Application of thermal analytical techniques in development of a safe and robust process for production of triacetoxyborohydride (STAB)

418

269

Note: Newly formed C-N bonds are labeled by asterisks (*); a blank entry for yield indicates no yield was given; STAB-H ) sodium triacetoxyborohydride; DCE ) 1,2-dichloroethane; DCM ) dichloromethane; DMAC ) N,N-dimethylacetamide; NMP ) N-methyl pyrrolidinone; AcOH ) acetic acid; DMF ) N,Ndimethylformamide; THF ) tetrahydrofuran; Me-THE ) 2-methyltetrahydrofuran; DIPEA ) N,N-diisopropylethylamine; MS ) molecular sieves; rt ) room temperature.

Section: Discussionmentioning

confidence: 99%

A Review on the Use of Sodium Triacetoxyborohydride in the Reductive Amination of Ketones and Aldehydes

Abdel-Magid,

Mehrman

2006

418

269

“…Therefore, we investigated the reaction mechanism using 11 B NMR spectroscopy and performed a safety assessment for the reaction process on the basis of the reaction mechanism using reaction calorimetry and gas evolution analyses. 9, 10 Reaction Mechanism. The detailed reaction mechanism was investigated so that the safety of the reaction using the reducing agents could be evaluated.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…However, the detailed reaction mechanism and safety assessment of the reduction process using NaBH 4 and TFA have not been reported. Therefore, we investigated the reaction mechanism using 11 B NMR spectroscopy and performed a safety assessment for the reaction process on the basis of the reaction mechanism using reaction calorimetry and gas evolution analyses. , …”

Section: Resultsmentioning

confidence: 99%

“…Therefore, we focused on the reduction conditions during the conversion of 1 to 2 using NaBH 4 and additives. However, the reduction process is highly exothermic, and evaluation of the safety of the process is difficult because the active species involved are not well understood. , We focused on performing a safety assessment based on the reaction mechanism because a deeper understanding of the reaction mechanism can help us better control the active species involved in the reduction process.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Process Safety Evaluation and Scale-up of a Lactam Reduction with NaBH₄ and TFA

Naka¹,

Ozawa²,

Toyama³

et al. 2015

The development of a practical and scalable method for the synthesis of morpholine derivative 2 via reduction of lactam 1 using NaBH4 and trifluoroacetic acid (TFA) is described. Through the mechanistic studies using 11B NMR spectroscopy, we observed that active species were generated during TFA addition, which avoids the deactivation of the active species involved in the reduction process. Process safety assessments were performed on the basis of the reaction mechanism using reaction calorimetry and gas evolution analyses. Furthermore, safety equipment was prepared to prevent the leakage of diborane gas during the reaction, and the process was successfully scaled up to the pilot plant at a 35 kg scale.

“…STAB is prepared by the addition of solid NaBH 4 to a solution of AcOH in a solvent, typically N , N -dimethylacetamide (DMAc) or toluene, followed by filtration of the resulting solid . The purity of the isolated solid depends on the efficiency of the reaction itself as well as the washing and drying protocols.…”

Section: Introductionmentioning

confidence: 99%

A Quantitative Assay of Sodium Triacetoxyborohydride

Zacuto¹,

Perona²,

Dunn³

2019

Sodium triacetoxyborohydride (STAB) is a common reducing agent with potency that degrades over time and is not uniformly assigned. A simple assay based on an aldehyde reduction has been developed to determine the active borohydride content of this reagent. The HPLC assay yield of a salicylaldehyde reduction has been shown to accurately determine this potency and has been validated against the H 2 evolution method as well as yields obtained from a reductive amination. The use of these assay data to adjust the STAB charge as well to optimize a reductive amination has been demonstrated.