Of the early antihistamines, most had a side effect of mild sedation; they made a person sleepy. More recently, a new generation of nonsedating antihistamines known as hista- mine H, receptor antagonists has been introduced. One of the most widely prescribed of these is fexofenadine (Allegra). This compound is nonsedating because the polarity of its carboxylic anion prevents it from crossing the blood-brain barrier. Following is a retrosynthetic analysis for the synthesis of fexofenadine. COOH HO Fexofenadine (Allegra) go H. COO НО (H) (C) NH Br COOH Br HO 4-Bromobutanal (В) (G) CN (F) Br (4-Bromophenyl)ethanenitrile (A) Br NH OEt Bromo- Ethyl 4-piperidine- carboxylate (E) benzene (D) (Note: The organolithium reagent C cannot be made directly from B because the pres- ence of the carboxyl group in B would lead to intermolecular destruction of the reagent by an acid-base reaction. In practice, B is first converted to its sodium salt by treatment with sodium hydride, NaH, and then the organolithium reagent is prepared.)
Of the early antihistamines, most had a side effect of mild sedation; they made a person sleepy. More recently, a new generation of nonsedating antihistamines known as hista- mine H, receptor antagonists has been introduced. One of the most widely prescribed of these is fexofenadine (Allegra). This compound is nonsedating because the polarity of its carboxylic anion prevents it from crossing the blood-brain barrier. Following is a retrosynthetic analysis for the synthesis of fexofenadine. COOH HO Fexofenadine (Allegra) go H. COO НО (H) (C) NH Br COOH Br HO 4-Bromobutanal (В) (G) CN (F) Br (4-Bromophenyl)ethanenitrile (A) Br NH OEt Bromo- Ethyl 4-piperidine- carboxylate (E) benzene (D) (Note: The organolithium reagent C cannot be made directly from B because the pres- ence of the carboxyl group in B would lead to intermolecular destruction of the reagent by an acid-base reaction. In practice, B is first converted to its sodium salt by treatment with sodium hydride, NaH, and then the organolithium reagent is prepared.)
Chemistry
10th Edition
ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
Section: Chapter Questions
Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
Related questions
Question
Is fexofenadine chiral? If so, which of the possible stereoisomers are formed in this synthesis?
Transcribed Image Text:Of the early antihistamines, most had a side effect of mild sedation; they made a person
sleepy. More recently, a new generation of nonsedating antihistamines known as hista-
mine H, receptor antagonists has been introduced. One of the most widely prescribed
of these is fexofenadine (Allegra). This compound is nonsedating because the polarity
of its carboxylic anion prevents it from crossing the blood-brain barrier. Following is a
retrosynthetic analysis for the synthesis of fexofenadine.
COOH
HO
Fexofenadine
(Allegra)
go
H.
COO
НО
(H)
(C)
Transcribed Image Text:NH
Br
COOH
Br
HO
4-Bromobutanal
(В)
(G)
CN
(F)
Br
(4-Bromophenyl)ethanenitrile
(A)
Br
NH
OEt
Bromo-
Ethyl 4-piperidine-
carboxylate
(E)
benzene
(D)
(Note: The organolithium reagent C cannot be made directly from B because the pres-
ence of the carboxyl group in B would lead to intermolecular destruction of the reagent
by an acid-base reaction. In practice, B is first converted to its sodium salt by treatment
with sodium hydride, NaH, and then the organolithium reagent is prepared.)
Expert Solution
This question has been solved!
Explore an expertly crafted, step-by-step solution for a thorough understanding of key concepts.
Step by step
Solved in 3 steps with 4 images
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, chemistry and related others by exploring similar questions and additional content below.Recommended textbooks for you
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Chemistry
Chemistry
ISBN:
9781305957404
Author:
Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:
Cengage Learning
Chemistry
Chemistry
ISBN:
9781259911156
Author:
Raymond Chang Dr., Jason Overby Professor
Publisher:
McGraw-Hill Education
Principles of Instrumental Analysis
Chemistry
ISBN:
9781305577213
Author:
Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:
Cengage Learning
Organic Chemistry
Chemistry
ISBN:
9780078021558
Author:
Janice Gorzynski Smith Dr.
Publisher:
McGraw-Hill Education
Chemistry: Principles and Reactions
Chemistry
ISBN:
9781305079373
Author:
William L. Masterton, Cecile N. Hurley
Publisher:
Cengage Learning
Elementary Principles of Chemical Processes, Bind…
Chemistry
ISBN:
9781118431221
Author:
Richard M. Felder, Ronald W. Rousseau, Lisa G. Bullard
Publisher:
WILEY