2)xH or --CH2)mCOOH where x is an integer of 1 or 2 and m is an integer of zero or 1; when R is hydrogen or --CH2)xH then R1 is --CH2)pCOOH where p is an integer of zero or 1, and when R is --CH2)mCOOH then R1 is selected from the group consisting of hydrogen or --CH2)yH where y is an integer of zero or 1.