Quinazoiine derivatives and their pharmaceutically acceptable acid addition salts having the general formula
wherein
R1 and R2 each represents hydrogen or alkyl;
R3 represents alkyl or substituted alkyl;
R7 and R8 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具有通式,其中 R1 和 R2 分别代表氢或烷基;R3 代表烷基或取代的烷基;R7 和 R8 分别代表烷氧基;Z 为氧或
硫;m 为零或 1;n 为零或 1 至 5 的整数。