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91
Organic Chemistry Forum / Re: HCl addition to 5-methyl-2-hexyne
« Last post by Hunter2 on March 16, 2025, 01:51:03 PM »
Why you dont consider Cl.
92
Organic Chemistry Forum / Re: HCl addition to 5-methyl-2-hexyne
« Last post by ve_90 on March 16, 2025, 12:34:43 PM »
Regarding Markovnikov's rule, when I add hydrogen to the triple bond (and then to the double bond), in all cases I get two equally stable secondary carbocations (because I don’t have one carbon less substituted than the other; both are equally substituted). Maybe I’m wrong, but I don’t consider Cl as a substituent. When I say “less substituted,” I mean in terms of carbon chains. Maybe I’m wrong? If not, I don’t understand your conclusion.
93
Organic Chemistry Forum / Re: HCl addition to 5-methyl-2-hexyne
« Last post by Hunter2 on March 16, 2025, 12:24:04 PM »
According Markovinkow you will get mainly the 3,3 - Di-Bromoproduct. H will add to the C with most H- atoms already.
94
Organic Chemistry Forum / HCl addition to 5-methyl-2-hexyne
« Last post by ve_90 on March 16, 2025, 11:58:23 AM »
When I add HCl to the triple bond of 5-methyl-2-hexyne, is it correct to form two secondary carbocations and proceed with the reaction mechanism through both, since they have the same stability? Can the same reasoning be applied to the subsequent attack on the double bond? Finally, I obtain three products: 2,3-dichloro-5-methylhexane, 2,2-dichloro-5-methylhexane, and 3,3-dichloro-5-methylhexane. Is it correct to say that 2,3-dichloro-5-methylhexane is the major product? It indeed results from the nucleophilic attack of the chloride ion on two carbocations (so, two of the four carbocation intermediates).

Thank you for your response!
95
Comments for Staff and Comments from Staff / Re: low traffic
« Last post by wildfyr on March 15, 2025, 09:26:51 PM »
Glad for your extra effort!
96
Comments for Staff and Comments from Staff / Re: we are again attacked by scrappers
« Last post by Borek on March 15, 2025, 04:14:11 AM »
Found a solution, probably only temporary, but should help at least for now.
97
Comments for Staff and Comments from Staff / we are again attacked by scrappers
« Last post by Borek on March 15, 2025, 03:37:13 AM »
Forum is sluggish, not much that I can easily do about it :(
98
Organic Chemistry Forum / Re: Boronic acid for suzuki-myura coupling
« Last post by rolnor on March 15, 2025, 01:07:54 AM »
Yes, what are you worried about could happen?
99
Comments for Staff and Comments from Staff / low traffic
« Last post by Borek on March 13, 2025, 06:52:01 AM »
In case anyone wonders why there are so little new posts as of lately - I did some changes to the CAPTCHA system (not going into details) and I am 99% sure what we see now is the true traffic. Whatever was happening several weeks/months ago was mostly bots reusing old questions from our forum or posted somewhere else. Sometimes you pointed me to the fact the question was asked in the past, sometimes I was able to trace these question back to their source (but it is time consuming, so I rarely tried). Typically after a week or two OP/bot would add a link to their signature, or answer the thread with "I got this", quoting large part of the text from some earlier post and adding link somewhere in the middle (often obscured by formatting).

Now these bots are gone, at least for some time.
100
Organic Chemistry Forum / Re: BODIPY decomposition after flash chromatography
« Last post by rolnor on March 13, 2025, 04:24:47 AM »
I have discovered that the asimmetric bodipy (actually the raw mixture after solvent removal and before the chormatography) is stable for weeks at room T and air. Another point is that I tried to extract al the amine from the mixture with DCM/water+HCl . Then to the final product I added some amount of silica gel to simulate the chromatography and the next day I found no decomposition. Of course Amine catalyze hydrolisis and binding to silica matrix, but this do not explain the decomposition of the bodipy moiety and most of all the different behaviour of simmetric and asymmetric bodipy (the former is uneffected and is stable even after the chirmatography without work up after the reaction).
So to summarize
- both symmetric and asymmetric bodipy are stable before chormatography (in the raw dry mixture with amines and other compunds that formes during the reaction)
-purification though silica gel starts asymmetric bodipy decomposition , but leaves the symmetric one uneffected
-working up the reaction seems to make the asymmetric boidipy stable after purification through silica gel (but I tried only one time and in small scale)

Boron containing compounds are a special world, they can surprice you with good stability towards acids and base
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