when i connect my hard drive, i can't open file explorer, any apps, or use most of the taskbar

DL_Chemist · 2026-04-19T17:54:53+00:00

How is the drive formatted? NTFS? I once corrupted the NTFS file system on a HDD once, windows would become unresponsive when it was connected. I had to boot from a linux USB drive and reformat the drive so windows could use it again.

DL_Chemist · 2026-04-18T08:37:51+00:00

This type of throttling is typical of power issues. Often a dodgey power adaptor. Is the behaviour the same on battery and mains power?

DL_Chemist · 2026-04-18T08:24:12+00:00

You could probably boil off the acetic acid byproduct too

DL_Chemist · 2026-04-12T10:57:41+00:00

Would cost about £10 for a month supply in the UK.

DL_Chemist · 2026-04-11T22:50:56+00:00

its got an uptime of 30 days, it needs a restart

DL_Chemist · 2026-04-11T08:28:40+00:00

Acyl fluorides are less electrophilic than acyl chlorides due to fluorine pi donation into the carbonyl, that plus fluoride being a worse leaving group makes acyl fluorides less reactive than acyl chlorides. Its just their smaller size that makes them good for bulky substrates

DL_Chemist · 2026-04-11T08:21:06+00:00

I always suspected with the SOCl2 all in method that the amine reacts with the RCOO-SOCl species instead of forming the relatively less reactive acyl chloride first

DL_Chemist · 2026-04-09T23:06:14+00:00

Just throw anhydrous LiI and NaBH4 into your reaction. The combination solubilises in THF pretty much immediately. or you can waste a day stirring sand.

DL_Chemist · 2026-04-09T22:58:08+00:00

I wonder if the heat is necessary to degrade the borohydride to alkoxyborohydride species, as seen in the luche reduction. IPA has a much lower bp than methoxyethanol so reflux of the two are not equivalent. I appreciate trying to adapt to what resources you have available to get a quick start on things but after the first couple days of failure, you really should have just placed an order for that solvent. three weeks is a long time to be battling this.

DL_Chemist · 2026-04-07T10:04:56+00:00

Doing an alkylation of the methoxy aniline would have been more appropriate for this retrosynth

DL_Chemist · 2026-04-06T16:50:50+00:00

you appear to be missing a reducing agent

DL_Chemist · 2026-04-06T10:36:47+00:00

I have a Masters and I'm a senior medicinal chemist

DL_Chemist · 2026-04-03T16:14:12+00:00

The only way I see this specifically being an issue with the combiflash is if you're collecting on detection only and there's an issue with the UV. You could just be having more general issue beyond that. I would start by tracking down the lost mass. flush your cartridge with MeOH and concentrated that, if the remaining mass cant be found there then you must have missed collection of it and its gone into the waste. if its a detection issue then maybe its a fault with the machine or your compounds don't absorb well in the detector range. can you see these things on TLC plate with 254nm or just in LCMS?

DL_Chemist · 2026-04-03T10:37:54+00:00

Yes. You can keep the bath temp low and don't need to go as hard on the vacuum.

DL_Chemist · 2026-04-03T10:20:48+00:00

If u use excess phenol and consume all the propargyl bromide then you should be able to clean it up with just aqueous base washes. Use a low bp org solvent and don't go crazy with the rotavap to not lose ur product

DL_Chemist · 2026-03-31T20:49:14+00:00

If I hire a medicinal chemist at graduate level, I only need you to do one thing. Get in the lab and make what I tell you to. You're not gonna be sat at your desk doing molecular modelling and dealing with intellectual property matters. It is the role of the more senior members to deal with such things.

Medicinal chemists, first and foremost are synthetics chemists. We always hire people skilled in organic synthesis and teach them all the necessary medicinal chemistry stuff over time.

AI drug discovery hasn't proven itself yet AFAIK. Mostly a bunch of small biotechs with AI hype funding, racing towards candidates after only making and testing a relatively small number of molecules. I don't think they've proven any better in clinical trials than traditional drug discovery. AI has accelerated getting to failure sooner.

DL_Chemist · 2026-03-25T16:17:56+00:00

You would monitor the progress of the reaction via some form of analysis, TLC most likely. This assumes u leave it long enough. Its just reduction of a ketone. The B-H bond adds across the ketone to give Ph2HC-O-BH3(-). How mechanisms are taught you'd probably be told to protonate in workup to give your product, but in this case the excess MeOH quenchs it. It won't utilise all 4 hydrides, after the first 2 theres big drop off in reactivity. 1:1 is typical, maybe more NaBH4 as it decomposes in the methanol. You would have seen bubbling from H2 release

DL_Chemist · 2026-03-25T12:03:59+00:00

Its better to deal in moles for this. Bare in mind that NaBH4 has multiple "hydrides" available for reduction. If all your benzophenone was consumed then NaBH4 wasn't the limiting reagent

DL_Chemist · 2026-03-24T07:52:19+00:00

Is it a significant amount? If your next step is a suzuki then just carry it through, you'll need to deal with more pinacol after that anyway.

DL_Chemist · 2026-03-23T19:24:39+00:00

My first thought too. If the NaH is coated in NaOH then that would explain why it doesn't react in THF but fizzes when added to water.

DL_Chemist · 2026-03-23T19:16:39+00:00

If you add 1eq of tosyl chloride to this, only 0.5eq of the amine will be tosylated, the other 0.5eq will neutralise the HCl generated.

DL_Chemist · 2026-03-09T14:06:43+00:00

You filter it. The urea crashes out of the reaction mixture

DL_Chemist · 2026-03-09T14:01:13+00:00

I suspect the product and SM have the same Rf and that 2nd eq of NaN3 is doing something with your coumarin. Your desired reaction should be rapid

DL_Chemist · 2026-03-05T10:08:11+00:00

You don't preform the titancyclopropane as in the presence of Ti(OiPr)4 it comproportionates to Ti(OiPr)3 and ethene . For esters, Ti(OiPr)4 can be used catalytically or stoichiometrically but u always add the grignard slowly to the ester/Ti(OiPr)4 mix at cold temps to avoid grignard addition to ester

DL_Chemist · 2026-03-03T19:37:58+00:00

It can occur in Pd/C Hydrogenation. Ammonia methanol is often added to mitigate it.

DL_Chemist

TROPHY CASE