The title compound C22H39NO9·CH3OH [systematic name: (S)-N-((S)-{(2S,4R,6R)-6-[(S)-2,3-di-hydroxy-prop-yl]-4-hy-droxy-5,5-di-methyl-tetra-hydro-2H-pyran-2-yl}(hy-droxy)meth-yl)-2-hy-droxy-2-[(2R,5R,6R)-2-meth-oxy-5,6-dimeth-yl-4-methyl-ene-tetra-hydro-2H-pyran-2-yl]acetamide methanol monosolvate], was isolated from the Asian citrus psyllid, Diaphorina citri Kuwayama, and crystallizes in the space group P21. 'Candidatus Profftella armatura' a bacterial endosymbiont of D. citri, biosynthesizes diaphorin, which is a hybrid polyketide-nonribosomal peptide comprising two highly substituted tetra-hydro-pyran rings joined by an N-acyl aminal bridge [Nakabachi et al. (2013 ▸). Curr. Biol.23, 1478-1484]. The crystal structure of the title compound establishes the complete relative configuration of diaphorin, which agrees at all nine chiral centers with the structure of the methanol monosolvate of the di-p-bromo-benzoate derivative of pederin, a biogenically related compound whose crystal structure was reported previously [Furusaki et al. (1968 ▸). Tetra-hedron Lett.9, 6301-6304]. Thus, the absolute configuration of diaphorin is proposed by analogy to that of pederin.
Keywords: Diaphorina citri; crystal structure; diaphorin; hydrogen bonding; pederin; ‘Candidatus Profftella armatura’.