Need To Deregister Scripts Via Functions.Php

Ok the following does work now, I think it was a caching issue and I forgot to add the correct priorities

Using the priorities now it definitely works and I also managed to de-register Buddypress scripts

add_action( 'wp_print_scripts', 'de_script', 100 );

function de_script() {
    wp_dequeue_script( 'jquery' );
    wp_deregister_script( 'jquery' );
     wp_dequeue_script( 'bp-legacy-js' );
    wp_deregister_script( 'bp-legacy-js' );

}