hypervalent_iodine

Always good to see my screen-namesake put to good use. Although it should be said that I in fact use a different hyperiodine complex for a different reaction. Still, I love all hyperiodine complexes equally. They are amazing.

A good alternative to IBX that is markedly more soluble is safe IBX, or SIBX. Alternatively, DMSO is a good solvent, as can be oxane in water. DMP, a derivative of IBX, is also a fantastic substitute - unless you have amines or sulfides in your compound (it's pretty functional group tolerant otherwise). DMP is also used to cleave diols, whereas IBX cannot (in excess, IBX will just oxidise both of the hydroxys to carbonyls).

I could go on for pages, really.

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.

From what I've read, there are actually a few metabolic processes where substituting arsenic in place of phosphorous does result in the irreversible inhibition of certain enzymes. Off the top of my head I couldn't tell you which enzymes, but I do recall reading it when I was looking into that article I mentioned in my above post (the one about bacteria).

I don't know about this enzyme specifically, but arsenates can mimic phosphates in a lot of cases - and they do a good job of it too. Interestingly, a somewhat recent study in America found a species of bacteria that can substitute arsenic in place of phosphate and maintain themselves reasonably well. There was a thread on that study some time ago in the Science News section. Do you have access to a university library site or access to a scientific journal search engine? If so, you might find it quite helpful. If not, you should try using Google scholar or try finding a biochemistry text book.

Picric acid, aresenic and cromyl chloride(CrO2Cl2). The last one gave me a headache that lasted for 2 days...

On the topic of picric acid, a few years ago there was a couple of barrels of it found on the top level of the math/astrophysics building at uni. Been there for years. I like to think it was the doing of a very patient chemist, trying to knock mathematicians off from their position at the top of the heirachy with brute force. This is just in the same that way our chemistry building is specifically designed to explode outwards and take out maths, molecular biosciences and engineering, should it ever be blown up. The latter two are clearly just for fun.

Well, do you understand what the term, 'mole' refers to?

Ceribethlam,

For future reference, try not to simply give out answers to what are clearly homework questions. Secondly, one of your answers was wrong. So if you are going to give help to people in chemistry in the future, please check you are giving correct advise.

Qwerty,

A few things you need to take notice of when doing these questions:

The total ionic charge of a species is equal to the sum of the charges of its components. There are a few rules to pay attention to when working out the charge on each individual atom within a molecule. The major ones for you are that oxygen and hydrogen, when present as part of a compound, have charges of 2- and 1+ respectively. The exception for oxygen is in the case of peroxides (such as H2O2), where it has a charge of 1-. The other thing to remember is that molecular species, such as O2, N2 etc have a charge of 0. You can use this information quite to work out the charges of other species within a compound, or conversely, the net charge of the compound itself. As an example, if knowing that H and O have 1+ and 2- charge respectively, I can say that the net charge of a water molecule is 0. This is because the net charge of the compound is equal to the sum if the charges of it's components. Thus, the net charge of water = 2 [+1] (for the 2 hydrogens) + [-2] = 0. You could also work the reverse way to get the charge of say, oxygen, where you know the net charge of the compound it's in (water in this example, so 0). The correlations that ceribethlam made regarding which species were being oxidized and reduced were correct, but you need to watch for that peroxide in the last question. The oxygens in the permanganate are all 2-, but the peroxide oxygens are not.

Hope the helps.

I don't agree so much with your little quip. Sure, there's an element of memorising at some point in the learning process, but that should only be for fundamental type processes. A more appropriate quote might have been, 'you can't abstract something unless you have something understood" . Memorising something is not the same as understanding something. For o. chem, curly arrows are a very simple way of achieving this. The more time you spend drawing them out, the more you can get a feel for how electrons move around and why. Simply, once you've got down why reactions occur, there is very little memory work necessary. As we have all said in one way or another, there are simply too many reactions in o. chem to memorise. There are of course aspects that are not so intuitive and things that you will need to learn. Generally though, it all comes back to one fundamental process or another.

Anatomy has no instinctual logic behind it - it is all memory work. Organic chemistry, as I and others have stated, is a fairly intuitive branch of science once you have a grasp on the basics. And although I sound like a broken record by saying this, memorising reactions will serve you no good (in the long run) whatsoever.

Finally, thinking about orbitals is definitely useful in a lot of cases - most notably in pericyclic chemistry and inorganic. However, you don't often have to consider vacant orbitals in much depth when looking at a reaction mechanism. With respect to the water as a leaving group - yes, to an extent, but there is a reason for why it is a good leaving group.

Geneks, I spend a lot of time tutoring first years in O. Chem here at my university. I can promise you that everything is so much easier and so much clearer if you can understand and draw curly arrows. Memorizing mechanisms, in my opinion, is pretty damn useless if you have no idea where the electons are going and why. It's the equivalent of memorizing the answer to a calculus question without actually knowing how to do calculus. I cannot stress enough how important it is for you to take some time out and read through a text book (McMurry and Clayden are good) and get a feel for curly arrows, what they mean and how to use them. If you can apply it to what you're learning in your class, it will do you a world of good. Memorizing reactions will not help you learn organic chemistry and what it's about.

No problems

I figured it might not be, but it could very well be a helping hand to someone else in the future.

Hey, anything I can do to make people realise that O. Chem is really not as disgusting as undergrad sometimes makes it out to be, I will do to my fullest extent. The world needs more chemists, in my opinion

This problems seems a little mean anyway. =) If it were just the H NMR, I'd be fine. It's the C NMR that's throwing me off so badly. =\

 

I'm a senior at Temple. The kicker is that I haven't had Organic Chemistry 1 in about 10 years. This is the only class standing between me and my BS (which is partly why it's taken me 10 years to get back to it...) I've been studying on my own since about August, so I feel as comfortable as I can with the subject. I got a 100% on my last quiz, I am grasping most of it. Amazingly enough, I'm actually starting to enjoy it (something I never thought I'd say!), though this particular problem is making me want to pull my hair out.

Understandable. They've certainly not made this easy for you. In the real world, we have 2D sepctra and our peaks are integrated, so don't get too scared away from organic chem. It's a pretty awesome subject, if I do say so myself

Horza2002 to the rescue!

Or maybe you could use it as a marital aid, i.e. if you could temporarily suspend familiarity with your partner for the sake of having an exciting 'first-date' experience.

I can see that ending in arrests and sexual offence charges; depending of course on if only one of both of them are deprived of the ability to recognise the other. Having said that, the latter case is nothing more than a tool for a wonderfully simple and clean cut divorce/break up.

It might just be me, but I can't see any spectra? Until I see it, I won't be much help because I would need to see the integration and Jz coupling constants. Just looking at what you've said for the ¹H NMR, I'm not sure your integrations are right. Are you given an empirical formula or mass spec at all?

Is your ¹³C spectra proton coupled or what? You don't normally get a proton coupled spectra without a decoupled one as well. Also, peak heights in ¹³C don't mean much of anything. Certainly not in the same way as in ¹H NMR.

Well I think the wiki article fairly much answered your question. Essentially, given enough electrons and low-lying (in terms of energy) orbitals, it is possible.

What are "molecular coordinates"? Do you mean the bond angles and bond lengths?

 

The only program that I know that comes close to what you want to do is chemdraw, but that's a Windows program... and probably not exactly what you're looking for.

Why do you use an apple machine for such scientific tasks? I know only people who use Windows or Linux for scientific work. And even for those systems, the program you want might not exist.

Not true. I have ChemDraw on my mac and it works just fine

Re. the OP. Are you looking for something that can model small compounds or protein type structures?

I tried putting the names together myself, now need someone to check them:

 

1a) (1R,4S,4aS,8aR)-4a,8a-dichloro-2,3,5,5,6,7,8,8-octahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

1b) (1R,4S,4aR,8aS)-4a,8a-dichloro-2,3,5,5,6,7,8,8-octahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

2a) (1R,4S,4aS,8aR)-6,7-dichloro-2,3,4a,5,5,8,8,8a-octahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

2b) (1R,4S,4aR,8aS)-6,7-dichloro-2,3,4a,5,5,8,8,8a-octahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

3a) (1R,4S,4aS,8aR)-4a-methoxy-5,8-dioxa-2,3,6,6,7,7,8a-heptahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

3b) (1R,4S,4aR,8aS)-4a-methoxy-5,8-dioxa-2,3,6,6,7,7,8a-heptahydro-1,4-methanonaphthalene-1,4-dicarbonitrile

 

Hope someone can help me with this,

 

sumi

 

 

 

Not quite.

Check your ChemDraw structures are correct. I drew all of your compounds in ChemDraw and got different names to the ones you listed here and the ones you say ChemDraw spat back. Very close to the ones you listed above, but your naming of the 'hydro' bits is wrong. Everything else is okay in 1a and b. In 2a and 2b, two of your stereochemistry assignments are wrong. 3a and 3b are not correct either. As I say, double check your drawings in ChemDraw are exactly the same as the picture you inserted in your OP. You should get your names right that way.

I haven't read everything in this thread, but I just wanted to offer a fast reply to the original poster's question: Is homosexuality genetic?

 

The answer is: NO

 

There has never been any conclusive (or even suggestive) scientific evidence to my knowledge that would imply that homosexuality is triggered

by the existence or lack of a specific gene. It is largely an unexplainable phenomenon...but it has everything to do with environmental conditions

and influences and nothing to do with genes.

Certainly, there are cultural/environmental factors that influence whether a person becomes or is homosexual. However, that is not to say that there is not also a genetic predisposition or that a person's preferred sexual orientation is not a compounded result of the two.

I spent ALL DAY doing TLC's today. Stupid phase transfer catalyst wouldn't get out of my compound so my column didn't quite work as I would have liked it to. I generally use a combination of UV and Goofy dip - works fine for most of what I do.

Also, the iodine stains are really good for sugars.

You need to stop posting these philosophical things in physics.

Ok...it's ethically irresponsible to have a family too early in ones developmental cycle because the risk of failure in the current Western social climate is disproportionately high....it is no longer taboo to divorce compared to 50 years ago or more (which previously COERCED people to stay together for fear of disdain and disapproval) and a consequence of this trend is more socially dysfunctional adults with no experience of stable relationships creating more and more dysfunctional families...it's self-perpetuating and muliplying ....if the social structure is too dynamic and fragmented within the family unit this will eventually erode cohesion and stability at the societal level. Inner city gangs are largely a' product of fragmented families and created by the innate human desire to to be part of a clearly defined and exclusive social group...that's their 'family'.

 

To allude to Shakespeare: if you are born within a tangled web...all you know how to weave is tangled webs.

 

There are macroscopic consequences to what happens at the microscopic family level.

I do not agree that this is always the case. I come from an extremely dysfunctional family and had a pretty rough childhood as a result. I do not, however, consider myself to be a dysfunctional adult (or at the very least, I sure hope I am not). Certainly there are hurdles to overcome, but if you have the right attitude and you are able to perceive not the error in the ways of your parents, but the susceptibility for error in your own self, the cycle of 'weaving tangled webs' can be broken. Having said that, my anecdote is my no means proof of what is the norm. Breaking the cycle of 'tangled webs' is indeed a hard thing to do.

Typically I'm looking for a formal (IUPAC) name rather than a decent informal name. "Carbonyl oxygen" seems like an informal name to me. I am, however, ok with decent informal names if people have a good one and don't know of a formal name.

 

I am going through reaction mechanisms at the moment. As I do such, I attempt to reduce each step into a three word phrase, such as "CarbO atk H+" for the first step in acetal formation w/ MeOH. CarbO in this case, inspired you by mississippichem, stands for carbonyl oxygen.

 

p.s.

 

I'm aware it's electron flow rather than atomic attack.

As the other two have said, carbonyl oxygen is an acceptable term. You could, obviously, generate a more specific name with a more detailed structure. However, since you are dealing with generalised structures, generalised terms are fine.

Also, be careful with your abbreviations. You don't need to make things overly complicated or else you mightn't understand it when you go back to it later. It is much easier, in my opinion, to actually draw the mechanism out with 'curly arrows' than it is to write it (unless you need to make specific notes regarding chemo/regio/stereo selectivity than you can show diagrammatically). That's what I teach to my first and second years, anyway. It seems to work better from a teaching perspective for people to be able to visualise what's going on through the aid of clear diagrams as opposed to paragraphs of text.

Coincidentally, I had a discussion on this subject with my 21 old year niece recently . She wants to travel around now she's got her degree and when she comes back she will settle down...in the meantime she might have 'random' experiences with people. I said this was a good idea and that she might try and put off settling down 'til she's at least in her mid-twenties, finally grown-up and got any need to 'experiment' with relationships out of the way. Too many people have families too early, then, when they are in their late-twenties get that urge to 'experiment' which they missed out when they were younger.

 

Hopefully, when she's reached that stage she will be fulfilled on the selfish/personal level and will be able to fully commit with no nagging/yearning distractions and give her future mate and any resulting off spring her undivided attention.

 

I say all this with the perspective of a person living in the UK, well aware of it's pretty high divorce rate, and wish to help her avoid the all too real possibility of marital unhappiness...especially for any children she may have.

Couldn't agree more. My mother's first marriage to my father was an utter disaster. The only reason they got married at all was because my mum was pregnant with me and her mother, being the conservative woman that she is, was very insistent they tie the knot as a result. 3 more kids later and 10 years of absolute hell and they finally went their separate ways.

I think that it's very much a case by case situation as to when the 'best' time is, if the time should ever come. If I (as a female) were to get married for instance, it would not be until after I finished my PhD and I am settled into a postdoctorate position. Having said that, I in fact have no intention to get married as I do not believe that I need the institution of marriage to confirm my love for another person. Recently, my mother got remarried for the purpose of being able to live in the same country as her partner after he got a job overseas. I guess the 'best' time for that marriage was before her visa expired

I find it very hard to believe that you only 'sometimes' think about this, given the number of threads you've started to the same tune.