1.5- Diazacyclooctane

DIAZACYCLOOCTANE, PENDANT ARM THIOLATO DERIVATIVES AND [7V,7V-BIS(2-MERCAPTOETHYL)-l,5-DIAZAC Y CLOOCTAN ATO]NICKEL(II)... 

Complexation228 of Zn2+ with the quadridentate 1,5-diazacyclooctane-N, A -diacetic acid (H2L) leads to formation of the trigonal prismatic [Zn(L)H20] species. The hydrolysis constant of the coordinated H20 (pKa = 8.6) is much lower than that of the coordinated H20 in the octahedral complex formed by ethylenediaminediacetate (pXa = 10.5). This increased acidity of coordinated H20 with decreasing coordination number has also been previously noted in the [Zn(Me6tren)H20]2+ cation,229 and has been attributed in part to the hydrophobic environment provided by the Me groups. This finding has important implications for the role of the... 

C-linked imidazole (29) (see 177), N-linked 1,2,4-triazole, or C-linked pyrimidine (94). Similar arm replacement in (165) has been achieved with pyrazole to give (176). For some formal hexaamines, like (172) and (175), the rigidity of the hgand restricts the coordination to triamines. A triamine can also be formed by adding an imidazole arm to an N atom in 1,5-diazacyclooctane (177). ... 

Using the knowledge that sterically blocking the axial positions in square planar systems effectively prevents an octahedral configuration from forming, nickel(II) and copper(II) complexes of a secondary mediumring diamine, 1,5-diazacyclooctane (daco), were synthesized (Figure 9) (67). 

The ligand (23) is derived from 1,5-diazacyclooctane functionalized by additional donor groups, such as imidazolyl and hydroxybenzyl.25 Results obtained with (23), showing a boat/ chair configuration in transition-metal coordination complexes, indicate that the nature of the pendant arm is a key factor governing the structures and properties of the complexes.25... 

The nomenclature of 1,5-diazocines is similar to that for azocines (82AHC115) and 1,4-diazocines (89AHC185), especially the latter. The completely conjugated compound (5) is called 1,5-diazocine. The partially saturated derivatives are prefixed dihydro-, tetrahydro-, etc. The totally saturated compound is called perhydro-1,5-diazocine, or 1,5-diazacyclooctane. 

Diazacyclooctanes 7 have found application as diuretic intermediates (62BEP613566) as antitumor agents and for treatment of chorea in dogs or muscular spasms in other animals (64USP3117963) as antihista-... 

The first use of a tosylamide in a cyclization reaction was reported nearly 100 years ago in German patents for the preparation of 1,4-ditosylpiperazine by Marckwald and Droste-Huelshoff (1898). Azetidine was also prepared by this process, as well as 1,5-diazacyclooctane using the appropriate halide and tosylamide (Bleier, 1899 Howard and Marckwald, 1899). A similar method was applied to macrocycles by Stetter and Roos (1954, 1955) when they reported the 2 2 cyclization reaction of an o ,(ij-dihalide with the dipotassium salt of an aromatic bis-sulfonamide as shown. Ring closure of an A-tosyl... 

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