Explore BrainMass
Share

Stereochemistry, Bonding and Formation

Liquid crystals

Are there differences between the cholesteryl benzoates and the cholesteryl esters having long carbon chains? why or why not?

Organic Chemistry Questions: stereochemistry and chirality centers

See attached file for full problem description. 1. Write the complete stepwise mechanism for this reaction. Be sure to show all intermediate structures and all electron flow using arrows. 2. Predict the products of the following reaction. Indicate regiochemistry and stereochemistry when relevant.

Resonance structures

Draw all resonance structures possible for the following ionic species: Make sure you clearly show all lone pairs and any formal charges. (See attached file for full problem description)

Lewis structures and polarity of molecules

Draw the Lewis dot structure for the following molecules. Use VSEPR theory to predict three-dimensional structure. Then predict whether the molecule is polar or non polar. Sulfur dichloride Silicon tetrabromide Oxygen difluoride Nitrite ion

Drawing Alkane/Alkene Structures

Write the structures of the following compounds a) 2,2-dibromo-3,3-dichloro-5,5-difluoro-6,6-diiodobicyclo{2.2.1}heptane b) hexamethylbicyclo{2.2.0}hexa-2,5-diene

structure of the original peptide

(See attached file for full problem description) Enzyme-catalyzed hydrolysis of a peptide yields mixtures of smaller peptides. Give the structure of the original peptide which yielded these parts following chymotrypsin and trypsin hydrolysis.

Multiple questions on monosaccharides, carbons, and sugars

I need the following questions answered in the next 45 minutes Thanks Sucrose is hydrolyzed to what two monosaccharides? 1. glucose and fructose 2. glucose and galactose 3. galactose and fructose 4. glucose and maltose Question 2 All chiral D-sugars rotate plane-polarized light 1. clo

Organic Chemistry

1. The compound 2-methyl-1,4-pentadiene would be classified as what type of diene? a. conjugated b. isolated c. cumulated d. internal 2. Select the least stable diene listed below: a. 2,3-pentadiene b. trans-1,3-pentadiene c. cis-1,3-pentadiene d. 1,4-pentadiene 3. Whic

Conjugation in Alkadienes & Allylic Systems

What are the differences between vinylic & allylic hydrogens in a Cyclohexene (ie. how many of each, what determines it)? Second, what is the best way to determine a conjugated diene? Are there any rules? In 1,1-dimethylallyl the cation is positive: which type of carbon is that, tertiary? In 1,3-butadiene is the act

Ozonolysis of alpha-terpinene

Ignore Structure A in the attached .jpg for this problem. Use only structures C and B Alpha -Terpinene, C10H16, a terpene found in coriander oil, absorbs only two moles of hydrogen, forming p-menthane, C10H20. Ozonolysis of Alpha -terpinene yields structure C in the attached .jpg; permanganate cleavage yields structure B.

Splitting pattern predictions

Help required for predicting the splitting patterns expected for each proton (proton 1 and proton 2) in 2,3-dimethylbutane. What is the number of adjacent hydrogens and what are the splitting patterns?

13C NMR spectral data

I need help with matching the spectral data to the correct structures. Please see attachment.

Stereochemistry of Anthracene and Polycyclic Benzenoid

I need some help with these two questions on stereochemistry, bonding and formation. 1. There are four reasonable resonance structures for anthracene. Draw them. 2. A large number of polycyclic benzenoid aromatic hydrocarbons are known. One of these, benz/a/pyrene, is a powerful carcinogen found in tobacco smoke. From the

SN1 Mechanism

(See attached file for full problem description with reaction) --- Consider the reaction below: If the above reaction occurs via an SN1 reaction mechanism, then propose an explanation for why a racemic mixture is not formed in this reaction. ---

Treatment of one stereoisomer of 2-iodo-3-phenylbutane

PROBLEM: Treatment of one stereoisomer of (2 ?, 3R)-2-iodo-3-phenylbutane with base, yields (E)-2-phenylbutene. a) Determine which enantiomer of 2-iodo-3-phenylbutene gives the E product (2R, 3R or 2S, 3R), and explain clearly (using unambiguous diagrams) why that is the case. b) Assign that enantiomer as either R or

Fischer projections

9. a. Using Fischer projections, draw all the possible stereoisomers 2, 4-dihydroxybutane (CH3-CHOH-CHOH-CH3) b. Label the relationships of your answers in "A" as enantiomers, diastereomers, or Meso ( if any) c. Assign absolute configurations to the chiral carbons n one of your Fischer projections. d. Indicate which of the

Aromatic compounds - trisubstituted derivatives

(See attached file for full problem description) How many possible trisubstituted derivatives C6H3X2Y can be obtained from the meta disubstituted benzene C5H4X2? (Ignore directive effects of the substituents X and assume that all positions on the ring are accessible to the reagent Y+)

Structures of Alkyl Halide

Match the structures below with the best description of the type of alkyl halide... See attached. Provide structures of products for the following reactions. Include 3-dimensional stereochemistry and absolute configurations where appropriate. If more than one product is possible, circle that which is predominant.

Organic Chemistry - Chlorination of Propane

The chlorination of propane yields 4 different dichloropropanes of formula C3H6Cl2. Using the following information to identify dichloropropanes A,B,C,D. i. If each dichloropropane is further chlorinated to yield trichloropropanes. Compound A gave one trichloropropane, B gave two, C and D each gave three. ii. Dichloropropane D

Hydrocarbon Chemistry Problems

1. For the compound, 1,2-dibromoethane, the most stable conformation would be a. eclipsed (0 degrees) b. gauche (60 degrees) c. eclipsed (90 degrees) d. anti (120 degrees) 2. The compound, 1,3-dimethylcyclobutane, is a constitutional isomer of which of the following? a. 1,3-dimethylcyclohexane b. 2,4-dimethylcyclobu

Enantiomer of cis-1-chloro-3-methylcyclopentane

Draw the enantiomer of cis-1-chloro-3-methylcyclopentane which is R at C-1. 1) What is the configuration of this molecule at C-3 (R and S)? 2) When cis-1-chloro-3-methylcyclopentane and trans-1-chloro-3-methylcyclopentane are treated with sodium iodide in aqueous acetone, their rates of substitution are strikingly differ