From amines to (form)amides: a simple and successful mechanochemical approach

• Federico Casti,
• Rita Mocci and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 1210–1216, doi:10.3762/bjoc.18.126

• mechanochemical conditions are presented. The two methodologies exhibit complementary features as they enable the derivatization of aliphatic and aromatic amines. Keywords: acetamides; formamides; mechanochemistry; N-formylation; p-tosylimidazole; Introduction The preparation of N-formylated and N-acetylated

• reactions [35][36][37][38][39][40][41][42]. In our effort to develop green and sustainable methodologies using mechanochemistry [43][44][45][46], we recently studied a protocol for synthesizing isocyanides using p-tosyl chloride (Ts-Cl) in basic conditions, starting from the corresponding formamides [47

• ]. In this work, we aimed to set compatible conditions to access formamides, envisioning the possibility of generating the isocyanide in a one-pot, two-step reaction. However, to the best of our knowledge, despite the notable improvement in the mechanochemical synthesis of the amide moiety [44][48][49

A versatile way for the synthesis of monomethylamines by reduction of N-substituted carbonylimidazoles with the NaBH₄/I₂ system

• Lin Chen,
• Xuan Zhou,
• Zhiyong Chen,
• Changxu Wang,
• Shunjie Wang and
• Hanbing Teng

Beilstein J. Org. Chem. 2022, 18, 1032–1039, doi:10.3762/bjoc.18.104

• cyanoformamides [75]. However, all of these works are primarily focused on the substitution reaction of N-substituted carbonylimidazoles. In our previous work, we conveniently prepared formamides by reducing N-substituted carbonylimidazoles with NaBH4 [62] (Scheme 1). The reaction mechanism shows that the H− ion

• reduction, and our method showed interesting reduction selectivity. To gain some preliminary insight into the reaction process, two representative intermediates for the synthesis of aliphatic methylamine 1c and aromatic methylamine 8c had been isolated and identified as corresponding formamides (see

• ) than that for N-alkyl carbonylimidazoles (about 1 h) can be well explained by the two-step mechanism. In step I, the N-aryl carbonylimidazoles might react much faster than N-alkyl carbonylimidazoles, because the stronger conjugation system of the resulting N-aromatic formamides made them more stable

A trustworthy mechanochemical route to isocyanides

• Francesco Basoccu,
• Federico Cuccu,
• Federico Casti,
• Rita Mocci,
• Claudia Fattuoni and
• Andrea Porcheddu

Beilstein J. Org. Chem. 2022, 18, 732–737, doi:10.3762/bjoc.18.73

• does not respect the octet rule, is less favoured (Figure 1). The synthetic approaches to this core are multiple, but numerous drawbacks severely limit their output. Common pathways generally involve formamides; one of the most known is Ugi’s method [17] which is based on the dehydration of a primary

• proposed. Tosyl chloride [19][20] and TCT (1,3,5-trichlorotriazine) [21] proved to be valuable alternatives to the aforementioned phosphorous compounds due to their powerful dehydrating ability. Lastly, Burgess reagent has been reported as a mild and selective dehydrating compound for formamides [22][23

• envisioned the feasibility of producing isocyanides from primary formamides by using anhydrides as dehydrating agents. Therefore, we focused our attention on acetic, trifluoroacetic, and isatoic anhydrides to achieve this. First attempts were made on acetic and trifluoroacetic anhydrides. The best results

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• formamides [11] and reduction of isothiocyanates to thioformamides [12] by its means. There have also been some catalytic protocols developed for the reduction of amides to imines. The most notable examples incorporate iridium complexes and silanes [13][14]. Cheng and Brookhart showed that the chlorobis

Aldehydes as powerful initiators for photochemical transformations

• Maria A. Theodoropoulou,
• Nikolaos F. Nikitas and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2020, 16, 833–857, doi:10.3762/bjoc.16.76

• activation (carbonyl C–H bonds of formamides). Some of the amides or ethers found to be compatible with this method are shown in Scheme 26. A wide range of heteroarenes 114 was also found compatible with this method, including substituted benzothiazole substrates, substituted benzimidazoles, and thiazoles

Hypervalent organoiodine compounds: from reagents to valuable building blocks in synthesis

• Gwendal Grelier,
• Benjamin Darses and
• Philippe Dauban

Beilstein J. Org. Chem. 2018, 14, 1508–1528, doi:10.3762/bjoc.14.128

• , arenes and heteroarenes [43][44]. A first solution to value the 2-iodobenzoic moiety released from EBX has arisen from the reaction of derivatives 22 with N-(aryl)imines 23 in the presence of 10 mol % of Pd(OAc)2, which gives access to tri- or tetrasubstituted furans 24 and N-(aryl)formamides 25 (Scheme

Unusual reactions of diazocarbonyl compounds with α,β-unsaturated δ-amino esters: Rh(II)-catalyzed Wolff rearrangement and oxidative cleavage of N–H-insertion products

• Valerij A. Nikolaev,
• Jury J. Medvedev,
• Olesia S. Galkina,
• Ksenia V. Azarova and
• Christoph Schneider

Beilstein J. Org. Chem. 2016, 12, 1904–1910, doi:10.3762/bjoc.12.180

• bonds in the structure of α-aminocarbonyl compounds is also a well-known transition-metal-catalyzed process, which gives rise to the occurrence of formamides and carboxylic acids [26][29]. In this case the system O2/TEMPO is used as a catalyst for the cleavage process, but the reaction also proceeds

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

• amides 119a–f in good yields (Table 9). The products of this transformation are strongly dependent on the electronic properties of the aromatic substituents at the carbon atom of the aldimines [288]. In the case of electron-donating substituents on the aryl fragment (Ar), formamides 119a–c are obtained

Microwave-assisted synthesis of (aminomethylene)bisphosphine oxides and (aminomethylene)bisphosphonates by a three-component condensation

• Erika Bálint,
• Ádám Tajti,
• Anna Dzielak,
• Gerhard Hägele and
• György Keglevich

Beilstein J. Org. Chem. 2016, 12, 1493–1502, doi:10.3762/bjoc.12.146

• (Scheme 2a) [33], by the condensation of formamides and diethyl phosphite using 2,6-di-tert-butyl-4-methylpyridine (DTBMP) as the base, and trifluoromethanesulfonic anhydride (Tf2O) as the catalyst (Scheme 2b) [34], or by the reaction of isonitriles with triethyl phosphite (Scheme 2c) [35][36

Fates of imine intermediates in radical cyclizations of N-sulfonylindoles and ene-sulfonamides

• Hanmo Zhang,
• E. Ben Hay,
• Stephen J. Geib and
• Dennis P. Curran

Beilstein J. Org. Chem. 2015, 11, 1649–1655, doi:10.3762/bjoc.11.181

• identified by 1D and 2D NMR experiments, IR and HRMS as 3-(2-formamidoethyl)-2-oxindole 25. The cyclizations of 23 and 24 gave comparable results. The corresponding formamides 26 and 27 were isolated in 42% and 54% yields, respectively. All three formamides are white solids with high melting points (>200 °C

• hemiaminal 29 opens in the other direction (with C–N bond cleavage) to give an α-formyl-γ-amino lactam, which then undergoes C-to-N transformylation. The analysis of the crude reaction mixtures by TLC showed that the spots of formamides 25–27 were present early and grew in intensity with time as the

• intensity of the spots of precursors 22–24 faded. This suggests that the formamides are forming during the reaction course, not during the flash chromatography. This conclusion was supported by an experiment with Bu3SnH conducted in C6D6 with direct NMR analysis. The resonances of the precursor 23 were

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• works, the oxidative coupling of alcohols, aldehydes, or formamides with 1,3-dicarbonyl compounds or phenols was accomplished in the presence of tert-butyl hydroperoxide and copper salts (Table 5). In most cases, the range of phenols applicable to the coupling is limited to 2-acylphenols. However, 2

• -(benzothiazol-2-yl)phenol was used along with 2-acylphenols as the OH-reagent in the study [153]. In the coupling with aldehydes, the components are taken in a nearly stoichiometric molar ratio. In the coupling with formamides, the latter served as the solvent. In the studies [155][156], 1,3-cyclohexanedione

• was used as the OH-reagent along with 1,3-ketoesters. However, the reaction with 1,3-cyclohexanedione gave products in low yields (19–26%). The coupling of a number of substituted salicylaldehydes with formamides was performed; the aldehyde group, which is prone to oxidation, remaining intact [157