33rd IChO Problem 6 Student code : Official version Organic chemistry of Indian spices The rhizomes of ginger ( Zingiber officinale ) are well known for their medicinal and flavoring properties. In Ayurveda (the traditional system of medicine in India), different formulations of ginger are used for the treatment of gastrointestinal problems, common cold and other ailments. Several compounds are responsible for the pungency of ginger. Many are simple substituted aromatic compounds with different side chains. Three of them, Zingerone, (+) Gingerol (to be referred hereafter as Gingerol only), and Shogaol are particularly important. Zingerone C 11 H 14 O 3 Gingerol C 17 H 26 O 4 Shogaol C 17 H 24 O 3 6.1 Zingerone gives positive FeCl 3 and 2,4–DNP (2,4–dinitrophenylhydrazine) tests. It does not react with Tollen’s reagent. Therefore, Zingerone contains the following functional groups: [Mark X in the correct boxes.] (a) alcoholic hydroxyl (e) ester (b) aldehydic carbonyl (f) alkoxyl (c) ketonic carbonyl (g) unsaturation (d) phenolic hydroxyl 2 marks
33rd IChO Problem 6 Student code : Official version Chemical shifts Multiplicity Relative intensity ( ) 2.04 singlet 3 2.69,271 two (closely spaced) triplets of equal intensity 4 3.81 singlet 3 5.90 broad singlet (D 2 O exchangeable) 1 6.4 – 6.8 two doublets with similar chemical shifts 3 and one singlet Alkenes cis 5 – 14 Hz (commonly around 6 – 8 Hz) trans 11 19 Hz (commonly around 14 – 16 Hz) The data obtained from the 1 H NMR spectrum of Zingerone are shown in Table 1.
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- Spring '08
- Ginger, Student Code, Official Version, zingerone