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' );
}