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Usage

Uses

Used in Pharmaceutical Industry:
Cinnoline is used as a key intermediate in the synthesis of various pharmaceutical compounds. Its unique structure and properties make it a versatile building block for the development of new drugs with potential therapeutic applications.
Used in Chemical Synthesis:
Cinnoline is utilized as a starting material in the synthesis of a wide range of organic compounds, including dyes, pigments, and other specialty chemicals. Its reactivity and stability contribute to its usefulness in various chemical reactions.
Used in Research and Development:
Cinnoline serves as a valuable research tool in the study of heterocyclic chemistry and the development of new synthetic methods. Its unique properties and reactivity make it an interesting target for exploration in academic and industrial research settings.

Purification Methods

It is distilled at high vacuum, then recrystallised from pet ether. Keep it under N2 in sealed tubes in the dark at 0o. The hydrochloride [5949-24-6] M 166.6 crystallises from EtOH/Et2O and has m 156-158o (yellow monohydrate), and dehydrates on sublimation at 110-115o/3mm. The picrate has m 196-196.5o. [Beilstein 23 H 173, 23 III.IV 1217.]

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

Upstream product

• 7052-13-3 cinnoline 
• 18514-84-6 4(1H)-cinnolon 
• 21905-86-2 cinnoline-4-carboxylic acid 
• 5678-02-4 pyridazine-3,4-dicarboxylic acid anhydride 
• 5339-08-2 N-(ortho-nitrophenyl)propylamine 
• 109-99-9 tetrahydrofuran 
• 67-56-1 methanol 
• 5152-84-1 4-chlorocinnoline 
• 477909-61-8 C₁₈H₁₇N₃ 
• 615-43-0 2-iodophenylamine 
• 477909-60-7 C₁₆H₁₆IN₃ 
• 22751-23-1 (2-nitrophenyl)acetyl chloride 
• 265670-91-5 3,3-diethyl-1-(2-ethynylphenyl)triaz-1-ene 
• 265670-90-4 3,3-diethyl-1-(2-((trimethylsilyl)ethynyl)phenyl)triaz-1-ene 

Downstream Products

• 2942-37-2 8-nitrocinnoline 
• 2942-36-1 5-nitrocinnoline 
• 26631-08-3 4-isopropylidene-1,1-dimethyl-[1,3,4]oxadiazino[4,3-a]cinnolin-2-one 
• 76051-75-7 1,2-dibenzoyl-4-cyano-1,2-dihydrocinnoline 
• 5192-04-1 7-aminoindole 
• 7678-83-3 3-(4-methoxyphenyl)cinnoline 
• 78593-33-6 3-bromocinnoline 
• 82453-00-7 3-iodocinnoline 
• 67888-34-0 8-bromocinnoline 

Relevant academic research and scientific papers

Formation of Bicyclic Azepines by Intramolecular Trapping of Didehydroazepines

Photolysis of 2-(3-aminopropyl)phenyl azides 6 gives 2,3,4,4a-tetrahydro-1H-pyridoazepines 7 in good yields, which are formed by intramolecular trapping of the ring-expanded didehydroazepine intermediate with an amino group.

One-pot homo- and cross-coupling of diazanaphthalenes via C-H substitution: Synthesis of Bis- and Tris-diazanaphthalenes

The transition metal-free coupling reactions of unactivated diazanaphthalenes were studied using only lithium tetramethylpiperidine (LiTMP) reagent. Symmetrical and nonsymmetrical bis-diazanaphthalenes were synthesized in moderate to high yield by homo- and cross-coupling of related monomers. In addition, the single-step synthesis of diquinoxalino [2,3-a: 2', 3'c] phenazine and 2,2': 3', 2″ - terquinoxaline using the appropriate equivalent amount of LiTMP was performed. The products were characterized by means of NMR spectroscopy and HRMS spectrometry.

Deciphering the mechanistic dichotomy in the cyclization of 1-(2-ethynylphenyl)-3,3-dialkyltriazenes: Competition between pericyclic and pseudocoarctate pathways

The mechanistic aspects of the cyclization of (2-ethynylphenyl)triazenes under both thermal and copper-mediated conditions are reported. For cyclization to an isoindazole, a carbene mechanistic pathway is proposed. The carbene intermediate can react with oxygen, dimerize to give an alkene, or be trapped either intermolecularly (using 2,3-dimethyl-2-butene to generate a cyclopropane) or intramolecularly (using a biphenyl moiety at the terminus of the acetylene to form a fluorene). Density-functional theory (DFT) calculations support a pseudocoarctate pathway for this type of cyclization. Thermal cyclization to give a cinnoline from (2-ethynylphenyl)triazenes is proposed to occur through a pericyclic pathway. DFT calculations predict a zwitterionic dehydrocinnolinium intermediate that is supported by deuterium trapping studies as well as cyclizations performed using a 2,2,6,6-tetramethylpiperidine moiety at the 3-position of the triazene.

Cyclization of 1-(2-alkynylphenyl)-3,3-dialkyltriazenes: A convenient, high-yield synthesis of substituted cinnolines and isoindazoles

A new route to isoindazoles and cinnolines through the cyclization of (2-alkynylphenyl)triazenes under neutral conditions is presented. The products that result from heating the starting triazenes depend on both the type of alkyne ortho to the triazene functionality and the temperature used. Butadiyne moieties ortho to dialkyltriazenes yield bis-isoindazole dimers when heated to 150 °C in MeI. A requirement for cyclization in MeI is that the (2-alkynylphenyl)triazene must contain a suitably electron-withdrawing substituent on the phenyl ring to deactivate the triazene toward methylation-induced decomposition to an iodoarene. Ethynyl moieties ortho to dialkyltriazenes yield both isoindazole dimers as well as 3-formylisoindazoles when subjected to the same conditions. Replacing MeI with 1,2-dichlorobenzene as solvent allows for the general cyclization of (2-ethynylphenyl)dialkyltriazenes. Heating to 170 °C results in a mixture of isoindazole and cinnoline products, whereas the cinnolines are produced exclusively in high yield at 200 °C. Alternatively, the isoindazoles can be obtained in good to excellent yield by stirring a 1,2-dichloroethane solution of the starting triazene with CuCl overnight at 50 °C.

Thermal Cyclization of (2-Ethynylphenyl)triazenes: Facile Synthesis of Substituted Cinnolines and Isoindazoles

formula presented High-temperature intramolecular cyclization of N,N-dialkyl-N′-substituted-2-ethynylphenyl)triazenes provides under neutral conditions both 6-substituted cinnolines and 5-substituted isoindazoles in moderate to excellent yields.

N-substituted 1-aminoindoles from electrogenerated N-substituted 2- (ortho-nitrosophenyl)ethylamines

An electrochemical methodology offering efficient access to N-alkyl- and N-aryl-substituted 1-aminoindoles has been developed. N-Substituted 2-(ortho- nitrosophenyl)ethylamines, electrogenerated in a 'redox' flow cell, undergo intramolecular cyclization to hydrocinnoline-type intermediates. Under slightly basic conditions, these undergo spontaneous ring-contraction to produce the N-substituted heterocycles in good yields. The reactions have been studied in slightly acidic and slightly basic aqueous alcoholic media.

Alkyl- or aryl-aminoalkoxy-benzene-sulfonyl indoles

The present invention relates to aminoalkoxyphenyl derivatives of formula: STR1 and its N-oxide and pharmaceutically acceptable salts, in which: B represents a--S--, --SO-- or --SO2 -- group, R1 and R2, which are identical or different, each denote hydrogen, a methyl or ethyl radial or a halogen atom, A denotes a straight-or branched-alkylene radical having from 2 to 5 carbon atoms or a 2-hydroxypropylene radial in which the hydroxy is optionally substituted by a lower alkyl radical, R3 denotes an alkkyl radical or a radical of formula: in which Alk denotes a single bond or a linear- or branched-alkylene radical having from 1 to 5 carbon atoms and Ar denotes a pyridyl, phenyl, 2,3-methylenedioxyphenyl or 3,4-methylenedioxyphenyl radical or a phenyl group substituted with one or more substituents, which may be identical or different, selected from halogen atoms, lower alkyl group or lower alkoxy groups, R11 denotes hydrogen or a lower alkyl, phenyl, diphenylmethyl, benzyl or halogenobenzyl radical, R4 denotes hydrogen or an alkyl radical, or R3 and R4 when taken together denote an alkylene or alkenylene radical having from 3 to 6 carbon atoms and optionally substituted with a phenyl radical or optionally interrupted by STR2 R represent hydrogen, an alkyl radical, a cycloalkyl radical, a benzyl radical or a phenyl radical optionally substituted with one or more substituents, which may be identical or different, selected from halogen atoms and from lower alkyl, lower alkoxy or nitro groups, are described. The compounds of the invention possess exceptional pharmacological properties, especially calcium transport inhibitory properties, as well as bradycardic, hypotensive and antiadrenergic properties.

Diazaarynes: 3,4- and 4,5-Didehydropyridazine By Electron Impact and Thermolytic Fragmentation of The Corresponding Dicarboxylic Anhydrides

The new hetarynes (1) and (2) heve been advanced as intermediates in the vapour phase both for the electron impact and the pyrolytic fragmentation pattern of pyridazine-3,4- and 4,5-dicarboxylic acid anhydrides (10) and (11), respectively.The presence of a peak at m/e 78 in the mass spectra of these compounds, as well as the formation of the diazanaphtalenes (12) and (13), respectively, from their thermolysis in benzene, appeared to support this proposal.