Five days later.
Fourth floor of the Medical Center Building at the University of Science and Technology.
At this moment, Xu Yun was standing on the operating table wearing a pure cotton lab coat, with six men and women of different heights standing in front of him.
"Now that everyone is here, let me briefly explain the project... Ahem, say a few words."
Xu Yun raised a stack of bound documents in his hand and quickly scanned the people in front of him.
A quick look at tinyurl.com/2p9emv8w will leave you more fulfilled.
"I received the project approval notice yesterday morning. Now we have all the procedures, facilities, and personnel in place, so our project team is officially established.
Our project team doesn't have a mentor leading us. I am the applicant and the primary person in charge. The laboratory will be available for two weeks, and the research records will be registered in your files. Regardless of the results, it will be considered a decent experience for all of you, which should be helpful in the future."
Upon hearing this, two of the six people in front of him couldn't help but show a hint of uncontrollable joy on their faces.
As one of the C9 members, the University of Science and Technology had an annual research and development budget of over ten billion yuan, which was among the top universities in the country.
Although this number seemed large, after deducting a series of projects such as the 973 Program, the 863 Program, the National Science and Technology Support Program, and the International Science and Technology Cooperation and Exchange Program, the funding and quotas allocated to each department were not as substantial as they seemed.
After being divided by some big shots, there was still some funding left, but there were not many high-quality project opportunities available.
Many graduate students worked for one or two semesters and still couldn't get involved in major projects. They could only silently serve their mentors like donkeys.
Therefore, when Xu Yun came to Tian Liangwei with the approval letter for the supplementary project, several struggling graduate students immediately nodded their heads. The shock frequency was like a massage stick. It was almost as if Xu Yun was saying that Chinese people don't deceive Chinese people.
To be frank, participating in a project of this level, regardless of whether there would be any results in the end, when applying for salary after graduation, they could demand at least an additional five hundred yuan per month!
Then Xu Yun paused and continued:
"The goal of our project is simple. We will attempt to synthesize a new substance by combining pheromones and the third-generation pyrethroid, in order to explore the direction of the fourth-generation pyrethroid. The ultimate goal is..."
Before he could finish his sentence, the several junior and senior students shouted in unison:
"Eradicate cockroaches!"
After speaking, everyone burst into laughter.
In the midst of laughter, a girl with short hair raised her hand and curiously asked Xu Yun, "Senior, why do you have such a strong resentment towards cockroaches?"
Xu Yun glanced at her lightly. This girl was called Tang Yiqiu, a senior student with good academic performance and reputation.
"...To me, it's a sad story, but telling it will make you all happy, so I refuse to answer."
After speaking, he raised the documents in his hand, and the pages rustled in the air.
"Alright, enough chit-chat. We have limited time. Everyone, check your gas masks and organic vapor cartridges, and put on your protective gowns. We will start the experiment in fifteen minutes!"
Then he glanced at Qiu Sheng:
"Lao Qiu, check the machines and circuit breakers. I will distribute the materials."
Qiu Sheng nodded:
"Understood."
Fifteen minutes later, everything was ready.
Xu Yun and the others' main experimental reagents this time included 2-phenylpyridine, 4-hydroxymethylphenylboronic acid, 2-naphthylboronic acid, 3-furanboronic acid, 3-benzothiopheneboronic acid, N-phenylpyrazole, benzoquinoline, [Ru(p-cymene)2Cl2], and so on.
In addition, there were more than thirty other reagents, including 2-bromopyridine, 2-bromo-4-chloropyridine, THF, DMF (N,N-dimethylformamide), DMSO, and 1,4-dioxane. (I have written the details in the author's note.)
At the same time, the others also took their positions one by one.
"To convert pheromones into pyrethroids, we need to first cyclize the CH3 ring. I plan to complete this through the hydrogenation reduction reaction of epoxy acetylene and 1-bromo-2-pentyne."
On the operating table, Xu Yun explained his thoughts while speaking to a tool... no, a junior student:
"Li Yi, I'm assigning this task to you."
"Understood!"
Li Yi, mentioned by Xu Yun, was a graduate student, 24 years old this year, with a buzz cut. Upon hearing this, he immediately started the operation.
At the same time, Xu Yun looked at Tang Yiqiu:
"Xiao Tang, you will be in charge of following up and trying to capture the optically active segment of epoxy sulfonic ester!"
"Understood!"
As everyone knew, under the catalysis of L-(+)-diisopropyl tartrate and tetraisopropyl titanate, allylic alcohol would undergo the Sharpless asymmetric epoxidation reaction, resulting in (2S,3R)-2,3-epoxy-1-tetradecanol.
Epoxy alcohol (2S,3R)-9, after being sulfonylated with toluenesulfonyl chloride and opened with high chloric acid, the absolute configuration of the third carbon atom would be reversed from R to S, resulting in (2S,3S)-tosyl-2,3-dihydroxy-1-tetradecanol ester. Then, by cyclizing with potassium carbonate and sulfonylation with toluenesulfonyl chloride, (2S,3S)-tosyl-1,2-epoxy-3-tetradecanol ester could be obtained, with a yield of up to 89%.
It was very simple and easy to understand.
A few minutes later, Tang Yiqiu raised her hand again, but this time she didn't ask why Xu Yun wanted to eradicate cockroaches:
"Senior, I have captured the epoxy sulfonic ester!"
"Good, what is the ee value?"
"It's still being determined... The epoxy alcohol and 2,4-dinitrobenzoyl chloride are still reacting... Oh, it's done. It's 93%!"
Upon hearing this, Xu Yun couldn't help but breathe a sigh of relief.The so-called ee value refers to the excess of enantiomers. The theoretical ee value of the hand-shaped epoxy sulfonic ester is 90%. The 93% measured by Xiao Tang is above the standard, which is considered a successful first small step.
Having completed the synthesis of the key optically active intermediate, the next step is to study the asymmetric synthesis of the target pheromone.
This step involves reacting the epoxy sulfonic ester with trimethylsilylacetylene to cause epoxy ring opening, then treating with potassium carbonate for ring closure and TMS removal, to produce (4S,5R)-4,5-epoxy-1-hexadecyne. The yield of this step is...
60%.
Yes, the first step is 89%, the second step is 60%.
Almost halved yield.
This is a very common situation in biochemistry. The further you go, the lower the yield, from 90% to 60%, then to 30%.
After seven or eight cycles, the yield of non-standard compounds may even be in single digits.
So why is it said that scientific research burns money? Just in the ten minutes that Xu Yun and his team started, including machine wear and tear, at least 1,000 yuan has been spent, which is a whole alliance leader.
The preparation of 5-epoxy-1-hexadecyne went smoothly. Just as Xu Yun and his team were preparing to take another step forward...
Suddenly, another graduate student responsible for nucleophilic substitution let out a sigh and said:
"Senior, the nucleophilic substitution reaction failed..."