In this paper, we first show that the regular solutions of compressible Euler equations in<i>R</i><sup>3</sup>with damping will not be global if the initial density function has compact support. This implies that<i>c</i><sup>2</sup>cannot be smooth across the boundary<i></i>separating the gas and the vacuum after a finite time, where<i>c</i>is the speed of sound. Then we study the local existence of solutions for isentropic gas flow in<i>R</i>when<i>c<sup></sup></i>, 0<<i></i>1, is smooth across<i></i>, using the energy method and the characteristics method.