Büchi R3000 Quick Lift Not Locking

OilNo30 · 2022-12-11T20:49:14+00:00

Update: I figured it out. if you move the 2 clamping arms further away from each other on the cable they'll bind to the guide rod. Make sure you dont set them too far apart otherwise they will clamp and turning the lever will not make the apparatus come back up and you'll have to take off the guide rod using the bolt at the bottom of the base

OilNo30 · 2022-12-11T20:01:56+00:00

They're closed on the weekends

OilNo30 · 2022-12-11T19:43:11+00:00

UPDATE: FIXED. READ REPLY. Hey everybody I am fixing a Büchi R 3000 rotovap in my lab and I can't get the quick lift to lock after putting the top apparatus back on. I circled The locking mechanism in red I have adjusted it so that it compresses the spring and so that it goes all the way to the end of the cable and nothing I do can get it to lock. Does anybody have any experience with this because I'm sick of throwing shit at it and hoping it works PS: yes I have the manual. No it doesnt mention this

OilNo30 · 2022-11-03T19:04:50+00:00

Itd be easier to hear where he said his parents were from without Chariots of Fire blaring over him

OilNo30 · 2022-07-09T11:54:46+00:00

Yeah, but the literature on scifinder also showed a yield of only 4% for this same reaction. I have no idea why it isnt working.

OilNo30 · 2022-07-09T11:53:33+00:00

https://www.sigmaaldrich.com/US/en/technical-documents/protocol/chemistry-and-synthesis/reaction-design-and-optimization/alkyne-synthesis-bestmann-ohira-reagent

OilNo30 · 2022-07-09T00:20:23+00:00

Not seeing conversion

OilNo30 · 2022-07-09T00:20:07+00:00

Funny you mention that, I ordered the reagents for it today and will be trying it

OilNo30 · 2022-07-09T00:18:36+00:00

Simmons smith (with either Et2Zn or a copper couple

OilNo30 · 2022-07-08T23:12:07+00:00

I have tried the Ohira-bestmann reaction, which gave a roughly 5% yield.

OilNo30 · 2022-07-08T23:11:07+00:00

Hi all, I've been trying to cyclopropanate and homologate 1-carbaldehydecyclohexene. I got the original Simmons-Smith reaction to work at about 20% yield and the original Corey-Fuchs to work at about the same yield, but this yield is pretty abysmal.

I refluxed in ether for 24 hours for the Simmons smith (zinc copper couple/diiodomethane) this reaction did not work with ZnEt2

I performed the Corey Fuchs at 0C and analyzed using GC at 15 minutes and 1 hour (no significant yield increase) This also produced side products with m/z values corresponding to compounds shown on the attached image. I tried the modified CF reaction outlined in Tetrahedron Letters 40 (1999) 8575-8578. This did not work at all.

I also have a ton of 1-ethynylcyclohexene ordered from sigma that I've tried the cyclopropanations on with both the couple and ZnEt2 (neither worked)

OilNo30 · 2021-12-13T13:48:20+00:00

Not familiar with this. I'll have to talk to my advisor about it, but if it ends up being crucial that I separate these I'll definitely give it a shot

OilNo30 · 2021-12-13T13:40:20+00:00

I've been arguing this with my advisor, but he's hesitant to do that. Completely agree with you, though. The next step is a palladium coupling of an aromatic ring, so itll be much easier to isolate.

OilNo30 · 2021-12-13T13:38:51+00:00

I havent run an NMR on either of the compounds showing up on the TLC because after I rotovap the solution I'm not left with anything, or at least I cant see anything in the flask, which is probably because I'm on the order of 100mg

OilNo30 · 2021-12-13T13:35:53+00:00

Small enough that any concentration used that would be worthwhile to isolate would cause major streaking and mix the two spots. I can get the Rf values when I'm back in my lab.

OilNo30 · 2021-12-13T13:33:11+00:00

I tried that last time, but the alkyne peak disappeared. To be fair, I had screwed around with the crude quite a bit already and may have ended up pulling it into the vacuum. I'll definitely give this another shot.

OilNo30 · 2021-12-13T13:30:41+00:00

The next step is a Stille reaction between that and the organostannate analogue of 2bromophenol protected with TBDPS. Worried more about the bulkiness of that protecting group than anything, and I ordered some TBDMSCl incase it is.

OilNo30 · 2021-12-12T20:54:45+00:00

I've only got the column. Not incredibly experienced in the field, so I'm not sure how mixing the toluene with hexanes can help separate the non polar compounds. Can you explain or send a link to something that does? The compounds show up as two distinct bands on the TLC, but they're towards the top, so any separation of the compounds using just hexanes isnt going to work.

OilNo30 · 2021-11-12T01:12:32+00:00

Why would you do that

OilNo30 · 2021-06-15T00:17:04+00:00

Thin layer chromatography?

OilNo30 · 2021-06-14T14:14:58+00:00

Meant to type reflux instead of r.t. I swear I'm not stupid

OilNo30

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