31592-08-2

Basic information

• Product Name: [1,2,4]Triazolo[1,5-a]pyrimidin-7(1H)-one
• Synonyms: 4,7-dihydro-1,2,4-triazolo<1,5-a>pyrimidin-7-one
• CAS NO: 31592-08-2
• Molecular Formula: C5H4N4O
• Molecular Weight: 136.11100
• Mol File: 31592-08-2.mol
• Article Data: 3

Chemical Properties

• CAS DataBase Reference: [1,2,4]Triazolo[1,5-a]pyrimidin-7(1H)-one(CAS DataBase Reference)
• NIST Chemistry Reference: [1,2,4]Triazolo[1,5-a]pyrimidin-7(1H)-one(31592-08-2)
• EPA Substance Registry System: [1,2,4]Triazolo[1,5-a]pyrimidin-7(1H)-one(31592-08-2)

Safety Data

• Hazardous Substances Data: 31592-08-2(Hazardous Substances Data)

Upstream product

• 61-82-5 3⁽⁵⁾-amino-1,2,4-triazole 
• 617-48-1 malic acid 
• 1117-37-9 ethyl (E)-3-(dimethylamino)acrylate 
• 64-18-6 formic acid 
• 32084-27-8 2-hydrazino-4(3H)-one-pyrimidine 
• 110-86-1 pyridine 
• 3674-13-3 2,3-dibromopropionic acid ethyl ester 

Downstream Products

• 52341-91-0 7-chloro-[1,2,4]triazolo[1,5-a]pyrimidine 
• 275-02-5 1-deaza-5-azapurine 

Relevant articles and documents

Studies with functionally substituted enamines: The reactivity of enaminals and enamino esters toward naphthoquinone, hydrazonoyl halides, aminoazoles and hippuric acid

Whereas enamines 1a,b react with naphthoquinone (2) to yield the naphthofuranals 5a,b, enamine ester 1c react with 2 to yield benzoindole derivatives 7. Enamine 1b reacts with hydrazonoyl halides 8 to yield 3,4-disubstituted pyrazoles 12. On the other hand, the enaminal 1a failed to react with 8, while enamine ester 1c afforded hydrazone 16 on treatment with 8. The enamino ester 1b afforded triethyl 1,3,5-benzenetricarboxylates on refluxing in acetic acid. Georg Thieme Verlag Stuttgart.

Preparation and pyrolysis of 1-(pyrazol-5-yl)-1,2,3-triazoles and related compounds

1-(Pyrazol-5-yl)-1,2,3-triazoles 8a, 9a and 10 are prepared by cycloaddition of 5-azidopyrazoles with methyl prop-2-ynoate. The regiochemistry of the process is confirmed by synthesis of 9a using an authentic route from ethyl 2-formyl-2-diazoacetate 13. Flash vacuum pyrolysis of 8a, 9a and 10 gives 5-methoxypyrazolo[1,5-a]pyrimidin-7-ones 16-18 by a mechanism involving an unexpected oxoketenimineimidoyl ketene rearrangement as the key step. The mechanism is supported by a 13C labelling experiment. A general route to pyrazolo[1,5-a]pyrimidin-7-ones from pyrazolylaminomethylene Meldrum's acid derivatives (e.g. 30-32) is also reported.