Norephedrine is a decongestant and appetite suppressant found in some cough-cold formulations; it is one of the stereoisomers of 2-amino-1-phenylpropan-1-ol.
(a) How many stereoisomers are possible for norephedrine?
(b) Assign the R/S configuration of the stereoisomer shown.

Question

Norephedrine is a decongestant and appetite suppressant found in some cough-cold formulations; it is one of the stereoisomers of 2-amino-1-phenylpropan-1-ol.

structure

(a) How many stereoisomers are possible for norephedrine?

(b) Assign the R/S configuration of the stereoisomer shown.

TestHub · Accepted Answer

(a) Norephedrine, C 6 H 5 -CH(OH)-CH(NH 2 )-CH 3 , has two asymmetric centres and no internal symmetry, so the number of stereoisomers = 2 2 = 4. (b) C 1 : priorities OH > C 6 H 5 > C 2 (N) > H; with H behind, the order runs anticlockwise : S. C 2 : priorities NH 2 > C 1 (O) > CH 3 > H : S. The structure shown is (1S, 2S). Ans. (D) (a) 4 (b) 1S, 2S.

Chemistry - STEREO ISOMERISM Question with Solution | TestHub

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