The next step is to form 1,2,3-Benzotriazin-4(3H)-one-14C (compound 4). In water dissolved sodium nitrite is added to anthranilamide and hydrochloric acid in ice water. Because this is a diazotization reaction, the product is pale-yellow again. After this the pH is adjusted to 8,5. This causes the ring closure to form 1,2,3-Benzotriazin-4(3H)-one-14C. This results in a sodium salt slurry that can be treated with hydrochloric acid, what lowers the pH down to 2 till 4. The 1,2,3-Benzotriazin-4(3H)-one-14C is collected, washed and dried.