Novel compounds of the formula ##STR1## in which X is hydrogen or --CH.sub.2 --OR.sup.5, Z represents OR.sup.4, NH.sub.2 or ##STR2## R.sup.2, R.sup.3, R.sup.4 and R.sup.5 each independently is hydrogen or ##STR3## at least one of R.sup.2, R.sup.3, R.sup.4 and R.sup.5 being ##STR4## Y and W each independently is oxygen, sulphur, NH or CH.sub.2, and R.sup.1, R.sup.6, R.sup.7 and R.sup.8 each independently is an optionally substituted hydrocarbon radical with up to 50 C atoms, stimulate the immune system.
                            该文描述了式子##STR1##中的新化合物,其中X为氢或--CH.sub.2 --OR.sup.5,Z代表OR.sup.4,NH.sub.2或##STR2##,R.sup.2、R.sup.3、R.sup.4和R.sup.5各自独立地是氢或##STR3##,其中至少一个是##STR4##,Y和W各自独立地是氧、
硫、NH或CH.sub.2,而R.sup.1、R.sup.6、R.sup.7和R.sup.8各自独立地是具有最多50个碳原子的可选取代的碳氢基团,可刺激免疫系统。