From Amino Alcohol to Aziridine in 15 weeks flat.
Like I said previously, our goal was to synthesize aziridine using a new method. We hoped that the new method would be simpler, easier to accomplish and also take less time.
We began the process by synthesizing aziridine using a traditional method that has been shown to work well in practice. This gave us a starting point to work with and something to compare the products of our subsequent experiments with. As expected, this synthesis worked out well and we got a little bit of product. Sadly, we threw out some of our product thinking that it was leftover from the reactant mixture so we did not weigh our product or calculate a percent yield.
Our first attempt at synthesizing aziridine using the new one pot reaction method proved unsuccessful. The reactant mixture was supposed to stir for 24 hours, then after some purifying steps the hope was that we would have plenty of product. This was not the case. After 24 hours we put the reaction vessel in the freezer and during the next lab period proceeded to purify our product. We took a mass spec and it showed that we apparently ended up not making product, so we decided that we would prepare the reaction again and let is stir for a week.
And so began attempt number two with the new reaction method. We again, prepared our one pot synthesis but this time let it stir for a week before purifying it. After this round, we ended up with no product reading in our mass spec yet again! But this time we decided to purify a small sample of our product using a microscale column. The authors of the paper we were following ran a column to purify their product so this made sense to us and it would take less time than running a full column.
From this purification we collected about 15 fractions. To see which fraction absorbed in the ultraviolet region we spotted each and looked at them under a black light. Only five of the samples absorbed in the ultraviolet region so we ran a TLC on those samples against aziridine in the hope that we would find our product in one of our fractions. Based on a mass spec of one of the fractions, we thought that one of those fractions looked like our product so we chose to run a second microscale column on that sample. This time we collected and spotted ten fractions, hoping to find one that had aziridine in it. Sadly we did not.
So with little time remaining we decided to try the experiment one last time, hoping that wecould be more accurate with our preparation and finally make our product. This time we let the reaction stir for four days before we took the steps to purify our product. After purification and a first mass spec it looked like we still didn't have any product. But thankfully we finally had a little bit of luck! Dr. Lieberman ran one last mass spec on a more concentrated sample of ours in the hope that we would find aziridine in our product. And this time, we did! So after fifteen weeks we managed to make trace amounts of aziridine using the new method to synthesize it in one reaction vessel.
The author's of the paper we followed for the new method of aziridine synthesis reported a 90% yield. We got nothing of the sort but we did get some yield! In the end we were able to take something we knew worked, the original synthesis, and change the process in the hope that we could still get product. We learned firsthand that good paper chemistry doesn't always turn into practical lab chemistry but we had a great time doing it!
The paper we based our new synthesis of aziridine off of can be found on the second tab under this experience.
We began the process by synthesizing aziridine using a traditional method that has been shown to work well in practice. This gave us a starting point to work with and something to compare the products of our subsequent experiments with. As expected, this synthesis worked out well and we got a little bit of product. Sadly, we threw out some of our product thinking that it was leftover from the reactant mixture so we did not weigh our product or calculate a percent yield.
Our first attempt at synthesizing aziridine using the new one pot reaction method proved unsuccessful. The reactant mixture was supposed to stir for 24 hours, then after some purifying steps the hope was that we would have plenty of product. This was not the case. After 24 hours we put the reaction vessel in the freezer and during the next lab period proceeded to purify our product. We took a mass spec and it showed that we apparently ended up not making product, so we decided that we would prepare the reaction again and let is stir for a week.
And so began attempt number two with the new reaction method. We again, prepared our one pot synthesis but this time let it stir for a week before purifying it. After this round, we ended up with no product reading in our mass spec yet again! But this time we decided to purify a small sample of our product using a microscale column. The authors of the paper we were following ran a column to purify their product so this made sense to us and it would take less time than running a full column.
From this purification we collected about 15 fractions. To see which fraction absorbed in the ultraviolet region we spotted each and looked at them under a black light. Only five of the samples absorbed in the ultraviolet region so we ran a TLC on those samples against aziridine in the hope that we would find our product in one of our fractions. Based on a mass spec of one of the fractions, we thought that one of those fractions looked like our product so we chose to run a second microscale column on that sample. This time we collected and spotted ten fractions, hoping to find one that had aziridine in it. Sadly we did not.
So with little time remaining we decided to try the experiment one last time, hoping that wecould be more accurate with our preparation and finally make our product. This time we let the reaction stir for four days before we took the steps to purify our product. After purification and a first mass spec it looked like we still didn't have any product. But thankfully we finally had a little bit of luck! Dr. Lieberman ran one last mass spec on a more concentrated sample of ours in the hope that we would find aziridine in our product. And this time, we did! So after fifteen weeks we managed to make trace amounts of aziridine using the new method to synthesize it in one reaction vessel.
The author's of the paper we followed for the new method of aziridine synthesis reported a 90% yield. We got nothing of the sort but we did get some yield! In the end we were able to take something we knew worked, the original synthesis, and change the process in the hope that we could still get product. We learned firsthand that good paper chemistry doesn't always turn into practical lab chemistry but we had a great time doing it!
The paper we based our new synthesis of aziridine off of can be found on the second tab under this experience.