Thermal reactions of N-benzylidene- and N-(2-pyridylmethylidene)-tert-butylamines (5 and 13) under FVT conditions have been investigated. Unexpectedly, at 800 °C, compound 5 yields 1,2-dimethylindole and 3-methylisoquinoline. In the reaction of 13 at 800 °C, 3-methylimidazo[1,5-a]pyridine was obtained as the major product. Mechanisms of these reactions have been proposed on the basis of DFT calculations. Furthermore, UV-photoelectron spectroscopy combined with FVT has been applied for direct monitoring and characterization of the thermolysis products in situ.

The McKenna reaction is a well-known and popular method for the efficient and mild synthesis of organophosphorus acids. Bromotrimethylsilane (BTMS) is the main reagent in this reaction, which transforms dialkyl phosphonate esters into bis(trimethylsilyl)esters, which are then easily converted into the target acids. However, the versatile character of the McKenna reaction is not always used to its full extent, due to formation of side products. Herein, demonstrated by using model examples we have not only analyzed the typical side processes accompanying the McKenna reaction, but also uncovered new ones. Further, we discovered that some commonly recommended precautions did not always circumvent the side reactions. The proposed results and recommendations may facilitate the synthesis of phosphonic acids.

Herein, an advantage of the use of IDSCRF- over UFF-radii-based solute cavities in GIAO/DFT calculations is presented for the C and especiallyN NMR chemical shifts made for several bicyclic aromatic nitrogen heterocycles in CDCl solution treated within the classical IEF-PCM solvation scheme. Successful application of the IDSCRF-radii in the non 1:1 joint multinuclear H/C and particularly H/C/N correlations of the measured δ values to those obtained theoretically is also documented for a series of test systems (-268 ≤ δ ≤ -72 ppm). The experimentally yet unknown δ's were found in this way for the title compounds via a trinuclear eq 1 determined for an optimally chosen value of the multiplication factor of initial raw δ data (m = 10). Such a simultaneous analysis of the δ data is proposed as a novel method to study the solution structure of the other similar conformationally homogeneous (bio)organic compounds. The issue of small spurious imaginary vibrational frequencies computed for a few molecular systems using the Gaussian 09 default UFF-radii is briefly considered as well.

Pyrrolopyridines and naphthyridines are formed by flash vacuum thermolysis (FVT) of 3‐ and 4‐pyridylmethylidene‐tert‐butylimines 8 and 15. Elimination of a methyl radical generates resonance stablized 2‐azaallyl radicals a1 and b1. The formation of pyrrolopyridines 9, 16 and 17 is rationalized in terms of cyclization of 1‐aziridinyl radicals a2 and b2. Formation of naphthyridine 10 from imine 8, and of 11 and 18 from imine 15, are in accord with cyclization of 1‐azaallyl radicals a6 and b9. Formation of naphthyridine 11 from 8, and of 10 and 19 from 15, indicate the operation of the spiro‐cyclization pathways forming intermediates a9 and b14. Formation of the 1,8‐naphthyridine 20 (3 %) indicates a rearrangement through aziridine b22 and biradical b23. DFT calculations at the CAM‐B3LYP/6‐311G(d,p) level support the proposed reaction mechanisms.

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Twelve phosphonopropionates derived from 2-hydroxy-3-imidazo[1,2-a]pyridin-3-yl-2-phosphonopropionic acid (3-IPEHPC) were synthesized and evaluated for their activity as inhibitors of protein geranylgeranylation. The nature of the substituent in the C6 position of imidazo[1,2-a]pyridine ring was responsible for the compound's activity against Rab geranylgeranyl transferase (RGGT). The most active inhibitors disrupted Rab11A prenylation in the human cervical carcinoma HeLa cell line. The esterification of carboxylic acid in the phosphonopropionate moiety turned the inhibitor into an inactive analog.

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