ChemicalBook > CAS DataBase List > Prazosin

Prazosin

Product Name
Prazosin
CAS No.
19216-56-9
Chemical Name
Prazosin
Synonyms
pressin;PRAZOSIN;furazosin;minipress;AKOS B020009;PrazosinBase;Terazosin-010;Prazosin USP/EP/BP;ART-CHEM-BB B020009;Terazosin Impurity15
CBNumber
CB8120869
Molecular Formula
C19H21N5O4
Formula Weight
383.4
MOL File
19216-56-9.mol
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Prazosin Property

Melting point:
278-280°C
Boiling point:
510.33°C (rough estimate)
Density 
1.3275 (rough estimate)
refractive index 
1.7600 (estimate)
storage temp. 
2-8°C
solubility 
DMSO (Slightly), Methanol (Slightly, Heated)
form 
Solid
pka
pKa 6.54(50% EtOH) (Uncertain)
color 
White to Off-White
Water Solubility 
3.2mg/L(22.5 ºC)
InChI
InChI=1S/C19H21N5O4/c1-26-15-10-12-13(11-16(15)27-2)21-19(22-17(12)20)24-7-5-23(6-8-24)18(25)14-4-3-9-28-14/h3-4,9-11H,5-8H2,1-2H3,(H2,20,21,22)
InChIKey
IENZQIKPVFGBNW-UHFFFAOYSA-N
SMILES
C(N1CCN(C2=NC(N)=C3C(=N2)C=C(OC)C(OC)=C3)CC1)(C1=CC=CO1)=O
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Hazard and Precautionary Statements (GHS)

Symbol(GHS)
Signal word
Warning
Hazard statements

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

Precautionary statements

P264Wash hands thoroughly after handling.

P264Wash skin thouroughly after handling.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

P321Specific treatment (see … on this label).

P332+P313IF SKIN irritation occurs: Get medical advice/attention.

P362Take off contaminated clothing and wash before reuse.

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N-Bromosuccinimide Price

Sigma-Aldrich
Product number
R736384
Product name
2-(4-(2-FUROYL)-1-PIPERAZINYL)-6,7-DIMETHOXY-4-QUINAZOLINAMINE
Purity
Aldrich<sup>CPR</sup>
Packaging
1 unit
Price
$113
Updated
2025/07/31
Sigma-Aldrich
Product number
R736384
Product name
2-(4-(2-FUROYL)-1-PIPERAZINYL)-6,7-DIMETHOXY-4-QUINAZOLINAMINE
Purity
AldrichCPR
Packaging
10MG
Price
$110
Updated
2024/03/01
TRC
Product number
P702333
Product name
Prazosin
Packaging
25mg
Price
$45
Updated
2021/12/16
Usbiological
Product number
462926
Product name
Prazosin
Packaging
1mg
Price
$368
Updated
2021/12/16
Biosynth Carbosynth
Product number
IA63850
Product name
[4-(4-Amino-6,7-dimethoxy-2-quinazolinyl)-1-piperazinyl]-2-furanyl-methanone
Packaging
25mg
Price
$65
Updated
2021/12/16
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Prazosin Chemical Properties,Usage,Production

Chemical Properties

Crystallized, melting point 278-280°C. Its hydrochloride ([19237-84-4]) is a white crystalline powder with a melting point of 275 (decomposition). Difficult to dissolve in ethanol, slightly soluble in isotonic saline and water. Odorless, bitter taste.

Originator

Hypovase, Pfizer, UK,1974

History

Prazosin is a drug used to treat hypertension. Prazosin is marketed by Pfizer and was initially approved by the FDA in 1988. It belongs to the class of drugs known as alpha-1 antagonists.
According to FDA, in October 2025, New Jersey-based drugmaker Teva Pharmaceuticals USA and drug distributor Amerisource Health Services issued voluntary nationwide recalls of over half a million bottles of various strengths of prazosine capsules, which may include a cancer-causing chemical.

Uses

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.

Uses

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.

Uses

Antihypertensive.

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.

brand name

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.

Side effects

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.

Synthesis

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.

Drug interactions

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.

Metabolism

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 Preparation Products And Raw materials

Raw materials

Preparation Products

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View Lastest Price from Prazosin manufacturers

Sigma Audley
Product
Prazosin 19216-56-9
Price
US $35.00-25.00/kg
Min. Order
1kg
Purity
99.8%
Supply Ability
200tons/year
Release date
2024-03-14
Zhuozhou Wenxi import and Export Co., Ltd
Product
Prazosin 19216-56-9
Price
US $15.00-10.00/KG
Min. Order
1KG
Purity
99%+ HPLC
Supply Ability
Monthly supply of 1 ton
Release date
2021-07-10
Zhuozhou Wenxi import and Export Co., Ltd
Product
Prazosin 19216-56-9
Price
US $15.00-10.00/KG
Min. Order
1KG
Purity
99%+ HPLC
Supply Ability
Monthly supply of 1 ton
Release date
2021-07-08

19216-56-9, PrazosinRelated Search:


  • 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)-piperazin
  • 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine
  • 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine.
  • 1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4-(2-furoyl)-piperazin
  • (4-(4-AMino-6,7-diMethoxyquinazolin-2-yl)piperazin-1-yl)(furan-2-yl)Methanone hydrochloride salt
  • Terazosin EP Impurity K
  • Terazosin-010
  • Terazosin Impurity15
  • [4-(4-Amino-6,7-dimethoxy-2-quinazolinyl)-1-piperazinyl]-2-furanyl-methanone
  • 2-(4-(2-furoyl)piperazin-1-yl)-4-amino-6,7-dimethoxyquinazoline
  • 4-amino-6,7-dimethoxy-2-(4-(2-furoyl)piperazin-1-yl)-quinazolin
  • furazosin
  • PRAZOSIN
  • pressin
  • PIPERAZINE, 1-(4-AMINO-6,7-DIMETHOXY-2-QUINAZOLINYL)-4-(2-FURANYLCARBONYL)-
  • minipress
  • AKOS B020009
  • 1-(4-amino-6,7-dimethoxy-2-quinazolinyl-4-(2-furanylcarbonyl)) piperrazine
  • ART-CHEM-BB B020009
  • PrazosinBase
  • Prazosin Hcl 19237-84-4 / Base
  • (2-Furanyl)[4-(4-amino-6,7-dimethoxyquinazoline-2-yl)piperazine-1-yl] ketone
  • 1-(4-Amino-6,7-dimethoxyquinazolin-2-yl)-4-(furan-2-ylcarbonyl)piperazine
  • 2-[4-(2-Furoyl)piperazin-1-yl]-6,7-dimethoxyquinazolin-4-amine
  • [4-(4-amino-6,7-dimethoxy-quinazolin-2-yl)piperazin-1-yl]-(2-furyl)methanone
  • [4-(4-amino-6,7-dimethoxyquinazolin-2-yl)piperazin-1-yl]-furan-2-ylmethanone
  • [4-(4-azanyl-6,7-dimethoxy-quinazolin-2-yl)piperazin-1-yl]-furan-2-yl-methanone
  • 1-(4-aMino-6,7-diMethoxy-2-quinazolinyl)-4-(2-furanylcarbonyl)piperazine hidrochloride
  • Methanone, [4-(4-amino-6,7-dimethoxy-2-quinazolinyl)-1-piperazinyl]-2-furanyl-
  • Prazosin USP/EP/BP
  • 2-[4-(furan-2-carbonyl)piperazin-1-yl]-6,7-dimethoxyquinazolin-4-amine
  • Linagliptin Impurity CD10125
  • Prazosin, 10 mM in DMSO
  • 2-(4-(2-FUROYL)-1-PIPERAZINYL)-6,7-DIMETHOXY-4-QUINAZOLINAMINE
  • (4-(4-amino-6,7-dimethoxyquinazolin-2-yl)piperazin-1-yl)(furan-2-yl)methanonee
  • 19216-56-9
  • C19H21N5O4