- Synthesis and Transformations of Methyl (E)-2-(Acetylamino)-3-cyanoprop-2-enoate und Methyl (E)-2-(Benzoylamino)-3-cyanoprop-2-enoate, Versatile Reagents for the Preparation of Polyfunctional Heterocyclic Systems
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Methyl (E)-2-(acetylamino)-3-cyanoprop-2-enoate (2a) and its 2-benzoyl analog 2b were prepared from the corresponding methyl (Z)-2-(acylamino)-3-(dimethylamino)propenoates 1. Multifunctional compounds 2 are versatile synthons for preparation of polysubstituted heterocyclic systems such as pyrroles 4, pyrimidines 5 and 6, pyridazines 7, pyrazoles 8, 9, and 11, and isoxazoles 10.
- Pizzioli, Lucija,Ornik, Brina,Svete, Jurij,Stanovnik, Branko
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p. 231 - 235
(2007/10/03)
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- 1,3-Dipolar Cycloadditions, 93. - The Astounding Reaction of Dimethyl 2,3-Dicyanofumarate with Diazomethane
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The reaction with excess of diazomethane furnished methyl 4-cyano-1-methylpyrazole-5- and -3-carboxylate (2 and 3) as well as the three N-methyl-1,2,3-triazolecarboxylic esters 4-6.A mechanistic study revealed a poly-step sequence.The initial formation of the pyrazoline 8 proceeded normal.Base catalysis effected an equilibration of trans- and cis-2-pyrazoline, 8(*)12, followed by a fragmentation into methyl 4-cyano-3-pyrazolecarboxylate (26) and methyl cyanoformate (32); a 4H-pyrazole is supposed to be the key intermediate.The final products mentioned above emerged from further reaction of 26 and 32 with diazomethane.
- Huisgen, Rolf,Mitra, Abhijit,Moran, Joaquin Rodriguez
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p. 159 - 170
(2007/10/02)
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- THE ASTOUNDING REACTION OF DIAZOMETHANE WITH DIMETHYL 2,3-DICYANOFUMARATE
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The title reaction afforded the pyrazole derivatives 3 and 4 as well as the N-methyl-1,2,3-triazolecarboxylic esters 5 - 7.The poly-step sequence was clarified; the key intermediates are the 1-pyrazoline 18, the 2-pyrazoline 2, the 4H-pyrazole 12, the pyrazole 22, and methyl cyanoformate.
- Huisgen, Rolf,Mitra, Abhijit,Moran, Joaquin Rodriguez
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p. 2429 - 2436
(2007/10/02)
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