H3C HB Ha CH3 CH3 CH3 H H3C HO Cholestanol differs from cholesterol only in the absence of a double bond in ring B. Draw the three-dimensional structure of cholestanol, and then determine the orientation of the following groups: #1: H at the junction of rings A & B with respect to ring A equatorial v #2: Methyl at the junction of rings A & B with respect to ring B axial #3: HB equatorial v II

Calculate the number of degrees of unsaturation for each molecular formula. a.C6H8 b.C40H56 c.C10H16O2 d.C8H9Br e.C8H9ClO f.C7H11N g.C4H8BrN h.C10H18CINO

Compound 1 Br Bri НІ T ... H The correct IUPAC names are: Compound 2 H Br Br I.. H Br The compounds are diastereomers not isomeric enantiomers identical constitutional isomers Compound 1: (2R, 3R)-1,2,3-tribromobutane, Compound 2: (2S, 3R)-1,2,3-tribromobutane Compound 1: (2R, 3S)-1,2,3-tribromobutane, O Compound 1: (2R,3R)-1,2,3-tribromobutane, Compound 2: (2S,3S)-1,2,3-tribromobutane Compound 2: (2R, 3R)-1,2,3-tribromobutane O Compound 1: (2S,3S)-1,2,3-tribromobutane, Compound 2: (2R,3S)-1,2,3-tribromobutane

Q6. Encircle the structures of all the chiral molecules drawn below and assign absolute configuration (R/S) to all the chiral atoms. Draw the Fischer projections of the enantiomers of all these molecules except epoxides. OH OH OH CH, H,C CH, CH, H,C H,C OH OH OH CH, H,C CH, CH

Which of these conformations is expected to be the lowest in energy, and which shows the conformation required for an E2 elimination? CI CI CI CH3 - H. „CH3 H `CH3 `CH3 CH3 H ČH3 1 2 3 is lowest energy; 2 or 3 is required for E2 elimination 3 is lowest energy; 1 is required for E2 elimination O 1 is lowest energy; 2 or 3 is required for E2 elimination O 1 is lowest energy; 2 is required for E2 elimination O 2 is lowest energy; 3 is required for E2 elimination

Which structure(s) represent(s) R configuration? CH3 CH3 CH3 wCH3 H. CH3 IV II II Select one: O II O IV O II, IV

Are they axial or equatorial? Thank you

Menthol is a common additive to dental products, topical analgesics, decongestants and many other everyday items. Below is the structure of menthol. Which is the most stable chair conformer of menthol? A a B b C C D d CH3 HO Menthol CH3 -CH3 но но но CH3 CH3 OH A. B

6. How many non-equivalent carbons are there in each of the following structures? H OCH 3 CH3 CH3 CI CI OH H3CO OCH3 H OCH3 OH H H H- H- CHO -OCH3 -OCH3 -OCH3 -OCH3 CH₂OCH 3

H- HO HO- HO OH H H OH H -H H CH₂OH Draw four different horizontal zig-zag bond line structures that correctly represent the Fischer projection of 2,3,4,5,6-pentahydroxyhexanal shown below. One of your bond-line structures should have the carbonyl on the left hand side of the molecule pointing up, another on the left side pointing down, another on the right side pointing up, another on the right side pointing down (the terminal CH₂OH is marked in blue) Also, assign each chirality center as (R) or (S) in the original Fischer projection (you only have to do this once as it's the same for all depictions of the molecule). H OH ОН. H H OH