Quinazoline derivatives and their pharmaceutically acceptable acid addition salts having the general formula ##STR1## wherein R.sup.1 and R.sup.2 each represents hydrogen or alkyl; R.sup.3 represents alkyl or substituted alkyl; R.sup.7 and R.sup.8 each represent alkoxy; Z is oxygen or sulfur; m is zero or 1; n is zero or an integer from 1 to 5, exhibit a cardiotonic activity with little tendency to cause tachycardia.
喹唑啉衍
生物及其药学上可接受的酸加成盐,其具有一般式##STR1##其中R1和R2均代表氢或烷基;R3代表烷基或取代烷基;R7和R8均代表烷氧基;Z为氧或
硫;m为零或1;n为零或1至5的整数,表现出心脏强心活性,且很少引起心动过速的倾向。