* Reagents : most commonly the base would be the alkoxide, R'O- * The reaction involves an ester enolate reacting with another molecule of the ester. * Remember enolates are good nucleophiles and the ester carbonyl C are electrophilic. * The products of these reactions are ketoesters which are important, useful synthetic intermediates. * Note that the product is the original ester with an acyl group added i.e. an acylation reaction has occurred.
1 Chemistry 250 Stereochemistry Workshop Question 2 ( 6 min) Febraury 2013 Two cis-trans isomers exist for 1-bromo-3-methylcyclohexane; they are cis-1-bromo-3-methylcyclohexane and trans-1bromo-3-methylcyclohexane: Two different chair conformations (Conformation 1 and Conformation 2) of cyclohexane with carbon atoms numbered 1 – 6 are given below. For the cis-1,3-dimethylcyclohexane draw methyl groups at carbons 1 and 3 in each of its two possible conformations. (2 marks) In each conformation, indicate whether the methyl groups are axial or equatorial. Which of the two conformations is more stable? Conformation ___2___ is the more stable (1 mark) In a similar fashion, draw the two conformations for trans-1-bromo-3-methylcyclohexane.
Substitutive Nomenclature: treats the halogen as a halo substituent on an alkane chain. The carbon chain is numbered in the direction that gives the substituted carbon the lower number. 4.3 IUPAC Nomenclature of Alcohols Place the Ol at the end 4.4 Classes of Alcohols and Alkyl
a) for a we first need to find a balanced equation for when the hydrocarbons combust to form CO2 and H20. Then we plug in the deltaHf values and plug these into the equation. a) C4H6 + 11/2O2 ==> 4CO2 + 3H2O Delta Hrxn = [4DeltaHf(CO2)+3DeltaHf(H2O)] - [DeltaHf(C4H6) + 11/2DeltaHf(O2)] = [4(-393.5kJ) + 3(-285.83kJ)] - [111.9kJ + 11/2(0kJ)] = -2543.39kJ C4H8 + 6O2 ==> 4CO2 + 4H2O Delta H rxn = [4DeltaHf(CO2) + 4DeltaHf(H2O)] - [DeltaHf(C4H8) + 6DeltaHf(O2)] = [4(-393.5kJ) + 4(-285.83kJ)] - [1.2kJ +6(0kJ)] = -2718.52kJ C4H10 +13/2O2 ==> 4CO2 +5H2O DeltaHrxn = [4DeltaHf(CO2) + 5DeltaHf(H2O)] - [DeltaHf(C4H10) + 13/2DeltaHf(O2)] = [4(-393.5kJ) + 5(-285.83kJ)] - [-124.7kJ +
Of course, before this can happen the pyruvic acid has to be converted into a form the citric acid cycle can actually use. The first step in regards to the citric acid cycle is that the pyruvic acid loses a carbon as CO2. In turn, the fuel molecules that are left are called acetic acid; and the oxidation of the fuel creates NADH. Lastly, “the acetic acid is attached to a molecule called coenzyme A (CoA) to form acetyl CoA. The CoA escorts the acetic acid into the first reaction of the citric acid cycle,” (Simon, E. J., Reece, J.
2 marks 4 Draw the structural formula of Compound G. 1 mark 5 Using the chemical shift correlation for 13C NMR, predict the number of peaks for Compound G and draw in the position of the peaks on the blank spectrum below, annotating each peak with its corresponding structure. (2 marks) 6 Draw the structural formula for 2-chloro but-2-ene. Below this draw a structural formula of an isomer of 2-chloro but-2-ene and name this substance.
The acid protonates the hydroxyl group, which creates water, a good leaving group. A beta hydrogen is then involved in the E1 process and a C=C double bond is formed. Since the starting material is not symmetric we obtain a mixture of products, with 1-Methylcyclohexene as the major product according to Zaitsev’s Rule. (1) The product is obtained by distillation, where it is accompanied by water and some phosphoric acid. Because of this, anhydrous sodium sulfate is used to remove the water from the solution.
lder report Lab 5: Diels-Alder Reaction The laboratory procedure used was written by Dr. John Barbaro of Rocky Mountain College. The Diels-Alder reaction is a well known example of cycloaddition chemistry. It is commonly known as [4+2] Cycloaddition. The reactants in the Diels-Alder reaction are a 1,3-diene and an alkene called the dienophile. The dienophile usually contains an electron-withdrawing group that is in conjugation to the double bond, making the double bond “electron poor”, thus initiating the addition reaction.
A) Cystine forms when the —CH2—SH R group is oxidized to form a —CH2—S—S—CH2— disulfide bridge between two cysteines. B) Cystine is an example of a nonstandard amino acid, derived by linking two standard amino acids. C) Cystine is formed by the oxidation of the carboxylic acid group on cysteine. D) Cystine is formed through a peptide linkage between two cysteines. E) Two cystines are released when a —CH2—S—S—CH2— disulfide bridge is reduced to —CH2—SH.
But HOH is a weaker base, and better leaving group. Adding a strong acid to the mixture allows protonation of the –OH group to give water as a leaving group. Once this protonation occurs, the mechanism that is followed depends on the nature of the R group (Williamson, Kenneth L.). In the presence of a strong acid, an alcohol can be dehydrated to form an alkene. The acid used in this experiment is 85% phosphoric acid and the alcohol is cyclohexanol.