4-Dimethylaminobut-2-ynoic Acid Hydrochloride, is used as a reactant in the synthesis of quinazoline derivatives such as (2Z)-Afatinib (A355305) which may be used in the treatment of some cancers. Molecular Formula: C6H9NO2 ?HCl Solubility: DMSO (Slightly), Methanol (Slightly) Molecular Weight: 127.143646