![]() ![]() Or you can buy them in a bottle. Sigma-Aldrich sells both (Figure 3).įigure 3. So it is no coincidence that S-carvone comes from spearmint plants and R-carvone comes from caraway seeds. If you open a bottle of the S-form you will smell caraway seeds (think: rye bread). If you open a bottle of the R-form you will smell spearmint. This is already interesting" or my feelings are gonna be hurt. And you'd damn well better say "Yes, Josh. ![]() This is where things get interesting (assuming that they haven't already been). (Left) Carvone (drawn in 2D) contains one asymmetric carbon (green dot) because it is bound to 4 different "things." (Right) The two carvone enantiomers in a 3D representation (1). So there are two enantiomers, both found in nature, that are mirror images of each other. In the case of carvone, it is clear that there is one asymmetric carbon atom (Figure 2). Space-filling models of carvone (Left) and benzene (Right). Enantiomers almost always have different biological properties. Rather, they are mirror images of each other. The definition of identical molecules is those that can be superimposed on each other. Although these have the same chemical formula they are not identical. Two hypothetical molecules in which a carbon atom (gray) is bound to four different substituents (aka "things"). This is because carbon is tetrahedral, not flat (1), at least most of the time (Figure 2).įigure 1. Once this happens that molecule can exist in two forms (Figure 1). Anytime that carbon atom is bound to four different substituents (a term that refers to atoms or groups of atoms) that carbon atom loses its symmetry (not surprisingly, these are called asymmetric carbon atoms). Here is the chemical structure of carvone in 2D:īut there is a topic in organic chemistry that has been the demise of many pre-meds - stereochemistry, which exists because carbon, the element which makes organic chemicals organic, always has four bonds, either to itself or other atoms. All you have to do is think about mirrors. This seemingly strange phenomenon, which is called asymmetry or chirality, is actually quite logical. These two sources are not accidental they perfectly demonstrate how some molecules, although they are seemingly identical are subtly different when displayed in 3D. Carvone is terpene (See Essential Oils - Not What The Name Implies) which is found widely in plants, mostly in caraway seeds and spearmint leaves. ![]()
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