Sulfanilamides, first antibiotics

There are two possible explanations for this. Either the very tiny amount of unprotonated amine reacts very rapidly with SO 3 in the para position or the reaction is reversible and the para-sulfonic acid is formed because it is stabilized by delocalization and least hindered. The product is important because the amides derived from it (sulfanilamides) were the first antibiotics, the sulfa drugs. 

The product is important because the amides derived from it (sulfanilamides) were the first antibiotics, the sulfa drugs. 

Animals are unable to synthesize folic acid (6.62) and must consume adequate quantities in their diets. Plants and bacteria, however, are able to make folic acid. The first step of this synthesis is catalyzed by dihydropteroate synthetase and reacts dihydroptero-ate diphosphate (6.69) and para-aminobenzoic acid (PABA, 6.70) (Figure 6.25). Because this pathway is not found in humans, inhibition of the reaction is a method to ultimately stop TMP synthesis in an invading bacterium while not impacting the infected host. The sulfonamides, often called sulfa drugs, are a class of antibiotic that exploits the folic acid pathway and inhibits dihydropteroate synthetase. Sulfa drugs bind in the same fashion as PABA and act as competitive inhibitors. The active form of the first sulfa drug is sulfanilamide (6.71). Sulfamethoxazole (6.72) is a sulfa drug that is widely prescribed today.26... 

The fact that Prontosil was inactive in vitro but active in vivo should have suggested that the dye was converted to an active compound by the mammalian organism, but this did not occur to the bacteriologists, who were content to have found a useful antibiotic. When scientists at the Pasteur Institute later investigated Prontosil, they noted that mice given the drug did not excrete a red compound. Urine analysis showed that the mice excreted para-acetamidobenzenesulfonamide, a colorless compound. Chemists knew that anilines are acetylated in vivo, so they prepared the nonacetylated compound (sulfanilamide). When sulfanilamide was tested in mice infected with streptococcus, all the mice were cured, whereas untreated control mice died. Sulfanilamide was the first of the sulfa dmgs. 

In Experiments 3A and 3B, you will carry out a crystallization of impure sulfanilamide using 95% ethyl alcohol as the solvent. Sulfanilamide is one of the sulfa drugs, the first generation of antibiotics to be used in successfully treating many major diseases, such as malaria, tuberculosis, and leprosy (see the essay "Sulfa Drugs," which precedes Experiment 46). 

The drug sulfanilamide (the first of the antibiotics), which is obtained... 

Protonsil is an example of a prodrug, a compound that becomes an effective drug only after it undergoes a reaction in the body. Sulfanilamide was the first of the sulfa drugs, and the sulfa drugs were the first class of antibiotics. Sulfanilamide acts by inhibiting the bacterial enzyme that synthesizes foUc acid, a compound that bacteria need for growth (Section 24.8). 

Sulfonamides—commonly known as sulfa drugs—were introduced clinically in 1934 as the first effective antibiotics (Section 19.22). Donald Woods, a British bacteriologist, noticed that sulfanilamide, initially the most widely used sulfonamide, was structurally similar to /)-aminobenzoic acid, a compound necessary for bacterial growth. 

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