Abstract: The invention relates to enkephalin analogs of the formula ##STR1## wherein in case of X is D-Val, D-Phe, Pro, D-Met, D-Met(O), D-Leu, D-Glu, D-Glu(Obzl), D-Lys, D-Lys(Z), or D-Arg,Y is Gly or Phe; andR isa) a direct bond,b) an alkylene group having from 1 to 6 carbon atoms,c) o-, m-, or p-phenylene group,d) a cycloalkane; orwherein in case ofX is D-Ala,Y is Phe; andR isa) a direct bond,b) an alkylene group having from 1 to 6 carbon atoms,c) o-, m-, or p-phenylene group, ord) a cycloalkane,its salts and hydrates, as well as a therapeutic composition containing at least one of the enkephalin analogs, as an effective component.

Abstract: The present invention relates to intermediates for synthesizing BH.sub.4 and derivatives thereof. The intermediates are shown as follows; ##STR1## wherein R.sub.1 is a hydrogen atom, alkyl, aralkyl, or aryl group; R.sub.2 is an alkyl, hydroxyalkyl, or polyhydroxyalkyl group; R.sub.3 and R.sub.4 are the same or different and represent alkyl, aralkyl, or aryl group; R.sub.5, R.sub.6, R.sub.7, and R.sub.8 are the same or different and represent a hydrogen atom or acyl group; R.sub.9 is an alkyl, aralkyl, or aryl group; R.sub.10 and R.sub.11 are the same or different and represent a hydrogen atom or acyl group; n is an integer of 5 or less; and HX is an acid. The invention also relates to a process for the preparation of L-biopterin.

Abstract: A novel polymer-metal complex containing quaternary nitrogen atoms, which is obtained by subjecting polyethylenepolyamine or polyethyleneimine to a reaction with a bifunctional compound represented by the formulaY--A--Zwherein Y and Z are same or different and are --CH.sub.2 X, --CH(OH)CH.sub.2 X or ##STR1## group, respectively, A is a single bond, --(CH.sub.2).sub.m --, --CH.sub.2 --O--CH.sub.2 -- or --CH.sub.2 --O--(CH.sub.2).sub.k --O--CH.sub.2 -- group, X is chlorine, bromine or iodine atom, m is an integral of 1 to 3, and k is an integral of 1 to 4, and then subjecting the resulting cross-linked polymer to a coordination of a polyvalent metal ion, a salt thereof, a process for the preparation thereof and a pharmaceutical agent comprising the same.