Abstract: Muramyldipeptide derivatives of the formula: ##STR1## wherein Y represents a mycoloyl group or a synthetic higher acyl group having total carbon number of C30-C90 and having at least a branched chain of long alkyl group on the .alpha.-position thereof,Q represents an -L-alanyl-D-isoglutamine group, a -glycyl-D-isoglutamine group or an -L-seryl-D-isoglutamine group;Salts of such derivatives; the method of preparing such derivatives and their salts; the derivatives and their salts having potent immunoadjuvant activities and antitumor activity and being applicable as the agent for the immunotherapy of cancer for humans and animals.

Abstract: A process for preparing a 2-halopyrimidine derivative represented by the formula: ##SPC1##Wherein R.sup.2 represents a hydrogen atom, a halogen atom, a lower alkyl group, an aryl group, and an amino group and R.sup.4 represents a lower alkyl group and X represents a halogen atom, which comprises reacting cyanoacetimidate derivative represented by the formula: ##EQU1## wherein R.sup.2 and R.sup.4 represent the same as above and M represents a mineral acid residue with cyanamide, to produce an N-cyanocyanoacetimidate ##EQU2## represented by the formula: WHEREIN R.sup.2 and R.sup.4 represent the same as above, and thereafter reacting said N-cyanocyanoacetimidate with a hydrogen halide.