Fine bubble technology for the green synthesis of fairy chemicals.

Fairy chemicals (FCs), such as 2-azahypoxanthine (AHX), are a potential new class of plant hormones that are naturally present in plants and produced via a novel purine metabolic pathway. FCs support plant resilience against various stresses and regulate plant growth. In this study, we developed a four-step method for synthesising AHX from 2-cyanoacetamide, achieving a good yield. Oxime was obtained from 2-cyanoacetamide via the oximation reaction. Cascade-type one-pot selective Pt/C-catalysed reduction of oxime, followed by a coupling reaction with formamidine acetate, yielded intermediate 5-amino-1H-imidazole-4-carboxamide (AICA). For the synthesis of AICA from oxime, we used modern fine bubble technology, affording AICA in 69% yield. Subsequently, we synthesised 4-diazo-4H-imidazole-5-carboxamide (DICA) from AICA via the diazotisation reaction. Notably, the synthesis of DICA from AICA was achieved, and the stability of previously known less stable DICA in the solid state was confirmed. Finally, PhI(OAc)2 (0.5 mol%) catalysed the intramolecular cyclisation of DICA in the green solvent water to yield AHX (overall yield of 47%). This study's innovative techniques and substantial discoveries highlight its potential influence and significance in FC science, thereby establishing a new standard for subsequent research.

Discrete dinuclear complex to extended 2D compound in a Cu-azido system by controlling coligand stoichiometry: synthesis and magneto-structural correlations.

This article describes syntheses, structural characterizations and magnetic studies of two different Cu(II)-azido compounds, a discrete dinuclear complex and an extended 2D network. The compounds, [Cu(µ(1,1)-N3)(N3)(Me2en)]2 (1) and [Cu3(µ(1,1,1)-N3)2(µ(1,1,3)-N3)(µ(1,1)-N3)2(µ(1,3)-N3)(Me2en)]n (2), have been synthesized by controlling the relative concentration of the blocking ligand, N,N-dimethylethylenediamine (Me2en). Compound 1 is a dinuclear compound which is formed by a doubly asymmetric µ(1,1)-N3 bridging ligand, while 2 is a rare Cu-azido system where four different types of binding modes of azide ligands are present in a single compound. Compound 2 contains a hexanuclear core, where the Cu(II) centres are connected to each other by µ(1,1,1), µ(1,1) and µ(1,1,3) bridging azide ligands. The hexanuclear core acts as a secondary building block and further assembles via µ(1,3) and µ(1,1,3) azide groups, forming a 2D network in the crystallographic ac plane. Interestingly, temperature-dependent magnetic study suggests that the dinuclear compound 1 exhibits an antiferromagnetic interaction through the µ(1,1)-N3 bridge, which has also been supported by density functional theory (DFT) calculations. In the case of 2, an overall dominant ferromagnetic interaction is observed while antiferromagnetic interaction operates between the hexanuclear cores.