Allocholapods

Significance

The synthesis of triamine 5 and two of its protected derivatives (6a and 6b) from bile acid 1 is reported. Enone 2 was produced utilizing well established chemistry, and subsequent reduction afforded triol 3, which had the desired stereochemistry at C-5. In turn, 3 was oxidized to 4, which was then converted into 5 with hydroxyl­amine followed by hydrogenation. The structure of 5 was established by X-ray crystallography of its Boc-protected derivative 6a. Reaction of 5 with phenyl isocyanate provided triurea 6b. This compound was tested as an anion receptor, and was found to have 2-5.4 fold higher binding constants than previously reported triurea 7 (J. Clare et al. J. Am. Chem. Soc. 2005, 127, 10739-10746). This increase is thought to stem from differences in the hydrogen-bonding network between the urea groups in 6b and 7.