Desperate people, accept the seed of my soul!

Jiang Yubai began to retrieve the molecular formula of the first segment of Shen Yanhui's synthesis route on the portable workstation.

Shen Yanhui's synthesis route is divided into three stages.

The first stage is the synthesis of basic precursors, which requires starting with simple aromatic compounds and constructing the core framework through three steps: nitration, reduction, and acetylation.

The second stage is the introduction of active groups, which requires the insertion of chiral epoxy groups at specific sites on the core skeleton. This step requires extremely high control over temperature and pH, as the slightest mistake can lead to ring-opening of the epoxy groups.

The third stage is the modification of the final product, which requires linking the intermediate obtained in the second stage with another branch chain through a amide bond to finally obtain the target molecule.

Shen Yanhui marked "My Habits" next to each reaction condition with a blue ballpoint pen—she was used to using an ice-salt bath for cooling instead of liquid nitrogen, potassium carbonate as an acid-binding agent instead of triethylamine, and silica gel column chromatography instead of recrystallization in the final purification step.

These habits were personal experiences she had accumulated over six years of synthetic work, and were not included in her formal report to the Five Mountains Society.

Only those who have been in the same group can understand it.

Jiang Yubai looked down at each item one by one, muttering to himself.

"For the nitration step, she uses mixed acid, and the temperature needs to be controlled at minus five degrees Celsius. An ice-salt bath can reach this temperature, but salt has to be added continuously—she said she doesn't like liquid nitrogen because it's too cold and slows down the reaction."

"For the reduction step, she used zinc powder and ammonium chloride. She didn't use palladium on carbon—the palladium on carbon catalyst provided by the Five Mountains Association wasn't pure enough, and she said she had to fry it every time she used it."

"She used dichloromethane as a solvent for the acetylation step. Chloroform didn't work; she said she tried it, and the yield was only 40%."

Shen Hanzhou sat beside Jiang Yubai, listening as Jiang Yubai deciphered his senior's handwritten notes line by line.

He studied the handwriting in these notes for six years, and he knew every chemical formula by heart.

But he had never really understood those "my habits" annotations in the synthesis route before.

When Shen Yanhui was alive, he would just organize the chromatograms and occasionally hand her reagents.

She says what temperature, and we use whatever temperature; she says what base, and we use whatever base.

He never asked why.

Now that his senior sister is dead, he listened to Jiang Yubai explain the reasons behind those "habits" one by one, and finally understood what his senior sister was doing those nights when she worked overtime in front of the fume hood until the early hours of the morning.

She used her six years of accumulated experience to combat the inferior reagents, inaccurate temperature control equipment, and incorrect synthesis parameters that were modified three times by the Five Mountains Association.

She knew that Wuyue would give her incorrect parameters, but she still wrote down the real correct parameters in each experimental record.

Then he turned off the lights in the fume hood and stood in front of the lab bench writing until 2 a.m.

She wiped away tears as she wrote.

"You just said that you were working on chromatograms the week before she died."

Jiang Yubai, without looking up, said, "You replied with 'I know,' thinking she would continue talking to you. But she didn't."

"She didn't."

Shen Hanzhou said the voice was very calm. "She turned off the light in the fume hood and stood in front of the lab bench writing something. I thought it was experimental records, so I didn't go over to look. The next morning, her workstation was empty, and the security team informed me that she had died accidentally due to an operational error. When I arrived at the autopsy room, she had already been sealed in a body bag."

"You saw the unfinished character for 'escape' under her fingernail."

"I saw it."

Shen Hanzhou said, "I took her hand out of the body bag, and there were paint chips from the edge of the dissection table under her fingernails. The first joint of her right index finger had the radical '辶' written on it, and the second joint broke off right at the beginning of the stroke. I recognized that character—when she wrote the character '逃' (escape), the '辶' radical would hook upwards, unlike when she wrote the character '送' (send).

Jiang Yubai stopped pointing.

The molecular formula editor on the screen is paused on the transition state model of the first-stage nitration reaction.

She paused for three seconds, then took a deep breath and continued swiping her finger across the screen.

"Then let her finish writing that one word she didn't complete, and we'll finish it for her."

She said, "Let's do nitration first."

Jiang Yubai rummaged through the pile of reagents left behind by Chiji and found some still usable nitric acid and sulfuric acid.

The label on the nitric acid bottle was mostly corroded, but the bottle itself was intact and had no cracks.

She used a graduated cylinder to precisely measure the mixed acid ratio, her hand was very steady, and the scale was read to one decimal place.

"An ice salt bath. Minus five degrees Celsius. She prefers to use coarse salt, not fine salt—coarse salt absorbs heat more evenly when dissolved."

Shen Hanzhou found the bag of coarse salt left behind by Chiji in the corner of the factory. The plastic bag was brittle and would break at the slightest touch.

He poured coarse salt into the ice water bath, stirred it with a glass rod, and the mercury column in the thermometer slowly dropped to minus five degrees Celsius.

Jiang Yubai placed the reaction flask into the ice-salt bath and began adding mixed acid dropwise.

Her hands were as steady as if she were operating a precision balance; every drop of mixed acid flowed down the inner wall of the reaction flask without splashing onto the wall.

The reaction solution changed from colorless to pale yellow, and then to dark yellow.

The thermometer remained at -5 degrees Celsius.

"Her experimental record states that the nitration step takes forty minutes and yields 82 percent."

Jiang Yubai said that she kept her eyes on the color changes in the reaction flask, "but forty minutes is an average value—when the room temperature is above 25 degrees Celsius, it should be shortened to 35 minutes, and when it is below 15 degrees Celsius, it should be extended to 45 minutes. She did not write it into the formal report, but only marked it in the footnote with a line 'adjust according to room temperature'."

What's the room temperature today?

"It's about 18 degrees Celsius inside the factory. We'll have to extend it to 45 minutes."

The nitration reaction was completed after 45 minutes.

The reaction solution changed from deep yellow to orange-red, and a layer of light yellow needle-like crystals precipitated at the bottom.

Jiang Yubai was filtered using a Buchner funnel, and the crystals formed a uniform layer of light yellow solid on the filter paper.

"Nitration products. The yield is estimated to be over 80%."

She transferred the crystals on the filter paper to the desiccator and wrote the first line of data in her lab notebook: "Step one complete. Next is reduction—zinc powder and ammonium chloride. She said she doesn't use palladium on carbon because the palladium on carbon catalyst provided by Wuyue Association is not pure enough and contains too much sulfur impurities, which will produce hydrogen sulfide as a byproduct when adding hydrogen."

"She told me."

Shen Hanzhou said, "Once, when she was using palladium on carbon for reduction, a rotten egg smell suddenly came out of the reaction flask, and the entire fume hood had to be cleaned. Since then, she has only used zinc powder."

"Did she tell you that she has to use freshly ground zinc powder? Commercially available zinc powder has too coarse a particle size, insufficient surface area, and slow reaction. She grinds it herself before each use."

Shen Hanzhou paused for a moment in silence.

No. She didn't say.

"Then I'll tell you now."

Jiang Yubai found a bottle of zinc powder in the pile of reagents; the label read "200 mesh".

She looked at the particles at the bottom of the bottle, shook the bottle, and the powder clumped together at the bottom.

"It's clumped together. It needs to be ground again."

She found the agate mortar left by Chiji in the drawer of the lab bench, poured in the clumps of zinc powder, and began grinding it in circles.