Pyridinderivate aus aliphatischen Nitroverbindungen. Synthese und Reaktionen von Salzen substituierter 1,3‐Di‐aci‐nitro‐ und 1,5‐Di‐aci‐nitro‐3‐nitroverbindungen

Abstract

Mannich-Basen von Nitroacetonitril, Methyl(nitromethy1)sulfon und Nitroessigsaure-methylester und Salze verschiedener 1,3-Di-aci-nitro-und 1,5-Di-nci-nitro-3-nitroverbindungen werden beschrieben und Reaktionen dieser Verbindungen im wa8rig-sauren Milieu untersucht. Aus Salzen von 1,5-Di-aci-nitro-3-nitroverbindungen entstehen Pyridinderivate. Dabei wird ein starker EinfluO der Substituenten beobachtet. CN-Gruppen an den Atomen C-1 und C-5 begiinstigen die Pyridinbildung vergleichsweise stark. Pyridine Derivatives from Aliphatic Nitro Compounds. -Synthesis and Reactions of Salts of Substituted 1,3-Di-uei-nitro and 1,5-Di-uci-nitro-3-nitro CompoundsThe synthesis of Mannich bases of nitroacetonitrile, methyl nitroniethyl sulfone and methyl nitroacetate and of the salts of several 1,3-di-aci-nitro and 1,5-di-aci-nitro-3-iiitro compounds are described. Reaction of acids with these compounds in aquous solution have been studied. Pyridine derivatives are formed from salts of 1,5-di-nci-nitr0-3-nitro compounds. This reaction is favoured by the presence of CN groups a t the C-1 and C-5 atoms.

Preparation of conjugated nitroalkenes: short review

“…The direct deamination processes are not attractive in the application of synthesis of conjugated nitroalkenes, because amino or alkylamino moieties are not good leaving groups [66]. In the consequence, the preparation of conjugated nitroalkenes on this way lead with very low yields [67]. Better results can be obtained via the pyrolysis of respective ammonium salts.…”

Transesterification of Methyl 2‐Nitroacetate to Superior Esters

“…Methyl 2‐nitroacetate ( 1c ) and ethyl 2‐nitroacetate ( 4a ) are the almost exclusive representatives of the 2‐nitroacetates, receiving considerable attention within the chemical community: their synthesis and reactivity being studied systematically since the nineteenth century . Owing to their 1,3‐dipole nature and acidity (p K a to 5.8), 2‐nitroacetates are involved in useful processes with electrophiles (Knoevenagel condensations/nitroaldol condensation,, conjugated addition, Mannich reaction, cyclopropanations, alkylations) and dipolarophiles (as good precursors of dipole intermediates in cycloadditions). Thus interesting molecular structures result: α‐amino esters, α‐keto esters, γ‐oxo acids as well as isoxazole derivatives .…”