Origin of the thiopyrone CTP-431 “unexpectedly” isolated from the marine sponge Cacospongia mycofijiensis

An intriguing hypothesis that latrunculin A, a well-known natural product, might have undergone transformation into the unprecedented thiopyrone CTP-431 upon long-term storage in methanol is advanced. Thus opening of the hemiacetal of latrunculin A, followed by E1CB elimination, and dehydration would give a polyene that could undergo intramolecular Diels-Alder reaction, followed by methanolysis of the thiazolidinone ring and ring closure by intramolecular thiol addition to an enone. Experimental evidence that the novel thiazolidinone to thiopyrone rearrangement can occur is presented.The marine sponge Cacospongia mycofijiensis, found in the ocean surrounding Fiji, is a source of several polyketide natural products with interesting biological properties,1 including the tubulin binding macrolide fijianolide B (also known as laulimalide),2,3 the HIF1 signal inhibitor mycothiazole,4,5 and the macrolide latrunculins (Figure 1).6 The thiazolidinone-containing latruculins are of mixed polyketide synthesis (PKS) and non-ribosomal peptide synthesis (NRPS) origin, and latrunculin A 1 disrupts microfilament assembly to such an extent that it is the most widely used chemical tool to study actin binding

Origin of the Thiopyrone CTP-431 “Unexpectedly” Isolated from the Marine Sponge <i>Cacospongia mycofijiensis</i>

An intriguing hypothesis that latrunculin A, a well-known natural product, might have undergone transformation into the unprecedented thiopyrone CTP-431 upon long-term storage in methanol is advanced. Thus, opening of the hemiacetal of latrunculin A, followed by E1CB elimination, and dehydration would give a polyene that could undergo intramolecular Diels–Alder reaction, followed by methanolysis of the thiazolidinone ring and ring closure by intramolecular thiol addition to an enone. Experimental evidence that the novel thiazolidinone to thiopyrone rearrangement can occur is presented

Origin of the Thiopyrone CTP-431 “Unexpectedly” Isolated from the Marine Sponge <i>Cacospongia mycofijiensis</i>

An intriguing hypothesis that latrunculin A, a well-known natural product, might have undergone transformation into the unprecedented thiopyrone CTP-431 upon long-term storage in methanol is advanced. Thus, opening of the hemiacetal of latrunculin A, followed by E1CB elimination, and dehydration would give a polyene that could undergo intramolecular Diels–Alder reaction, followed by methanolysis of the thiazolidinone ring and ring closure by intramolecular thiol addition to an enone. Experimental evidence that the novel thiazolidinone to thiopyrone rearrangement can occur is presented

Origin of the Thiopyrone CTP-431 “Unexpectedly” Isolated from the Marine Sponge <i>Cacospongia mycofijiensis</i>

An intriguing hypothesis that latrunculin A, a well-known natural product, might have undergone transformation into the unprecedented thiopyrone CTP-431 upon long-term storage in methanol is advanced. Thus, opening of the hemiacetal of latrunculin A, followed by E1CB elimination, and dehydration would give a polyene that could undergo intramolecular Diels–Alder reaction, followed by methanolysis of the thiazolidinone ring and ring closure by intramolecular thiol addition to an enone. Experimental evidence that the novel thiazolidinone to thiopyrone rearrangement can occur is presented