The Pyridazinones, Alkoxy‐ and Aryloxy‐Pyridazines, and Related Compounds

1‐Phenyl‐cyclopenteno[1,2‐d]‐1,2,3‐rriazolo‐5‐spiro‐4′‐[perhydropyrazolino‐3′,5′‐dione] (5) afforded in situ, by oxidation with lead tetraacetate, the corresponding cyclopentenotriazolo‐spiropyrazolodione 6, which was trapped with dienes giving the hetero‐Diels‐Alder adducts 10–12 in good yields. The Diels‐Alder reactions were examined on the basis of AM1 MO calculations. Total assignment of the 1H‐ and 13C‐nmr chemical shifts as well as the relative configuration of these adducts was accomplished with the help of 2D (1H‐1H COSY, 1H‐1H NOESY, 1H‐13C XHCORR, 1H‐13C COLOC) and NOE difference spectroscopy. The structures of compounds 11a and 11b were also examined by molecular modeling.

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One pot synthesis of 6,12‐dihydro‐1,3,7,9‐tetramethyl‐5H, 11H‐dipyrido[1,2‐a:1′,2′‐d]pyrazine‐2,8‐dione by hilbert‐johnson reaction of 2‐chloromethyl‐3,5‐dimethyl‐4‐methoxypyridine

Orešić

Danilovski

Dumić

et al. 2001

Journal of Heterocyclic Chem

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By heating 2-chloromethyl-3,-5-dimethyl-4-methoxypyridine (1) either neat or in solution methoxy group cleavage was achieved, followed by dimerisation to poorly soluble 6,12-dihydro-1,3,7,9-tetramethyl-5H,11H-dipyrido[1,2-a:1',2'-d]pyrazine-2,8-dione (3) in almost quantitative yield with methyl chloride evolution. To our knowledge this is the first example of such Hilbert-Johnson preparation of dipyridopyrazinediones. Recrystallization of 3 from the hydrochloric acid yielded 6,12-dihydro-2,8-dihydroxy-1,3,7,9tetramethyl-dipyrido[1,2-a:1',2'-d]pyrazinediylium dichloride (4), neutralization of which gave back the pyrazine-2,8-dione 3. The molecular structures of both compounds 3 and 4 have been unambiguously confirmed by single crystal X-ray structure analysis.

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The Pyridazinones, Alkoxy‐ and Aryloxy‐Pyridazines, and Related Compounds

Cited by 3 publications

References 409 publications

Generation and dienophilic properties of 1‐benzyl‐1H‐1,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione

Generation and dienophilic properties of 1‐benzyl‐1H‐1,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione

Diels‐alder adducts of a spirocyclopentenotriazoloazodienophile. Assignment of their ¹H and ¹³C NMR spectra

One pot synthesis of 6,12‐dihydro‐1,3,7,9‐tetramethyl‐5H, 11H‐dipyrido[1,2‐a:1′,2′‐d]pyrazine‐2,8‐dione by hilbert‐johnson reaction of 2‐chloromethyl‐3,5‐dimethyl‐4‐methoxypyridine

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The Pyridazinones, Alkoxy‐ and Aryloxy‐Pyridazines, and Related Compounds

Cited by 3 publications

References 409 publications

Generation and dienophilic properties of 1‐benzyl‐1H‐1,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione

Generation and dienophilic properties of 1‐benzyl‐1H‐1,2,3‐triazolo[4,5‐d]pyridazine‐4,7‐dione

Diels‐alder adducts of a spirocyclopentenotriazoloazodienophile. Assignment of their 1H and 13C NMR spectra

One pot synthesis of 6,12‐dihydro‐1,3,7,9‐tetramethyl‐5H, 11H‐dipyrido[1,2‐a:1′,2′‐d]pyrazine‐2,8‐dione by hilbert‐johnson reaction of 2‐chloromethyl‐3,5‐dimethyl‐4‐methoxypyridine

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Diels‐alder adducts of a spirocyclopentenotriazoloazodienophile. Assignment of their ¹H and ¹³C NMR spectra