Passage
Malaria is caused by the parasite Plasmodium falciparum and is transmitted through a female mosquito bite. Although there are antimalarial treatments available, P. falciparum has become resistant to many of these drugs. P. falciparum cells contain a respiratory organelle called the apicoplast that is necessary for the parasite's survival but is not found in humans. Therefore, a new drug that targets this organelle could be useful in the treatment of malaria.A portion of the apicoplast protein ferredoxin (PfFd) is shown in Figure 1, with certain amino acid residues labeled. In the apicoplast, ferredoxin NADP⁺ reductase (PfFNR) interacts electrostatically with PfFd and catalyzes an electron transfer reaction. A compound that selectively inhibits this interaction could be a beneficial antimalarial agent.
Figure 1 Structure of a portion of PfFdChalcone (Compound 3) is a compound that interacts with PfFd and exhibits antimalarial properties. A series of chalcone derivatives (Compounds 4-8) were synthesized via the aldol condensation shown in Scheme 1, where nucleophilic addition of Compound 1 to Compound 2 is followed by elimination to yield α,β-unsaturated carbonyl molecules, Compounds 3-8.
Scheme 1An inhibition assay was performed to compare chalcone (Compound 3) and its derivatives by determining the extent to which these compounds inhibited electron transfer between PfFNR and PfFd (Table 1) .Table 1 Inhibition of electron transfer assay results
Adapted from H. Suwito et al. "Design and synthesis of chalcone derivatives as inhibitors of the ferredoxin - ferredoxin-NADP+ reductase interaction of Plasmodium falciparum: pursuing new antimalarial agents." Molecules. ©2014 MDPI.
-If Compound 4 is heated and treated with a base, which of the following functional groups would result from this reaction?

Question

Passage
Malaria is caused by the parasite Plasmodium falciparum and is transmitted through a female mosquito bite. Although there are antimalarial treatments available, P. falciparum has become resistant to many of these drugs. P. falciparum cells contain a respiratory organelle called the apicoplast that is necessary for the parasite's survival but is not found in humans. Therefore, a new drug that targets this organelle could be useful in the treatment of malaria.A portion of the apicoplast protein ferredoxin (PfFd) is shown in Figure 1, with certain amino acid residues labeled. In the apicoplast, ferredoxin NADP⁺ reductase (PfFNR) interacts electrostatically with PfFd and catalyzes an electron transfer reaction. A compound that selectively inhibits this interaction could be a beneficial antimalarial agent.

Figure 1 Structure of a portion of PfFdChalcone (Compound 3) is a compound that interacts with PfFd and exhibits antimalarial properties. A series of chalcone derivatives (Compounds 4-8) were synthesized via the aldol condensation shown in Scheme 1, where nucleophilic addition of Compound 1 to Compound 2 is followed by elimination to yield α,β-unsaturated carbonyl molecules, Compounds 3-8.

Scheme 1An inhibition assay was performed to compare chalcone (Compound 3) and its derivatives by determining the extent to which these compounds inhibited electron transfer between PfFNR and PfFd (Table 1) .Table 1 Inhibition of electron transfer assay results

Adapted from H. Suwito et al. "Design and synthesis of chalcone derivatives as inhibitors of the ferredoxin - ferredoxin-NADP+ reductase interaction of Plasmodium falciparum: pursuing new antimalarial agents." Molecules. ©2014 MDPI.
-If Compound 4 is heated and treated with a base, which of the following functional groups would result from this reaction?

Quizplus · Accepted Answer

11ecba2d_12a4_d68b_a3bf_53273b5d4fac_MD0008_00 A retro-aldol reaction is the reverse of an aldol condensation. Either the aldol product (β-hydroxy ketone) or the dehydration product (enone or enal) is heated and treated with base, causing the carbon-carbon bond between the α- and β-carbons to break. The retro-aldol reaction yields two products: either two ketones, two aldehydes, or one of each. The products depend on the substituents on the carbonyl carbon and the β-carbon. If the carbonyl carbon is bonded to a hydrogen atom before the reaction (ie, it was already an aldehyde), it will still be an aldehyde after the reaction. If the β-carbon is bonded to a hydrogen, it will become an aldehyde. If the carbonyl or β-carbon are not bonded to hydrogen, they will become ketones. Compound 4 is an enone in which the β-carbon is bonded to hydrogen and the carbonyl carbon is not. Therefore, a ketone will form from the carbonyl and an aldehyde will form from the β-carbon when Compound 4 is heated and treated with a base. (Choice B) A ketone is formed in this retro-aldol reaction, but the other product is an aldehyde rather than an alcohol. An alcohol cannot be a product of a retro-aldol reaction. (Choice C) Because the carbonyl carbon is not bonded to any hydrogen atoms, it will not form an aldehyde. (Choice D) Because the β-carbon contains a hydrogen substituent, it will not form a ketone. Educational objective: The retro-aldol reaction is the reverse of the aldol condensation. When heated and treated with base, the carbon-carbon bond between the α- and β-carbons is broken, forming two ketones or two aldehydes, or one of each, depending on the substituents on the carbonyl carbon and the β-carbon. Aldehydes form if the carbonyl and/or β-carbon has hydrogen substituents, whereas ketones form if all substituents are carbon chains.

Passage Malaria Is Caused by the Parasite Plasmodium Falciparum and Is