Abstract: Disclosed are a benzonitric heterocyclic compound, a preparation method therefor and the use thereof. Provided in the present invention is a benzonitric heterocyclic compound represented by formula I, or a pharmaceutically acceptable salt thereof, which can be used as a histone deacetylase inhibitor, has a selective inhibitory effect on HDAC6, and has characteristics such as a high efficiency, low toxicity and ideal pharmacokinetic properties.

Abstract: At least one active pharmaceutical ingredient is chosen from polycyclic quinazolines of formula V, pharmaceutically acceptable salts thereof, and hydrates of the pharmaceutically acceptable salts. The active pharmaceutical ingredients disclosed may be inhibitors of protein tyrosine kinase inhibitors and/or aurora kinase. The active pharmaceutical ingredients can be used for treating cancers susceptible to treatment with protein tyrosine kinase inhibitors and/or aurora kinase inhibitors.