this disclosure concerns novel quinazoline compounds of formula as defined in the specification and compositions comprising such novel compounds . these compounds are useful anticancer agents , especially in inhibiting the function of the egf receptor tyrosine kinases , her1 tyrosine kinase , and her2 tyrosine kinase . thus , the disclosure also concerns a method of treating hyperproliferative diseases or conditions , such as various cancers and benign prostate hyperplasia , by use of these novel compounds or a composition comprising such novel compounds .