In 1862, it was discovered that cholesterol (for structure, see Section 4-7) is

Chapter 17, Problem 62

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In 1862, it was discovered that cholesterol (for structure, see Section 4-7) is converted into a newsubstance named coprostanol by the action of bacteria in the human digestive tract. Make use of thefollowing information to deduce the structure of coprostanol. Identify the structures of unknownsJ through M as well. (i) Coprostanol, upon treatment with Cr(VI) reagents, gives compound J,UV lmax(e) 5 281(22) nm and IR 5 1710 cm21. (ii) Exposure of cholesterol to H2 over Pt resultsin compound K, a stereoisomer of coprostanol. Treatment of K with the Cr(VI) reagent furnishescompound L, which has a UV peak very similar to that of compound J, lmax(e) 5 258(23) nm,and turns out to be a stereoisomer of J. (iii) Careful addition of Cr(VI) reagent to cholesterolproduces M: UV lmax(e) 5 286(109) nm. Catalytic hydrogenation of M over Pt also gives L.