CONDENSATION OF BIS(BETA-ALANINATO)COPPER(II) WITH FORMALDEHYDE AND AMMONIA

Various complexes have been prepared by the template condensation of alpha-amino acids with formaldehyde or acetaldehyde in the presence of metal ions(1-5). In particular, glycine has received much attention(1-4). For example, (3N, 7N - 1,3,5,7-tetraazabicyclo[3.3.1]nonyl)-diacetato nickel(II) (1) has been prepared by condensing bis(glycinato)nickel(II) dihydrate with formaldehyde and ammonia at pH 8.5(4). More recently(5), complex (2) has been prepared by condensing bis(L-alaninato)copper(II) with formaldehyde and ammonia. These reactions are interesting for the following reasons: [GRAPHICS] (i) Products (1) and (2) have their amino acidato chelate rings cis with respect to each other, which implies that during the condensation process they must have undergone conversion from the initial trans arrangement of the amino acid units(6,7) to a cis arrangement; (ii) Whereas the copper(II) analogue of (1) is formed in the reaction of bis(glycinato)copper(II) monohydrate with formaldehyde and ammonia(4), the nickel(II) analogue of (2) does not result in the reaction of bis(L-alaninato)nickel(II) with formaldehyde and ammonia(5); (iii) Bis(DL-alaninato)copper(II) monohydrate does not yield product similar to (2) on condensation with formaldehyde in the presence of ammonia at pH 8.5, but instead yields another products (3) (3,5). Here we describe the preparation of (3N, 7N - 1,3,5,7-tetraazabicyclo[3.3.1]nonyl)di-3-propionato copper(II), (4) from the condensation of bis(beta-alaninato)copper(II) hexahydrate with formaldehyde and ammonia.