hypervalent_iodine

Engineering is a separate degree to a BSc with a physics major, so I don't see it being a problem. You'll just need to go through the application process (via the state's tertiary admissions centre) and possibly contact any universities you are considering for further information. I would recommend looking at the Go8 universities first - USyd, UNSW, UQ, Monash, UMelbourne, etc. If you were wanting to get exemptions from courses based on analogous courses you have completed as part of your physics major, then you would have to discuss this with each university as they will undoubtedly have differing positions.

Attacking me is not going to get you an answer. Your post lead me to believe that you thought the CCl4 was reacting with the pyridine, so that's where my response came in to it. Additionally, nowhere did I say CCl4 was polar. In fact, I do believe I said the opposite. The above sequence of events you've drawn - I take it that's with the NBS/carbon-tet/HCl system? It would make sense to me that if this system was forming the tribromide salt (which I am still not convinced about) you mentioned that it would act as a source of Br3-, which should be able to react with another molecule of your ketone to give you product (depending on reaction rates I suppose). What makes you so sure that reaction didn't give you product? Did you try purify and isolate it at all? Believe me about doing my PhD, don't believe me; it doesn't really bother me. As you are new to the field, let me give you some advice: being rude to people who try to help you will not make your career, whatever that may be, a smooth one and nor will it make it an easy one. There was a misunderstanding on my part in my initial response, likely due to what I assume is an English barrier, which could have been quite easily remedied with a simple clarification rather than questioning my credentials (which I can promise you are real). I have one final question for you, which I can assure you will be my last since you don't seem to want my help; why have you still not gone and looked up SciFinder, as I suggested in my first post? You would have answered your own question before you even got to typing your second reply to this thread. As another piece of friendly advice, usually SciFinder is the first port of call when you're looking up protocol for reactions (which makes me want to question why you didn't go there in the first place). Edit: I just re-read my post and saw the bit where I said CCl4 was polar. I would just like to clarify that this was a typo and I had meant to say non-polar. While you stated your question clearly, your post was a little convoluted. You'll also find that I did point you in the direction of an answer in my first post, which you are clearly yet to consult.

I am a PhD level organic chemist. Yourself? CCl4 is a polar, aprotic solvent. The only way I can see your suggestion working is if the chlorine attacked the pyridine N to give a salt, which doesn't really make sense since the nitrogen is (as you pointed out) basic and reactive towards Lewis acids rather than Lewis bases. CCl4 used to be the 'go-to' solvent in electrophillic halogenations of alkenes due to it being completely inert under the conditions. Given that this reaction uses similar conditions, I just can't see how this would be the case. Additionally, why would it choose to form a salt with CCl4 and not react directly with the Br2, which is considerably more likely to react there? Or perhaps more poignantly, why do you think the bromine is reacting at the nitrogen and not on one of the ring carbons? Even with that said, I still don't see why it would do that over reacting with the alpha position next to the ketone. Unless I am misinterpreting what you said in your OP (which is likely due to the English barrier; no offense meant), NMR indicated no bromination. So what proof do you have except that the colour of your compound looking a little off (which by the way, is proof of nothing)? It is quite likely that carbon-tet isn't even dissolving your compound given how aliphatic it is; to be honest, I have no idea why you used CCl4 at all given how impractical it is over other perfectly viable solvents like DCM or similar. A search of your thiazole component, which still contains an aromatic N, in SciFinder will show you that bromination at the ketone is not only possible, but possible in high yields. Additionally I thought I should point out something you learn here in second year that you may like to refresh yourself on: if you take pyridine by itself, bromination with Br2 in the presence of a Lewis acid gives substitution meta to the nitrogen as the major product, rather than substitution on the nitrogen.

No need to get snarky, I was simply asking why. I did actually come back here with a solution for you, but seeing as you think being rude to the only member offering an answer (to a question quite easily solved with a quick SciFinder search, really) is an acceptable way to approach matters, I think I'll just keep it to myself. Edit to add: I doubt it is reacting with the pyridine N. Just FYI.

Firstly, I'm not sure I understand the aversion to Br2; why won't you use it? It's toxic and corrosive, sure, but it's fairly easy to use. To answer your question, a SciFinder search showed that most use HBr, Br2 or a combination thereof. You should do a SciFinder search yourself and see which one you are most comfortable with; all of the reactions I saw gave yields over 70% (or they claimed to, anyway).

Unfortunately, my long range integrated NMR-HPLC eyes are down for maintenance, so it's hard for me to say either way from all the way over here. In all seriousness though, the easiest way to tell would be to just run a proton NMR. DEPC decomposes at above 150oC, however it is sensitive to moisture. So it should be okay, unless you've left your samples open to atmosphere, in which case they are probably decomposed.

I think you lost everybody the moment you said you were doing alchemy.

Kind of but not really, it depends how you look at the reaction. Read this link, it gives a good explanation of the limitations using your example. Truth be told, the Arrhenius definition is inherently limited in its application. Generally we consider amines as acting as either a Lewis base, since amines can donate a lone pair of electrons, or as a Bronsted-Lowry base (which is more or less the same as the Arrhenius definition, but not as limited), as they can accept H+.

A little off topic, but ok. His signature is a link to some random company, which is a typical spam-bot type thing to do. From reading other posts by this member, it looks like they are copy-pasting other people's replies from the thread to make it look like they're making a relevant contribution, but they've later added ad-spam to their signature. One of the more clever spam-bot tactics, but it's still obvious spam. Anyway, I've reported it, so I assume swansot or someone will be along shortly to clean up.

His signature tells me it's all spam, so I've reported it.

Ok, well in that case the simple answer is yes, but you have to notate your arrows correctly. If you don't include reagents above/below your arrows, then your ability to do that is dependant on the nature of what compound 'b' and 'c' are. If, for example, 'b' was a reactive intermediate or a transition state, then yes you can simply draw the reaction going from a to c. The way that you can and furthermore, the way you should draw reactions depends entirely on the reaction and the point you are trying to make (i.e. the context of the reaction). I'll try and give an over-view of it as best as I can. Since I don't know your level of chemistry education, I'll apologise in advance if some of the jargon I use is confusing or foreign to you. I'll start with the following example of a Friedal-Crafts alkylation reacting benzene with t-butyl chloride in the presence of AlCl3. We can draw the reaction in the simplest expression as this: However, similar to your generalised example given in the OP, this is not a full representation of the structures that form during the course of the reaction. Thus, if we ignore arrow pushing, we can also draw it as this: You'll notice the product here is not the product I drew in the first reaction, which brings me to my first point. Rather than drawing all that out again, we can draw multiple arrows to represent the multiple steps taken to forming the product: Multiple arrows can be used in a number of contexts. For example, in your reaction, rather than drawing out product 'b', you could simply draw is as this: As a word of caution though, I should point out that the magical multiple arrows aren't applicable in every situation. If the in-between steps are irrelevant to whatever point you are making or are a re-hash of steps you've already drawn (as in the Friedal-Crafts reaction, above), then you can use them. Their use does come with an obvious loss of information though, so if using them means you're sacrificing vital steps or it makes what you are saying convoluted, you shouldn't use them. Another example using the multiple arrows representation comes from a reaction I overviewed in my own research proposal and also illustrates another way to draw reactions: In this reaction I used the multiple arrows so that I could show the initial starting material and the final reaction in the total synthesis of the natural product, discorhabdin C. Doing this does two things: I didn't waste valuable page space with reactions that were not pertinent to the point of the text and the reader could clearly see which reaction I was pointing out. The other thing I wanted to point out with this reaction is seen in the last arrow leading to discorhabdin C. You'll notice there are two sets of reagents listed, set 1.) and 2.). This represents another way by which multi-step reactions may be represented without having to draw the bits in between. If we consider your simplified scheme of 'a' forming product 'c' as being the result of two separate reactions, you could draw it like this: Or simply like this: The final case is if we consider transition states or reactive intermediates. Without going into too much detail about exactly how these form, what they are and the difference between the two, it is enough to state that they are structures or configurations that form during the course of a reaction but are generally high-energy and short lived. Typically they are drawn if you are trying to give mechanistic insight into a reaction are are usually shown with square brackets around them. Intermediates don't always have to abide by the square brackets rule (the cationic intermediate structures in the Friedal Crafts reaction I drew are an example of this), while transition states do. Transition states additionally have a 'double-dagger' drawn on the outer-top-right of the brackets. Again, the necessity to show these structures depends entirely on the context of your argument. If you are making comments about the mechanism of a reaction, then you draw them. If it's for an undergraduate assignment or exam, it's usually required that you draw them. If it's neither of the two, then you generally don't have to. This only applies to unidirectional arrows. In the other part to your question, could you perhaps clarify do you mean this kind of arrow: or this kind: They both mean different things, but in either case you cannot apply the same principles as with the mono-directional arrow. In this case, you could have to include 'b' in your scheme. Anyway, I hope that helps. If you need any clarification, feel free to ask more questions.

Could you perhaps provide some more context? Are you asking this in terms of chemical reactions?

Sounds to me like copper sulfate, though I could be entirely wrong on this as I am by no means an expert in this area.

Not odd at all, in fact it is a very common motif in natural products, etc. If you have access to SciFinder through a university/institution, you should go on it and do a substructure search of that compound. You will find thousands of compounds containing that type of core. Your confusion may have been from assuming that the structure you drew was flat, which would of course seem a little odd. However, it is not flat. The 3D structure of the compound you've drawn will have the bridge head (the two carbons you've drawn inside the cyclohexane ring) sticking out from the main ring like this:

No problems, glad I could help

The positive charge on the amine of the side chains is a result of the uncharged amine being being a Lewis base. The reason it is basic is because an uncharged amine has a lone pair of electrons (hence why it is a Lewis base). It can use that lone pair of electrons to react with a Bronsted acid and pick a H+. The slide seems a little deceiving in my opinion as it is not because it is positively charged that it is a base, rather it is because it is a base that it is positively charged at low pH. To show what's happening, I drew some diagrams for you. For lysine, we can see the amine picking up the extra proton by way of the lone pair of electrons (drawn as two dots above the amine nitrogen): And for arginine we have fairly much the same thing, except now there are resonance structures (didn't draw the arrow pushing on this one, but you get the idea):

Well, they are positively charged at physiological pH because the amine is basic and picks up a H+ from solution, not the resulting -NH3+. You are right that the amine side chain (-NH2) is a Lewis base. Given that the definition of a Lewis base is an electron lone pair donator can you think of why the amine fits the Lewis base description? If you know how to draw Lewis dot structures, try it for the amine. If not, let me know and I'll walk you through it

As someone else pointed out, that is very much dependant on the person. For me, if I were to suddenly stop drinking coffee (even if I'm on a cup a day) I would get migraines, hot/cold flushes and severe nausea to the point where I wouldn't be able to even keep down so much as water or painkillers. It's certainly not the nicest of experiences. That being said, back before I started uni it did give me a good go-to if I ever needed a weekend off work

Paint?

Ah, ok. You should be a little clearer in your questions to solve confusion. The question still seems a little vague, but I suspect I know where it is wanting you to go with it. You should consider the structure-activity relationship between the amino acid residues in GSH and glutathione S-transferase - i.e. how it is associated with the binding pocket of the enzyme, etc. Glycine having no real functional side chain doesn't normally participate in many enzymatic reactions, so I suppose you need to as yourself what else it might be doing? I found this paper, which may be of some assistance. If I'm still not on the right track with what you want, I apologise. Please be a little clearer with what you're actually needing so we can better help you

Alright, so given that this is a homework question I can't outright give you the answer. There is one major point you should consider here: - Glutathione is a tripeptide. So you need to ask yourself: what is it made out of? The answer should be pretty obvious once you work that out. You should make use of the wikipedia article on glutathione if this is still puzzling you. Failing that, please feel free to ask some more specific questions about what you're having trouble with

No one is trying to discourage amateur chemistry outright in this thread. What we discourage is ill-informed amateur chemistry. Honestly though, I think this thread has gone off topic enough. The OP doesn't appear to have any intention of returning, so let's leave it at that. Gutter_ca, you may be interested in this thread, which more or less summarises how we tackle chemistry threads of this nature. It is sticky business trying to distinguish between backyard chemists who know what they're doing (believe it or not, we do have a few on this site who I would give advise to any day of the week) and those who simply do not (or are feigning intelligence for the purpose of getting certain information).

We have a container of each of them in our lab. Unfortunately the basic one I needed looked a little bit dodgy, so I had some sent up from my collaborators with some alumina plates, which should be in tomorrow I honestly wouldn't even be bothering with alumina if it weren't for the fact that my stuff is tricky to purify on the small scales I do it on and that it decomposes if I so much as put a silica container within 2 meters of it. Once I build up to larger scales, I'm just going to do a Kugelrohr distillation, which is much easier and a personal favourite of mine (if only because I get to use the word Kugelrohr). That being said, I'll still need to use alumina for the next bit so I figure I may as well become an expert now. The reference you mention would be very much appreciated, thank you

Ah right, gotcha. I thought you were loading it with neat TEA and then running it with a 1% TEA/solvent, which would be incredibly wasteful. Yes, each to their own. Since I've started in research labs I think I've been taught about a thousand different ways to run columns, but in the end it comes down to what you're most comfortable with in your hands. Another thought I just had is maybe using an alumina column instead of silica. I'm not too familiar with using such columns at present, but I do know you can buy them activated and they can work in purifications where silica does not. I myself am about to embark on series of reactions using basic alumina with some alkaloids that are annoyingly very sensitive to silica; I'm just waiting for CSIRO to send me some goodies . Perhaps spin-1/2-nuclei might know more about it (I would also be keen to hear your opinion on alumina actually as no one in my group who isn't busy writing up their thesis seems to have worked with it before).