Hi friend..
When you publish a new topic, that is to say when you are creating a post, the title of the same has to be much more specific than a simple \"hello\", for example in your case a good title is \"synthesis of sulfamethoxypyridazine\ ", which would help others interested in the topic to reach the forum.
The synthesis of sulfa sulfamethoxypyridazine will depend on the initial disconnection that is carried out, in order to produce precursor molecules (synthetic equivalents) that are easy to work with.
Everything will depend on the reactions that one knows and knows that produce acceptable yields.
I suggest one of them, which requires the synthesis of 3-chloro-6-methoxypyridazine as a precursor molecule, because it seems to me that this heterocilc is much easier to obtain.
Greetings