D-meth vs L-meth

PeterPoppa

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For anyone who's had to listen to my rants about Positive and Negative Ketamine are now going to have to listen to me talking about YET ANOTHER concept I don't quite understand...
 

BongoBongo

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Another Bump worth looking at....especially....

The link in the first post above.

Upon reading through the posts one can understand a little bit more of the chemistry and then make sense of the different types of results one may feel after ingesting.
 
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Munchee

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Bahahah I saw this thread and thought soma was still posting in here. Are these back from the archived AusDD?
 

BigTrancer

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Almost, Bongo's been using the search function and digging back through the earliest threads Aus Discussion :) I could merge this with Nanna's thread, but they would be at the top of the thread due to the date... I guess its a neat bump, it refers to something in the OD Forum Archive.

Bongo: If Aus Discussion is upside-down, try "sort by last post time - descending" ;)

BT :)
 

Nice Tits

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What we really need is someone like Phase Dancer to simplify all the chemistry mumbo jumbo. I'd say that I have a better than average understanding of chemistry but that goes straight over my head.

Nice Tits
 

phase_dancer

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Two types of isomer are relative to MDMA and amphetamine/ meth.

R and S represent absolute configuration; where the order of placement of attached groups on a chiral carbon determines assignment.

D and L are optical isomers. Assignment is given depending upon how polarized light is deflected. i.e. is the deflection positive ((+) dextrorotatory) or negative ((-) levorotatory)

Optical isomers are NOT related to absolute configuration, but often an L will also happen to be an R (-), and a D an S (+).

Simply put, Isomers are different 3D representations of the same molecule. In these examples, D and L are like right and left feet (but with toes in odd positions that can't be superimposed on the opposite foot)

If The Shoe Fits...


It not a perfect analogy but in regards to receptor binding, think of it as being like a Right foot fitting a Right shoe.

The receptor that the drug is to bind with is a bit like the shoe, and the meth like the foot. Try putting a perfectly fitting left shoe on a right foot. It might fit with a struggle, but it's definitely not as easy a fit as the right shoe is.

Your receptors (and many enzymes and other bio-molecules) are also like the shoe. A molecule shaped correctly will fit in with ease, with the "toes" sitting nicely in their respective spaces. The opposite foot might go in, but toes are squashed up in places and loosely bound in others. It also usually takes some effort to squeeze on the boot (more energy)

Most biological processes including receptor docking, binding etc are energy efficient processes. If it don't fit properly in one place, then it might 'look' around for something else. In the case of L and D meth, D has a "best fit" with NE and DA target receptors. Enzymes pick up most of the non-bound L meth and metabolize it into hydroxyl (OH) substituted compounds which enable further metabolism or faster elimination.

D meth on the other hand spends quite a bit of time intimately associated with the receptors, chatting away and stimulating much gossip (secondary actions). Eventually the "janitor" enzymes come along and pick up the D meth, where its then carried through a similar process to that of the L. *

Some L meth will bind with receptors, although as mentioned it's hardly the snug fit D produces. However, the binding is an on again - off again relationship, so it's usually picked up by enzymes when "off again" D meth on the other hand may bind (on and off) for much longer, as the fit is more energy efficient. Sometimes the opposite isomer may bind as effectively, but causes little or no secondary actions.


Please note this is a very simple analogy. There are other things happening which don't necessarily apply to this model.


*Note: This a very simple and partly inaccurate model. Different isomers may be metabolized via completely different routes or via different intermediates.
 
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chugs

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http://www.bluelight.ru/ubb/Forum19...5.html?reload=4

is extremely interesting, espeically the discussion re different isomer's of MDMA.

I always thought the drug, MDMA was of one type and the different effects people felt were due to mood & setting...and that people saing that it was the drug were talking out of their ass.

however it appears they were correct. Whats to stop a chemist from creating a different isomer of MDMA and hence give a huge variety of effect? What if drug dealers were crushing up pills of different mixes and restamping. There would be mixes of different isomers and thus different effects.

could there be different isomers of LSD, which could also explain the wide range of effects?
 

phase_dancer

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Whats to stop a chemist from creating a different isomer of MDMA and hence give a huge variety of effect? What if drug dealers were crushing up pills of different mixes and restamping. There would be mixes of different isomers and thus different effects.
Very unlikely. Unless a stereo-selective synthesis is employed (e.g. using a protection group attached to L or R alanine and then chlorinating before reacting in a Freidal Crafts acylation with 1,3 benzodiazole ) then the product will be racemic as, in all likelihood it would be made from a planar precursor (MDP2P).

To separate the isomers requires either using HPLC with some tricks, or using an optically pure form of tartaric acid or other with 2 stereo centres. The resulting conjugates have different solubilities and so allows for separation. By altering pH the MDMA is then able to be separated from the conjugate.

As to why it's never likely done in practice. Too much work, and for a product that most people probably wouldn't consider as good as a 50:50 or racemic product. See PHiKAL # 109

You might find something useful from this old post of mine....please ignore over rated comments from other posters :\

Isomers of MDMA

Only the D isomer of LSD is active

Edit: spelling-grammar, and a chem correction...naughty me:\
 
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chugs

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hahah - that is a great post - me thinks i'm going to have chew over that for a few days....its stuff like this that really creates a desire to go to uni and do organic chemistry
 

BongoBongo

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Phase-dancer,

Your analogy is rather good. Can you explain further, in lay terms, the potential different psychological effects from the different isomers.

Had my old school teacher explained Chem. like you, I would have stayed in class and not legged it into physics.

Keep up the good work PD
 

phase_dancer

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^^ I'll give it a go. Remember, it's a general description in laymans terms, and so the analogy could easily be pulled to pieces or criticized.

I'll use G protein receptors as an example. This type of receptor is a serpentine length of protein which can be imagined as a long folded snake which traverses the outer cell membrane 7 times. Some of the outer section strands (helices) come together and form "pockets" where an agonist or antagonist may bind. These are known as binding domains. The drug normally binds to several amino acid residues present on different helices.

There is a certain flexibility among some strands of the receptor, so they allow for different shaped molecules to bind. The "perfect" agonist may cause very little straining or movement of the chemical bonds of the amino residues.


When binding occurs, as can be imagined, the 3D shape of the binding molecule is critical if a particular desired effect is to be achieved. The enantiomers (non-superimposable isomers) are very different to each other in this regard. While the S isomer may bind easily with minimal receptor conformation (movement) required, the R may be a different story altogether. It may not even bind at all. Lets say it does.

Inside the cell another series of events occurs that results in secondary actions. The "easy fit" isomer may invoke a much greater secondary response in that cell. The awkward fit may not create much at all. Secondary actions can affect other receptors on the cell membrane, particulary ion channels where a + or - effect can occur which alters the excitability of the cell, which in turn can cause a cascading effect. Binding can also activate enzymes present on the cell membrane.

As mentioned, some molecules may bind very well, but don't create any secondary actions. These compounds are known as antagonists, and essentially - if binding is more energetically favorable- will "turn off" the receptor while the drug is binding. Sometimes this is a temporary thing; i.e. the molecules leaves things as it found them. Other antagonists will irreversibly bind. This may reduce normal (unbinded state) actions of the cell.

Psychological effects are mostly manifestations of the secondary actions. So while one isomer causes a myriad of cascading reactions resulting in =D, the opposite isomer may only cause a :( response.

Hope this is of some help. You may find a better explanation in the Advanced Drug Discussion forum
 

BongoBongo

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Very well done Phaser..

Thank you for your time and explaination!!!!
 

bill joe

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phase_dancer said:
Two types of isomer are relative to MDMA and amphetamine/ meth.

R and S represent absolute configuration; where the order of placement of attached groups on a chiral carbon determines assignment.

D and L are optical isomers. Assignment is given depending upon how polarized light is deflected. i.e. is the deflection positive ((+) dextrorotatory) or negative ((-) levorotatory)

Optical isomers are NOT related to absolute configuration, but often an L will also happen to be an R (-), and a D an S (+).

Simply put, Isomers are different 3D representations of the same molecule. In these examples, D and L are like right and left feet (but with toes in odd positions that can't be superimposed on the opposite foot)

If The Shoe Fits...


It not a perfect analogy but in regards to receptor binding, think of it as being like a Right foot fitting a Right shoe.

The receptor that the drug is to bind with is a bit like the shoe, and the meth like the foot. Try putting a perfectly fitting left shoe on a right foot. It might fit with a struggle, but it's definitely not as easy a fit as the right shoe is.

Your receptors (and many enzymes and other bio-molecules) are also like the shoe. A molecule shaped correctly will fit in with ease, with the "toes" sitting nicely in their respective spaces. The opposite foot might go in, but toes are squashed up in places and loosely bound in others. It also usually takes some effort to squeeze on the boot (more energy)

Most biological processes including receptor docking, binding etc are energy efficient processes. If it don't fit properly in one place, then it might 'look' around for something else. In the case of L and D meth, D has a "best fit" with NE and DA target receptors. Enzymes pick up most of the non-bound L meth and metabolize it into hydroxyl (OH) substituted compounds which enable further metabolism or faster elimination.

D meth on the other hand spends quite a bit of time intimately associated with the receptors, chatting away and stimulating much gossip (secondary actions). Eventually the "janitor" enzymes come along and pick up the D meth, where its then carried through a similar process to that of the L. *

Some L meth will bind with receptors, although as mentioned it's hardly the snug fit D produces. However, the binding is an on again - off again relationship, so it's usually picked up by enzymes when "off again" D meth on the other hand may bind (on and off) for much longer, as the fit is more energy efficient. Sometimes the opposite isomer may bind as effectively, but causes little or no secondary actions.


Please note this is a very simple analogy. There are other things happening which don't necessarily apply to this model.


*Note: This a very simple and partly inaccurate model. Different isomers may be metabolized via completely different routes or via different intermediates.
I've done a bit of chem so i already knew bout d and l isomers, not nearly the level your at though. Im so impressed how you can put it so easily in lamens terms, good job as asways.
 
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