Why doesn't the compiler give an error when the typedef const pointer is used with an extra const?

The following is the error as expected:

int* const const p = new int; // g++ error: duplicate cv-qualifier

But below there is no error, even if it is equivalent to the previous one:

typedef int* const intp_const;
intp_const const p = new int;  // ok !
        // ^^^^^ duplicate ?

Why constdoes the compiler ignore extra ?

[Note: intp_const constdoes not match const char* constbecause it is possible *p = <value>;.]