METAL-DIRECTED SYNTHESES OF DITHIADIAZACYCLOTETRADECANE MACROCYCLES WITH PENDANT ALCOHOL AND NITRO OR CARBOXYLATE GROUPS INVOLVING MACROCYCLE RING EXPANSION

Copper(II)-directed condensation of 4-hydroxymethyl-3,6-dithiaoctane-1,8-diamine with nitroethane or diethyl malonate and formaldehyde yielded (anti-6-methyl-6-nitro-1,11-dithia-4.8-diazacyclotetradecan-13-ol)copper(II) and (diethyl 13-hydroxy-1,11-dithia-4,8-diazacyclotetradecane-6,6-dicarboxylate)copper(II) respectively in good yields. The latter was readily converted by decarboxylation and hydrolysis in aqueous base to the copper(II) complex of anti-13-hydroxy-1,11-dithia-4,8-diazacyclotetradecane-6-carboxylic acid from which the free ligand can be obtained by zinc-acid reduction of the copper ion, whereas the former can be converted by zinc-acid reduction directly to the hydrochloride salt of the free anti-6-amino-6-methyl-1,11-dithia-4,8-diazacyclotetradecane-6 13-ol ligand. The condensations should yield a thirteen-membered macrocycle with a pendant hydroxymethyl group fused to a macrocyclic ring carbon, but the molecules undergo a Wagner-Meerwein or alternate carbon skeleton rearrangement to yield the fourteen-membered macrocycle with a pendant alcohol group. The pendant alcohol can act as an axial donor group. as illustrated in the crystal structure analyses of (anti-6-methyl-6-nitro-1,11-dithia-4,8-diazacyclotetradecan-13-ol)copper(II) and (anti-13-hydroxy-1,11-dithia-4,8-diazacyclotetradecan-6-carboxylato)copper(II) as perchlorate salts. The former complex crystallizes in the monoclinic P2(1)/n space group, a = 8.703(2), b = 18.699(2), c = 13.293(2) Angstrom, beta = 105.15(1)degrees and the latter in the monoclinic P2(1)/n space group, a = 7.450(1), b = 15.325(2), c = 16.772(1) Angstrom, beta = 98.38(1)degrees. In both complexes the alcohol is disposed anti to the nitro or carboxylate group, In the former, the copper ion lies in a distorted-octahedral environment of two sulfur donors (Cu-S-av 2.333 Angstrom), two nitrogen donors (Cu-N-av 2.016 Angstrom), the pendant alcohol donor [Cu-O 2.365(3) Angstrom] and a perchlorate anion [Cu-O 2.544(3) Angstrom], whereas in the latter a dimer with each copper in a very distorted octahedral environment exists where each carboxylate bridges to the alternate copper ion [Cu-O 2.293(3) Angstrom] and the alcohol is weakly bound [Cu-O 2.520(3) Angstrom] in addition to the macrocycle heteroatoms (Cu-N-av 2.035, Cu-S-av 2.353 Angstrom).