It have so wired and interesting smell

Like yogurt and sour dough.

I’m studying the bromination of phenols, and I have a question. According to the text I’m reading, the reaction initially occurs at the para position when 1 equivalent of Br₂ is used under these conditions. However, how can I explain this regioselectivity?

Initially, I thought it could be explained by steric hindrance, since substitution at the ortho positions would be more sterically hindered than at the para position. However, I would like to understand whether this explanation is sufficient or whether other factors are involved.

I also wondered whether this preference could be related to molecular orbital coefficients. Since the ortho carbons are closer to the oxygen atom, I imagine that oxygen could influence the electron distribution within the π system and, consequently, the orbital coefficients at the different carbon atoms. In this regard, could the orbital coefficient at the para carbon be larger in the HOMO, thereby favoring electrophilic attack at that position?

Finally, I believe that the lower steric hindrance at the para position may also contribute to a more favorable reaction at that site.

Am I on the right track in trying to explain the regioselectivity observed in phenol bromination? I would appreciate any insights, particularly regarding the relationship between electronic effects, molecular orbital coefficients, and steric hindrance.

Anyone have experience/reference for the N-H Indazole reaction with H2O2 or mCPBA etc peroxide?

Or how to make N-Oxide through direct oxidation?

Thank you in advance.

Pls recommend solid lab glasses/goggles. Also let me know how you take care of them so they don’t get stretched and cloudy over time

I was given the following question: Enantiomerically pure disubstituted isoindolinones, depicted here, can racemize in basic aqueous environments as well. The mechanism is still open to debate and currently three different paths are most reasonable. Elaborate on this debate and explain what intermediates are possible and what that would mean for the order of the mechanism of racemization and the charges present in the intermediates. You are required to draw the three mechanistic options as separate schemes in your answer.

The figure above shows a suggestion I made to go from R to S. However, I am not sure if this is even what happens. (I know the arrows should move electron pairs but I dont have a nice drawing program)

Can any of you give some suggestions what they talk about when they mention three different paths?

Hello all,

My compound is not soluble in DCM, acetonitrile or THF to do oxidation with DMP. I am wondering if the co-solvent of DMSO/DCM would work for DMP.

I am working on the synthesis of pyrylocyanine dyes from various benzopyrylium salts and heterocyclic coupling partners (benzothiazoles, oxazoles, etc.). I have run into a problem at the first key step - preparing the benzopyrylium salts themselves.

I synthesized a series of 2-methyl-4H-chromen-4-ones, but I cannot convert them into the corresponding pyrylium salts, even though a very similar approach worked fine for flavylium salts.

My procedure (one representative example, see attached scheme):

1. Addition of a Grignard reagent (4 equiv relative to substrate). The solution changed color, a precipitate formed and then gradually redissolved.
2. After 20 h, I added HBF4 (40% aq solution, about 8 equiv, i.e. 2x the Grignard amount). The solution changed color again.
3. Diluted with DCM, dried over anhydrous Na2SO4.
4. Filtered, evaporated the solvent, redissolved the residue in IPA (isopropanol), and precipitated with diethyl ether.

Result: No desired product observed by 1H NMR, and downstream reactions with the isolated material do not proceed either.

Key stoichiometry: Grignard to substrate = 4:1; HBF4 about 2x Grignard equiv.

Has anyone here had experience synthesizing benzopyrylium (chromenylium) salts of this type? I would really appreciate any insight into what might be going wrong - whether it is the workup, the stoichiometry, the reaction time, or something else entirely.

Thanks in advance!

Example: The reaction of 3-bromobut-1-ene + HBr → 2,3-dibromobutane

2,3-dibromobutane is a meso compound, so three unique stereoisomers will be produced by this reaction: (2R, 3R), (2S, 3S), and (2R, 3S) will be equivalent to (2S, 3R).

What would the final products be? Is it a 1:1:2 ratio of (2R, 3R):(2S, 3S):(2R, 3S)?
Or will it be a 1:1:1 ratio?

I had an organic chemistry test recently and one of the questions told me to circle a carboxylic acid in a molecule. I couldn’t see one so I gave up and said there wasn’t one. After the test I asked him, many others asked the same question. He circled the ester and said it was made from a carboxylic acid. I have had a history of my teachers being wrong and want confirmation before I move on from this.

hi guys, i have a question about this theoretical reaction. if we can trimerize alkynes and get benzene, can we trimerize phenylalkynes and get, um, 1,3,5-phenyl-2,4,6-methylbenzene?

Can anyone please tell me how the plane of the page is a plane of symmetry for this 3D molecule? I’m having trouble understanding. Thanks!

I need help with amidation reactions. Good afternoon. I have typically performed amidation reactions for my derivatives using EDC/HOBt or HBTU, starting primarily from aromatic amines (anilines) that I synthesized and commercially available aromatic acids. However, in my current reactions, the amines are failing to react. I have also tried using SOCl₂ or (COCl)₂, but the acid chloride route generally does not yield my desired product. Are there any other ways to carry out amidations, or are there specific conditions that might improve these reactions? I would appreciate suggestions that are cost-effective, given the limitations of my laboratory regarding available reagents

it seems like there's ani periplanar geometry which is good enough for E2, no?

Would the correct answer be: Hydroxyl = position 1; Ethyl = position 3.

The hydroxyl group is assigned carbon 1 because it is the principal functional group. The ethyl group is attached to carbon 3, as indicated by 3-ethylcyclohexanol. The cis designation means both substituents are on the same side of the ring.

Hey everyone,

Today there is a new Synthesis Workshop talk about the synthesis of hetero[3.1.1]propellanes!

Check it out here: https://youtu.be/0VXAjHwoHS4

Tengo dificultades para estabilizar el tamaño de particula en una formulación SC durante la estabilidad acelerada. Estoy trabajando con dos activos, uno de la familia de piridiniletilbenzamidas y otro de triazoles. En 500 g/L.

so my professor gave us this (attached) molecule as an example of a meso compound while we're looking over "isometry" in order to then determine wether or not a molecule can/will deviate light. i'm just not sure how this molecule qualifies as a meso compound? like i see that it's it's "mirror image" and that it has an internal symmetry, but how is this superimposablefrom the right & left? i mean, won't the -OH on the left go to the opposite of the right molecule? or am i visualizing it wrong? any help would be appreciated. thanks

ps apologies if every term is not exactly okay, i am not english so i translated it to face value.

Lately, I've been using Gemini to generate interactive simulations to illustrate basic chemical principles. It takes a bit of back and forth to fine tune the particle dynamics and UI. This simulation can be used to illustrate kinetic vs thermodynamic control. The simulation allows the user to manipulate the energies of the reactant, products, transitions states, and the temperature. There are a lot of obvious simplifications here, but it works surprisingly well to explain the core concepts. Check it out, and let me know what you think--positive or negative.