Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

These compounds react with pyridine and 2,4-dinitro-chlorobenzene in the Zincke reaction. The first step of the Mannich reaction reacts formaldehyde with one of them, and the degree of these compounds is determined by reacting them with benzyl sulfonyl chloride in the Hinsberg test. The Ing-Manske reaction is one variant on a method for producing them which generally uses potassium phthalamide and alkyl halides; that is the Gabriel synthesis. Biological examples of them include alkaloids and norepinephrine, as well as aniline. For ten points, name these functional groups which contain a basic nitrogen atom with a lone pair of electrons, generally derived from ammonia.
Science