Ueber Diazoanhydride

“…The pyrazole derivatives I and II with carbonyl substituents in the 3-and 5-positions of the heterocycle were prepared with slight modifications of the procedures reported in the literature [13,14] and were used in the subsequent Schiff base formation (Scheme 2). Proper conditions turned out to be critical in order to achieve reasonable yields in the final condensation step and to assure formation of the difunctionalised products.…”

Section: Synthesis and Structural Characterisation Of Ligandsmentioning

confidence: 99%

“…Compounds I, [13] II [14] and HL 3 [7] were synthesised according to published procedures. In order to improve the conversion yield in the last step of the synthesis of II, a mixture of water and ethanol (1 : 4) instead of pure water was used as the solvent.…”

Section: Experimental Section Generalmentioning

confidence: 99%

Pyrazolate‐Based Dinuclear α‐Diimine‐Type Palladium(II) and Nickel(II) Complexes – a Bimetallic Approach in Olefin Polymerisation

et al. 2006

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Ni 2 Br 3 ] 3 . Complexes 1a -4a can be described as bimetallic versions of Brookhart-type a-diimine palladium complexes, where dissociation into mononuclear species is prevented by the dinucleating scaffold and the proximate metal ions are suitably positioned to work in concert during substrate transformation. Upon activation of the complexes with MAO and exposure to ethylene, polyethylene is formed. Whereas the palladium complexes display moderate activities, nickel complexes are very active. From structure/activity correlations it is evident that the presence of backbone substitutents at the pyrazolate scaffold as well as bulky ortho aryl substituents is advantageous for polymerisation. Overall, activities of the Ni complexes and the microstructure of the polymer obtained (total branching, T m and molecular weights) are still rather similar to the data reported previously for mononuclear cationic diimine nickel complexes.

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“…[1][2][3][4] The α-diazocarbonyl compounds produced by diazo transfer are an important class of versatile synthetic intermediates due to their ability to generate reactive carbenes, [5][6][7] carbenoids, [7][8][9][10][11][12][13][14][15][16][17][18][19][20] ketenes and other heteroanalogous intermediates. [21][22][23][24][25][26] Despite being routinely used in small scale α-diazocarbonyl synthesis, tosyl azide is not suitable for use at larger scales. Tosyl azide has an impact sensitivity of 50 kg·cm, and explosive thermal decomposition can initiate at 120 °C.…”

Section: Introductionmentioning

confidence: 99%

Taming tosyl azide: the development of a scalable continuous diazo transfer process

et al. 2016

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Heat and shock sensitive tosyl azide was generated and used on demand in a telescoped diazo transfer process. Small quantities of tosyl azide were accessed in a 'one pot' batch procedure using shelf stable, readily available reagents. For large scale diazo transfer reactions tosyl azide was generated and used in a telescoped flow process, to mitigate the risks associated with handling potentially explosive reagents on scale. The in situ formed tosyl azide was used to rapidly perform diazo tranfer to a range of acceptors, including β-ketoesters, β-ketoamides, malonate esters and β-ketosulfones. An effective in-line quench of sulfonyl azides was also developed, whereby a sacrificial acceptor molecule ensured complete consumption of any residual hazardous diazo transfer reagent. The telescoped diazo transfer process with in-line quenching was used to safely prepare over 21 g of an α-diazocarbonyl in >98% purity without any column chromatography.

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Ueber Diazoanhydride

Cited by 297 publications

References 18 publications

Integrated Micro‐Flow Synthesis Based on Photochemical Wolff Rearrangement

Integrated Micro‐Flow Synthesis Based on Photochemical Wolff Rearrangement

Pyrazolate‐Based Dinuclear α‐Diimine‐Type Palladium(II) and Nickel(II) Complexes – a Bimetallic Approach in Olefin Polymerisation

Taming tosyl azide: the development of a scalable continuous diazo transfer process

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