ACID-CATALYZED REARRANGEMENTS BETWEEN 3,4-DIHYDRO-2H-1,5-BENZOOXAZOCINE AND 3,4-DIHYDRO-2H-1,5-BENZOTHIAZOCINE AND THEIR MACROCYCLIC (16-MEMBERED, 24-MEMBERED AND 32-MEMBERED) OLIGOMERS

Treatment of 2-(3-azidopropoxy)benzaldehyde with triphenylphosphine in diethyl ether, followed by sequestration of the products with nickel( II) thiocyanate and subsequent liberation from the complex with aqueou s ammonia, produces the 16-membered dimer of 3,4-dihydro-2H-1,5-benzoo xazocine. The dioxadiaza diimine macrocycle 3 undergoes an acid-cataly sed rearrangement in solution into an equilibrium mixture that include s the trioxatriaza triimine (24-membered) 8 and tetraoxatetraaza tetra imine (32-membered) 9 macrocycles, as well as the diimine. The oligome rs in [H-2]chloroform differ in the H-1 NMR chemical shifts of the pro tons on the central carbon atoms of the propane-1,3-diyl links, thereb y allowing an investigation of the factors involved in the rearrangeme nts between the macrocyclic oligomers. Thus, the rearrangements of the macrocyclic polyimines into equilibrium mixtures of the various oligo mers occurs with t(1/2) 7-10 min, but the position of the equilibrium in each case is dependent upon the imine equivalent concentration of t he solution, 3,4-Dihydro-2H-1,5-benzothiazocine undergoes a similar re arrangement, The equilibrations have been ascribed to facile intermole cular transiminations between the oligomers in the presence of traces of acid and to the similarities of the thermodynamic stabilities of th e 16-, 24- and 32-membered oligomers. The crystal and molecular struct ures of ammonium nitrate salts of the 16-membered diamine 11 and 32-me mbered tetraamine 10 derivatives of the corresponding macrocyclic benz ooxazocines are reported.