- Continuous Synthesis and Separation ofp-Bromobenzyl Bromide Using Atom-Efficient Bromination ofp-Bromotoluene without Any Organic Effluent: Potential for Green Industrial Practice
-
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.
- Sancheti, Sonam V.,Yadav, Ganapati D.
-
p. 2071 - 2080
(2021/09/13)
-
- Process for the preparation of benzylimidazole derivatives
-
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.
- -
-
Page/Page column 3
(2010/02/11)
-
- Process for the preparation of benzylimidazole derivatives and for losartan
-
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.
- -
-
Page/Page column 5
(2010/02/12)
-
- Process for preparing 2,4,5-trisubstituted imidazoles from N-acylated alpha-amino nitriles
-
The invention is a process for preparing an imidazole of formula I which comprises treating an N-acylated α-amino nitrile with a phosphine and a carbon tetrahalide of the formula CX4, wherein X is Cl or Br, to form a haloimidazole of the formula wherein R1 is selected from the group consisting of hydrogen, C1-6alkyl, —CH2-aryl, and aryl; and R2 is selected from the group consisting of hydrogen, C1-6alkyl, —CH2—O-aryl and aryl; and X is selected from the group consisting of Cl and Br.
- -
-
-
- Use of an angiotensin II receptor antagonist for the preparation of drugs to increase the survival rate of renal transplant patients
-
The present invention relates to the use, for the preparation of drugs to increase the survival rate of transplant patients, including renal and heart transplant patients, of a therapeutically effective amount of an angiotension II receptor antagonist compound, such as the class of substituted imidazoles represented by formula (I) and in particular by losartan potassium, 2-butyl-4-chloro-[(2′-tetrazol-5-yl)biphenyl-4-il]methyl]-5-(hydroxymethyl)imidazole potassium salt.
- -
-
-
- INSULIN SENSITIVITY WITH ANGIOTENSIN II RECEPTOR BLOCKING IMIDAZOLES
-
This invention relates to a novel method of using an Angiotensin II antagonist for the improvement of insulin sensitivity alone or in conjunction with the treatment of hypertension. Angiotensin II antagonists such as the class of substituted imidazoles represented by formula I: STR1 and specifically by Losartan, 2-butyl-4-chloro-1-[(2'-tetrazol-5-yl)biphenyl-4-yl]methyl]-5-(hydroxymethyl)imidazole potassium salt.
- -
-
-
- Polymorphs of losartan and the process for the preparation of form II of losartan
-
Polymorphic forms of Losartan (Formula I) STR1 and a process for the preparation of Form II of Losartan. Losartan is known to be useful in the treatment of hypertension.
- -
-
-
- Treatment of atherosclerosis with angiotensin II receptor blocking imidazoles
-
A method of treatment for atherosclerosis and/or reducing cholesterol using an angiotensin II antagonist. This method of treatment can be used in conjunction with the treatment of hypertension. Substituted imidazoles such as STR1 are useful as angiotensin II receptor antagonists for this method of treatment. A method of treatment for atherosclerosis and/or reducing cholesterol using an angiotensin II receptor antagonist in combination with an HMG-Co A reductase inhibitor. A method of treatment for atherosclerosis and/or reducing cholesterol using an angiotensin II receptor antagonist in combination with an HMG-Co A reductase inhibitor and an angiotensin converting enzyme inhibitor. Also within the scope of this invention are pharmaceutical compositions for this method of use.
- -
-
-
- PROCESS FOR PREPARING BIPHENYLTETRAZOLE COMPOUNDS
-
Method for the preparing biphenyltetrazole compounds which are angiotensin II receptor antagonists or which are useful intermediates to prepare angiotensin II receptor antagonists. An illustrative biphenyl tetrazole compound is 2-n-butyl-4-chloro-1-[(2'-(tetrazol-5-yl)-1,1'-biphenyl-4-yl)methyl]-1H-imi dazole-5-methanol, potassium salt.
- -
-
-
- Efficient synthesis of losartan, a nonpeptide angiotensin II receptor antagonist
-
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.
- Larsen,King,Chen,Corley,Foster,Roberts,Yang,Lieberman,Reamer,Tschaen,Verhoeven,Reider,Lo,Rossano,Brookes,Meloni,Moore,Arnett
-
p. 6391 - 6394
(2007/10/02)
-