The title compound was prepared from 3-pyridazin-4-yl-benzoic acid methyl ester [prepared by the following sequence: i.) An equimolar mixture of glyoxylic acid and m-tolyl-acetaldehyde [CAS-No. 72927-80-1] was heated to 135° C. for 17 h. ii.) The obtained crude 5-hydroxy-4-(m-tolyl)-2(5H)-furanone and hydrazine hydrate in BuOH were refluxed for 18 h according to J. Med. Chem. 1987, 30, 239. iii.) The obtained 5-m-tolyl-2H-pyridazin-3-one was heated with excess phosphorous oxychloride to 95° C. for 4 h. iv.) The obtained 3-chloro-5-m-tolyl-pyridazine was hydrogenated in MeOH and EtOAc over 5% Pd/C in the presence of NaOAc at 23° C. v.) The obtained 4-m-tolyl-pyridazine was oxidized with KMnO4 in aqueous HOAc at 100° C. for 4 h. vi.) The obtained 3-pyridazin-4-yl-benzoic acid was esterified with SOCl2 in MeOH at 60° C.] by treatment with lithium tert-butyl acetate according to general procedure K (method b). Obtained as a yellow oil (554 mg).
