The facile one-pot synthesis of N-imidoylbenzotriazoles via a Beckmann rearrangement of ketoximes

Carbodiimide-Mediated Beckmann Rearrangement of Oxyma-B as a Side Reaction in Peptide Synthesis

“…In this case, instead of the usually migrating alkyl groups, a carbonyl group in trans-position to the leaving OH formed a new C-N bond (Figure 7A) [20]. A similar reaction was used previously for the preparation of Nimidoylbenzotriazoles [28]. In that case, a sulfonate group was employed for the activation of the hydroxyl group of various oximes, which is necessary to trigger the rearrangement [29].…”

“…To understand the influence of the C=O group on the Beckmann rearrangement, we performed the reaction of isonitroso Meldrum's acid (HONM) and DIC with alanine-loaded CTC resin [34]. In this case, no product with the desired molecular weight was observed but only a mixture of several impurities with higher mass values, which were difficult to identify, probably due to the A similar reaction was used previously for the preparation of N-imidoylbenzotriazoles [28]. In that case, a sulfonate group was employed for the activation of the hydroxyl group of various oximes, which is necessary to trigger the rearrangement [29].…”

Atypical and Asymmetric 1,3‐P,N Ligands: Synthesis, Coordination and Catalytic Performance of Cycloiminophosphanes

“…Treating neat cyclohexanone with hydroxylamine ⋅ HCl salt by grinding them together in a mortar, while slowly adding NaOH, yielded the corresponding pure oxime conveniently, even on large scale (120 mmol, 82 %; Scheme 1). [15] Next, under an atmosphere of nitrogen, the oxime was activated in situ as the corresponding methylsulfonate with methylsulfonyl chloride and triethylamine in MeCN at 0 °C [11c,16] . Benzotriazole was added and the mixture was heated to reflux for 2 h to facilitate the ring expansion and trap the nitrilium ion.…”

“…Benzotriazole was added and the mixture was heated to reflux for 2 h to facilitate the ring expansion and trap the nitrilium ion. The reported work‐up [11c] was significantly simplified by adding water to the crude mixture to precipitate pure 4 as a white solid in good yield (60 %); alternatively, evaporation, extraction into Et 2 O and filtration over neutral alumina also provides 4 (58 %). Single crystals suitable for X‐ray diffraction analysis were obtained from Et 2 O and revealed a remarkably flat conformation [N1−C1−N2−N3=179.54(8); C6−C1−N2−N3=−0.37(12)], presumably due to N1⋅⋅⋅H11 and N3⋅⋅⋅H6A hydrogen bonding (2.50 and 2.29 Å, respectively; Figure 6).…”

Radical Carbonitrosation and Recycling of the Waste Gas Nitrogen Monoxide

“…b-Aryloximes represent versatile synthetic building blocks of natural products [40] and numerous synthetic applications have been reported. Besides the well-known Beckmann [41] and Neber [25a] rearrangements, the reduction of compounds such as 9 e-9 h to aromatic amino acids [42,43] is a further example. Owing to the low sensitivity of the carbonitrosation reaction towards oxygen, we have been able to demonstrate its applicability for recycling of nitrogen monoxide occuring as waste gas.…”