How many chiral centers are in ephedrine?

Introduction. Ephedrine has two chiral centres and can therefore exist in the form of four stereoisomers: 1R,2S-(-)-ephedrine, 1S,2R-(+)-ephedrine, 1S,2S-(+)-pseudoephedrine and 1R,2R-(-)-pseudoephedrine (Table 1).

Ephedrine is a common starting compound for methamphetamine synthesis. It possesses two chiral center carbon atoms and has Four Stereoisomers, (1R,2S)-(-)-ephedrine, (1S,2R)-(+)-ephedrine, (1S,2S)-(+)-pseudoephedrine, and (1R,2R)-(-)-pseudoephedrine.

The key to finding chiral carbons is to Look for carbons that are attached to four different substituents. We can immediately eliminate any carbons that are involved in double bonds, or that have two hydrogens attached. Given this, we find that there are three chiral carbons.

Test 1: Draw the mirror image of the molecule and see if the two molecules are the same or different. If they are different, then the molecule is chiral. If they are the same, then it is not chiral. (This is the most comprehensive test but is the most difficult to apply.)

Chiral Center Examples

The central carbon in serine is a chiral carbon. The amino group and hydrogen can rotate about the carbon. While chiral centers in organic chemistry tend to be carbon atoms, other common atoms include phosphorus, nitrogen, and sulfur. Metal atoms may also serve as chiral centers.

1 Answer

1. A) When the molecule is unsymmetrical and contains ‘n ‘ chiral carbon atoms: Total no. of stereoisomers = 2^n.
2. B) When the molecule is unsymmetrical and has even number of stereogenic centres or chiral carbon atoms: Total no. …
3. C) When the molecule is symmetrical and has odd no. of stereogenic centres.

Explanation: Diastereomers are compounds that contain Two or more Chiral centres and are not mirror images of each other. For example, the aldopentoses each contain three chiral centres. Thus, D-ribose is a diastereomer of D-arabinose, D-xylose, and D-lyxose.

Ephedrine has two chiral carbons and has Two enantiomers, (1R,2S)-(-) and (1S,2R)-(+)-ephedrine, shown in Figure 2B, and two diastereomers, (1S,2S)-(+)-pseudoephedrine and (1R,2R)-(-)-pseudoephedrine, shown in Figure 4.

Enantiomers (all Five Chiral centers are flipped). Identical (drawing is flipped vertically but they are the same structure).

Ephedrine is also used to treat breathing problems (as a bronchodilator), nasal congestion (as a decongestant), myasthenia gravis, narcolepsy, menstrual problems (dysmenorrhea), or urine-control problems. Ephedrine is available under the following different brand names: Akovaz, and Corphedra.

As a vasoconstrictor, Epinephrine is 100 to 1,000 times more potent than ephedrine. 1 Mix-ups between these two drugs have resulted in serious patient harm. The Closed Claims Project of the American Society of Anesthesiologists found that errors involving epinephrine are particularly dangerous.

To determine whether the chirality center is R or S you have to first prioritize all four groups connected to the chirality center. Then, rotate the molecule so that the fourth priority group is on a dash (pointing away from you). Finally, determine whether the sequence 1-2-3 is (R) clockwise or (S) counterclockwise.

Isocitric acid is a compound with chiral centers—carbon atoms with Four different groups bound to them. There are always two versions of a chiral center, one being the mirror image of the other.

So the molecule has 6 chiral centres. All 6 carbons have 4 different groups attached to central carbon atoms.

The molecules which contain chiral centers and a plane of symmetry are known as Meso compounds.