ChemicalBook CAS DataBase List Telmisartan

Telmisartan synthesis

11synthesis methods

Product Name:Telmisartan
CAS Number:144701-48-4
Molecular formula:C33H30N4O2
Molecular Weight:514.62

Telmisartan can be prepared in eight steps starting with methyl 4-amino-3-methyl benzoate; the first and second cyclization into a benzimidazole ring occur at steps 4 and 6 respectively.

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144701-48-4
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Yield:144701-48-4 98.6%

Reaction Conditions:

Stage #1: 4'-[[4-methyl-6-(1-methyl-1H-benzimidazol-2-yl)-2-propyl-1H-benzimidazol-1-yl]methyl]biphenyl-2-carboxylic acid methyl esterwith methanol;sodium hydroxide;water for 2 h;Heating / reflux;
Stage #2: with acetic acid in water;

Steps:

1

In a 1000 ml three-necked round bottom flask equipped with a reflux condenser, a thermometer and a magnetic stirrer, 4-[(1,4'-dimethyl-2'-propyl[2,6'-bi-1H-benzimidazol]-1'-yl)methyl]-[1,1'-biphenyl]-2-carboxylic acid methyl ester (50 g, 0.095 mole) was charged, and methanol (300 ml) was added followed by addition of water (26 ml) and 47% NaOH solution (27 ml). The mixture was refluxed for 2 hours. Part of the solvent was evaporated and water (500 ml) was added in portions at 85° C. to afford a solution. The insoluble matter was removed by filtration and the mixture was neutralized with a solution of acetic acid (31.7 ml) in water (75 ml). The thus obtained crude Telmisartan cake was collected by filtration and washed with water to obtain 150 g of wet Telmisartan, which was dried under vacuum to obtain 48 g of the crude product in 98.6% yield, having a purity of 97%.

References:

US2006/276525,2006,A1 Location in patent:Page/Page column 7