November 01, 2024, 08:22:24 AM
Forum Rules: Read This Before Posting


Topic: benzodiazepin decomposition  (Read 5235 times)

0 Members and 2 Guests are viewing this topic.

Offline jack2020

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
benzodiazepin decomposition
« on: March 09, 2014, 06:09:11 AM »
hi all
what makes benzodiazepins decomposition? does the 7 membered ring open in moisture or heat? and what is  the product of this decompoition?
thanks for your help

Offline billnotgatez

  • Global Moderator
  • Sr. Member
  • ***
  • Posts: 4428
  • Mole Snacks: +224/-62
  • Gender: Male
Re: benzodiazepin decomposition
« Reply #1 on: March 09, 2014, 06:26:10 AM »
Forum rules require you show some work
please read forum rules

Offline jack2020

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: benzodiazepin decomposition
« Reply #2 on: March 09, 2014, 06:50:36 AM »
Forum rules require you show some work
please read forum rules
ok, I tried to synthesize benzodiazepin, after reaction compelation the tlc showed only 2 spot, one of them was starting material and the other was more polar and showed flourcent (may be the product), we didn't have vacum in lab so I heated the mixture to evaporate the solvent, I dissolved the mixture in benzene and peterolieom ether and it was kept in refregerator after 2 days, the TLC showed 2 more spot (ie.4 spot in general) one of these 2 spots was unpolar and the other which was observed in visible region, was prevaded as the bottom of the TLC paper changed color to yellowafter a short time (10min)!!
now I am in doubt that what has happened?

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7367
  • Mole Snacks: +533/-147
Re: benzodiazepin decomposition
« Reply #3 on: March 09, 2014, 08:18:55 AM »
I think your initial conclusion, that the ring opened due to moisture or heat, is a fairly good one.  Can you write out a structure, that fits your observations, for us?  That is, you have the initial structure, the ring has been opened, and H2O has reacted .. how exactly, to produce what, that is more polar?  Specifically what will probably require a mass spec, or maybe even an NMR, but we don't do that for every failed synthesis.
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline jack2020

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: benzodiazepin decomposition
« Reply #4 on: March 09, 2014, 12:41:08 PM »
The product should be sth like diazepam, and can you suggest what is that spot in tlc which pervades or in general, which compounds can show a spot like this, unfortunately I don't have any spectrum at this stage

Offline Arkcon

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 7367
  • Mole Snacks: +533/-147
Re: benzodiazepin decomposition
« Reply #5 on: March 09, 2014, 03:12:29 PM »
OK, tey to be more clear when you write, so we can help, that is help ... you use most of your knowledge and we give hints, that's how this board works:

The product should be sth like diazepam,

That doesn't mean anything.  Check your spelling, and use the real word.

Quote
and can you suggest what is that spot in tlc

No.  I can't.  And I also don't want to do your work for you.  So no, I won't.

Quote
which pervades


per·vade:

verb

1.  (esp. of a smell) spread through and be perceived in every part of.

2.  to become diffused throughout every part of


Sorry, but this word you used is meaningless here.  Try again.  Ask what you want, so you can understand what you're asking for, and see if maybe you're asking for too much from us.

Quote
or in general, which compounds can show a spot like this
,

In general, no I can't do this.  There's nothing general about this reaction, and nothing specific about a particular spot.  If you've made the product, and you see its impure and you want to conclude that its decomposed, then you have to show how it happened.

Quote
unfortunately I don't have any spectrum at this stage

I figured.  So, why not begin this problem by drawing the structure of your desired product, and your possible contaminant?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Offline jack2020

  • Regular Member
  • ***
  • Posts: 10
  • Mole Snacks: +0/-0
Re: benzodiazepin decomposition
« Reply #6 on: March 09, 2014, 03:28:02 PM »
The product is diazepam http://en.wikipedia.org/wiki/Diazepam and the only thing that I guess is ring opening as impurities, I have found in internet that it has a balance with the opened ring form with water, (I mean water can open the ring), unfortunately I can't send attachment may be due to my browser problems,
also I do apologize for my poor English, in explanation about the spot, I meant the spots some how such as benzaldehyde which propagate (hope not to made mistake again) of course my spot (as impurity) propagates much more than benzaldehyde spot on TLC paper.
« Last Edit: March 09, 2014, 03:40:07 PM by jack2020 »

Offline zsinger

  • Full Member
  • ****
  • Posts: 374
  • Mole Snacks: +18/-60
  • Gender: Male
  • Graduate Chemist
Re: benzodiazepin decomposition
« Reply #7 on: March 16, 2014, 06:18:40 PM »
Jack,
While I am always happy to answer your questions, it appears to me that you are trying to synthesize/alter drugs of this sort.  You would not be asking some of these questions if you had the proper knowledge to manufacture them.  Not trying to sound snobby, nor am I saying that I do…..I just don't want to hear of any poisonings, deaths, or anything of the matter.  PM me if you would like to chatter privately.
                   -Zack
"The answer is of zero significance if one cannot distinctly arrive at said place with an explanation"

Sponsored Links