Progress in the Chemistry of Cytochalasans
3
bioactivities, merocytochalasans have attracted considerable interest from organic
and biosynthetic chemists as well as pharmacologists.
In the process of completing this work, it was noted that there is some confusion
in the assignment of trivial names of certain cytochalasans, since either the same
compound may have different names or else different compounds have been assigned
the same name. Therefore, synonyms have been merged in this chapter, such as
“cytochalasin D (2) (zygosporin A)”. In turn, for the homonyms, these have denoted
by adding the family name of the corresponding author after the trivial name, such
as “cytochalasin N Natori (14)” and “cytochalasin N Edwards (20).” There are also
some cytochalasans reported with neither a trivial name nor a chemical name in the
original literature, so their original bolded code numbers with the relevant literature
information have been used to identify them, such as “compound 1 (68) Bioorg.
Med. Chem. Lett. 2015, 25, 1823” [7] and “compound 15ii (80) Org. Lett. 2019, 21,
4163” [8].
A conscientious effort has been made to cover cytochalasans as comprehensively
as possible in this chapter. Although not all relevant literature reports may have been
included, it is hoped that this contribution will provide a good understanding of
cytochalasans, and also may arouse additional wide scientific interest in their further
investigation.
2 The Structural Diversity of Cytochalasans and Their
Origins
Based on the different amino acids involved in their construction, cytochalasans
have been classified generally into five groups [1], including “cytochalasins” (with a
phenylalanine residue, Sect. 2.1), “pyrichalasins” (with a tyrosine or a related derivative residue, Sect. 2.2), “chaetoglobosins” (with a tryptophan residue, Sect. 2.3),
“aspochalasins” (with a leucine residue, Sect. 2.4), and “alachalasins” (with an
alanine residue, Sect. 2.5). In 2012, a new type of cytochalasan named “trichalasin” (with a valine residue, Sect. 2.6) was reported by Zou and coworkers from
Trichoderma gamsii, but this trichalasin group still has only one member, trichalasin A (477) [9]. Thus, there are altogether six groups of cytochalasans in terms of
the different amino acids incorporated into the polyketide skeleton (Fig. 1). In this
contribution, 477 cytochalasans have been included: comprising 163 cytochalasins,
46 pyrichalasins, 133 chaetoglobosins, 127 aspochalasins, seven alachalasins, and
one trichalasin (Table 1). For each group of cytochalasans, they can be divided further
into several sub-classes based mainly on the different types of macrocyclic ring fused
to the isoindolone moiety, such as a carbocyclic ring (usually with odd-numbered
carbons), a lactone ring, a carbonate ring, or a seco-ring. Merocytochalasans are
listed separately as a sub-class under the groups of cytochalasins, chaetoglobosins,
and aspochalasins. Besides changes occurring on ring C, additional modifications of
3
bioactivities, merocytochalasans have attracted considerable interest from organic
and biosynthetic chemists as well as pharmacologists.
In the process of completing this work, it was noted that there is some confusion
in the assignment of trivial names of certain cytochalasans, since either the same
compound may have different names or else different compounds have been assigned
the same name. Therefore, synonyms have been merged in this chapter, such as
“cytochalasin D (2) (zygosporin A)”. In turn, for the homonyms, these have denoted
by adding the family name of the corresponding author after the trivial name, such
as “cytochalasin N Natori (14)” and “cytochalasin N Edwards (20).” There are also
some cytochalasans reported with neither a trivial name nor a chemical name in the
original literature, so their original bolded code numbers with the relevant literature
information have been used to identify them, such as “compound 1 (68) Bioorg.
Med. Chem. Lett. 2015, 25, 1823” [7] and “compound 15ii (80) Org. Lett. 2019, 21,
4163” [8].
A conscientious effort has been made to cover cytochalasans as comprehensively
as possible in this chapter. Although not all relevant literature reports may have been
included, it is hoped that this contribution will provide a good understanding of
cytochalasans, and also may arouse additional wide scientific interest in their further
investigation.
2 The Structural Diversity of Cytochalasans and Their
Origins
Based on the different amino acids involved in their construction, cytochalasans
have been classified generally into five groups [1], including “cytochalasins” (with a
phenylalanine residue, Sect. 2.1), “pyrichalasins” (with a tyrosine or a related derivative residue, Sect. 2.2), “chaetoglobosins” (with a tryptophan residue, Sect. 2.3),
“aspochalasins” (with a leucine residue, Sect. 2.4), and “alachalasins” (with an
alanine residue, Sect. 2.5). In 2012, a new type of cytochalasan named “trichalasin” (with a valine residue, Sect. 2.6) was reported by Zou and coworkers from
Trichoderma gamsii, but this trichalasin group still has only one member, trichalasin A (477) [9]. Thus, there are altogether six groups of cytochalasans in terms of
the different amino acids incorporated into the polyketide skeleton (Fig. 1). In this
contribution, 477 cytochalasans have been included: comprising 163 cytochalasins,
46 pyrichalasins, 133 chaetoglobosins, 127 aspochalasins, seven alachalasins, and
one trichalasin (Table 1). For each group of cytochalasans, they can be divided further
into several sub-classes based mainly on the different types of macrocyclic ring fused
to the isoindolone moiety, such as a carbocyclic ring (usually with odd-numbered
carbons), a lactone ring, a carbonate ring, or a seco-ring. Merocytochalasans are
listed separately as a sub-class under the groups of cytochalasins, chaetoglobosins,
and aspochalasins. Besides changes occurring on ring C, additional modifications of