The Use of Polymer Supports in Organic Synthesis. 17. The Synthesis of Unsymmetrical Diamides and Monoamide Monotosylamides from Symmetrical Diamines

A 1 or 2% crosslinked divinylbenzene‐styrene copolymer, incorporating benzyl alcohol groups ( 1 ) was treated with p ‐nitrophenyl chloroformate to give a polymer‐bound benzyl p ‐nitrophenyl carbonate ( 2 ). The reaction of ( 2 ) with an excess of the symmetrical diamines 1,4‐diaminobutane ( 3a ), 1,6‐diaminohexane ( 3b ), 1,8‐diaminooctane ( 3c ), 1,10‐diaminodecane ( 3d ) and 1,12‐diaminododecane ( 3e ) gave the respective monoprotected polymer‐bound aminocarbamates ( 4a‐e ). Benzoylation or tosylation of ( 4a‐e ) gave the polymer‐bound N‐benzoyl or N‐tosyl carbamates ( 7a‐e ) or ( 8a‐e ) respectively. Cleavage of ( 7a‐e ) with trifluoroacetic acid liberated the N‐benzoyl‐N'‐trifluoroacetyl‐1, ω‐diaminoalkanes ( 9a‐e ) in 80% yield. Cleavage of ( 8a‐e ) with HCl in benzene, followed by acetylation yielded N‐acetyl‐N'‐tosyl‐1, ω‐diaminoalkanes ( 11a‐e ) in 80% yield. From both cleavage reactions about 20% of the symmetrical diamines were recovered as their N,N'‐ditrifluoroacetyl or N,N'‐diacetyl derivatives ( 10a‐e ) or ( 12a‐e ) respectively.