Pyridazone 2- -6-methyl

Another series of compounds which are easily accessible from levulinic acid are pyridazone and pyridazine derivatives. Levulinic acid and its esters condense almost quantitatively with hydrazine to ve 6-methyl-3-P3rridazinone (XLVI), which is readily dehydrogenated by means of bromine to give 6-methyl-3-pyridazone (XLVII). 

Chlorination of the pyridazone yields 3rchloro-6-methyl-pyridazine (XLVIII) which on treatment with ammonia gives 3-amino-6-methyl-pyridazine (XLIX). The sulfanilamide derivative (L) has promising... 

In a similar manner to that for pyridines, pyridazines 68 were synthesized from functionalized hydrazines 66 via pyridazones 67 using an RCM/elimination/ triflation approach (09CC3008). The metathesis precursors 66 were synthesized in two steps from commercially available tosyl hydrazide (not shown). Substituents can be incorporated at aU ring positions, which was clearly exemplified by the introduction of a methyl group in different positions of the pyridazine (Scheme 19). 

Pyridazone, 2-vinyl-6-methyl-4,5-benz-3- Methacrylate, methyl 0.21 1.65 897... 

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