Consider the following premises. p_1 -> p_6. q_6 -> r_6. ~r_6. p_6 -> q_6. Can we infer ~p_1 from them?
 From p_6 -> q_6, q_6 -> r_6 we can infer p_6 -> r_6. From p_1 -> p_6, p_6 -> r_6 we can infer p_1 -> r_6. Finally, from p_1 -> r_6, ~r_6 we can infer ~p_1. Therefore, the answer is yes.