Chemistry help here

[Jetset]

I found this stuff DL-MBDB:HCL = C12H17NO2•HCl 1.0 MG/ML IN METHANOL and was wondering how close this stuff is to just plane MBDB = C12H17NO2.


Also this chemical DL-MDEA = C12H17NO2 1000 UG/ML IN METHANOL and was wondering how close this stuff is to just plane MDEA =3,4-metilenedioxi-n-etilanfetamina


Any chemistry buffs knowledge is greatly appreciated

[Alfa]

If I remember right DL-MBDB is just MBDB. DL-MDEA is just MDEA. Every substance has a D and a L isomer, also called S or R isomer, which means the molecule is either twisted to the left side or right side. It makes a difference in effect. For example S-MDMA is mainly stimulating, while R-MDMA is mainly euphoric. With most amphetamines the S isomers are more active. I am amazed that practicly nobodytalks aboutthis very important distinction.

[Kemikaru_Tenshu]

Alfa is mostly correct with one exception. Optical isomers are the result of the absence of planar symmetry in the molecule. For this reason only asymmetric molecules (chiral molecules) have optical isomers. Molecules without a chiral center by definition have no optical activity.


When both the D and L are present in the description the compound is a racemic mixture (or racemate)of the two isomers, meaning that they are both present in the solution in an even amount. This leaves the solution as a whole not optically active, even though it consists of optically active constituents.


~KT

[Alfa]

Can you please explain why the presence of both optical isomers in a mixture leaves the solution as not optically active? What effect does this have pharmacologically?


Can you say that the effects of D-PA plus L-PA equal the effects of DL-PA or is it a one plus one is three situation?

[Kemikaru_Tenshu]

When a substance is in a solution which is homogeneous, the distribution of the solutes (in this case the d and l isomers) is even throughout. As each of the isomers rotates a plane of polarized light to a certain degree in polar opposite directions, the effects cancel each other out and the solution is no longer optically active. This itself has no effect on the pharmacology, and does not change either of the isomers in any way. It's just a property of racemate solutions.


Where you run into problems is as follows: if only one of the isomers is pharmacologically active (or if only one has DESIRED pharmacological activity) it is possible that the other can act as a competitive inhibitor. What this means is that if a racemic mixture is ingested, the two molecules compete for available receptors and only one of every two receptors on average will receive the necessary input required for the desired activation. While in the best case this means that you’re only getting half the effect from the administered dose, in some cases the other isomer may cause undesirable effects. This in a sense will change the results of the experience as a whole. Also, in some cases the isomer with the undesirable characteristics may have a greater receptor affinity, and will spend more time at the receptor than the "good" isomer. This, as I'm sure you can see, causes even more problems.


I'm guessing by PA you mean phenylalanine, in this case dl-PA would mean the same thing as saying "an equimolar mixture of both d-Phenylalanine and l-Phenylalanine". Whenever you see a DL in from of something it just means that it's a racemic mixture of the two isomers.





~KT

[Jetset]

Damn I am glad I have made such good friends here, It just blows it for forensics though.

[Alfa]

You might want to explain what you mean so others understand as well Jetset.


TK: Thanks for the mental uplifting.

[thadj]

What I's like to add is that it seems to me that it's not very likely that for instance some D-phenethylamine will have greater affinity for the same receptor as the corresponding L-phenehtylamine binds to. It just doesnt seem logical to me that a mirror image could have higher affinity to the same receptor. More likely is for instance that 1 molecule binds which great affection to some serotonin-subreceptor, causing psychotomimmetic effect, while the mirror-molecule binds with less affinity to this receptor and with great affinity to some adrenergic receptor, causing unwanted overstimulating effects.



Kemikaru-Tenshu, do you have any references to back up this theory about competiting enantionmeres?

[Kemikaru_Tenshu]

^^If you look at what you just said you will see that you ARE thinking along the same lines. In your example, the fact that the chemical's mirror image has a greater affinity for the adrenergic receptor than its counterpart causing unwanted side effects, such as over stimulation, is a good example of exactly what I was talking about.


Most chemicals interact at more than one type of receptor, and the slight differences in their structures causes them to have a greater of lesser affinity for certain receptors. This is why some chemicals with so little difference in their structures can have such different effects.
I don’t have any references off hand, although I’m sure I could dig some up. I’m pretty sure there is a study out there on receptor affinity of synthetic opiates that covers this in detail. I can take a look through this mess on my computer if you’d like.

~KT

[thadj]

Well what got my attention is this line you wrote:



"Where you run into problems is as follows: if only one of the isomers is pharmacologically active (or if only one has DESIRED pharmacological activity) it is possible that the other can act as a competitive inhibitor."



As I see it you are saying that 1 isomer is an agonist (causing the desired effect), while the other isomer is a competitive antagonist. I find it quite hard to believe that two mirror images act on the same receptor but in opposite ways..



Im interested in studies covering this, but if its a lot of work for you, dont bother, I could look into it myself.



Kind regards

[Kemikaru_Tenshu]

Here's one page. It's not the best, but if I come accross that opiate study I'll post it too.


http://www.australianprescriber.com/...49_isomers.htm

The so-called inactive enantiomer (one that has much less affinity for the drug's target site) is not necessarily an inert substance with no effects in vivo. For example, the cardiotoxicity of bupivacaine is mainly associated with the (R)-enantiomer, the psychomimetic effects of ketamine are more associated with the (R)-enantiomer, and (S)-baclofen antagonises the effects of (R)-baclofen. The beneficial effects of a drug can therefore reside in one enantiomer, with its paired enantiomer having:
no activity
some activity
antagonist activity against the active enantiomer
completely separate beneficial or adverse activity from the active enantiomer.

Hope this helps.

~KT

[thadj]

Interesting, thanks

[Jetset]

Sorry been away for a while. I found a site that sells these items but they are listed for forensics reasearch. I did ga as far as adding the items to a shopping cart but I stopped till I could get a better understanding of what this site was and what could happen. They did not ask for any ID or anything of such other than a business name and all. But i guess it is closely watched site. Don't be fooled all.

[pancho]

sorry this is off subject but you know all of you are extremely smart as hell. I was reading this and i pick up some of whats going on but half of it jus flew by me. where did you learn this stuff, like at college or you research chemistry???I want to learn about how drugs workso i've been tryin to learn about that stuff. i learned all i know through readin text books at the library.

[Kemikaru_Tenshu]

^^^I research chemistry, and I go to college for chemistry. Here's what I recommend:

• Introduction to Medicinal Chemistry : How Drugs Act and Why ISBN: 0471185450
• Foye's Principles of Medicinal Chemistry ISBN: 0683307371
• Burger's Medicinal Chemistry and Drug Discovery, Volume 1 ISBN: 0471575569
• Burger's Medicinal Chemistry and Drug Discovery, Volume3 ISBN: 0471575585

Those suggestions are also in the order in which you should tackle them. The first is a good general overview, and has some cool information about opiate agonists/antagonists including a section on the drug etorphine (check this out for some basic info on etorphine http://opioids.com/etorphine/immobilon.html ) in addition to the basics of "how drugs act and why".
The second is arguably the best textbook for a 2 or 3 semester introductory and intermediate treatment of drug discovery and pharmacodynamics.
The third and fourth are two volumes in a five volume set of an advanced study of medicinal chemistry. The first volume provides the basis for the approach to individual drug types taken in the next four volumes. The third volume in the series is the one which focuses on a lot of the drug classes that are of interest to us as recreational drug users and chemists. These include anesthetics, sedatives and hypnotics, and analgesics. I'm in the process of making my way through the last two currently and I guarantee that they are VERY interesting but also VERY technical.
These four should keep you busy for a long while. Let me know what you think when you have a chance to check them out.

~KT

[pancho]

arebasic chemistryclass's what you want to take or do you have to take specific ones and are they availible at most colleges, or do you have to go to one specifically for chemistry. thanks for the resourse's

[Kemikaru_Tenshu]

^^^^You will need to take basic chemistry classes first in order to understand the more complicated material. For example; if you don't understand hydrogen bonding, dipole-induced dipole attractions, and dispersion forces, you won't understand receptor affinity. The subtleties of structural differencesand their correspondence to increased/decreased activity at a sight will hinge on your understanding of molecular orbitals. The lower chemistry sequence, general chem I & II and organic chem I & II, will give you the firm basis you will need to understand these in depth topics. These classes should be available at any technical school, college, or university. The classes which deal with this material specifically are medicinal chemistry classes and pharmacology classes which are first through third year medical school classes (not premed) and first through fourth year pharmacology classes. These aren't as widely available and most are only open to those accepted into the major. For these you may have to learn from a book. I do this for the higher level ones, as I plan to be an organic chemist and not a medical doctor.

~KT

[TheLight01]

Well what i want to know is if i have some DL-Methylone for example.. is this equally active as D-Methylone or L-Methylone?
and say that someone orders methylone from a online supplier what for is that? is that D- orL- or DL-Methylone ?

Thanks!

[Alfa]

Methylone has only one isomer. It is the purity i.e. which by-products the substance contains what matters. Cheap routes of production normally tend to yield high levels of unwanted metals.

[robertone]

Swim disagree!




Both the alpha and the beta are asymetric atoms and therefor methylone has 4 possible optical isomers:

• (L)-(+)-Methylone
• (L)-(-)-Methylone
• (D)-(+)-Methylone
• (D)-(-)-Methylone

Depending on the synthetic root there will be 2 or 4 of the optical isomers present in the racemic methylone.
Unless tidy-some separated of course

[Alfa]

I may have been misinformed by several chemists. I'd welcome more views on this.

[Nagognog2]

Interesting. Any idea how to prove this and separate the racemates? Gel electrophoresis?

[robertone]

Originally Posted by Nagognog2

Interesting. Any idea how to prove this and separate the racemates? Gel electrophoresis?

Swim has to guess, but is sure that Nagognog2 is a skilled chemist. Swim doesn't know much about electrophorese but for analitical purposes chiral chromatography can be used if there's a proper chiral gel available. Swim propose to try a classical separation by recrystalise their diastereomers. Switip can take a look at the separation of racemic ephedrine, which is well known and documented!

Swim would like to know the physical and psychotropic proportions of the pure enantiomers too and of indeed all four stereoisomers comes out in equal quantity!

[robertone]

To answer some questions Swim saw in several occasions.

In chemistry, a racemate is a mixture of equal amounts of left- and right-handed stereoisomers of a chiral molecule. Because the two isomers rotate plane-polarised light (they are optically active) in opposite directions, a racemic mixture does not rotate plane-polarised light. The first known racemic mixture was 'racemic acid', which Pasteur found to be a mixture of the two enantiomeric isomers of tartaric acid. For more see wikipedia's "Racemic page"

For a more enhenced explanation about optical isomers see Wikipedia's "Optical isomerism page". A must read to know the difference between (+/-)-, D/L- and R/S- naming system.

An other must read in this matter is Wikipedia's "Isomer page". Really needed to understand what isomers actually are and to obtain a better understanding about the difference between isomer and optical isomer as well a basic about cis/trans- isomers (think about cis-isosafrol and trans-isosafrol).

[glorf]

there is no chance in hell of getting optically active acetone or any other C=O carbon, not until carbon starts having 5 or more bonds.

there are only two isomers of methylone.

and so of course oxidation of either (-)ephedrine or (+)pseudoephedrine gives a single product, (-)methcathinone.