| abstract |
The compounds of the formula (1) ** Formula ** in which H represents one of the alkyl, alkyloxy, alkenyl, or alkynyl residues having 1 to 12 carbon atoms, or aryl residues, 10 R2 represents H, one of the alkyl, alkyloxy, alkenyl or alkynyl residues having 1 to 12 carbon atoms, or aryl residues; R3 represents H; X represents 0 or S; A- represents any negative ion; and n> = 0,1, 2, 3, 4, 5, 6, 7, 8, 9,10. |