Sulfamic acid: An efficient and green catalyst for synthesis of 1,5‐benzodiazepines under solvent‐free conditions

Benzodiazepine Synthesis and Rapid Toxicity Assay

“…The range of student yields of crude and purified product was significantly lower than that reported in the literature − and can partially be attributed to the shorter reaction times used in this experiment (30 min versus a minimum of 3 h). The reaction can be monitored by GC−MS analysis, where the diimine intermediate is detected within minutes and slowly cyclizes into benzodiazepine product.…”

“…Recent reports in the primary literature have demonstrated a variety of methods for synthesizing 1,5-benzodiazepine regioisomers via acid-catalyzed condensation−cyclization reactions between 1,2-diaminobenzene and ketone reactants − . Although not explored in this study, variations on this experiment could include the execution of this reaction via ultrasound or microwave heating , the evaluation of different acid catalysts ,, , or the implementation of a green-chemistry approach by performing such reactions in water , .…”

More Sustainable Approaches for the Synthesis of N-Based Heterocycles

“…From testing of several Lewis acids, InBr 3 proved to be the most efficient catalyst for this reaction . Recently, sulfamic acid was also reported as a catalyst for this reaction leading to better yields under solvent-free conditions than in solution. , When such condensation is carried under MWI, acetic acid can be used as catalyst, leading to the desired benzodiazepines in excellent yields (90−99%) in up to 7 min of reaction time . In a room temperature procedure, the reaction of 2,2-dimethoxypropane with o -phenylenediamines in the presence of bismuth triflate yielded the 1,5-benzodiazepines after 2−4 h reaction time …”

The EcoScale as a framework for undergraduate green chemistry teaching and assessment

“…As an extension of this calculation, students had to then analyze a provided research literature procedure for their reaction in terms of the EcoScale (29,(33)(34).…”