Heterocyclization of 5-(Arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones with Arenecarbaldehyde Oximes in the Presence of N-Bromosuccinimide and Triethylamine

Russian Journal of Organic Chemistry - 5-(Arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones reacted with substituted benzaldehyde oximes in the presence of N-bromosuccinimide and triethylamine to...     

Reaction of Allyl Phenylcarbamate with Benzaldehyde Oximes in the Presence of N-Chlorobenzenesulfonamide Sodium Salt

Allyl phenylcarbamate reacts with benzaldehyde oxime and ring-substituted benzaldehyde oximes in ethanol in the presence of N-chlorobenzenesulfonamide sodium salt to give the corresponding 3-aryl-5-(phenylcarbamoyloxymethyl)-4,5-dihydroisoxazoles.     

Synthesis of 3-(aminooxoethyl)-6-methyl-1-(thiethan-3-yl)-pyrimidine-2,4-(1H,3H)-diones

A new approach to prepare 2-chloroacetamides has been developed, based on the reaction of chloroacetyl chloride with excess of secondary amines. Alkylation of 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-dione with the synthesized 2-chloroacetamides in the presence of potassium carbonate has afforded N ³-acetamido-substituted 6-methyl-1-(thiethan-3-yl)pyrimidine-2,4(1H,3H)-diones.     

Reaction of 2-Propynyl Phenylcarbamate with Benzaldehyde Oximes in the Presence of N-Chlorobenzenesulfonamide Sodium Salt

2-Propynyl phenylcarbamate reacts with substituted benzaldehyde oximes on heating in ethanol in the presence of N-chlorobenzenesulfonamide sodium salt, yielding the corresponding 3-aryl-5-(phenylcarbamoyloxymethyl)isoxazoles.     

Reaction of 3-(Arylmethylidene)-1-pyrrolines with Acetone. Synthesis of Norhygrine Derivatives

Russian Journal of Organic Chemistry - An efficient procedure has been developed for the synthesis of analogs of the alkaloid norhygrine by reaction of 3-(arylmethylidene)-1-pyrrolines with...     

Reaction of dichlorocarbene with 1-(2,4,6-tri-t-butylphenyl)-1-phosphaallenes

1-(2,4,6-Tri-t-butylphenyl)-1-phosphaallene reacted with dichlorocarbene to give 2-dichloromethylene-1-(2,4,6-tri-t-butylphenyl)-1-phosphirane. The structure was confirmed by X-ray crystal structure analysis. A similar isomerization product was obtained in the reaction of dichlorocarbene with 3-phenyl-1-(2,4,6-tri-t-butylphenyl)-1-phosphaallene.     

Synthesis and properties of 5-[bis(1-heteroazulen-3-yl)methylidene]pyrimidine-2,4,6(1,3,5H)-triones

The synthesis and properties of a novel type of 5-[bis(1-heteroazulen-3-yl)methylidene]pyrimidine-2,4,6(1,3,5H)-triones (13a-c) and (14a-c) are studied. The synthetic procedure is based on addition of bis(1-heteroazulen-3-yl)methyl cations with barbituric acid and subsequent oxidation by o-chloranil. Structural characteristics of 13a-c and 14a-c were clarified on inspection of the ¹³C NMR spectral data and X-ray crystal analysis. Based on the investigation of the UV-vis spectra of 13a-c and 14a-c and their protonated cations, conformational change of the heteroazulene-moiety and the barbituric acid-moiety is suggested. In the CV measurements of 13a-c and 14a-c, two reversible reduction waves are observed, indicating the stabilizing ability of heteroazulenes toward the corresponding radical and anion species. Furthermore, 13a-c and 14a-c exhibit one irreversible oxidation wave and the corresponding reduction wave appearing in a far negative region, which suggested a conformational change in the radical cation during the redox process. The conformational change is rationalized on the basis of the MO calculations.     

Influence of solvents on the molecular and crystal structure of the complex of 1,3-diallyl-5-[3-(diphenylphosphino)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione with palladium(II) dichloride

X-ray diffraction study demonstrated that the molecular and crystal structures of the complexes of 1,3-diallyl-5-[3-(diphenylphosphino)propyl]-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (1) with PdCl₂ are determined to a large degree by intra- and intermolecular short contacts between different-polarity groups of the complex molecules. The strength and the existence of the complexes may be affected by the solvents from which the crystals are grown. Published inIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1199–1204, July, 2000.     

Synthesis and properties of 1-Benzothiopyrano[2,3-d]-pyrimidine-2,4-(3H)diones (10-thia-5-deazaflavins)

Treatment of 6-arylthiouracils with the Vilsmeier reagent (dimethylformamide-phosphorus oxychloride) gave the corresponding 6-arylthio-5-formyluracils, which could alternatively be prepared by the condensation of 6-chloro-5-formyluracils with thiophenols. Dehydrative cyclization of the above 5-formyluracils with polyphosphoric acid gave 1-benzothiopyrano[2,3-d]pyrimidine-2,4-(3H)diones (10-thia-5-deazaflavins). These 10-thia-5-deazaflavins oxidized alcohols to give the corresponding carbonyl compounds with the aid of strong base, and they were hydrogenated to 1,5-dihydro-10-thia-5-deazaflavins. Treatment of 10-thia-5-deazaflavins with concentrated aqueous potassium hydroxide led to the exclusive formation of 1,5-dihydro-10-thia-5-deazaflavins and 1,5-dihydro-10-thia-5-deazaflavin-5-ones via intermolecular oxidation-reduction (disproportionation) between initially formed 1,5-dihydro-5-hydroxy-10-thia-5-deazaflavins and unchanged 10-thia-5-deazaflavins.     

5-(1-Alkenyl)-1, 3, 4-oxadiazol-2(3H)-one

3-(2-alkenoyl)-thiocarbazic acid O-methyl esters 1 are desulfurated by bromine and the unknown intermediates are transformed by alkali to 5-(1-alkenyl)-1, 3, 4-oxadiazol-2(3H)-ones ( 2 ). This type of oxadiazolone substitution is not realizable by the common ring closure of hydrazides with phosgene due to pyrazolidinone ring closure of unsaturated acids with hydrazine.     

Synthesis of 1-(2,4,6-trichlorophenyl)-3-(3-nitro- and 2-chloro-5-nitroanilino)-5-pyrazolones

A convenient one flask synthesis of 1-aryl-3-nitroanilino-5-pyrazolones in yields of 60–65% is described. Synthesis involves initial reaction of ethyl 3-ethoxy-3-iminopropionate hydrochloride and a nitroaniline in methanol producing an imidate ester. The imidate ester is then reacted with an arylhydrazine forming an amidine. The amidine is then cyclized with base.     

Reaction of 2-Phenyl-4-(ethoxymethylene)-5(4H)-oxazolone with 3,4-Dithio-toluene in the Presence of Lewis Base

A convenient procedure for the synthesis of thiocoumarin by the condensation of 2-phenyl-4-(ethoxymethylene)-5-(4H)-oxazolone with 3,4-dithio-toluene in the presence of triethylamine is reported. Here, both thio groups are able to react with the carbonyl group to produce a mixture of isomeric products at ambient temperature. Only one of the isomers upon heating gives a new coumarin product.     

Preparation of 5-(1-Aminocyclohexyl)-2(1H)-Pyridinones Via the Ritter Reaction

A series of 5-(1-aminocyclohexyl)-2(1H)-pyridinones was prepared in 16-32% yield. The key step is a Ritter reaction of the analogous alcohols. The results reported demonstrate the difference in reactivity between the closely related 2-alkoxy-pyridines and 2 (1H)-pyridinones.     

The kinetics and mechanism of aqueous cleavage of imide bond in 5, 5-diethyl barbituric acid (5, 5-diethyl-2,4,6-(1H, 3H) pyrimidinetrione) in a highly alkaline medium

The kinetic study of alkaline hydrolysis of 5, 5-diethyl barbituric acid has been carried out at various [O H] and different temperatures ranging from 85–95°C. The reaction follows an irreversible first-order consecutive reaction path of the type \documentclass{article}\pagestyle{empty}\begin{document}${\rm A}\buildrel{{k1{\rm obs}}}\over\longrightarrow{\rm B}\buildrel{{k2{\rm obs}}}\over\longrightarrow$\end{document} X under pseudo-first-order kinetic conditions. A, B, and X represent for 5, 5-diethyl barbituric acid, diethyl malonuric acid, and ammonia, respectively. The pH-rate profiles obtained at three different temperatures reveal distinct phases which are attributed to a change in rate-determining step with change in [O H]. On the basis of the observed data, a possible mechanism has been discussed.     

Reaction of Triethyl Phosphonoacetate Anion with Phenylhydrazones: A New Method for the Preparation of 3(2H)-Pyridazinones

Various 5,6-disubstituted-2-phenyl-3(2H)-pyridazinones 4 have been synthesised by reacting triethyl phosphonoacetate anion with monophenylhydrazone of 1,2-dicarbonyl compounds 2.     

Reaction 5-(Arylmethylidene)pyrimidine-2,4,6(1<Emphasis Type="Italic">H</Emphasis>,3<Emphasis Type="Italic">H</Emphasis>,5<Emphasis Type="Italic">H</Emphasis>)-triones with L-Proline and Aldehydes

Boiling in toluene of 5-(arylmethylidene)pyrimidine-2,4,6(1H,3H,5H)-triones with L-proline and aldehyde led to the formation of previously unknown substituted 1′-arylhexahydro-1H-spiro[pyrimidine-5,2′-pyrrolysine]-2,4,6(1H,3Н,5Н)-triones.