Solid-phase synthesis of 1,5-disubstituted 2-aryliminoimidazolidines

The solid-phase synthesis of 1,5-disubstituted 2-aryliminoimidazolidines, starting from resin-bound N-acylated amino acid amides, is described. Exhaustive reduction of resin-bound acylated amino acid amides with borane-THF afforded the corresponding disecondary amines. Further reaction, with arylisothiocyanates in the presence of mercuric chloride (HgCl2) yielded the corresponding resin-bound 1,5-disubstituted 2-aryliminoimidazolidines. Cleavage of the product from the resin using HF/anisole (95/5) for 1.5 h at 0 degreesC gave the desired products in good yield and purity. The preparation of a large combinatorial library of such compounds is also discussed.