Section 2507 - Superintendent of schools; associate superintendents1. The superintendent and any associate superintendent of schools in each school district shall hold his position subject to the pleasure of the board of education, except that the superintendent of schools may be appointed for a term of not to exceed five years, provided that the terms or provisions of any employment contract between the superintendent and the board of education relating to an increase in salary, compensation or other benefits, shall not be based on or tied to the terms of any contract or collective bargaining agreement that the board of education has or will enter with the teachers or other employees of the school district.2. A superintendent or an associate superintendent may vacate his position by filing a written resignation with the board of education. No person shall be eligible to the position of superintendent of schools, deputy superintendent of schools, associate superintendent of schools, assistant superintendent of schools or other superintendent of schools in such city school district unless he shall possess or be entitled to a superintendent's certificate as provided in section three thousand three of this chapter.