Writing Experimental Records in English: A Comprehensive Guide

Add Reagents

To a mixture (suspension / solution / slurry) of compound 12 (487 mg, 1 mmol) and o-phenylenediamine (948 mg, 6 mmol) in CH₂Cl₂ (15 ml) being cooled to 0℃ was added the DCC (226 mg, 1.1 mmol).

Anhydrous lithium iodide (1.38 g, 10.3 mmol) was added in five portions (dropwise / in one portion / in portions) to a stirred solution of compound 12 (10.90 g, 51.5 mmol) in CH₂Cl₂ (120 ml).

A round-bottom flask was charged with compound 3 (1.75 g, 5.27 mmol), LiCl (1.17 g, 26.3 mmol), DMSO (100 ml) and H₂O (378 µl).

Add in portions/portionwise

Add in one portion

Add dropwise

Catalytic Amount

Et₃N (20 mL, 142 mmol) and a catalytic amount of DMAP were added to the solution of compound 1 (4.549 g, 46.4 mmol) in CH₂Cl₂ (120 ml) at 0℃.

Gas Protection

To a stirred -78℃ solution of trimethylsilylacetylene (4.44g, 45.5 mmol) in THF (10 ml) under argon, n-butylithium (1.6M in hexane, 28.25 ml) was added dropwise.

Introduce Gas

An ozone-enriched stream of oxygen was bubbled through a cold (-78℃) solution of

compound 9 (128 mg, 1.409 mmol) in CH₂Cl₂ (5 ml) until it turned light blue. The

solution was purged with argon at -78℃ for 10 min to remove the excess O₃.

Feeding via Double-Needle Tube

The mixture was added to a solution of compound 2 (3.00 g, 12.8 mmol) in THF (48 ml) via cannula over a period of 30 min.

A solution of compound 29 (100 mg, 0.19 mmol, 1.0 equiv) in dry DMSO (1.5 ml) was cannulated under argon to a vigorously stirred mixture of powdered potassium

superoxide (62 mg, 0.87 mmol, 4.5 equiv) and 18-crown-6-ether (23 mg, 0.087 mmol, 0.45 equiv) in dry DMSO (0.5 ml).

Feeding via Syringe

To a stirred solution of compound 15 (8.61 g, 21.2 mmol) was added a solution of

p-toluenesulfonic acid (6.0 g) in CH₂Cl₂ via syringe over 5 min.

Control Reaction Temperature

A solution of compound 1 (10 g, 1 mol) in EtOAc (20 ml) was added dropwise (via addition funnel or syringe) to the above mixture at 10℃ (while maintaining gentle reflux; while keeping internal temperature between 10℃ – 30℃).