The Solid-State and Solution Conformations of (+)-Chelidonine

✍ Scribed by Miyoko Kamigauchi; Yuko Miyamoto; Kinuko Iwasa; Makiko Sugiura; Zjujiro Nishijo; Narao Takao; Toshimasa Ishida; Yasuko In; Masatoshi Inoue

• Publisher: John Wiley and Sons
• Year: 1990
• Tongue: German
• Weight: 409 KB
• Volume: 73
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19900730813

✦ Synopsis

Abstract

The solid‐state and solution conformations of (+)‐chelidonine (1), a biologically active alkaloid, were determined by X‐ray diffraction and ^1^H‐NMR spectroscopy, X‐Ray diffraction analysis revealed a conformer with B/C ‘anti‐type’ cis conjunction, a half‐chair of ring B, and a twist half‐chair of ring C. One H~2~O molecule per one alkaloid molecule was cocrystallized and stabilized by H‐bonding with OHC(11). Analysis of the thermal behavior of the crystal showed more thermal stability in the monohydrate than the anhydrate. The NMR measurement of concentration and temperature dependences in CDCl~3~ and in (CD~3~)~2~SO suggested that the OH group of 1 was intramolecularly H‐bonded to N(5) in (CD~3~)~2~SO and intermolecularly H‐bonded to the solvent in CDCl~3~. Conformational‐energy calculations by the MNDO method showed that the intramolecular H‐bond was little affected by the conformational stabilization of 1.