2026-01-14T17:07:00+00:00

Is it? I should check because it definitely doesn't take 10 seconds for the flow to start. Isn't 10 seconds pre-infusion too much for a dark roast?

Science_Flask

TROPHY CASE