I. Ravina

Exotic Amino Acids. 6. Synthesis of Substituted 4-Oxo-4H-pyrido[1,2-a]pyrimidines

Abstract2-Pyridylaminomethyleneisopropylidenemalonates, prepared from ethoxymethyleneisopropylidenemalonate and 2-aminopyridines, form 4-oxo-4H-pyrido[1,2-a]pyrimidines at their melting points and are separated from the reaction mixture by sublimation.

1-(1-Carboxy-2-R-4-methylcyclohex-4-enyl)carbonyl- and 1-(2-R-4-Methylcyclohex-4-enyl)carbonyl-3,5-dimethyl(diphenyl)pyrazoles

Abstract1-(1-Carboxy-2-R-4-methylcyclohex-4-enyl)carbonyl- and 1-(2-R-4-methylcyclohex-4-enyl)carbonyl-3,5-dimethyl(diphenyl)pyrazoles have been obtained from the reaction of monohydrazides of 2-R-methyl-4-cyclohexen-1,1-dicarboxylic acids and hydrazides of 2-R-4-methyl-4-cyclohexen-1-monocarboxylic acids with acetylacetone and dibenzoylmethane. The conditions for the formation of the pyrazoles depend on the nature of the substituents in the hydrazide starting materials and the structure of the 1,3-diketone used.

Synthesis of Derivatives of 3,5-Dioxopyrazolidine

The reaction of monohydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids with ethoxymethylenemalonic acid diethyl ester leads to N-(2,2-diethoxycarbonylethylenyl)hydrazides of 2-R-4-methylcyclohex-4-ene-1,1-dicarboxylic acids, which are acylated by the anhydrides of trifluoroacetic and acetic acids with the formation of derivatives of 3,5-dioxopyrazolidine and 5-oxopyrazoline respectively.

Synthesis of 3-{3-[(4-methylcyclohex-3-enyl-carbonyl)amino]-4-oxo-3,4-dihydroquinazolin-2-yl}propanoic acid anilides

With the aim of discovering potential diuretic agents amongst quinazoline anilides we have prepared anilides of 3-{3-[(4-methylcyclohex-3-enylcarbonyl)amino]-4-oxo-3,4-dihydroquinazolin-2-yl}propanoic acid. Optimal conditions for obtaining of the starting acid have been established, and anilides have been synthesized by the mixed anhydrides method.

Synthesis of 1-Acyl-5-amino-4-ethoxycarbonylpyrazoles from Monohydrazides of Cyclohexenedicarboxylic Acids and Ethyl Ethoxymethylenecyanoacetate

Heating monohydrazides of cyclohexenedicarboxylic acids with ethyl ethoxymethylenecyanoacetate at reflux gives the corresponding N-substituted hydrazides. This reaction carried out in pyridine gives 1-acyl-5-amino-4-ethoxycarbonylpyrazoles.

Synthesis of Derivatives of Pyrazolin-1H-3-ones from 2′-N-Substituted Monohydrazides of Cyclohexenedicarboxylic Acids

Abstract2-(6-Aryl-4-methylcyclohex-3-enecarbonyl)-4-ethoxycarbonylpyrazolin-1H-3-ones have been synthesized from 2′-N-(2,2-diethoxycarbonylvinyl)monohydrazides of 6-aryl-4-methylcyclohex-3-ene-1,1-dicarboxylic acids by boiling in DMF, pyridine, or toluene in the presence of potassium carbonate. Under analogous conditions, but without potassium carbonate, 2′-N-substituted hydrazides of cyclohexenecarboxylic acids are obtained.

Synthesis of Derivatives of 1,3,4-Oxadiazoles Based on Monohydrazides of 2-Aryl-4-methyl-4-cyclohexen-1,2-dicarboxylic Acids

The corresponding derivatives of 1,3,4-oxadiazoles have been synthesized by the reaction of monohydrazides of 2-aryl-4-methyl-4-cyclohexen-1,1-dicarboxylic acids with triethyl orthoformate or triethyl orthoacetate.

Interaction of hydrazides of 2-aryl-4-methyl-4-cyclohexene-1,1-dicarboxylic acids with certain heterocyclic aldehydes

Monohydrazides of 2-aryl-4-methyl-4-cyclohexene-1,1-dicarboxylic acids react with 2-thiophene-, 3-pyridine-, and 4-pyridinecarbaldehydes to form the corresponding acylhydrazones of hydrazides of mono- or dicarboxylic acids of the cyclohexene series depending on the temperature.

Exotic Amino Acids. 8. Synthesis of Monomethyl Esters of N-Arylaminomethylenemalonic Acids

N-Arylaminomethyleneisopropylidenemalonates, obtained from ethoxymethyleneisopropylidenemalonate and aromatic amines, underwent methanolysis to form monomethyl esters of N-arylaminomethylenemalonic acids. The conditions of their formation and their yields depend on the nature and positions of the substituents in the aromatic ring of the initial amine.