234-80-0

Basic information

• Product Name: S-TRIAZOLO[3,4-A]PHTHALAZINE
• Synonyms: S-Triazolo[3,4-α]phthalazine;1,2,4-Triazolo[3,4-a]phthalazine;NSC 116341;Hydralazine IMpurity 04;Hydralazine Triazolo IMpurity
• CAS NO: 234-80-0
• Molecular Formula: C₉H₆N₄
• Molecular Weight: 170.18
• Product Categories: Fluorescent Labels and Indicators;Fluorescent Labels & Indicators;Metabolites & Impurities;Aromatics;Heterocycles;Impurities;Intermediates & Fine Chemicals;Pharmaceuticals
• Mol File: 234-80-0.mol
• Article Data: 2

Chemical Properties

• Melting Point: 195.5-196°C
• Boiling Point: °Cat760mmHg
• Flash Point: °C
• Appearance: /
• Density: 1.45g/cm³
• Refractive Index: 1.79
• Storage Temp.: Refrigerator
• Solubility: Acetonitrile (Slightly), DMSO (Slightly), Methanol (Slightly)
• PKA: 0.88±0.30(Predicted)
• CAS DataBase Reference: S-TRIAZOLO[3,4-A]PHTHALAZINE(CAS DataBase Reference)
• NIST Chemistry Reference: S-TRIAZOLO[3,4-A]PHTHALAZINE(234-80-0)
• EPA Substance Registry System: S-TRIAZOLO[3,4-A]PHTHALAZINE(234-80-0)

Safety Data

• Hazardous Substances Data: 234-80-0(Hazardous Substances Data)

Usage

Chemical Properties

Off-White to Yellow Solid

Uses

An impurity of the drug Hydralazine (H716531).

InChI:InChI=1/C9H6N4/c1-2-4-8-7(3-1)5-11-13-6-10-12-9(8)13/h1-6H

Upstream product

• 304-20-1 hydralazine hydrochloride 

Downstream Products

• 21537-95-1 3-bromo[1,2,4]triazolo[3,4-a]phthalazine 

Relevant articles and documents

Interactions between drug substances and excipients. 1. Fluorescence and HPLC studies of triazolophthalazine derivatives from hydralazin hydrochloride and starch

The strength of hydralazine hydrochloride (I) 10 mg tablets, containing starch as an excipient, decreases significantly with time. An investigation to determine the basis for the drop in strength showed that starch exposed to the drug exhibited fluorescence at 414 nm. As model compounds IIIa and V, which contain a triazolophthalazinyl moiety, also fluoresce at about 414 nm, it is proposed that the emission is due to a triazolophthalazine derivative (IIIc) resulting from hydralazine hydrochloride and starch. Degradation of IIIc generates s-triazolo[3;4-a]phthalazine (IIIb), and a small amount of IIIb is detected in aged tablets. IIIc in aged tablets can be converted to IIIb by acid-catalyzed hydrolysis. The quantity of IIIb determined by HPLC amounts to most of the "missing" hydralazine hydrochloride. The reaction between hydralazine hydrochloride and starch is believed to cause the unexpected drop in the strength of hydralazine hydrochloride tablets.