On some Frobenius groups with the same prime graph as the almost simple group ${ {bf PGL(2,49)}}$

The prime graph of a finite group $G$ is denoted by $Gamma(G)$ whose vertex set is $pi(G)$ and two distinct primes $p$ and $q$ are adjacent in $Gamma(G)$, whenever $G$ contains an element with order $pq$. We say that $G$ is unrecognizable by prime graph if there is a finite group $H$ with $Gamma(H)=Gamma(G)$, in while $Hnotcong G$. In this paper, we consider finite groups with the same prime graph as the almost simple group $textrm{PGL}(2,49)$. Moreover, we construct some Frobenius groups whose prime graphs coincide with $Gamma(textrm{PGL}(2,49))$, in particular, we get that $textrm{PGL}(2,49)$ is unrecognizable by its prime graph.