Prazosin

Bezeichnung:Prazosin

CAS-Nr19216-56-9

Englisch Name:Prazosin

CBNumberCB8120869

SummenformelC19H21N5O4

Molgewicht383.4

MOL-Datei19216-56-9.mol

Synonyma

Prazosin

Prazosin physikalisch-chemischer Eigenschaften

Schmelzpunkt	278-280°C
Siedepunkt	510.33°C (rough estimate)
Dichte	1.3275 (rough estimate)
Brechungsindex	1.7600 (estimate)
storage temp.	2-8°C
Löslichkeit	DMSO (Slightly), Methanol (Slightly, Heated)
Aggregatzustand	Solid
pka	pKa 6.54(50% EtOH) (Uncertain)
Farbe	White to Off-White
Wasserlöslichkeit	3.2mg/L(22.5 ºC)

Gefahreninformationscode (GHS)

Prazosin Chemische Eigenschaften,Einsatz,Produktion Methoden

Originator
Hypovase, Pfizer, UK,1974
Verwenden
Prazosin is used for treating mid-to-moderate hypertension. When using this drug, blood pressure is reduced without any significant change in indicators of cardiac function such as frequency, coronary flow, or cardiac output.
Verwenden
Antihypertensive.
Verwenden
Prazosin is used to treat average or moderate hypertension. Upon taking this drug, blood pressure drops without substantial changes in indicators of heart work, such as rate, coronary flow, and cardiac output. Prazosin is used for weak to moderate hypertension.
Definition
ChEBI: A member of the class of piperazines that is piperazine substituted by a furan-2-ylcarbonyl group and a 4-amino-6,7-dimethoxyquinazolin-2-yl group at positions 1 and 4 respectively.
Manufacturing Process
Preparation of 2-Chloro-4-Amino-6,7-Dimethoxyquinazoline: To 800 ml of a solution of anhydrous ammonia in tetrahydrofuran at room temperature is added 30 g of 2,4-dichloro-6,7-dimethoxyquinazoline [F.H.S. Curd et al., J. Chem. Soc., p 1759 (1948)]. The mixture is stirred for 44 hours. The precipitate (29 g, MP 267° to 268°C) is filtered and recrystallized from methanol to yield 19 g of 2-chloro-4-amino-6,7-dimethoxyquinazoline, MP 302°C (dec.).
Preparation of 2-(1-Piperazinyl)-4-Amino-6,7-Dimethoxyquinazoline: To 5 g of 2-chloro-4-amino-6,7-dimethoxyquinazoline, is added 20 g of a 25% solution of piperazine in ethanol. The mixture is heated at 160°C for 16 hours in a pressure bottle. The solvent is then evaporated and the residue is recrystallized from methanol/water.
Preparation of 2[4-(2-Furoyl)-Piperazinyl]-4-Amino-6,7-Dimethoxyquinazoline: To 0.10 mol 2-(1-piperazinyl)-4-amino-6,7-dimethoxyquinazoline in 300 ml methanol is added with vigorous stirring, 0.10 mol 2-furoyl chloride. After addition is complete, the mixture is stirred for 3 hours at room temperature. The solids are filtered to give the desired product, MP 278° to 280°C.
Trademarks
Minipress (Pfizer).
Therapeutic Function
Antihypertensive
Clinical Use
Prazosin is effective in reducing all grades of hypertension. The drug can be administered alone in mild and (in some instances) moderate hypertension.When the hypertension is moderate or severe, prazosin generally is given in combination with a thiazide diuretic and a -blocker. The antihypertensive actions of prazosin are considerably potentiated by coadministration of thiazides or other types of antihypertensive drugs.
Prazosin may be particularly useful when patients cannot tolerate other classes of antihypertensive drugs or when blood pressure is not well controlled by other drugs. Since prazosin does not significantly influence blood uric acid or glucose levels, it can be used in hypertensive patients whose condition is complicated by diabetes mellitus or gout. Prazosin and other -antagonists find use in the management of benign prostatic obstruction, especially in patients who are not candidates for surgery. Blockade of -adrenoceptors in the base of the bladder and in the prostate apparently reduces the symptoms of obstruction and the urinary urgency that occurs at night.
Nebenwirkungen
Although less of a problem than with phenoxybenzamine or phentolamine, symptoms of postural hypotension, such as dizziness and light-headedness, are the most commonly reported side effects associated with prazosin therapy. These effects occur most frequently during initial treatment and when the dosage is sharply increased. Postural hypotension seems to be more pronounced during Na deficiency, as may occur in patients on a low-salt diet or being treated with diuretics, - blockers, or both.
Synthese
Prazosin, 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furoyl)-piperazine (12.2.12), is synthesized from 2-amino-4,5-dimethoxybenzoic acid, which upon reaction with sodium cyanate undergoes heterocyclation into 2,4-dihydroxy-6,7-dimethoxyquinazoline (12.2.9). Substituting hydroxyl groups of this compound with chlorine atoms by reaction with thionyl chloride, or a mixture of phosphorous oxychloride with phosphorous pentachloride gives 2,4-dichloro-6,7-dimethoxyquinazoline (12.2.10). Upon subsequent reaction with ammonia, the chlorine atom at C4 of the pyrimidine ring is replaced with an amino group, which leads to the formation of 4-amino-2-chloro-6,7-dimethoxyquinazoline (12.2.11). Introducing this into a reaction with 1-(2-furoyl)piperazine gives prazosin (12.2.12) [38¨C47].
Veterinary Drugs and Treatments
Prazosin is less well studied in dogs than hydralazine, and its capsule dosage form makes it less convenient for dosing. Prazosin, however, appears to have fewer problems with causing tachycardia, and its venous dilation effects may be an advantage over hydralazine when preload reduction is desired. It could be considered for therapy for the adjunctive treatment of CHF, particularly when secondary to mitral or aortic valve insufficiency when hydralazine is ineffective or not tolerated. Prazosin may also be used for the treatment of systemic hypertension or pulmonary hypertension in dogs.
Arzneimittelwechselwirkung
Potentially hazardous interactions with other drugs
Anaesthetics: enhanced hypotensive effect.
Antidepressants: enhanced hypotensive effect with MAOIs.
Avanafil, vardenafil, sildenafil and tadalafil: enhanced hypotensive effect - avoid.
Beta-blockers: enhanced hypotensive effect, increased risk of first dose hypotensive effect.
Calcium-channel blockers: enhanced hypotensive effect, increased risk of first dose hypotensive effect.
Diuretics: enhanced hypotensive effect, increased risk of first dose hypotensive effect.
Moxisylyte: possibly severe postural hypotension when used in combination.
Stoffwechsel
Prazosin is extensively metabolised in the liver, mainly by demethylation and conjugation; some of the metabolites have antihypertensive activity.
It is excreted as metabolites and 5-11% as unchanged prazosin mainly in the faeces via the bile.

Prazosin Upstream-Materialien And Downstream Produkte

Prazosin Anbieter Lieferant Produzent Hersteller Vertrieb Händler.

19216-56-9, Prazosin Verwandte Suche:

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