i include the conventional non toxic salts or the quaternary ammonium salts of the compounds of formula i formed e g from non toxic inorganic or organic acids for example such conventional non toxic salts include those derived from inorganic acids such as hydrochloric hydrobromic sulfuric sulfamic phosphoric nitric and the like and the salts prepared from organic acids such as acetic propionic succinic glycolic stearic lactic malic tartaric citric ascorbic pamoic sulfanilic 2 acetoxybenzoic fumaric toluenesulfonic methanesulfonic ethane disulfonic oxalic isethionic and the like the pharmaceutically acceptable salts of the present invention can be synthesized from the compounds of formula i which contain a basic or acidic moiety by conventional chemical methods generally the salts are prepared by reacting the free base or acid with stoichiometric amounts or with an excess of the desired salt forming inorganic or organic acid or base in a suitable solvent or various combinations of solvents the compounds of the present invention may have asymmetric centers and occur as racemates racemic mixtures and as individual diastereomers with all possible isomers including optical isomers being included in the present invention non limiting examples of the novel compounds of this invention are as follows the novel compounds of this invention are prepared by the following non limiting procedures str2 the reaction is carded out at room temperature 20 u00b0 30 u00b0 c at a ph in the range of 2 7 acidic by the addition of glacial acetic acid or hydrochloric acid for.