The application of activated carbon (Darco KB) for the acceleration and direction of the transformation of various 2H-pyran-2-ones with N-substituted maleimides toward isoindole derivatives through the reaction sequence cycloaddition/elimination/dehydrogenation is described. In this reaction, the catalyst mainly influences the dehydrogenation step, which is essential to avoid the formation of bicyclo[2.2.2]octenes as the other possible products. We found that the combination of Darco KB, as the metal-free catalyst, and decalin, as the solvent in a closed vessel, represents the most successful conditions. A comparison of the effect of various dehydrogenation catalysts and reaction conditions is also presented. In addition, we have proven that the aromatization occurs via a hydrogen transfer from the cyclohexadiene intermediate to the maleimide derivative (therefore producing succinimides). This transfer is facilitated by the active surface of the heterogeneous carbon-based catalyst.

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A six-step synthetic route from 4-chloro-2-methylaniline to 5-chloro-2-(cyclobut-1-en-1-yl)-3-(trifluoromethyl)-1H-indole (1) has been reported. Compound 1a is a key impurity of reverse transcriptase inhibitor efavirenz, an important anti-HIV/AIDS drug. Synthetic challenges, dead ends, and detours are discussed.

The high frequency of the synthetic cannabinoid receptor agonists (SCRAs) emergence renders this group of new psychoactive compounds particularly demanding in terms of detection, identification, and responding. Without the available reference material, one of the specific problems is differentiation and structure elucidation of constitutional isomers. Herein, we report a simple and efficient flow chart diagram applicable for a rapid nuclear magnetic resonance (NMR) identification and differentiation between azaindoles, 4‐, 5‐, 6‐, and 7‐azaindole, which is a common structural motif of synthetic cannabinoids. The flow chart diagram is based on 1H NMR and 1H–15N NMR spectra, and to prove the concept, it has been tested on 5F‐MDMB‐P7AICA (1). Spectral and analytical data including standard 1D and 2D NMR spectra, gas chromatography−mass spectrometry (GC−MS), Fourier transform infrared−attenuated total reflectant (FTIR−ATR), Raman, melting point, and combustion analysis are provided for compound 1.

Pt(0.5 wt %)‐Al‐SBA‐15 and Pt(0.5 wt %)‐Al‐MCM‐41 bifunctional catalysts were prepared by wet impregnation and investigated in the hydrogenation of anthracene and the hydrogenolysis/hydrogenation of a series of synthesized Diels–Alder adducts with anthracene and anthracene derivatives. The mesoporous texture of the investigated catalysts allowed the hydrogenation of these substrates to a large extent. In direct correlation with the size of the Pt particles, Pt‐Al‐SBA‐15 exhibited a higher activity. Both catalysts exhibited a strong Lewis acidity associated with the presence of the Al extra‐framework species. The acidity of these catalysts afforded the esterification of the reaction byproduct, that is, succinic anhydride, with methanol or ethanol, and the hydrocracking/decyclization of one hydrogenated ring to lead to 1,2,3,4‐tetrahydronaphthalene derivatives. A good correlation with the calculated values of the reaction Gibbs free energy has been evidenced.