Question

2.73 Many compounds with desirable medicinal properties are iso- lated from natural sources and are thus referred to as natural products, However, a compound's medicinal properties are often known before the structure of the compound has been determined. Below are exam- ples of compounds where the first proposed structure was incorrect.14 In each case, the corresponding correct structure is also shown. Identify all functional groups in each pair of compounds and then compare the similarities and differences between their molecular structures. (a) OH HO Proposed structure of cholesterol Correct structure of cholesterol

Answer 1

10 он propesed structure of t he Correct structure of cholestert cholestero Funetional groups: - alcohot (-on) [functional group :- alcohol (-OH) ( Cyclic alrene (e- e s ) eyelie alkone (e=0) similarities of molecular stratue : la Both structure contrain - on gr. with cyclohexyl ring. I Both have similar side chain to Difference better two struetures: proposed stuetue have two six-membered rings and two fire-membered rings but actual stmature have 3 six-membered rings and one five membered ring. c = c present in agrepentire fire-membered ring in propiced stucture but e=é double bond prest in six-membered ring in actual structure. In od struetme two methyl branching gr. a. in attached at ring junction but in proposed Awalne one methyl and one ethyl branching gr. is attached at ring junction. In proposed structure the stereochemisty of the attached groups are a not shown but the it is shown in the correct struetme ve burada

benz OCH Correct structure of porritoxin Functional grs: - Methoxy (-0 CH3). cyclic amide (-CO NR). alcohol (-o) Aegelic. ether (-0-). alkone (e=c). side chain Probased structure of porritoxin functional gps: - Methoxy (- 0CH) Cyclic amide (-CONH) cyclic ether (-c-o-e) Acyclic ether (alp. - o - arm) . alone (e-c) Similarities of in molecular structures : . Both stratmes have similar ethexy . Both stretwes have one methyl gr. attached with aromatic ring 10 Both en stmatures have cyclic amide group attached with aromatic benzene ntene Pung. ding | Differences of molecular structures: lamigay sa | proposed stuetme contain one six menbered aromatic ring and ore 8-membered ring but the correet strative contain, one six membered aromatic ring and one five membered ring gehen an. @ proposed strmeture have no aliphatic alcohol gr. but correct stue ture have one aliphatic alcohol gr. To proposed sucture have 8- membered cyclic anide and ether linked ring but correat stretwee have five-membered cyclic amide ring with a branch alcohol.