Synthesis and Characterization of Aplysinopsin Analogs

Spontaneous Biomimetic Formation of (±)‐Dictazole B under Irradiation with Artificial Sunlight

“…Finally, close analysis of a previous crystallographic study of two synthetic aplysinopsin analogues not only mirrored our findings, but also opened the way to an improved understanding of the process. [28] In short, first, crystals were obtained from crystallization in DMF with a molecule of DMF incorporated into the lattice; second, a perfect head-to-tail anti arrangement between two adjacent sheets imposes a geometry that is highly favorable for the light-induced [2+2] reaction.…”

Synthesis and structure–affinity relationships of novel small molecule natural product derivatives capable of discriminating between serotonin 5-HT1A, 5-HT2A, 5-HT2C receptor subtypes

“…The 2-imino-1,3-dimethylimidazolidin-4-one and 3-ethyl-2-imino-1-methylimidazolidin-4-one were synthesized by methylation or ethylation of creatinine (2-amino-1-methyl-2-imidazolin-4-one) utilizing a procedure by Kenyon and Rowley14 (Figure 2). Single crystal structures were determined for 1 and 2 and in both cases the double bond linking the indole and imidazolidine rings (C8-C1′) were in the E-configuration15. Compounds 1 and 3–8 can exist in two tautomeric forms: one where the imine double bond is endocyclic and the other where the imine double bond is exocyclic as shown.…”

“…The procedures utilized for the synthesis of indole-3-carboxaldehydes and their halogenated derivatives were those reported previously by Jiang et al13, Johnson et al15, Kalir and Szara22, Noland and Reich23, James and Snyder24, and Somei et al25. Briefly, Phosphorus (V) oxychloride (4.25 g, 0.028 mol) was added drop wise to DMF (6 mL) cooled in an ice bath.…”

Spontaneous Biomimetic Formation of (±)‐Dictazole B under Irradiation with Artificial Sunlight

“…Nevertheless, in the presence of triplet photosensitizers, significant dimer formation was not observed. [36] In line with this hypothesis, the aforementioned crystallographic structures [28] gave us valuable indications concerning both the spatial arrangement of structures such as 3 in the solid state and the electronic structure of the creatinine moiety, which may preclude their direct dimerization. [35] Furthermore, according to Schmidt's topochemical postulate, the precise packing of molecules (i.e., with properly placed reactive centers) also controls the outcome of [2+2] photodimerization reactions in the solid state.…”

“…[28] In short, first, crystals were obtained from crystallization in DMF with a molecule of DMF incorporated into the lattice; second, a perfect head-to-tail anti arrangement between two adjacent sheets imposes a geometry that is highly favorable for the light-induced [2+2] reaction. In fact, complexation with CuOTf may move the head-to-tail stacked pair of monomers closer together, thereby shortening the distance between the reactive double bonds.…”