253-52-1

Basic information

• Product Name: Phthalazine
• Synonyms: 2,3-Diazanaphthalene;beta-Phenodiazine;β-Phenodiazine;4,5-BENZOPYRIDAZINE;2,3-BENZODIAZINE;BENZO[D]PYRIDAZINE;PHTHALAZINE;PHZ
• CAS NO: 253-52-1
• Molecular Formula: C₈H₆N₂
• Molecular Weight: 130.15
• EINECS: 205-963-2
• Product Categories: Building Blocks;Heterocyclic Building Blocks;Pyridazines
• Mol File: 253-52-1.mol

Chemical Properties

• Melting Point: 89-92 °C(lit.)
• Boiling Point: 189 °C29 mm Hg(lit.)
• Flash Point: 178-180°C/15mm
• Appearance: Slightly brown to beige/Crystalline Powder
• Density: 1.1509 (rough estimate)
• Vapor Pressure: 0.000782mmHg at 25°C
• Refractive Index: 1.6231 (estimate)
• Storage Temp.: 2-8°C
• Solubility: Chloroform (Slightly), Methanol (Slightly)
• PKA: 3.47(at 20℃)
• Water Solubility: Soluble in water, methanol, chloroform.
• Merck: 14,7370
• BRN: 109240
• CAS DataBase Reference: Phthalazine(CAS DataBase Reference)
• NIST Chemistry Reference: Phthalazine(253-52-1)
• EPA Substance Registry System: Phthalazine(253-52-1)

Safety Data

• Hazard Codes: Xi,Xn
• Statements: 36/37/38-68
• Safety Statements: 24/25-37/39-36-26-36/37/39
• WGK Germany: 3
• TSCA: Yes
• Hazardous Substances Data: 253-52-1(Hazardous Substances Data)

Usage

Uses

Used in Pharmaceutical Industry:
Phthalazine is used as a chemical compound for the development of various pharmaceutical applications. Aminophthalazine compounds, derived from phthalazine, serve as effective phosphodiesterase (PDE) inhibitors, which play a crucial role in the treatment of various diseases and conditions.
Used in Anticancer Applications:
Phthalazine derivatives, including copper and platinum complexes, are used as anticancer agents, particularly in inducing apoptosis in breast cancer cell lines and renal hyperemia. These derivatives have shown potential in targeting and eliminating cancer cells, contributing to the development of novel cancer treatments.
Used in Chemical Research:
Phthalazine serves as a key component in chemical research and development, particularly in the synthesis of various organic compounds and materials. Its unique structure and properties make it a valuable building block for creating new molecules with specific functions and applications in different industries.

Synthesis Reference(s)

Journal of Heterocyclic Chemistry, 2, p. 206, 1965 DOI: 10.1002/jhet.5570020219

Purification Methods

Phthalazine crystallises from diethyl ether or *benzene, and sublimes under a vacuum. The hydrochloride forms needles from EtOH with m 235-236o(dec) and the picrate has m 208-210o. [Armarego J Appl Chem 11 70 1961, Beilstein 23 H 174, 23 III/IV 1233.]

InChI:InChI=1/C8H6N2/c1-2-4-8-6-10-9-5-7(8)3-1/h1-6H

Upstream product

• 5784-45-2 1-chlorophthalazine 
• 4752-10-7 1,4-dichlorophthalazine 
• 52866-89-4 1,1',2,2'-tetrahydro-1,1'-biphthalazine 
• 21452-55-1 1-cyano-1H-phthalazine-2-carboxylic acid diethylamide 
• 484-23-1 1,4-bis(hydrazino)phthalazine 
• 65997-87-7 (E,Z)-Benzaldehyde azine 
• 38710-51-9 2-methyl-phthalazinium; iodide 
• 5678-02-4 pyridazine-3,4-dicarboxylic acid anhydride 
• 21415-94-1 1-cyano-1H-phthalazine-2-carboxylic acid diphenylamide 
• 643-79-8 o-phthalic dicarboxaldehyde 
• 13152-89-1 1,2,3,4-tetrahydrophthalazine 
• 10034-85-2 hydrogen iodide 
• 302-01-2 hydrazine 
• 25641-99-0 α,α,α',α'-tetrachloro-o-xylene 

Downstream Products

• 106590-18-5 5-phenyl-phthalazine 
• 97435-88-6 2-benzyl-phthalazinium; chloride 
• 59648-14-5 pyridazine-4,5-dicarboxylic acid 
• 17300-02-6 1,2-benzenedimethanamine 
• 26641-27-0 4-isopropylidene-1,1-dimethyl-1,11b-dihydro-[1,3]oxazino[4,3-a]phthalazin-2-one 
• 1624-26-6 2,3-dihydro-1H-cyclopenta[b]naphthalene 
• 78287-39-5 2-(2-chloromethylbenzoyl)-1-cyano-1,2-dihydrophthalazine 
• 106937-56-8 1,10b-Dihydro-1,1-diphenylpyrrolo<2,1-a>phthalazin-2,3-dicarbonsaeure-dimethylester 
• 128404-65-9 13-benzoylindeno<1',2':5,4>pyrrolo<2,1-a>phthalazin-12-one 
• 152897-86-4 6-<(4-Chlorophenyl)amino>-2,4-dimethyl-1H,2H-phthalazino<2',1':3,4>pyrimido<4,5-d>pyrimidine-1,3(2H,4H)-dione 
• 13925-27-4 1-Cyano-2-benzoyl-1,2-dihydrophthalazine 
• 65397-76-4 2-benzoyl-1-ethoxy-1,2-dihydro-phthalazine 
• 108965-28-2 Dimethyl 2-Benzoyl-1,2-dihydro-1-phthalazinylphosphonate 
• 152897-85-3 2,4-Dimethyl-6-(phenylamino)-1H,2H-phthalazino<2',1':3,4>pyrimido<4,5-d>pyrimidine-1,3(2H,4H)-dione 

Relevant articles and documents

DUAL PHOTOREACTIONS OF PHTHALAZINE FROM THE LOWEST EXCITED SINGLET AND TRIPLET STATES

Phthalazine undergoes the photoreduction and the photo-reductive dimerization simultaneously to give 1,2-dihydrophthalazine and its dimer (1H,1'H,2H,2'H-1,1'-biphthalazine), respectively, upon ultraviolet light irradiation in 2-propanol.It has been suggested that the photoreduction proceeds through the lowest excited singlet state and the photodimerization through the lowest triplet state.

Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents

Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).

Visible-Light Photocatalyzed Deoxygenation of N-Heterocyclic N-Oxides

A scalable and operationally simple method is described that allows for the chemoselective deoxygenation of a wide range of N-heterocyclic N-oxides (a total of 36 examples). This visible-light-induced protocol features the use of only commercially available reagents, room-temperature conditions, and unprecedented chemoselective removal of the oxygen atom in a quinoline N-oxide in the presence of a pyridine N-oxide in the same molecule through the judicious selection of a photocatalyst.

Ligand Redox-Controlled Tandem Synthesis of Azines from Aromatic Alcohols and Hydrazine in Air: One-Pot Synthesis of Phthalazine

A controlled tandem synthetic route to azines from various alcohols and hydrazine hydrate by the use of a Ni(II) complex of 2,6-bis(phenylazo)pyridine as a catalyst is reported. In marked contrast to the previous report, the reaction is operative using an earth-abundant metal catalyst, milder reaction conditions, and aerobic conditions, which though are desirable but unprecedented in the literature. The catalytic reaction has a vast substrate scope including a single-step synthesis of phthalazine from 1,2-benzenedimethanol and hydrazine hydrate via intramolecular coupling. Mechanistic investigation suggests that the coordinated ligand redox controls the reaction by the use of a reversible azo (N=N)/ hydrazo (NH - NH) redox couple where the metal center is used primarily as a template.

Nitrogen activation and conversion method promoted by divalent rare earth iodine compound

The invention belongs to the technical field of organic chemical synthesis, and particularly relates to a method for activating and converting nitrogen through a divalent rare earth compound. A divalent rare earth diodide is used as a reducing agent, a solvent is added in, the mixture reacts with nitrogen, then a hydrogen source is added in, and then the mixture reacts with an aldehyde or ketone compound to obtain an azine or pyridazine compound. According to the method, the nitrogen is activated and converted into the organic compound containing nitrogen on the mild condition. Compared with a classical ammonia synthesis path, strict reaction conditions such as high temperature, high pressure and ammonia oxidation are avoided, and the method is of great significance in developing the new technology of nitrogen molecule activation and broadening the application range of rare earth metal in organic synthesis.

One-pot synthesis of phthalazines and pyridazino-aromatics: A novel strategy for substituted naphthalenes

A new one-pot strategy for the synthesis of phthalazines and pyridazino-aromatics starting from aromatic aldehydes has been developed. A variety of substituents ranging from electron withdrawing to donating is tolerated furnishing the desired 1,2-diazine in good to excellent yields. The products have been applied to the bidentate Lewis acid catalyzed inverse electron-demand Diels-Alder (IEDDA) reaction opening a novel two-step entry into substituted naphthalenes, such as Naproxen.

Pyridinium chloride: A new reagent for N-demethylation of N-methylazinium derivatives

A new N-demethylation reaction of N-methylazinium derivatives by using boiling pyridinium chloride is described. The reaction is quite clean, fast and yields are almost quantitatives.

Aryl-fused and hetaryl-fused-2,4-diazepine and 2,4-diazocine antiarrhythmic agents

Aryl-fused- and hetaryl-fused-2,4-diazepines of formula XXXVI, benzodiazocines of formula XXX, benzodiazepines of formula II STR1 δ-aminoamides of formula III and aryldimethanamines of formula XXXVII STR2 wherein A is an aryl or hetaryl ring; R1 is hydrogen, alkyl, aryl or hetaryl; R2 is hydrogen, alkyl, substituted alkyl, or aryl; R3 is alkyl, aryl, aralkyl or heteroatom substituted alkyl or aralkyl; R4 is hydrogen or alkyl; R5 is hydrogen, alkyl, aryl or hetaryl; R6 is hydrogen, alkyl, alkoxy, halogen or a fused benzene ring; R9 is hydrogen, alkyl, or substituted alkyl; and R10 is hydrogen, alkyl, or substituted alkyl. The invention further relates to processes for the preparation of, pharmaceutical compositions containing, and methods of treating cardiac arrhythmia with the compounds of formulas XXXVI, XXX, II, III, and XXXVII.

Electron-transfer Reactions. I. The Application of Derivative Linear-sweep Voltammetry for the Determination of the Rate Constants for Electron Transfer between Two Different Organic Anion Radicals

The kinetic of homogeneous electron-transfer reactions between different anion radicals, A-. and B-. can be conveniently studied by derivative linear-sweep voltammetry under conditions where the dianions, B2-, are rapidly protonated. The method involves measurements of the ratio, R'I(A/B) = I'A/I'B, where I'A and I'B are the maximum values of dI/dt for the reduction of A and B, at different sweep rates for solutions containing both substrates.Working curves have been calculated by digital simulation for the concentration ratios, C0B/C0A = 1, 2, 5 and 10.The approximate kinetic range of the method is given by expression (ii). 104 1/(dm3 mol-1 s-1) 8 (ii) The application of this type of measurement is illustrated by the electron transfer from the anion radicals, A-., of several aromatic compounds to the anion radicals, B-., of azobenzene and 4,4'-dimethylazobenzene.The fit of the experimental data to the working curves is generally excellent for substrates having similar diffusion coefficients.The measured rate constants vary from 2.5x106 dm3 mol-1 s-1, for A = phthalazine and B = azobenzene, to 2.7x104 dm-3 mol-1 s-1, for A = anthracene and B = 4,4'-dimethylazobenzene.

Some Reactions of N-Alkoxycarbonyl Reissert Compounds with Heterocumulenes: Formation of the Imidazoisoquinoline and Imidazophthalazine Systems and Related Chemistry

Chloroformate derived Reissert compounds of isoquinoline and of phenanthridine on treatment with base undergo cyclisation with isothiocyanates to give in good yields corresponding imidazoisoquinoline and imidazophenanthroline derivatives.Phthalazine Reissert compound analogues give open chain adducts under the same conditions which can be cyclised to derivatives of the novel imidazophthalazine system by heating in the presence of molecular sieves.When carbon disulphide is the heterocumulene cyclisation is not observed but open chain dithio-ester derivatives can be isolated on alkylation of the intermediate sodium salts.