Negotiations designed to end a strike of Cotera Bros. employes and to prevent a general sympathy strike in uarez were begun today by Melchor Solis, representative of Governor Foglio Miramontes of Chihuahua. Leaders of the Northern Feder ation of Labor, who previously an nounced their readiness to call a general strike, said today they will await outcome of the negotiations. Thirty-four employes of Cotera Bros., coffee roasters, have been on strike since last Tuesday as a re sult of a wage dispute.