
TY  - JOUR
A1  - Park, Kyoung Ju 
A1  - Kim, Jin-Ho 
A1  - Meehan, George V. 
A1  - Nishimura, Tomoko 
A1  - Lindoy, Leonard F. 
A1  - Lee, Shim Sung 
A1  - Park, Ki-Min 
A1  - Yoon, Il 
T1  - New Macrocyclic Ligands. XV. Isomeric, Benzylated and Xylyl-Linked Macrocyclic Ligands Derived from Selectively Protected N<emph type="8">3</emph>O<emph type="8">2</emph>-Donor Rings
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 2003
VL  - 55
IS  - 12
SP  - 773
EP  - 778
KW  - 
UR  - https://doi.org/10.1071/CH02164 
N2  - Direct alkylation of the N3O2-macrocycle 1,12,15-triaza-3,4 : 9,10-dibenzo-5,8-dioxacycloheptadecane (1) with benzyl bromide in the presence of sodium hydrogen carbonate (in the respective molar ratios 1.0 : 2.0 : 1.3) led to a mixture of the mono-, bis-, and tris-N-benzylated derivatives (2)&#8211;(6) which were separated using their differential solubilities in warm acetone, fractional crystallization, coupled with column chromatography on silica gel. The X-ray structure of the symmetrical dibenzylated product (4) (as its HNO3 salt) is described. In a parallel study, N-protection of (1) using 1.7 molar equivalents of di-tert-butyl dicarbonate (Boc)2O yielded a mixture from which the symmetrical and unsymmetrical di-protected isomers (8) and (9) were separated by chromatography. Reaction of the symmetrically protected derivative (8) with benzyl chloride in the presence of excess sodium carbonate, followed by removal of the Boc groups, provided an alternative route to the corresponding (symmetrical) mono-N-benzylated macrocycle (2). A similar strategy, involving the use of &#945;,&#945;&#8242;-dibromo-p-xylene as a dialkylating agent, was employed to bridge a pair of N-diprotected macrocycles of type (8) or (9) to yield isomeric linked products (12) and (14), respectively. Deprotection of the resulting bis-macrocyclic products gave the &#39;central&#39; and &#39;side&#39; linked ligands (13) and (15), respectively. 
ER  -

