TY - JOUR
T1 - Confirmation of the Revised Structure of Samoquasine A and a Proposed Structural Revision of Cherimoline
AU - Dhoro, Francis
AU - Parkin-Gibbs, Jesse
AU - McIldowie, Matthew
AU - Skelton, Brian W.
AU - Piggott, Matthew J.
PY - 2018/7/27
Y1 - 2018/7/27
N2 - The identity of the natural product samoquasine A has remained obscure since its isolation from custard apple seeds in 2000. One of the proposed structures, benzo[f]phthalazin-4(3H)-one, was prepared in two steps by regioselective ortho-lithiation/formylation of N,N-diisopropyl-2-naphthylamide, followed by cyclization with hydrazine, but was shown to be different from the natural product. Perlolidine, another candidate structure, was synthesized by a novel route involving a β-selective Heck reaction of butyl vinyl ether. Both perlolidine and samoquasine A are converted by trimethylsilyldiazomethane into the same N-methyl derivative. In addition, the 13C NMR spectra of perlolidine and another structurally mis-assigned natural product, cherimoline, are almost identical. Thus, both samoquasine A and cherimoline are actually perlolidine.
AB - The identity of the natural product samoquasine A has remained obscure since its isolation from custard apple seeds in 2000. One of the proposed structures, benzo[f]phthalazin-4(3H)-one, was prepared in two steps by regioselective ortho-lithiation/formylation of N,N-diisopropyl-2-naphthylamide, followed by cyclization with hydrazine, but was shown to be different from the natural product. Perlolidine, another candidate structure, was synthesized by a novel route involving a β-selective Heck reaction of butyl vinyl ether. Both perlolidine and samoquasine A are converted by trimethylsilyldiazomethane into the same N-methyl derivative. In addition, the 13C NMR spectra of perlolidine and another structurally mis-assigned natural product, cherimoline, are almost identical. Thus, both samoquasine A and cherimoline are actually perlolidine.
UR - http://www.scopus.com/inward/record.url?scp=85050716195&partnerID=8YFLogxK
U2 - 10.1021/acs.jnatprod.8b00319
DO - 10.1021/acs.jnatprod.8b00319
M3 - Article
C2 - 30020782
AN - SCOPUS:85050716195
VL - 81
SP - 1658
EP - 1665
JO - Journal of Natural Products
JF - Journal of Natural Products
SN - 0163-3864
IS - 7
ER -