Glucopyranosylidene-spiro-benzo[b][1,4]oxazinones and -benzo[b][1,4]thiazinones: Synthesis and Investigation of Their Effects on Glycogen Phosphorylase and Plant Growth Inhibition

Sándor Kun, Nándor Kánya, Norbert Galó, András Páhi, Attila Mándi, Tibor Kurtán, Péter Makleit, Szilvia Veres, Ádám Sipos, Tibor Docsa, László Somsák

Research output: Contribution to journalArticle

Abstract

Glucopyranosylidene-spiro-benzo[b][1,4]oxazinones were obtained via the corresponding 2-nitrophenyl glycosides obtained by two methods: (a) AgOTf-promoted glycosylation of 2-nitrophenol derivatives by O-perbenzoylated methyl (α-d-gluculopyranosyl bromide)heptonate or (b) Mitsunobu-type reactions of O-perbenzoylated methyl (α-d-gluculopyranose)heptonate with bulky 2-nitrophenols in the presence of diethyl azodicarboxylate (DEAD) and PPh3. Catalytic hydrogenation (H2-Pd/C) or partial reduction (e.g., H2-Pd/C, pyridine) of the 2-nitro groups led to spiro-benzo[b][1,4]oxazinones and spiro-benzo[b][1,4]-4-hydroxyoxazinones by spontaneous ring closure of the intermediate 2-aminophenyl or 2-hydroxylamino glycosides, respectively. The analogous 2-aminophenyl thioglycosides, prepared by reactions of O-perbenzoylated methyl (α-d-gluculopyranosyl bromide)heptonate with 2-aminothiophenols, were cyclized in m-xylene at reflux temperature to the corresponding spiro-benzo[b][1,4]thiazinones. O-Debenzoylation was effected by Zemplén transesterification in both series. Spiro-configurations were determined by NMR and electronic circular dichroism time-dependent density functional theory (ECD-TDDFT) methods. Inhibition assays with rabbit muscle glycogen phosphorylase b showed (1′R)-spiro{1′,5′-anhydro-d-glucitol-1′,2-benzo[b][1,4]oxazin-3(4H)-one} and (1′R)-spiro{1′,5′-anhydro-d-glucitol-1′,2-benzo[b][1,4]thiazin-3(4H)-one} to be the most efficient inhibitors (27 and 28% inhibition at 625 μM, respectively). Plant growth tests with white mustard and garden cress indicated no effect except for (1′R)-4-hydroxyspiro{1′,5′-anhydro-d-glucitol-1′,2-benzo[b][1,4]oxazin-3(4H)-one} with the latter plant to show modest inhibition of germination (95% relative to control).

Original languageEnglish
Pages (from-to)6884-6891
Number of pages8
JournalJournal of Agricultural and Food Chemistry
Volume67
Issue number24
DOIs
Publication statusPublished - Jun 19 2019

Keywords

  • ECD-TDDFT
  • anomeric spirocycle
  • benzo[ b][1,4]oxazinone
  • benzo[ b][1,4]thiazinone
  • glycogen phosphorylase
  • inhibition
  • plant germination
  • spiro-compound

ASJC Scopus subject areas

  • Chemistry(all)
  • Agricultural and Biological Sciences(all)

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