Organic Synthesis – list of problems
The following list of Organic Synthesis problems deals with the three aspects described below:
- Reactivity of molecules with more than one functional group.
- Synthetic sequences involving the chemistry of different functional groups.
- Preparation of molecules from fragments with a smaller number of carbon atoms.
From acetylene and as many reagents as you think necessary, prepare the Z and E isomers of 6-methylhept-3-ene.
Obtain 1-phenylpropan-2-one from (bromomethyl)benzene.
Design a procedure to obtain 2-phenylacetamide from bromobenzene.
Suggest a procedure to perform the following transformations:
Pentyl bromide is reacted with magnesium in ether to give compound A. A reacts with ethylene oxide followed by aqueous acid to give B. When B is oxidized with PPC in CH2Cl2 it gives C, which reacts with phenylmagnesium bromide to give D, after treating with aqueous hydrochloric acid. Determine the structures of compounds A, B, C and D, based on the sequence of reactions described.
Describe a procedure to obtain 6-methyltetrahydro-2H-pyran-2-one (δ-caprolactone) from 4-bromobutanal.
Employing cyclohex-2-enone as starting material prepare 4-oxocyclohex-2-enocarboxylic acid.
Ethyl p-aminobenzoate is commercially known as benzocaine. It is widely used in medicine as a local anesthetic. Design a procedure to obtain such a product from benzene.
Design a procedure for the synthesis of methyl pentanoate from 1-bromobutane.
Using as starting products or carbon source compounds (I-V), design a synthetic procedure for the preparation of a) and b).
Starting from ethanol, as the only carbon compound, describe a synthesis for the following molecules:
Deduce in a reasoned way, which compounds from the following list will be obtained more easily by a malonic synthesis.
An alkene of molecular formula C6H12 gives by ozonolysis propanal as the only product. Treatment with a peracid leads to an optically active compound. Propose the structure of such an alkene.
Complete the following table, taking into account the stereochemistry of the compounds obtained (A-X).
|Br2 / Cl4C||H2O2 / OsO4 (cat.)||Ozonolysis||KMnO4 (hot)||Peracids||HBr / peroxides|
Complete the following table (A-I) of reactivity of alcohols.
|PCC /CH2Cl2||CrO3 / H3O+||KMnO4|
Complete the following table (A-P):
Complete the following scheme (A-K):
Design a procedure to prepare propane-1,1,1,2,3-tetracarboxylic acid from:
Indicate the reagents (A-M) needed to perform the following transformations:
Deduce the structures of the compounds A-F.
Complete the scheme (A-G):
Deduce the structures of the compounds (A-G) shown in the scheme, from the reactions that take place.
Propose a procedure to perform the following transformations (a-d):
Complete the scheme, describing the reactants A-G.
Complete the following scheme (A-E), indicating the reagents needed for this purpose, and keeping in mind that transformations A and D require two steps.
Design a procedure to perform the following synthesis:
Complete (A-D) the synthesis of 5-ethyl-6-methylhepta-1,6-diol from allyl bromide, according to the following scheme:
Describe the reactions necessary to transform the reagent methyl 6-oxoheptanoate into the product 6-oxoheptyl benzoate.
When acetic acid is treated with bromine in the presence of phosphorus, compound A is obtained. Reaction of A with NaCN / DMSO leads to the formation of B. If B is reacted with an aqueous mineral acid in the presence of ethanol C (C7H12O4) is obtained. If C is treated with sodium ethoxide in ethanol, followed by benzyl bromide leads to the formation of D (C14H18O4). Hot acid hydrolysis of D leads to E (C9H10O2). Deduce the structures of A, B, C, D and E.
A compound A of molecular formula C7H14O can be obtained from B (C6H10O) or from C (C7H12) interchangeably. When it is obtained from B, lithium dimethylcuprate is needed, whereas if it is prepared from C it is necessary to use diborane, followed by H2O2 in basic medium. Determine the structures of A, B and C, knowing that B is synthesized from cyclohexene and peracetic acid.
Bromobenzene reacts with magnesium in THF to give compound A. A is transformed by bubbling CO2 and treating with an acid, to give B (C7H6O2). Treatment of B with methanol in acid medium leads to C (C8H8O2). When C is reacted with 2 mol of A and subsequent acidification, D (C19H16O) is obtained. Deduce the structures A, B, C and D based on the reactions described.
Design a synthetic route to perform the following transformation:
Cyclopentene when treated with a mineral acid leads to the formation of a compound A which when the corresponding calculation is carried out, presents an unsaturation. When A is treated with potassium dichromate in an acidic medium B is obtained. The reaction of B with m-chloroperbenzoic acid leads to the formation of C. Deduce the structures of compounds A-C.
Design a feasible procedure for the preparation of the following compounds (a-d) by malonic or acetylacetic and related syntheses.
The molecule known as disparlura is a pheromone of a moth species, the synthesis of which is partially described in the following scheme. Deduce the structure of the compound.
From cyclohexanone, prepare the following compounds (a-d):
Design a procedure for the preparation of the following compound from benzenonitrile.
Starting from cyclopentene, prepare compounds (a) and (b).
Complete the scheme, describing the reagents A-F.