- Pyrazolotriazines-1,2,4. II Etude des Pyrazolotriazinones, des pyrazolotriazinediones et des pyrazolotriazinethiones
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The synthesis of 1,2-dihydro-1-oxopyrazolo-1,2,4-triazine was achieved by rearrangement of 2-(5-pyrazolyl)-1,3,4-oxadiazole under alkaline conditions.The cyclization of the N-carbethoxyhydrazone of the pyrazole-5-carboxaldehyde gave the 3,4-dihydro-4-oxopyrazolo-1,2,4-triazine.Electrophilic substitutions of the 1-pyrazolotriazinone were made either on the lactam nitrogen with methylsulfate, benzyl chloride and monochloroacetic acid or on the pyrazole ring with bromine.The synthesis of pyrazolo-1,2,4-triazine was made from the 1-pyrazolotriazinone via the 1-pyrazolotriazinonethione.The methylation of 1-pyrazolotriazinonethione and 8-bromo-1-pyrazolotriazinonethione afforded N- and S-methyl derivatives.The synthesis of 1,2,3,4-tetrahydropyrazolo-1,2,4-triazine-1,4-diones was achieved by cyclising N-carbethoxyhydrazides of pyrrole-5-carboxylic acid.The structures of the derivatives were determined by 1H-nmr.
- Lancelot, Jean Charles,Maume, Daniel,Robba, Max
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p. 817 - 822
(2007/10/02)
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