Soal IChO Ke-26

THEORETICAL PROBLEM No 6

(18 blue points, 9 red points)

An optical active compound A (C₁₂H₁₆O) shows amongst other a strong IR-absorption at 3000-3500 cm^-1, and two medium signals at 1580 and 1500 cm^-1. The compound does not react with 2,4-dinitrophenylhydrazine (2,4-D). Upon treatment with I₂/NaOH, A is oxidized and gives a positive iodoform reaction.

Ozonolysis of A (a. O3; b. Zn, H⁺) gives B (C₉H₁₀O) and C (C₃H₆O₂). Both B and C give precipitation when treated with 2,4-D, and only C gives positive reaction with Tollens reagent. Nitration of B (HNO₃/H₂SO₄) may give two mono-nitro compounds D and E, but in practical work only D is formed.

Acidification followed by heating of the product formed by the Tollens reaction on C gives compound F (C₆H₈O₄). The compound gives no absorption in IR above 3100 cm^-1.

a) Based on the above information draw the structure formula(e) for the compounds A-F and give the overall reaction scheme, including the (2,4- D) and the products of the Tollens and iodoform reactions.

b) Draw C in an R-configuration. Transform this into a Fischer projection formula and state whether it is a D or L configuration.