143722-29-6Relevant articles and documents
Continuous Synthesis and Separation ofp-Bromobenzyl Bromide Using Atom-Efficient Bromination ofp-Bromotoluene without Any Organic Effluent: Potential for Green Industrial Practice
Sancheti, Sonam V.,Yadav, Ganapati D.
, p. 2071 - 2080 (2021/09/13)
This work focuses on the bromination ofp-bromotoluene (PBT) using different brominating agents such as liquid Br2, NaBr-NaBrO3, NaBr-NaBrO3-NaCl, NaBr-H2O2, and HBr-H2O2. NaBr-NaBrO3-NaCl is an eco-friendly brominating agent obtained from a bromine recovery plant. Both NaBr-NaBrO3and NaBr-NaBrO3-NaCl were found to be nonhazardous and efficient brominating agents. Pure NaBr-NaBrO3resulted in the best PBT conversion with 79.7% Br atom efficiency in water and 98.2% average Br atom efficiency using dichloroethane as a solvent. Dichloroethane is de facto no longer used in the US and Europe and is not eco-friendly; the process with water as a solvent is the best. The substrate to active bromine molar ratio of 3:1 was found to be sufficient to get the maximum selectivity ofp-bromobenzyl bromide (PBBB). The low-temperature crystallization method was used for separation cum purification of the product. Unreacted PBT was recycled along with the dibromo byproduct obtained. The dibromo product, which was built up gradually in the reaction mixture over 10 successive batches, was converted back into PBBB/PBT through NaBH4treatment of the mother liquor. This continuous process is highly sustainable and produces zero organic waste, making it potentially attractive toward green industrial implementation.
Process for the preparation of benzylimidazole derivatives and for losartan
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Page/Page column 5, (2010/02/12)
A process for the preparation of benzylimidazole derivatives useful as intermediates for preparation of losartan, novel intermediates for their preparation and a process for the preparation of losartan.
Efficient synthesis of losartan, a nonpeptide angiotensin II receptor antagonist
Larsen,King,Chen,Corley,Foster,Roberts,Yang,Lieberman,Reamer,Tschaen,Verhoeven,Reider,Lo,Rossano,Brookes,Meloni,Moore,Arnett
, p. 6391 - 6394 (2007/10/02)
A highly efficient, convergent approach to the synthesis of the angiotensin II receptor antagonist losartan (1) is described. Directed ortho-metalation of 2-trityl-5-phenyltetrazole provides the key boronic acid intermediate 10 for palladium-catalyzed biaryl coupling with bromide 5 obtained from the regioselective alkylation of the chloroimidazole 2. This methodology overcomes many of the drawbacks associated with previously reported syntheses.