Theoretical Test

10. Natural Products – Structural Analysis (9 pts)Licorice (Glycyrrhizia. Uralensis)Licorice RootThe flavor extracted from the licorice root is 50 – 150 times sweeter thantable sugar.The most important and abundant compound responsible for the sweetness andmedicinal effects of licorice is glycyrrhizin (C 42 H 62 O 16 ).Glycyrrhizin requires three equivalents of NaOH to effect neutralization.``When glycyrrhizin was subjected to acid hydrolysis, Glycyrrhizinic acid (A(C 30 H 46 O 4 )) and B (C 6 H 10 O 7 ) were obtained in a 1:2 molar ratio (figure 1).Figure 1.HOOCglycyrrhizin(C 42 H 62 O 16 )HClH 2 OOHH+2 B (C 6 H 10 O 7 )HOHA (Glycyrrhizinic acid)When glycyrrhizin was methylated with methyl iodide (MeI) at every possiblesite before hydrolysis, hydrolysis produced A’ (methyl glycyrrhizinate), C and D(figure 2). B, C and D exist as mixtures of anomers.Figure 2.glycyrrhizin(C 42 H 62 O 16 )i) MeI, Ag 2 Oii) HCl / H 2 OA' (C 31 H 48 O 4 ) + C (C 9 H 16 O 7 ) + D (C 10 H 18 O 7 )18