Malonates in Cyclocondensation Reactions

Abstract

The use of malonates such as diethyl malonates 9, (chlorocarbonyl)ketenes 15 and bis(2,4,6-trichlorophenyl) malonates 18 as reagents for cyclocondensation with 1,3-dinucleophiles to give six-membered heterocycles is described. Further attempts to use malonates such as bis(trimethylsilyl) malonates 19 and bis(carbamimidoyl) malonates 29 as new cyclocondensation agents are described .

Syntheses and Reactions of 5-Unsubstituted 11b-Methyl-1,2,3,11b-tetrahydro-pyrido[3,2,1-jk]carbazoles Having a Strychnos Alkaloids Partial Structure

“…However, this reaction path has some disadvantages. As second possibility, the formation of tetrahydropyrido[3,2,1-jk]carbazol-6-ones 9 was investigated by building up the 4-hydroxy-2-pyridone part from tetrahydrocarbazoles 3 as enamine part, and malonate 5a as C-3 source, via a 3-step reaction sequence which has attracted our attention in similar ring systems for many years [10,11]. In this reaction way, the formation of a pyrono-pyridocarbazole ring system takes place, followed by the stepwise degradation to the pyrido-carbazole ring system.…”

Syntheses and Reactions of 5-Alkyl- and 5-Aryl-11b-Methyl-1,2,3,11b-Tetrahydro-Pyrido[3,2,1-jk]carbazoles Having a Strychnos Alkaloids Partial Structure

“…The thermal cyclocondensation of 4a-methyl-2,3,4,4a-tetrahydro-1H-carbazoles 3a-c with diethyl phenylmalonate and diethyl benzylmalonate (red colored) in diphenylether as the solvent gave via reactive ketene intermediates [11] pyrido-carbazolones, which could be formed in two isomeric structures. The spectral analysis showed that a ring closure directed to the aromatic ring producing 7 can be ruled out, because of the lack of an olefinic proton at position 8 and an fourth aromatic proton from the carbazole part.…”

“…However, when the cyclization reaction was performed without solvent at 200 °C with the highly reactive bis-(2,4,6-trichlorophenyl) n-butylmalonate (5d), the so-called "active malonate" [11,18], the ring closure proceeded in good yields of 70% to 6e. The electrophilic attack formed in all three examples a 5,5-disubstituted pyridinedione structure deriving from the CH-acidic group of the α,γ-dioxo tautomer of 6a in position 5.…”

“…4-Hydroxy-2-pyridone itself has been used as Recently we published the syntheses and reactions of a series of pyrido[3,2,1-jk]carbazol-6-ones B with two aromatic benzo rings in the carbazole moiety [9], and of tetrahydropyrido[3,2,1-jk]carbazol-6-ones with one hydrogenated benzo ring of type C [10] (red partial structure), having the pyridone part fused to the aromatic part of the carbazole. Building up the 4-hydroxy-2-pyridone part starting with enamines or azomethines on one side, and reactive malonic acid derivatives on the other side, has attracted our attention for many years [11]. To direct the ring closure reaction to the desired position, in the present work 2,3,4,9-tetrahydrocarbazoles 3 ("indolenines") are tested as substrates for diethyl and trichlorophenyl malonates.…”

Difatty Acyl Urea from Corn Oil: Synthesis and Characterization

“…Fatty amides were synthesized from fatty acids with urea instead of amine compounds 12) . Since urea has two amide groups, it reacts with diester such as diethyl malonate to form barbituric acid 13,14) . Vegetable oil is triester of glycerol with different saturated and unsaturated fatty acids.…”