@article{oai:tiu-tijc.repo.nii.ac.jp:00000044,
 author = {柿澤, 寛 and Kakisawa, Hiroshi},
 journal = {研究紀要, Bulletin of Tsukuba International University},
 month = {Mar},
 note = {The chemical structure of ptilomicalin, an antiviral alkaloid obtained from a marine sponge, and of quartromicins, antibiotic nonalkaloids from a fungous metaborite, has been determined on the bases of chemical and spectroscopic analyses. The alkaloid is composed of a polysubstituted guanidine located in the bottom of concave carbon framework, which is connected to spermidine through ω-hydroxy fatty acid. Ptilomicalin has been found to recognize particular anions of some amino acid derivatives and to differentiate the prochiral methyl groups of isobutyric acid. The molecular features of these behaviors were deduced by detailed NMR analyses. Quartromicin A_3 has structure consisting of four tetronic acid moieties in a single macrocyclic ring and galactose. This compound exists as mixed salts of sodium and potassium when isolates. Treatment of the mixture with an aqueous solution of calcium chloride results in complete exchange of alkali metal ions initially present with calcium cation. On the contrary, an addition of sodium chloride solution to the calcium salt of A_3 caused no replacement with sodium cation at all. Moreover, the broad signals of the ^1H NMR spectrum of A_3-mixed salt remarkably sharpens in the spectrum of quartromicin A_3-Ca. This finding suggests that the calcium salt of quartromicin A_3 has a fixed conformation, presumably because calcium cations are incorporated and fixed tightly to the macrocyclic ring comprised of tetronic acids., 6, KJ00004010972, P},
 pages = {31--41},
 title = {分子認識能を有する低分子天然有機化合物},
 volume = {3},
 year = {1997},
 yomi = {カキサワ, ヒロシ}
}