There are prepared compounds of the formula <IMAGE> where R and R1 are saturated and preferably linear alkyl groups in which the sum of carbon atoms in the two alkyl groups is 4 to 30, ONE OF R and R1 can also be hydrogen, R2 is hydrogen or if {HEAD ~ R3} is hydrogen, then R2 is {TAIL ~ the group} <IMAGE> where n is 1 to 10, R3 is hydrogen or, if R2 is hydrogen, then R3 is the group 
There are prepared compounds of the formula < IMAGE > where R and R1 are saturated and preferably linear alkyl groups in which the sum of carbon atoms in the two alkyl groups is 4 to 30 , ONE OF R and R1 can also be hydrogen , R2 is hydrogen or if { HEAD ~ R3 } is hydrogen , then R2 is { TAIL ~ the group } < IMAGE > where n is 1 to 10 , R3 is hydrogen or , if R2 is hydrogen , then R3 is the group
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH