Synthesis and characterization of novel conformers of (E)-2-(3-nitro-H-imidazo[1,2-a]pyridin-2-ylthio)-N'-benzylideneacetohydrazide derivatives.

Eighteen new N-acylhydrazones (9a-r) containing the imidazo[1,2-a]pyridine scaffold were synthesized through a seven steps reaction sequence, ending with a condensation of 2-(3-nitro-H-imidazo[1,2-a]pyridin-2-ylthio)acetohydrazide with various benzaldehyde derivatives (8a-r). All synthesized compounds were characterized by 1D NMR (1 H and 13 C NMR) and 2D NMR (NOESY) spectroscopic analyses and high-resolution mass spectrometry (HRMS). The analysis of 1 H NMR data performed at room temperature in deuterated dimethylsulfoxide (DMSO-d6 ) revealed the presence of (E)-2-(3-nitro-H-imidazo[1,2-a]pyridin-2-ylthio)-N'-benzylideneacetohydrazide (9a-r) as a mixture of two conformers, namely, syn-periplanar E (sp E) and anti-periplanar E (ap E). For all N-acylhydrazones that were synthesized, the sp E conformer was found to be the major form except in the case of hydrazone derived from o-hydroxybenzaldehyde.

Elaboration of Functionalized Organophosphates.

In this study, the rapid transformation of inexpensive phenols into polyfunctionalized cyclohexenones containing a phosphonate in one pot is described. Such systems readily obtained from simple aromatic compounds could open up a multitude of synthetic possibilities. For example, this scaffold was easily and stereoselectively transformed into the corresponding enol functionality in the same pot by the addition of sodium borohydride.

Towards routine organic structure determination using Raman microscopy.

Raman microscopy can reveal a compound-specific vibrational "fingerprint" from micrograms of material with no sample preparation. We expect this increasingly available instrumentation to routinely assist synthetic chemists in structure determination; however, interpreting the information-dense spectra can be challenging for unreported compounds. Appropriate theoretical calculations using the highly efficient r2SCAN-3c method can accurately predict peak positions but are less precise in matching peak heights. To limit incorrect biases while comparing experimental and theoretical spectra, we introduce a user-friendly software that gives a match score to assist with structure determination. The capabilities and limitations of this approach are demonstrated for several proof-of-concept examples including the characterization of intermediates in the total synthesis of deoxyaspidodispermine.

Synthesis of Deoxyaspidodispermine Based on a Functional Protecting Group Strategy.

A synthesis of deoxyaspidodispermine was produced from homotyramine. This approach is based on the application of a functional protecting group strategy that not only masks the reactivity of sensitive groups during crucial steps but also possesses a moiety desired in the final target, which is transferred to the substrate at the time of deprotection. This synthesis highlights an aza-Michael-Smiles ring-closure cascade, which enables the formation of a tetracyclic system from a nosylamide protecting group.