Hydrocarbon-based fuel compositions which provide improved cetane ratings and a method of making them which comprises admixing a major amount of a petroleum fraction of the diesel boiling range and a small, effective amount of at least one compound having the general formula: ##STR1## where R is H, CH.sub.3 or A; R' is H, CH.sub.3 or C.sub.2 H.sub.5 ; A is ##STR2## or is ##STR3## R" is H or C.sub.1-3 alkyl; and x is 1 or 2.