hypervalent_iodine

You're still missing something (and the compound in the OP is an acetal, by the way). Draw the mechanism and you'll probably work it out. A

William, both the OP and your post are missing one critical reagent in your synthesis. Since I assume the need for this answer has expired, I will give you a big hint by telling you that the compound is an acetal. What is required for acetal formation to occur?

Alright, the first question you should ask yourself is what find of functional group is in your product? You identified the key reagent to making it, acetone, but you're missing one other thing needed to make this particular functional group. It may help you to look at the mechanism.

00rich, I am somewhat conflicted with how to respond to this. One the one hand, the fact that you have access to solvents like carbon-tet and the various other chemicals lends credibility to your claim that this is for research. On the other hand, I did in fact find what I am 99% sure is the source you are using for this synthesis and I am extremely confused as to why a research group would use this particular web site for any sort of synthetic protocol. One other thing that becomes glaringly obvious upon having read this synthesis is that (and I mean as little offense in this as possible) you have no clue what you are doing when it comes to reading and interpretting chemical methodology. So here is my solution for you. I am not comfortable tellig you what you've done wrong and how to fix it in this forum due to T&C's. If this is for research purposes and you are part a legitimate research group, something I am quite sure you do have access too is contacts and/or colleagues. Get a chemist in your department or building or where ever to come and help you. You have quite badly misread the methodology of your synthesis and synthetic chemistry is not something you should be playing with if you don't know what you are doing. I cannot stress that last part enough.

YOu won't be able to combine those two together in a useful fashion for your end-product. Break this down some more. Instead of looking up commercially available material, try thinking about what kind of reactions make carbon-carbon bonds - Horza suggested you think about what kind of reactions you know of that make carbon-carbon bonds onto phenyl rings, and this is a very apt hint. Try writing reactions you know down and have a look at how you can apply them to your substrate.

And so now do you feel like telling us why you're making PCP derivatives?

Appolinaria you're cherry-picking posts and arguing needlessly now. We've given you plenty of other examples that illustrate the point.

00rich, you've already got one thread on this topic. One's enough.

That's a bit restrictive, don't you think? Do you only want American people to participate in your survey? The large number of questions on the survey assume American residency. Regarding question three: What if I was 30 years old? Do I answer over or under? Perhaps you should specify who it is you actually want to do this survey. In any case, I would change question 3 and get rid of question one as a multiple choice. Possibly make it one where people write in either their country or US state of residence.

As a further example to StringJunky's and something I hinted at in a post on page one, a lot of the quintessential name reactions still routinely taught and used within chemistry are ones that were discovered in the 1800's. This was all done before the concept of an atom had been properly elucidated - heck, we didn't even know what bonding really was until the early 1900's. One of my favorite examples and someone who has always amazed me is Emile Fischer. He managed to correctly discern the relative stereochemistry of all the simple 4-6 membered sugars (and by a fortuitous roll of the dice, their absolute stereochemistry as well) by simple chemical correlation. This was before the invention of things we use today such as NMR and X-ray crystallography. As I said before, solving chemical problems does not need a knowledge, or even an awareness in some cases, of the physics that governs them at their most fundamental level.

Moo, I think that's exactly what Mrs Zeta was saying. I could be missing something, though.

I was telling moo a story the other day that serves to illustrate her last point, so I'll share it here too. Recently I went away on a holiday with a group of my friends. One night, I was playing 500 (a card game) with 3 other people who had either finished their degree or finished the vast majority of it; one of those people was a chemical engineer, one a biophysicist/mathematician and the last one a physicist. We were drinking a bottle of port we purchased collectively a few years prior and of the four of us, 2 had cups that were the same and the other two had completely different ones. When it came to the near-end of the bottle, we needed to divide the final bit of port evenly and were undecided how to do it. I suggested we pour two equal amounts into the identical cups, using one as the standard measure and the other to pour into the other two cups. My physicist friend scoffed and accused me of being a chemist, telling me that you could do it more efficiently by pouring into each cup for the same time at the same rate. He proceeded to say that if he were an astrophysicist, he probably wouldn't bother with either approach and take the bottle for himself, since the error margin is in large orders of magnitude. That of course did not agree with the rest of us, so we took the chemistry approach instead. He also mentioned that being the quantum physicist that he is, the difference in volume in each glass wouldn't be even close to accurate enough for him unless there was an exactly even distribution with an error 10^-whatever. At that point he was given his now poured glass and told to make do. So you see, different strokes for different folks. Same question, two different solutions.

In their own speculations thread, of course.

Empirical formula aren't particularly informative in terms of well, anything. You're not really going to be able to predict how a reaction will proceed without the structures. KMnO4 is an oxidising agent, and a very strong one at that; there is no way it is going to reduce anything. Converting ascorbic acid to DHA is in fact an oxidative process, as Horza noted. Isolation of compounds from a reaction mixture is typically done using silica flash-column chromatography (if you've ever used a TLC plate to separate pen ink pigments, it's essentially the same thing, but in a column). There are other ways such as distillation, prep TLC, etc., but columns are usually the first go-to. Occasionally you get lucky and remove your product with a simple liquid-liquid extraction work-up. The person who wrote that is slightly incorrect. It will not hydrolyse to give 2,5-diketogluonic acid, but 2,3-diketogluonic acid. At an educated guess, I would say that oxygen of the water will attack at the ester carbonyl, breaking the ring open and giving you your product. As Horza said, though, this would be a tough reaction to get to completion. A quick search the final step will happen, but the mechanism is evasive in the literature and it doesn't seem that water would do the job by itself. I found one paper that uses calcium hypochlorite to cleave alpha-ketones, which I suppose could work with your substrate. A search of the literature suggests that non-enzymatic oxidative and non-oxidative decomposition of ascorbic acid is in fact quite convoluted in terms of the number of products you get. One paper I read isolated over 50 products, which would be somewhat difficult to separate properly without good equipment.

You're entitled to your opinion, however it's not really related to the OP. It's asking whether chemistry answers more important questions than physics, not, 'is chemistry higher up than physics in terms of hierarchy'.

I never said they did.

Perhaps I should have elaborated some more in my above post. Our understanding of the finer details of chemistry and the way atoms behave is very much attributed to questions answered by physics. Therefore, one could say that in a very indirect sense, all answers stemming from chemistry owe themselves, in part, to physics. This was perhaps more evident at the inception of QM and the various chemical theories and models that derived from it. In the words of Sir William Bragg on the topic of the 'Progress of Physical Science' (Sir Halley Stewart lecture, 1935): This was, however, in the 1930's and while chemistry certainly does rely in this knowledge, it does not need to concern itself with such intricacies to derive solutions to modern chemical problems; see the entire field of organic chemistry for more. Certainly, there are areas within chemistry that overlap quite heavily with modern physics; this I suppose begs the question of where does chemistry stop being applied physics and starts being a discipline in its own right? You could also ask the same question of biology in relation to chemistry or of physics in relation to math. I'm reminded of this: And so, the question still remains, which area answers the more important questions? Again, you need to define what is considered important and what is not and you need to define the boundaries of where one area stops being a strict application of the other. Furthermore, how do you measure the concept of importance quantitatively enough to make any testament as to which is more beneficial? The problem I see with defining what you use as a measure is that it would most likely be inherently bias towards one discipline. For instance, if I were to make my measure 'the number of human lives saved as a result of X', I would be selecting for for the area more concerned with medicinal application. You would therefore have to make it a summation of a number of indicating factors, the problem then being, 'how do you weight them?' and once again, 'how do you quantify them in a consistent and non-bias manner?' To summarize, I don't think this is really a question that can be fairly or properly answered past the fact that they both contribute to mankind. They are both necessary areas in advancing our repertoire of scientific knowledge and in the general progression of our technological society. They are, however, not mutually exclusive and as such remain, 'blended into one,' in such a way that you cannot really separate a given question into one or the other discipline.

It depends on your compound. Some will decompose at the temperatures required to distill them or the solvent they're in. Generally though, if you're just trying to remove solvents, rotary evaporators followed by high-vacuum pumps/lyophilizers are the way to go. They use reduced pressure to decrease the boiling point of the components in the mixture, allowing volatile substances to be removed fairly easily without the need for much heat.

And yet you'll notice that of the three other replies, two from physics majors one from a chemistry major, not one of them said that their discipline was the better of the two Not everybody is so altruistic in their choice of majors. I do chemistry because I love doing chemistry, not because I think that the work I do will make a great impact on society. A lot of people study science for similar reasons - i.e. they do science because they find science interesting, not necessarily because the application (if one exists) will be useful (although it certainly does help when procuring grant money).

How do you define what is and what isn't an important question, though? I would say chemistry perhaps has a more direct impact on society in the questions it answers (for the most part, at least), but the ability to answer them is reliant so heavily on questions already answered/being answered by physics that it is impossible to say which is more beneficial.

That is strange. Did you notice any other bands in the gel at all? I suppose you'll just have to change primers and see what happens.

Well, yeah, but undergrad is rarely concerned with making things easy, now is it? Also, you must be really bored.

It might be easier for your question to be answered with more specific knowledge of your primer sequence, the thermocycling conditions you used, etc. In any case, here's a few points I picked up in my time working in a genetics lab (I should note a disclaimer here that I am actually a chemist and my time in said lab was both brief and a few years ago, so some of my points may need checking): If your annealing temperature is too low, you will get your primers binding quite strongly at other sites of the template, resulting in false product or no product at all. Too high will mean that the primers are unable to bind properly, if at all, which results in no product. If your equipment allows it, it may be worth-while doing multiple PCR's simultaneously with a annealing temperature gradient from about 40oCon the cool end of the heating block to 60oC on the other end. If you run a gel of the amplified cDNA, you should be able to work out the approximate optimal temperature and furthermore, if the temperature is affecting where in the template you're amplifying (assuming there is sufficient size difference). Is it possible to excise the fragment you're after with a restriction enzyme at all? Even if you can get it within a few hundred bp flanking either side, this may help you get more specific binding of your primers to where you want. If you have too many A-T pairings in your primer (more than 50% is probably too much), the primer may not form strong enough bonds with your target, resulting in mismatch. This also affects the annealing temperatures you should use; as a general rule of thumb, G-C pairs (being the more strongly bonded base pair due to their one extra hydrogen bond) will be able to withstand higher annealing temperatures than will A-T pairs. How big is your target fragment? Too large a fragment will probably mean the extension phase isn't working properly, which may be why you aren't seeing it. If it's too small, there's a chance you're missing detecting it when you're extracting it from the gel. Avoid using A-T pairs on the 3' end of your primer. A-T pairs on this end result in something known as 'breathing' and may give you mismatches. Similarly, runs of three or more G's or C's on the 3' end may also promote mismatches at other G or C rich areas of the DNA sequence. Your primers should be about 18 or so bp long. If they're too short, there is an increased likelihood of mismatch. To summarise, I would test to see if the annealing temperature is affecting specificity in your samples and then have a look at your primer design. It sounds like you will have to change one or both of your primers.

I have not used SCOPUS and I have not ever used WOS for anything except chemistry, biology and once, psychology, making my opinion rather limited. That being said, I do actually quite like web of science as a back up search engine. During my undergrad, I used it quite heavily. It is quite often able to locate certain papers that my university library and Google scholar, etc. cannot find, which is a definitely handy. It is better than Google scholar in some respects, since you can sort your results by year, citations and relevance (among others). As well, I find filtering through multiple authors, journals, publication years, etc. is much easier and straight-forward with WOS than with Google scholar. I do, however, have some slight problems with it. My primary issue with WOS is that when you are searching topics, it doesn't have the capacity to compensate for minor spelling errors or alternate ways of spelling words (you dastardly Americans and your persistent use of the letter, 'z', is always messing with my WOS searches). Even more annoying for me as an organic chemist is that it doesn't like characters of any kind, at all, ever; I have to systematically go though each title I want to look up, remove all the Greek symbols, hyphens, commas, apostrophes, etc. Really, you are better off using combinations of as many search engines as you can be bothered with and that you trust. If I'm doing in-depth research for something, I tend to use WOS, SciFinder and Google scholar, rather than one or the other. You get a much more comprehensive bank of papers that way.

Currently, there are a few. Sharpless, Suzuki and Heck come to mind. E.J. Corey is also great if only for the quantity of work he's produced. Grubb is another.