Horza2002

First of all, I'm sorry I didn't reply, I totally forgot about it! So sorry!! One thing you need to be careful of is that you can't predict what enantiomer you will get, there is no chiral enviroment to direct the attack and so you will get a racemix mixture. While in principle, the opening of the epoxide should give you an anti relationship to the resulting hydroxyl group, in this case, the piperidine nitrogen will scramble is and so will give a mix of syn and and anti bromo/hydroxy group. I am very confused by the proton NMR as well though...it doesn't seem right to me, unless im missing something obvious. Another thing that annoys me about these schemes is that the reagentss they choose can lead to several different products.

This artcile published in Nature, probably the most reputable scientific journals around, outlines the major flaws in organic farming. http://www.nature.com/nature/journal/v410/n6827/pdf/410409a0.pdf One interesting point that they make, one that I have never considered until now, is the disease risk has reduced massively since the use of synthetic pesticides and fungisides have been used. Fumonisin and patulin, two mycotoxins resoponsible for increasing the risk of certain cancers, are known to be at least twice as prominant in organic food where fungisides have not been used. There is another study, referenced in the above article, that estimates stomach cancer levels have been slashed by 60% because of the abundance of fruit and vegtables arising from increased production avoiding organic farming. The article also provides the nessary references to back up my statements about the issues with manure. In addition to the ones I've already outlines, the degredation of manure produces a lot of methane and nitric oxide, both of which are major greenhouse gases. Organic farming does the exact opposite of conserving land!!!! You need far larger areas of land cleared and devoted to farming than convential farming...and where do you think that extra land is going to come from? Clearing forests and such....over 70% of the land in the UK is used for farming (see reference)...to produce enough food for large population is going to need at least this level of usage....even higher if you want to use organic farming. Reducing soil acidity and increasing pH soil levels are the same thing...pH is a measure of acidity

From what I understand, then no it won't inhibit the enzyme. What it will most likely do, as hypervalent has said, is take the place of phosphate and incorportate itself into the product. The catalytic mechanism for the desired transformation requires the use of a cystein residue in the active site. The exposed thiol of the cystein is what tethers the starting material to the active site aswell as catalysing the reactions. As a result, inhibitors of this enzyme will be ones that infere with this thiol group. Oxidsers (that convert the thiol to a sulphoxide or sulphone) or heavy metals (palladium, gold, lead) will inhibit this enzyme; heavy metals are very thiophilic.

I assume you are aware of how solubility arises? So bascially, when you add the second solvent (the one that does not dissolve the product), the proudct can no longer stay in solution. For the spdium chloride example I gave above, in water, the sodium and chloride ions are seperate and surronded by water molecules. This system is more stable than the crystal form of sodium chloride so it dissolves. However, when you add acetone, the situation changes. While the oxygen atoms of the acetone are still able to coordinate to the sdoium ion and stabilise it, there are no hydrogen atoms avaliable for donation to stabilise the chloride ion. As a result, the chloride is far less stable that it would be in the solid form. At a critical concentration of acetone, the negative stabilisation of the chloride outweighs that which the sodium is stabilised and so the solid form of sodium chloride is once again favoured and so crystalisation occurs (see the attached file for a diagram). In fact, I did a crystalisation today in the lab. I had a phsophonium salt that dissolved in toluene (probably because of the pi-interactions resulting from the three benzene rings my product had and that of the toluene). However, once I added a few drops of diethyl ether (which is incapable of forming pi-interactions), my product started to crystalise out. Again, this is is a toss up between how stable the solution form is and how long it takes for your second solvent to disrupt this system. Doc1.doc

Osmium tetroxide (highly posionous in contact with skin), phosphorous tribromide (generally very nasty and brominates just about anything it touches), t-BuLi (nasty but gives a pretty red flame if your let it touch air), selenium dioxide, sodium cyanide (no explanation needed) and hydrofluroic acid...think thats it for the last year.

I would be extremly suprised if that proton was that high. Protons above 7ppm are either aromatics or they are aldehyde (unless there are some interesting ring systems). Can you put what you propose for X1-6 so we can see if your along the right lines. I've come up with a structure but I want to see what you;ve got so I can give you the helping nudges.

Organic farming does not increase yeild or anything like that...in fact organic farming is far more damaging to the enviroment than conventional farming. Using manure as a fertiliser is bad, not only because it can spread E. coli and other pathogenic species, but the nutrients in it are easily leached out during rainfall and contaiminate natural water supplies. It is also far less effective as a fertiliser than synthetic ones. The natural pesticides that they use are also far more damaging to the enviroment; they kill all insects indiscriminantly whereas synthetic ones show selectivity to the pest you are trying to remove. There is a reason why we abandoned organic farming and turned to modern agriculture....organic farming is just too inefficient at producing food on a scale that the worlds population now requires

That is all you need. Start by righting out an equation that defines the equilbrium constant and then rearrange for C

Once you know what a "mole" means...you should be able to come up with a simple equation that relates moles, mass and a third property.

Do you mean how it works? Heres goes then: Recrystallisation: typically, you need to use a solvent in which the product is soluble in hot solvent but not in the cold. So you dissolve your crude product up in a hot solvent and then let it cool down. As it cools, the product crystallises out while the impurites stay in solution allowing you to simply filter off the product. With a mixed solvent system it could be for two reasons: Your crude product only dissolves in the mixture of solvents (e.g. a DCM methanol mixture) so you need to use them before you can attempt the recrytalisation You use one solvent to dissolve all the crude product and then add the second, which your product is insoluble in, to force the recrystalitsation. An example of this is sodium chloride dissolves in water, then add a few drops of acetone and the sodium chloride crystalises out

Lol yer...I was a little concerned for a minute when you suggested using large amounts of methyl iodidie in a garage...there are sooo many problems that could arise! In terms of the methods we've discussed so far, the palladium chloride is probably the best for a grage chemist (although palladium us still reasonably toxic) but is relatively stable too. I'm not sure if the route I proposed is used or not, but I just thought it might be a new method to do it...it keeps the catalytic cycle going simply by changing the conditions...and thanks, I thought it was quiet creative The best way I would have said is to remove some some acetic acid, react it with oxalyl chloride with catalytic DMF or thionyl chloride to give the acid chrloide. That would be the best way I think industrially.

What do you mean by a virtual 3D laboratory? There is a branch of chemistry called computational chemistry. That is based on using computers to predict the behaviour and properties of lots of molecules by performing a whole range of very complex calculations on a MASSIVE range (typically several million variations of the initial perameters). To a reasonable extent, these calculations are a good approximations to what actually occurs so they could be considered a 3D laboratory. However, you need speclised equipment and reasonably powerful computers to be able to do this so you probably won't be able to get some. If one mean, is there software that allows you to perform chemical reactions in a a virtual way, then possibley but only reactions that are already known. And I'm sure you'd be able to find software using Goggle to be able to draw lab equipment and the like.

Arr ok I was looking for something that modified it will it had literally just been transcribed. I guess though, if you think about it, any further chemical change would be post-translationl seeing as it has occured after the protein was made...even if that modification occurs hours/days/weeks latter in another part of the body.

HI there, your questions are physics based so this post might get moed there instead. At the moment, scientists do not know how life began, but there are several theories as to how this occured, http://en.wikipedia.org/wiki/Abiogenesis. You are implying the existance of a supernatural being (whether it be God or some other invisible being), that is not science so be careful about that. Supernovea are relatively well understood at the moment and has been known for a long time that several of the elements essential for modern life afre produced in these events. The angular velocity of the Earth was preserved when the swirling cloud of dust and rocks that made the Earth collapsed in on each other...it is simple the conservation of angluar momentum, nothing more. And no, it shouldn't be extended to inculude the air....air doeesn;t reproduce, need to eat, etc.

Slow, the mechanism they give in that paper is the same as the on I proposed in the file I attatched (black arrows). The only differrence is that I didn't have the palladium coordinating to the alkene, which makes perfect sence actually. So I would say that might be a good way of making acetic anhydride. The key will be doing it with no water present. And like I said, if you warm the reaction up to 30-40oC, you will boil off the ethanal byproduct and help drive the reaction to completion. At this point I should point out that ethanal is rather a nasty compound to ingest. It has been shown that it binds irreversibly to several essential protiens that often lead to organ damage and is also a carcinogen. Mississippichem, if you were to replace one of the iodide ligands on the rhdoium, then you might be able to eliminate acetic anhydride instead of the acid iodide. However, if you did that, then the cent.ral catalytic scheme would then stop so you would need a stoichiometric amount of methyl iodide in the reaction (warning methyl iodide is a carcinogenic). If you were to use a different start material, methyl acetate and lithium ioidide, I wonder if this might work (see attached file). Halides are known to very mild methyl ester hydrolsis agents..although typically you use chloride in this reaction I've done this many times (by accident and on purpose). This would then give lithium acetate and mehtyl iodide that in the prescene of the rhodium catalyst would then undergo the Monstanto process to generate acetyl iodide. This would be EXTREMELY reactive and so then react with the lithium acetate to regernate the lithium iodide and acetic anhydride. So I guess the changes would be that you don't add water or methanol and then change your starting material; what you think Mississippichem? However, if slow wants to actually do these reactions, then I think the palladium chlroide one is going to me more practial. From the experimental procedure I read in that paper, you simply add them all together and then stirr them..and if you Dean-Stark the ethanal off as it forms you should drive the reaction forward. Slow, you could make yourself a Dean-Srark apparatus to help in that reaction. Getting hold of the thr rhodium catalyst for this Montstanto-analagoude mechanism would, I imagine, prove very difficult. http://en.wikipedia.org/wiki/Dean-Stark_apparatus new.pdf

To acetylate that hydroxyl group, you could treat it with potassium carbonate and acetic anhydride reasonably easily yes. As for those other reaction conditions you found, I'm not enitrely sure about that. While I can come up with a mechanism for this transformation to give ethanal and acetic anhydride, im not sure what the palladium chloride is doing there. See my file attached for my proposed mechanism. Basically, you are doing an ester hydrolysis but in the absence of water. Once you've pronotated the vinyl acetate, water would normally attack (red arrows)...however as there is none in your reaction, the less nucleophilic acetate anion could act react instead (black arrows). The tetrahedral intermediate would then collapse to give acetic anhydride and the enol tautomer of ethanal. Seeing as ethanal boils at 20oC, doing this reaction at 30oC should help drive the reaction forward. I have missed out the second hydrogen transfer step in the mechanism as well to save time. Like I said, I'm not sure why the palladium chloride is there. I know that palladium chloride is used in the synthesis of vinyl acetate as the catalyst to react ethene with acetate. So if anything, the palladium acetate will actually catalyse the decomposition of vinyl acetate back to its starting materials. There will be other ligands coordinated to the palladium during this process but I have left them off for clarity. The final step is a beta-hydride elimination, a very useful and interesting reaction...id recommend reading about its use in modern catalysis if your interested chemistry. acet.pdf

Ive just done a quick literature search and can;t find much about it either...are you sure its Vitamin A?

Yes, most commonly, plastics are made of carbon, hydorgen and oxygen...however there are a great many that don't. Sulphur and silicon are good examples....there are also examples of metal containing polymers (e.ge. some new antibacterial polymers that have silver ions as part of their structure)....polymer chemistry is MASSIVE and incredably diverse... Thinking about it, you can pretty much make any polymer you want. All you need is a compound that has at least two functional groups (either the same or different) and the right reaction conditions.

There is another key phrase there: You can't please everyone Not matter what society in what country, you cannot please everyone...there are just too many view points on any given subject/ideal that many of them are bound to be opposits. Generally, here in the West, we go on the basis that the majority view is the one we adopt seeing as its the one most people agree with/want. However, in these countries, it is the minority that are ruling and telling the majority what to do. The rebel could indeed pardon themselve, because it would only be high treason against a government/leadership that doesn't exist anymore...I'm sure that is what happened in all the Revolutions during the Medieval era (French, Russian and the English Civil war).

If you notice though, the current situation in Libya and Egypt are people rebelling against the leaders that they had no say in being in charge. And normally, these dictators have a "secret police" type organisation to quell any attempt to remove thir leader. However, as history has shown, you can only oppress people for so long before they fight back...and again, there is only so much peaceful protests can do. If that doesn't get what people want and the opposition attempt to silence them, then the only thing thats going to happen is violence.

This has long been an idea of how the first primitive cells were formed...you only have to pour cooking oil into the kitchen sink to see how "cells" are formed in water. Although this is interesting that they move around...although im not convinced about the "metabolism" bit...the hydrolysis would occur with or without the cell surronding it.

Lol might be a little of topic but thyre justdifferrent methods of how MS works. If u want to know, start a new thread and im sure we'll all be happy to fill u in on how they all work!

Right, so it was a simulated NMR then as one of the those (position two) should be a doublet of triplets which it wasnt (unless it just wasnt clear on the spectra provided). And bring oin the questions! O chem ROCKS!! Well that would depend on the ionisation source. If it was ESI, then quiet probably not (as im makng 4-methyl pentan-1-bromide atm and it doesn;t show up in the ESI)...however, if your using EI or CI, then I would expect you to see it yes.

A cheap nebuliser to pump petrol thorugh with a ignition source

At what level are you aiming this essay to be set at? High school, university?