Barbiturates, including "truth serums" seen in movies like Meet the Fockers and sedatives that may have led to the untimely death of Jimi Hendrix, are often synthesized using what type of reaction sequence involving two consecutive enolate alkylations

Explanation:

Diethyl malonate is more acidic than monocarbonyl compounds (pKa=13) due to their alpha hydrogens being attached to two carbonyl groups. Thus, the malonic ester is easily converted to its enolate ion by reaction with sodium ethoxide in ethanol. The product of the alkylation of the malonic ester leaves a hydrogen atom acid in an alpha position, so the alkylation process can be repeated a second time to produce a dialkylated malonic ester.

In this case, when urea is treated with diethyl malonate in the presence of sodium ethoxide base, the second alkylation step occurs intramolecularly to generate a cyclic product, barbituric acid.

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definition

                    entropy is a measure of the randomness or the extent of disorder of a chemical process.

                      enthalpy is a measure of the heat change of a reaction occurring at a constant pressure.

measurement units:

                        entropy is measured in joule per kelvin (jk⁻¹)   whereas enthalpy is measured in joule per mole (jmol⁻¹)

requirements:

                            entropy has no requirements or limits, and its change is measured by the division between the heat change of the chemical process and the temperature.

                              in contrast, enthalpy can only be related to the heat change of the reaction under standard conditions.