r 4 are as previously defined the reaction is carried out by combining the substituted alkylene diamine iii with the chloroformate iv in an inert solvent such as benzene toluene tetrahydrofuran and the like and stirred at from 0 u00b0 c to the reflux temperature of the reaction mixture for from 2 hours to 3 days since the reaction in its initial period is occasionally exothermic a useful technique for this process is to have the initial reaction take place at a lower temperature such as from 0 u00b0 c to room temperature and then when the reaction no longer appears exothermic raise the temperature to the desired reaction temperature during the course of the reaction one mole of hydrogen chloride is released for each mole of product produced and it may be advantageous to include in the reaction mixture a molar equivalent or a slight excess of a base such as a tertiary amine the amine reacts with the hydrogen chloride and removes it from possible interference with the reaction the compounds of this invention may be isolated and used as the free base or as a pharmaceutically acceptable acid addition salt such salts are formed by reaction of the free base with the.