ChemicalBook > Product Catalog > Biochemical Engineering > Inhibitors > GPCR & G Protein > Endothelin Receptor Antagonists > Bosentan
Bosentan Chemical Properties
- Melting point:107-110°C
- Boiling point:742.3±70.0 °C(Predicted)
- Density 1.325±0.06 g/cm3(Predicted)
- storage temp. -20°C Freezer
- CAS DataBase Reference147536-97-8(CAS DataBase Reference)
- HS Code 29350090
Bosentan Usage And Synthesis
- DescriptionBosentan was introduced in the US as a twice-daily oral treatment for pulmonary arterial hypertension. It can be synthesized in five steps via condensation of diethyl (2- methoxyphenoxy)malonate with pyrimidine-2-carboxamidine to give the precursor of the symmetrical central dichloropyrimidine ring which is then successively treated with the potassium salt of 4-tert-butylbenzenesulfonamide and the sodium salt of ethylene gycol. Bosentan is the first endothelin (ET) receptor antagonist to be launched. ET-1, the most potent endogenous vasoconstrictor known, has been demonstrated to play a major role in the functional and structural changes observed in pulmonary hypertension. Bosentan is a mixed ETA and ETB receptor antagonist that inhibits the pulmonary arterial vasoconstricting effect of ET-1 predominantly mediated via ETA receptors on smooth muscle cells. In a hypoxia-induced model of pulmonary hypertension in rat, it reduced the development of pulmonary hypertension as well as right ventricular hypertrophy and prevented pulmonary arterial remodeling. In clinical trials, patients treated with bosentan showed a 20% increase in exercise capacity compared to placebo as measured by the six minute walk test. Bosentan not only improved the distance walked by patients but also significantly decreased mean pulmonary artery pressure, mean pulmonary vascular resistance, mean capillary wedge pressure and mean right atrial pressure. It demonstrated a beneficial selectivity for the pulmonary vasculature since it had no significant effect on mean aortic blood pressure and systolic vascular resistance. The compound is hepatically metabolized into three major metabolites by CYP3A4 and 2C9 and almost exclusively eliminated in the bile. Although large interspecies differences in systemic plasma clearance was observed (1.5 mL/min/kg in dogs to 72 mL/min/kg in rabbits), a satisfactory systemic clearance (2 mL/min/kg) was measured in human. The most frequent adverse effect was reversible elevation of liver transaminases. This adverse reaction appears to be due to intracellular accumulation of cytotoxic bile salts resulting from inhibition of the hepatocanalicular bile salt export pump by bosentan.
- Chemical PropertiesPale Yellow to Off-White Solid
- OriginatorRoche (Switzerland)
- UsesA mixed endothelin receptor antagonist. Used as a vasodilator. Antihypertensive.
- Manufacturing Process4-t-butyl-N-[6-chloro-5-(2-methoxyphenoxy)-2-(pyrimidin-2-yl)-pyrimidin-4-
yl]benzenesulphonamide were heated to 100°C, cooled for a further 4 hours,
poured on to ice and adjusted to pH 3 with 1 M tartaric acid. The suspension
obtained was extracted with ethyl acetate, the organic extracts were
combined, washed with water, dried with sodium sulfate and concentrated
under reduced pressure. The residue was chromatographed on silica gel with
CH2Cl2-ethyl acetate 9:1 and yielded 4-t-butyl-N-[6-(2-hydroxyethoxy)-5-(2-
a solid. Sodium salt melted at 195°-198°C.
The 4-t-butyl-N-[6-chloro-5-(2-methoxyphenoxy)-2-pyrimidin-2-yl)-pyrimidin- 4-yl]benzenesulfonamide was prepared starting from pyrimidine-2- carboxamidine hydrochloride via rac-5-(2-methoxyphenoxy)-2-(pyrimidin-2- yl)tetrahydropyrimidine-4,6-dione and 4,6-dichloro-5-(2-methoxyphenoxy)- 2,2'-bipyrimidine.
- brand nameTracleer (Actelion).
- Therapeutic FunctionEndothelin receptor antagonist
- General DescriptionBosentan, N-[6-(2-hydroxyethoxy)-5-(2-methoxyphenoxy)-2-pyrimidin-2-yl-pyrimidin-4-yl]-4-tertbutyl-benzenesulfonamide (Tracleer, Bozentan), was thefirst endothelin receptor antagonist marketed in the UnitedStates. Bosentan works by competitively blocking the endothelinreceptor subtypes ETA and ETB. In binding to thereceptors, it blocks the effects of endothelin, which includeconstriction of the vascular smooth muscle, which leads tonarrowing of the blood vessels and hypertension. Althoughit is not selective for the ETA receptors, it does have a higheraffinity for that subtype over ETB. However, the clinical significanceof selectivity over preferential receptor bindinghas not been demonstrated. Bosentan is an inducer ofCYP2C9 and CYP3A4, and patients using bosentan must bemonitored for liver toxicity.
- HazardA reproductive hazard.
- PharmacokineticsBosentan is mainly eliminated from the body by hepatic metabolism and subsequent biliary excretion of the metabolites. Three metabolites have been identified, formed by CYP2C9 and CYP3A4. The pharmacokinetics of bosentan are dose-proportional up to 500 mg/day (multiple doses). The pharmacokinetics of bosentan in pediatric patients with PAH are comparable to those in healthy subjects, whereas adult patients with PAH show a twofold increase in clearance. Severe renal impairment and mild hepatic impairment do not have a clinically relevant influence on its pharmacokinetics. Bosentan generally should be avoided in patients with moderate or severe hepatic impairment and/or elevated liver aminotransferases. Inhibitors of CYP3A4 increase the plasma concentration of bosentan as well as cause an increase in the clearance of drugs metabolized by CYP3A4 and CYP2C9 because of induction of these metabolizing enzymes. The possibility of reduced efficacy of CYP2C9 and CYP3A4 substrates coadministered with bosentan is increased. No clinically relevant interaction was detected for P-glycoprotein. Bosentan can increase plasma levels of ET-1.
- Clinical UseBosentan is an orally administered, nonselective ET-1 receptor antagonist blocking ETA and ETB receptors and is approved for the treatment of patients with PAH. Following oral administration, bosentan attains peak plasma concentrations in approximately 3 hours, with an absolute bioavailability of approximately 50%. Food has no clinically relevant effect on its absorption recommended doses. Bosentan is approximately 98% bound to albumin, with a volume of distribution of 30 L. Its terminal half-life after oral administration is 5.4 hours and is unchanged at steady state.
- Side effectsAdverse effects include hypotension, headache, flushing, increased liver aminotransferases, leg edema, and anemia. Bosentan may cause birth defects and, therefore, is contraindicated in pregnancy. It also can cause liver injury.
- Bosentan Impurity 5 Bosentan Impurity 17 Bosentan Impurity 18 2-Cyanopyrimidine 5-(2-Methoxyphenoxy)-[2,2'-bipyrimidine]-4,6(1H,5H)-dione 2-(2-Methoxyphenoxy)propanedioic acid diethyl ester Bosentan Impurity 7 Bosentan Impurity 2 Bosentan Impurity 10 Bosentan Impurity 3 Bosentan Impurity Bosentan Impurity 1 Bosentan Impurity 6 Bosentan Impurity Diethyl chloromalonate 4-(1,1-dimethylethyl)-N-[6-(ethenyloxy)-5-(2-methoxyphenoxy)[2,2''-bipyrimidin]-4-yl]-Benzenesulfonamide Bosentan Impurity 11 Bosentan Impurity 4
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