Prepare 4-phenylurazole from ethyl carbazate and then oxidize the urazole with gaseous dinitrogen tetroxide to yield 4-phenyl-1,2,4-tri- azoline-3,5-dione la. Modification of the ethyl carbazate procedure in which analytically pure monoalkylhydrazine hydrochlorides were isolated in greater than 90% yield, starting from a ketone or aldehyde. Treatment of primary amines is with chloroamine or hydroxylamine-0-sulfonic acid and the condensation of a carbonyl compound with ethyl carbazate. The FeCl 3 -catalyzed reaction of ethyl carbazate (2 b) proceeded readily to give β-hydroxyester 3 b in better yield. A new one-pot neat synthesis of some 5-aryl-2,4-dihydro-3H-1,2,4-triazol-3-ones through cyclocondensation of ethyl carbazate with aryl nitriles catalyzed by DMAP as an efficient and basic nucleophilic catalyst is described.
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Aplicaciones
Preparar 4-fenilurazol a partir de carbazato de etilo y, posteriormente, oxidar el urazol con tetróxido de dinitrógeno gaseoso para producir 4-fenil-1,2,4-triazolina-3,5-diona. Modificación del procedimiento de carbazato de etilo en el que se aislaron clorhidratos de monoalquilhidracina analíticamente puros en una producción superior al 90 %, a partir de una cetona o un aldehído. El tratamiento de las aminas primarias se lleva a cabo con ácido hidroxilamina-0-sulfónico y la condensación de un compuesto carbonílico con carbazato de etilo. De la reacción catalizada con FeCl 3 del carbazato de etilo (2 b) surgió fácilmente β-hidroxiéster 3 b en una producción mejor. Se describe una nueva síntesis ordenada en un solo recipiente de algunas 5-aril-2,4-dihidro-3H-1,2,4-triazol-3-onas a través de la ciclocondensación de carbazato de etilo con aril nitrilos catalizados por DMAP como catalizador nucleofílico eficiente y básico.
Solubilidad
Muy soluble en agua.
Notas
Almacenar en un lugar fresco. Mantenga el recipiente bien cerrado en un lugar seco y bien ventilado. Almacenar lejos de los agentes oxidantes fuertes.
RUO – Research Use Only
General References:
- A. Davoodnia,; M. Bakavoli,; M. Soleimany,;H. Behm. A new one-pot neat synthesis of 1,2,4-triazol-3-ones through 4-(N,N-dimethylamino) pyridine (DMAP) catalyzed cyclocondensation of ethyl carbazate with aryl nitriles. Chinese Chemical Letters. 2008, 19 (6),685-688.
- N. I. Ghali,; D. L. Venton,; S. C. Hung,; G. C. Le Breton. High-yielding synthesis of monoalkylhydrazines. J. Org. Chem., . 1981, 46 (26), 5413-5414.
- Forms crystalline ethoxycarbonyl hydrazones with aldehydes and ketones. With o-acylphenols, Pb(OAc)4 treatment of the resulting hydrazone results in replacement of the phenolic OH with ethoxycarbonyl, providing a route to ethyl o-acylbenzoates: Tetrahedron Lett ., 31, 6781 (1990).
- Reaction with methyl ketones, followed by treatment with SOCl2, leads to 4-substituted 1,2,3-thiadiazoles: J. Am. Chem. Soc., 77, 5359 (1955). In the presence of base, these readily lose N2 to give alkynethiolates: Can. J. Chem., 46, 1057 (1968):
- More recently, this sequence has been used in the synthesis of dendrimers from 1,3,5-triacetylbenzene: J. Chem. Soc., Perkin 1, 2203 (1994).