Preparation of 1-(3',1'H,6'-Pyridazinone)-3,6-pyridazinedione. Attempts to Prepare Bicyclic Dimaleic Hydrazide^1,2

Quantum Yield for Production of CH 3 NC in the Photolysis of CH 3 NCS

“…Although this mechanism does not apply under atmospheric conditions because SO, does not build up to sufficiently high levels, the reaction of CH3NC with 0,, NO,, or HO, might result in production of the highly toxic (26) CH,NCO. The conversion of alkyl isocyanides to isocyanates by O3 (27) and NO (28) has been observed in solution. Laboratory studies on the chemistry of CH,NC, along with accurate field measurements of MITC, CH,NC, and CH3NC0 concentrations, are thus needed to adequately assess the health risks resulting from the agricultural use of metam-sodium.…”

Concise routes to pyrazolo[1,5-a]pyridin-3-yl pyridazin-3-ones

“…Compound 22 was prepared either by alkylation of 21 with benzyl bromide or by rearranging the synthetic sequence: beginning with hydrolysis of 3,6-dichloropyridazine (19) to 6-chloropyridazin-3(2H)-one (23), 14 followed by N-benzylation to 24 15 and finally Sonogashira coupling with 3-methyl-1-butyne. Alkyne 22 was also unreactive with pyridine N-imine at room temperature.…”

Polychloroheteroaromatic Compounds

“…and di-chloro-derivatives (211; Rl= R2 = CI) (these exist as 3-hydroxy-6(IH)pyridazinones), which give 3,6-dichloro- [394,395] , 3,4,6-trichloro- [396][397][398], and tetrachloro-pyridazine [397], respectively, on treatment with phosphorus oxychloride. A detailed study of the preparation of 3,6-dichloropyridazine from maleic hydrazide showed that the product is usually contaminated with 3-chloro-6(1H)-pyridazinone and compound (212) [399][400][401]. The latter is formed by a reaction between the 3,6-dichloro-derivative and the pyridazinone.…”