Titration of Nonstabilized Diazoalkane Solutions by Fluorine NMR

Rendina, Victor L.; Kingsbury, Jason S.

doi:10.1021/jo202214e

Cited by 20 publications

(14 citation statements)

References 25 publications

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“…[ 1 ] However, most diazo compounds are known to be hazardous chemicals with relatively low stability and explosive property. [ 1,2 ] Thus, there is a continuous effort on the search for new and safer surrogates to replace the commonly used unstable diazo compounds, [ 3,4 ] and alternatively, the development of new methods and technologies that allow for safer preparation and use of these compounds. [ 5 ] However, the drawbacks remain.…”

Section: Methodsmentioning

confidence: 99%

Copper‐Catalyzed Decarboxylative Hydrophosphinylation of α‐Acyl‐α‐Diazoacetates

et al. 2020

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A simple copper‐catalyzed decarboxylation–denitrogenation C–P coupling reaction of α‐acyl‐α‐diazoacetates with hydrophosphoryl compounds is reported. The reaction may proceed via a process involving the generation of (diazomethyl)ketones after hydrolysis in the presence of water and the hydrophosphinylation of the copper carbene intermediates. This finding may suggest the potential use of the relatively more readily available α‐acyl‐α‐diazoacetates as replacement of (diazomethyl)ketones in some cases.

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Section: Methodsmentioning

confidence: 99%

Copper‐Catalyzed Decarboxylative Hydrophosphinylation of α‐Acyl‐α‐Diazoacetates

et al. 2020

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“…NMR acquisition parameters: for 1 H: number of points = 16k, d1 = 10 s, pw90 = 14.6 ms, pw = 7.3 ms or 45 , 8 scans; for 19 F: number of points = 64k, d1 = 10 s, pw90 = 13 ms, pw = 6.5 ms or 45 , 16 scans. [7] Chemical shifts of 1 H signals are referenced to residual HOD at 4.75 ppm. Chemical shifts of 19 F signals are referenced to KF at À125.30 ppm.…”

Section: Methodsmentioning

confidence: 99%

Quantification of hydrogen fluoride-based reagents using a bifunctional NMR internal standard

Zhou

Hammond

2016

Journal of Fluorine Chemistry

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A B S T R A C TA new procedure for quantifying the composition of hydrogen fluoride-based reagents by a combination of 1 H and 19 F NMR titration has been developed. An aliquot of a hydrogen fluoride reagent sample and a bifunctional internal standard-ethyl trifluoroacetate, were digested with excess KOH in D 2 O; and subjected to quantitative NMR analysis. This procedure provides a more convenient operation and more accurate results than traditional volumetric titration.

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“…This method does not have some of the drawbacks of existing routes, such as peracetic acid (40%) use, and has a considerably shorter reaction time. However, the instability of DDM prevents the DDM content from being precisely ascertained using general high-performance liquid chromatography (HPLC) or gas chromatography (GC). − In addition, DDM must be synthesized immediately before use and cannot be stored. Ketone has been found to be the main byproduct during DDM preparation.…”

Section: Introductionmentioning

confidence: 99%

Precise Preparation of a High-Purity Key Intermediate of Tazobactam

Zhou

et al. 2020

Org. Process Res. Dev.

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In situ IR was used to precisely prepare high-purity diphenylmethyl 6α-bromopenicillanate 8, a key intermediate of tazobactam. 8 was obtained when 6α-bromopenicillanic acid 2 reacted with diphenyldiazomethane (DDM). 2 is unstable and must therefore react immediately with DDM upon preparation. DDM is also unstable. As DDM decomposes rapidly upon preparation, the DDM content cannot be precisely determined using high-performance liquid chromatography (HPLC) or gas chromatography (GC). Therefore, good yield and purity are difficult to obtain, resulting in large batch-to-batch variations (yield 69.3–82.8%, purity 89.8–98.4%) for 8. The developed preparation method for 8 involved the use of in situ IR to monitor the reaction process and achieved good results (82.7–83.1% yield and 97.3–98.5% purity). This method was also used to prepare the key intermediate for the synthesis of cephalosporin derivatives, which have high industrial value.

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Titration of Nonstabilized Diazoalkane Solutions by Fluorine NMR

Cited by 20 publications

References 25 publications

Copper‐Catalyzed Decarboxylative Hydrophosphinylation of α‐Acyl‐α‐Diazoacetates

Copper‐Catalyzed Decarboxylative Hydrophosphinylation of α‐Acyl‐α‐Diazoacetates

Quantification of hydrogen fluoride-based reagents using a bifunctional NMR internal standard

Precise Preparation of a High-Purity Key Intermediate of Tazobactam

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