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盐,其一般式为##STR1## 其中R.sup.1和R.sup.2分别代表氢或烷基;R.sup.3代表烷基或取代烷基;R.sup.7和R.sup.8各代表烷氧基;Z为氧或
硫;m为零或1;n为零或1至5的整数,表现出心力增强活性,且很少引起心动过速。