Preparation of 3-(alkylamino)imidazo[1,2-a]pyridine-2-carbaldehydes via Kornblum oxidation and unexpected ring-opening reactions of the corresponding alcohols under oxidative conditions

• Sandile J. Mkhize,
• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2026, 22, 763–770, doi:10.3762/bjoc.22.58

• ; Kornblum oxidation; oxidative ring-opening; reductive amination; Introduction Imidazo[1,2-a]pyridines display a wide range of different biological activities, and this scaffold has come to be regarded as being biologically privileged [1]. Compounds containing the imidazo[1,2-a]pyridine core have been

• , which might have occurred here, can be achieved by means of the Kornblum oxidation [33] and thus our attention turned to the very mild oxidation conditions of this reaction and we did not explore the tosylation reaction further. Conversion of the alcohols 17a–d into bromides 21a–d was successfully

• ]pyridine-2-carbaldehydes has been developed that proceeds via the 2-methyl esters resulting from the Groebke–Blackburn–Bienaymé reaction, followed by reduction to the corresponding alcohols, bromination and then mild Kornblum oxidation. Other typical oxidation reagents such as PCC, IBX and laccase gave

Modern synthetic pathways towards eribulin and its subunits

• Sebastian Dominik Graf

Beilstein J. Org. Chem. 2026, 22, 495–526, doi:10.3762/bjoc.22.37

• )-methyl-2,3-dihydroxypropanoate, respectively (Scheme 18) [93]. Again, Nicholas etherification of both starting materials was conducted to afford 175 in 5:1 dr. The major isomer was further transformed to 176 in a microwave oven via Kornblum oxidation. Radical cyclization and DMP-oxidation yielded

A new synthesis of Tyrian purple (6,6’-dibromoindigo) and its corresponding sulfonate salts

• Holly Helmers,
• Mark Horton,
• Julie Concepcion,
• Jeffrey Bjorklund and
• Nicholas C. Boaz

Beilstein J. Org. Chem. 2026, 22, 167–174, doi:10.3762/bjoc.22.10

• -nitrobenzaldehyde, which is accomplished by benzylic bromination followed by a Kornblum oxidation. This gentle oxidation avoids the need for chromium trioxide-mediated or nitrone-based methods. While other published syntheses of 6,6’-dibromoindigo have resulted in higher overall yields, our approach offers the

• sulfonation. In line with developing a shortened synthetic scheme, we chose p-bromotoluene (5), as a starting material, as nitration would yield 3 in a single step. Benzylic bromination followed by a Kornblum oxidation would then yield 4 in three steps from 5 without the use of a chromium(VI) oxidant or

• synthesized compound 3 via nitration of 5, it was necessary to oxidize its methyl group to an aldehyde to yield 4-bromo-2-nitrobenzaldehyde (4). We sought to accomplish this transformation by first using a benzylic bromination of 3 to yield 4-bromo-2-nitrobenzyl bromide (6), followed by a Kornblum oxidation

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

• Long-Yi Xi,
• Ruo-Yi Zhang,
• Lei Shi,
• Shan-Yong Chen and
• Xiao-Qi Yu

Beilstein J. Org. Chem. 2016, 12, 1072–1078, doi:10.3762/bjoc.12.101

• of luotonin F and derivatives from aromatic ketones and 2-aminobenzamides via iodination/Kornblum oxidation/annulation [25]. We envisioned that 2-aminobenzenesulfonamides would undergo a similar reaction to afford 3-acylbenzothiadiazine 1,1-dioxides. Herein, we report the first synthesis of 3

• ). To shed light on the mechanism of this reaction, a control experiment was conducted. It is known that acetophenones can undergo halogenation and further Kornblum oxidation to give phenylglyoxal in a I2/DMSO system [33][34]. We isolated the product in 85% yield by heating phenylglyoxal and 2a in DMSO

• isolated after stirring 12 h at 80 °C. On the basis of this experiment described above and literature [13][35][36], a possible mechanism was proposed in Scheme 7. The halogenation of 1a with iodine results in the formation of compound A, which, via Kornblum oxidation, provides phenylglyoxal B. The

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33