Synthesis of Some 3-Mercaptopyridazine Derivatives

6-Methyl-2,4-Disubstituted Pyridazin-3(2H)-ones: A Novel Class of Small-Molecule Agonists for Formyl Peptide Receptors

“…A suspension of the appropriate derivatives 12a or 12b ,24 respectively (0.5–1.11 mmol), and 6 N NaOH (6–8 mL) in ethanol (2 mL) was stirred at rt to 80 °C for 1–4 h. The mixtures were then concentrated in vacuo, diluted with cold water, and acidified with 6 N HCl, and the final products were filtered off with suction and recrystallized from ethanol.…”

“…In Scheme 2 is depicted the synthesis of compounds 14a-x (Table 2). The dihydropyridazinone 10 22 was converted into the previously described 4-benzyl derivatives 11b,c 23,24 and the new 11a by condensation with the appropriate aromatic aldehyde in the presence of KOH. Compounds 11, in turn, were alkylated with ethyl bromoacetate to give the esters 12ac, whose 12b,c were previously reported.…”

“…In Scheme is depicted the synthesis of compounds 14a − x (Table ). The dihydropyridazinone 10 was converted into the previously described 4-benzyl derivatives 11b , c , and the new 11a by condensation with the appropriate aromatic aldehyde in the presence of KOH. Compounds 11 , in turn, were alkylated with ethyl bromoacetate to give the esters 12a − c , whose 12b , c were previously reported. , Alkaline hydrolysis of compounds 12 gave the known 13c and the new carboxylic acids 13a , b .…”

“…The dihydropyridazinone 10 was converted into the previously described 4-benzyl derivatives 11b , c , and the new 11a by condensation with the appropriate aromatic aldehyde in the presence of KOH. Compounds 11 , in turn, were alkylated with ethyl bromoacetate to give the esters 12a − c , whose 12b , c were previously reported. , Alkaline hydrolysis of compounds 12 gave the known 13c and the new carboxylic acids 13a , b . These compounds were treated with ethyl chloroformate in THF in presence of triethylamine, affording the intermediate mixed anhydrides, which, in turn, were transformed into the final amides 14a − s and 14u − x by treatment with the appropriate aryl or cycloalkyl amine.…”

Synthesis of New Thieno- and Pyrazolo- pyridazine Derivatives

“…5,6-Di(pyridin-2-yl)-3-thioxo-2,3-dihydropyridazine-4carbonitrile 2 has been prepared via the reaction of 3-oxo-5, 6-di(pyridin-2-yl)-2,3-dihydropyridazine-4-carbonitrile 1 with P 2 O 5 in dry xylene. 7 Alkylation of the pyridazinethione 2 with chloroacetone in sodium ethoxide 8 gave 2-S-acetonylpyridazine 3 which on cyclisation by boiling in 10% ethanolic potassium hydroxide afforded thieno[2,3-c]pyridazine 4. The structures of both 3 and 4 were established from their correct analytical data, and IR spectra which showed the absence of CN group while a newly born NH 2 group was detected.…”