Limits
In all instances only esters can be used with stable acyl components that can withstand the harsh conditions of the Fries rearrangement. If the aromatic or the acyl component is heavily substituted then the chemical yield will drop due to steric constraints. Deactivating meta-directing groups on the benzene group will also have an adverse effect as can be expected for a Friedel–Crafts acylation.
Read more about this topic: Fries Rearrangement
Famous quotes containing the word limits:
“As nature requires whirlwinds and cyclones to release its excessive force in a violent revolt against its own existence, so the spirit requires a demonic human being from time to time whose excessive strength rebels against the community of thought and the monotony of morality ... only by looking at those beyond its limits does humanity come to know its own utmost limits.”
—Stefan Zweig (18811942)
“This teaching is not practical in the sense in which the New Testament is. It is not always sound sense in practice. The Brahman never proposes courageously to assault evil, but patiently to starve it out. His active faculties are paralyzed by the idea of caste, of impassable limits of destiny and the tyranny of time.”
—Henry David Thoreau (1817–1862)
“Europe has what we do not have yet, a sense of the mysterious and inexorable limits of life, a sense, in a word, of tragedy. And we have what they sorely need: a sense of life’s possibilities.”
—James Baldwin (1924–1987)