A new type of macrocycc polyethers has been synthesized.It consists of an azacrownether as mother ring,e.g.1,7-dioxa-4,10-diaza-cyclododecane(1a)or 1,7,10,16-tetraoxa-4,13-diaza-cycloocatadecane(1b),and two side chains attached on the two nitrogen atoms of 1a or 1b.A numberof these new crown ethers are obtained by alkylation of the two secondary amino groups of 1a or 1bwith corresponding halides,BrCH_2(CH_2OCH_2)_nCH_2OR,in the presence of potassium carbonate.The crown-alkali metal complex thus obtained is hydrolyzed by acid.In order to obtain pure crownether the reaction mixture is treated with tetramethylammonium hydroxide and followed by solventextraction.The ability of complexing alkali cations of macrocyclic polyethers in terms of the equilibriumconstant have been studied by the method of solubilities of salts in chloroform.It is shown that thesize of the mother ring,the number of oxygen atoms either in the ring or in the side-chains,and theionic radius of the alkali metal are the factors governing the stability of the metal complexes.Mostof these new crown ethers possess high ability for alkali metal complexation some of them,such asN,N’-di-β-methoxyethyl-1,7-dioxa-4,10-diaza-cyclododecane(13a),possesses higher selectivity forNa~+ and K~+ ions than 18-crown-6-and 4,4’(5’)-dimethylbenz-30-crown-10. A new type of macrocycc polyethers has been synthesized. It consists of an azacrownether as a mother ring, eg1,7-dioxa-4,10-diaza-cyclododecane (1a) or 1,7,10,16-tetraoxa-4,13 A number of these new crown ethers are obtained by alkylation of the two secondary amino groups of 1a or 1b with the corresponding halides, BrCH 2 (CH 2 OCH 2) _nCH_2OR, in the presence of potassium carbonate. crown-alkali metal complex obtained obtained hydrolyzed by acid. order to obtain pure crownether the reaction mixture is treated with tetramethylammonium hydroxide and followed by solventextraction. ability of complexing alkali cations of macrocyclic polyethers in terms of the equilibriumconstant have been studied by the method of solubilities of salts in chloroform. It is shown in thesize of the mother ring, the number of oxygen atoms either in the ring or in the side-chains, and theionic radius of the alkali. metal are the factors governing the stability of the metal complexes. Most of these new crown ethers possess high ability for alkali metal complexation some of them, such as N, N’-di-β-methoxyethyl-1,7-dioxa-4,10- diaza-cyclododecane (13a) possesses higher selectivity for Na ~ + and K ~ + ions than 18-crown-6-and 4,4 ’(5’) - dimethylbenz-30-crown-10.