- The synthesis of 7-substituted-2, 3-dihydropyrido [4, 3-d]pyridazine-1, 4-diones and 1, 4-Dioxo-7-substituted-1, 2, 3, 4-tetrahydropyrido[4, 3-d]pyridazine 6-oxides from methyl ketones
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A general four-step transformation of alkyl, cycloalkyl, aryl, and heteroaryl methyl ketones via 3-(dimethylamino)-1-substituted-prop-2-en-1-ones, followed by microwave [2+2] cycloaddition of dimethyl acetylenedicarboxylate, cyclization of (2E, 3E)-2-[(dimethylamino)methylene]-3-(2-substituted)succinates with ammonia or hydroxylamine hydrochloride into 2-substituted-pyridine-4, 5-dicarboxylates and their N-oxides and final cyclization with hydrazine hydrate into of 7-substituted-2, 3-dihydropyrido[3, 4-d]pyridazine-1, 4-diones and 1, 4-dioxo-7-substituted-1, 2, 3, 4-tetrahydropyrido[ 4, 3-d]pyridazine 6-oxides is shown.
- Prek, Benjamin,Stanovnik, Branko
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p. 798 - 803
(2018/01/17)
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- A simple metal-free synthesis of 2-substituted pyridine-4,5-dicarboxylates and their N-oxides
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Herein a simple, metal-free synthesis of 2-alkyl-, 2-cycloalkyl-, 2-aryl-, and 2-heteroaryl-substituted pyridine 3,4-dicarboxylates and their N-oxides from the corresponding methyl ketones in good to excellent yield, demonstrated with 22 examples in each case, is described. The method complements the current coupling reactions of 2-heterocyclic organometallic reagents.
- Bezen?ek, Jure,Prek, Benjamin,Gro?elj, Uro?,Kasuni?, Marta,Svete, Jurij,Stanovnik, Branko
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experimental part
p. 4719 - 4731
(2012/07/28)
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- Novel pyridine-formation reactions of 2-(phosphoranylideneamino)acrylaldehydes with acetylenic esters. Synthesis of 2-mono-and 2,5-disubstituted nicotinates
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Preparation of 2-(phosphoranylideneamino)acrylaldehydes, novel formyl-substituted (vinylimino)phosphoranes, was accomplished by the reaction of formyl-2H-azirines with triphenylphosphine. Their novel pyridine-formation reactions with acetylenic esters ach
- Kanomata, Nobuhiro,Nakata, Tadashi
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p. 2551 - 2558
(2007/10/03)
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- Hexacarbonylmolybdenum-induced Reaction of Isoxazoles. Cycloaddition of Isoxazoles with Acetylenic Esters and Related Reactions
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In the presence of hexacarbonylmolybdenum, substituted isoxazoles undergo a cycloaddition reaction with dimethyl acetylenedicarboxylate across the C-4-C-5 bond to give 3,4-bis(methoxycarbonyl)pyridine derivatives.In a similar cycloadition of isoxazoles with methyl propiolate, 4-(methoxycarbonyl)pyridine derivatives were also obtained.The β-carbon atom of methyl propiolate could intervene in the bonding with the C-5 position of the isoxazoles regioselectively.A mechanism involving a complexed 2-oxa-3-azabicyclohepta-3,6-diene derivative and the subsequent N-Oand C-1-C-5 bond cleavage leading to a complexed (β-ketovinyl)nitrene intermediate is proposed for the formation of pyridine derivatives.In order to clarify the mechanistic aspect, the reaction of 4-phenyl-2-oxa-3-azabicyclohepta-3,6-diene and its related compounds were also studied to give pyridine derivatives.
- Kobayashi, Tomoshige,Nitta, Makoto
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p. 152 - 157
(2007/10/02)
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- HEXACARBONYLMOLYBDENIUM-INDUCED FORMATION OF PYRIDINES FROM ISOXAZOLES AND ACETYLENIC ESTER
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Upon treatment with Mo(CO)6 in anhydrous benzene, substituted isoxazoles undergo a novel inclusion of dimethyl acetylenedicarboxylate across the C4-C5 bond and loss of an oxygen atom to lead to pyridines.
- Kobayashi, Tomoshige,Nitta, Makoto
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p. 1233 - 1236
(2007/10/02)
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