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Cholic acid 2a has been converted into two new orthogonally-protected triamino scaffolds, 13 and 14. The synthesis proceeds via the bis-Boc-NH-substituted azide 10, for which an improved preparation is described. After removal of the Boc groups, the two axial amines are differentiated through a novel monoprotection employing 1-(2-nitrobenzenesulfonyloxy)-benzotriazole 29. Regioselectivity of > or 50 : 1 is achieved, presumably reflecting an exceptional sensitivity to steric hindrance. Protection of the remaining amino group as Boc or Alloc gives the scaffolds in approximately 40% overall yield from cholic acid. Scaffold 13 has been sequentially deprotected and derivatised with N-carbamoyl amino acids, to give a model for tripodal peptide libraries.

[reaction: see text] A lipophilic alpha-keto amide, inhibitor of pancreatic lipase, was synthesized using a lipidic 2-amino alcohol as backbone. The chiral key intermediate 2-(tert-butyloxycarbonylamino)-D-undecen-5-ol was synthesized starting from D-glutamic acid. The inhibitor formed a stable monomolecular film at the air/water interface as shown by a force/area curve. Inhibition studies using the monomolecular film technique with mixed films of 1,2-dicaprin containing variable proportions of the inhibitor showed a 50% decrease in lipase activity at a 0.14 molar fraction.

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