Tertiary amines, carboxylic acids and alcohols (especially phenols) are effective accelerators. Organic compounds are classified according to functional groups, alcohols, carboxylic acids, amines, etc. Common substrates for proton abstraction are alcohols, phenols, amines, and carbon acids. With good nucleophiles such as thiols, amines, and even amides, no acid catalyst is required. Ethers and tertiary amines are typically employed. It reduces quaternary ammonium cations into the corresponding tertiary amines. Nitrosamines are carcinogenic compounds formed by the reaction of nitrites and amines. Typical Lewis bases are conventional amines such as ammonia and alkyl amines. Examples of nucleophiles are hydroxide ion, alkoxides, amines and halides. Alkenes can be prepared indirectly from alkyl amines. Cooking proteins at high temperature can lead to the formation of heterocyclic amines (HCAs). The molecule is one of the three isomeric amines of pyridine. Nitrosamines are produced by the reaction of nitrites and secondary amines. It is sometimes used in the synthesis of aryl amines. There is some flexibility in the conditions for conjugating NHS-esters to primary amines.