Synthesis of Macrocyclic Pyrimidine Derivatives

A reaction was studied of previously unknown 1,3-bis(2-hydroxy-3-chloropropyl)uracil, 1,3-bis(2- hydroxy-3-chloropropyl)-6-methyluracil, and 1,3-bis(2-hydroxy-3-chloropropyl)-5-fluorouracil with 1,3-bis[3-(3-methyl-2H-5-pyrazolon-1-yl)-2-hydroxypropyl]-6-methyluracil.     

Synthesis of 6-[4-(allyl/phenyl)-5-thioxo-1,2,4-triazol-3-yl]pyrimidine-2,4-diones and their reaction with electrophiles

Cyclization of 1-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-6-yl)carbonyl-4-R-thiosemicarbazides in basic medium gave 6-(4-R-5-thioxo-1,2,4-triazol-3-yl)pyrimidine-2,4-diones (R = Allyl, Ph). Alkylation of the latter with iodomethane occurred at the sulphur atom to give the corresponding methylsulfanyl derivatives. Acetylation using acetyl chloride occurred at the N₍₁₎ atom of the triazole ring to the corresponding acetyl derivative when R = Ph but for R = Allyl the acetylation did not occur under the same conditions. In the presence of bromine in refluxing methanol the indicated allyl-substituted compound cyclizes to 6-bromomethyl-3-(2,4-dioxo-1,2,3,4-tetrahydropyrimidin-6-yl)-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole. Under Mannich and bromination conditions the methylsulfanyl derivatives prepared form derivatives at the 5 position of the uracil ring: 5-methylmorpholino-(piperidino)-and 5-bromo-(4-R-5-thioxo-1,2,4-triazol-3-yl)pyrimidine-2,4-diones respectively. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 906–912, June, 2006.     

Synthesis and structure of hydrazones obtained by the reaction of 2-[6-methyl-2,4-dioxo-1-(thietan-3-yl)-1,2,3,4-tetrahydropyrimidin-3-yl]acetic acide hydrazide with β-dicarbonyl compounds

Reaction of 2-[6-methyl-2,4-dioxo-1-(thietan-3-yl)-1,2,3,4-tetrahydropyrimidin-3-yl]acetic acid hydrazide with β-dicarbonyl compounds proceeds regioselectively; the structure of the formed hydrazones is governed by the structure of the β-dicarbonyl reaction component. The reaction with acetyl- and propionylacetone afforded 3-[2-(5-alkyl-3-methyl-1H-pyrazol-1-yl)-2-oxoethyl]-6-methyl-1-(thietan-3-yl)pyrimidin-2,4(1H,3H)-diones, with aroylacetones, 5-hydroxypyrazoline derivatives which are present in DMSO solutions in E′ conformation with respect to the amide bond. The condensation products with acetoacetic acid derivatives have a linear structure and consist of mixtures of E,Z- and E′,Z′-isomers owing to the geometric and conformational isomerism.     

Synthesis of 1,3-Bis[3-X-2-(X-acetoxy)propyl]-6-methyl- 1,2,3,4-tetrahydropyrimidine-2,4-diones

A procedure was developed for synthesizing nitrogen-and-sulfur-containing pyrimidine derivatives by reactions of 1,3-bis(3-chloro-2-hydroxypropyl)-6-methyluracil with 1-butanethiol and chloroacetyl chloride, followed by treatment of the resulting 1,3-bis[3-chloro-2-(chloroacetoxy)propyl]-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione with 1-butanethiol, morpholine, and piperidine. Oxidation of the sulfur-containing products with NaIO₄ gave the corresponding sulfoxides.     

<Emphasis Type="Italic">N</Emphasis>-substituted 2-(6-amino-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-2-oxoacetamides

In reaction of 6-aminouracyles with ethyl oxochloroacetate ethyl 2-(6-amino-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-2-oxoacetates were obtained, which by further reaction with various amines afforded oxo(pyrimidinyl)acetamides. According to the data of biological tests, the synthesized compounds showed low antibacterial and antitumor activity.     

Design,synthesis and in vitro evaluation of tetrahydropyrimidine-isatin hybrids as potential antitubercular and antimalarial agents

A series of 5-substituted-3-[{5-(6-methyl-2-oxo/thioxo-4-phenyl-1,2,3,4-tetrahydropyrimidin-5-yl)-1,3,4-oxadiazol-2-yl}-imino] -1,3-dihydro-2H-indol-2-one were synthesized,characterized and screened for their anti-tubercular and antimalarial activity.     

Preparation of 1-[ω-(1,4,5,6-Tetrahydropyrimidin-2-Yl)Alkyl]Thymines

One-stage preparation of 1-[ω-(1,4,5,6-tetrahydropyrimidin-2-yl)alkyl]-thymines from 1-(ω-cyanoalkyl)thymines and a 1:1-mixture of 1,3-diaminopropane and ethanol saturated with hydrogen sulfide is described. 1-(2-Cyanoethyl)-thymine gave a facile reversal of the Michael reaction to thymine under the conditions used. The reaction of 1,3-bis(3-cyanobenzyl)thymine with the above reagent produced 1,3-bis[3-(1,4,5,6-tetrahydropyrimidin-2-yl)benzyl]thymine.     

Reactions of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with Electrophiles

 Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives.     

Four component tandem Knoevenagel–Michael strategy for the assembly of arylaldehydes,N,N'-dimethylbarbituric acid, 4-hydroxy-6-methyl-2H-pyran-2-one and morpholine into unsymmetrical scaffold with three different heterocyclic rings

A new type of four component tandem Knoevenagel–Michael reaction has been found consisting in the assembly of benzaldehydes, N,N'-dimethylbarbituric acid, 4-hydroxy-6-methyl-2H-pyran-2-one and morpholine in alcohols, other organic solvents or water at room temperature without catalyst or any other additives, which results in the selective formation of unsymmetrical scaffold with three different heterocyclic rings in 63–98% yields. The crystal structure of morpholinium 5-[(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)(4-nitrophenyl)methyl]-1,3-dimethyl-2,6-dioxo-1,2,3,4-tetrahydropyrimidin-6-olate has been confirmed by X-ray diffraction.     

Reactions of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with Electrophiles

Summary.  Treatment of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with haloalkanes yielded oxadiazole S-alkyl derivatives, whereas its reaction with formaldehyde and amines resulted in formation of oxadiazole N(3)-aminomethyl derivatives. The alkylation of 2-alkylsulfanyl-5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles with methyl bromoacetate proceeded at the N(1)-position of pyrimidine to give 2-alkylsulfanyl-5-(1-methoxycarbonylmethyl-6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazoles, whereas aminomethylation, bromination, or nitration took place at position 5 of pyrimidine ring and afforded the corresponding 5-pyrimidine substituted derivatives. Received May 9, 2001. Accepted (revised) August 17, 2001     

Condensation of thiourea with uracyl derivatives containing ketone and ketoester fragments,alkylation and macrocyclization of the condensation products

By condensation of thiourea with 6-methyluracyl derivatives containing ketone and ketoester fragmenst in the alkyl chains attached to the nitrogen atoms of the pyrimidine ring the products containing 6-methyl- or 3,6-dimethyluracyl fragment and one or two 6-methyl-4-oxo-2-thio-1,2,3,4-tetrahydropyrimidin-5-yl fragments were synthesized. These compounds can be alkylated with alkyl bromides.     

Synthesis of 5-(6-Methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-amino-1,2,4-triazole-3-thione and its Reactions with Polyfunctional Electrophiles

Summary.  In the reaction of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-1,3,4-oxadiazole-2-thione with hydrazine hydrate, 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-amino-1,2,4-triazole-3-thione was formed. The reactions of the latter with ethyl bromoacetate and chloroacetonitrile in the presence of triethylamine proceeded under formation of the corresponding S-alkylated derivatives, whereas from its reaction with ω-bromoacetophenone and ethyl 4-chloroacetoacetate triazolothiadiazines were obtained. Treatment of the title compound with ethyl 2-chloroacetoacetate led to the formation of 5-(6-methyl-2,4-dioxo-1,2,3,4-tetrahydro-3-pyrimidinyl)-methyl-4-N-acetylamino-(3-ethoxy-carbonylmethylthio)-1,2,4-triazole. Performing of the latter reaction without basic catalyst gave a triazolothiadiazine. Treatment of the S-alkylated derivatives with sodium methoxide resulted in triazolothiadiazines via a cyclocondensation reaction. Received November 20, 2000. Accepted January 15, 2001     

Design,synthesis,in vitro evaluation of tetrahydropyrimidine-isatin hybrids as potential antibacterial,antifungal and anti-tubercular agents

A series of 5-substitued-3-(5-(4-(furan-2-yl)-6-methyl-2-oxo/thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)-1,3,4-thiadiazol-2- ylimino)indolin-2-one derivatives were synthesized,characterized and were screened for anti-bacterial,anti-fungal and antitubercular activity.     

Mannich Reaction as a Convenient Route to New Macrocyclic Compounds Containing an Uracil Fragment

Mannich reaction of 1,3-bis[4-(2-mercaptomethylphenoxy)butyl]-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione, formaldehyde, and N-benzylamine afforded a 24-membered macrocyclic compound containing an uracil fragment, 1,3-(11-benzyl-6,7:15,16-dibenzo-5,17-dioxa-9,13-dithia-11-aza-6,15-heneicosadiene-1,21-diyl)-6-methyl-1,2,3,4-tetrahydropyrimidine-2,4-dione.     

Novel tandem hydration/cyclodehydration of alpha-thiocyanatoketones to 2-oxo-3-thiazolines. Application to thiazolo[5,4-c]quinoline-2,4(3aH,5H)-dione synthesis

Novel tandem hydration of alpha-thiocyanatoketones to thiocarbamates followed by in situ cyclodehydration to fused 2-oxo-3-thiazolines is described. The reaction is applied to the synthesis of [1,3]thiazolo[5,4-c]quinoline-2,4(3aH,5H)-diones (4). Concentrated sulfuric acid was found to be critical for the reaction as both corresponding 2,3-dioxo-1,2,3,4-tetrahydroquinolin-3-yl thiocyanates (2) and S-(2,4-dioxo-1,2,3,4-tetrahydroquinolin-3-yl) thiocarbamates (3) rapidly hydrolyze in the presence of water to 4-hydroxyquinolin-2(1H)-ones (1).     

Design and synthesis of novel dinucleotide analogs

Syntheses of dinucleotide analogs, (S,R) cis-(4-((4-amino-2-oxopyrimidin-1(2H)-yl)methyl)-1,3-dioxolan-2-yl)methyl (2R,3R,5R)-2-(hydroxymethyl)-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-tetrahydrofuran-3-yl hydrogen phosphate (5a) and (S,R) cis-(5-((4-amino-2-oxopyrimidin-1(2H)-yl)methyl)-1,3-oxathiolan-2-yl)methyl (2R,3R,5R)-2-(hydroxymethyl)-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-tetrahydrofuran-3-yl hydrogen phosphate (5b), were accomplished by the use of a new strategy. The use of phenyldichlorophosphate (Method A) as the coupling reagent was shown to possess superiority relative to the reported use of di(1H-benzo[d][1,2,3]triazol-1-yl)phenyl phosphonate (Method B).     

Synthesis and characterization of Schiff bases derived from 5-aminouracil and N-heterocyclic aldehydes

New Schiff bases of 5-aminouracil have been synthesized by the 1: 1 condensation with N-heterocyclic aldehydes. The new compounds were characterized by elemental analyses and ¹H NMR spectroscopy. Under similar conditions, the condensation of 6-aminouracil with aldehydes failed to yield the desired Schiff base. Interestingly, the reaction of 6-aminouracil with 6-methylpyridine-2-carbaldehyde resulted in an unusual compound, 2-methyl-6-[7-(6-methylpyridin-2-yl)-2,4-dioxo-1,2,3,4-tetrahydropyrimido[4,5-d]pyrimidin-5-yl]-pyridinium methanesulfonate, whose crystal structure was elucidated by X-ray crystallography.     

α,ω-Bis(3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)alkanes and products of their cyclization, pyrimidinophanes: intra- and intermolecular interaction in crystals and in solutions

Reaction of α,ω-bis(3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)alkanes with paraformaldehyde leads to pyrimidinophanes, which contain four 3,6-dimethyluracil fragments, connected to each other by the methylene chains. A comparative study of intra- and intermolecular interactions of “open” and macrocyclic uracil derivatives in the crystal state and in solution was performed. According to the NMR spectroscopy data, there is no self-association of “open” and macrocyclic compounds in chloroform solutions, whereas the X-ray data revealed the intermolecular π-π contacts between the 3,6-dimethyluracil fragments in the crystals of these compounds. Conclusions on the presence of intramolecular interactions in chloroform solutions of α,ω-bis(3,6-dimethyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)alkanes and pyrimidinophanes were made based on the UV spectra, which were interpreted in terms of hypo- and hyperchromic effects relatively to the model uracil derivative. These conclusions correlate with the X-ray data: there are no intramolecular π-π contacts between the 3,6-dimethyluracil fragments both in the crystals and in solutions of “open” compounds, positions of these fragments relatively to each other in the molecules of pyrimidinophanes are defined by the lengths of the polymethylene bridges. The intramolecular stacking effect between the opposite uracil rings is observed for the macrocycles with trimethylene and hexamethylene chains, whereas there is no such interactions in pyrimidinophanes with tetramethylene chains. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 119–131, January, 2008.     

Synthesis,DFT study,molecular docking and insecticidal evaluation of some pyrazole-based tetrahydropyrimidine derivatives

Abstract

The building block synthon, 1-(4-(1,3-diphenyl-1H-pyrazol-4-yl)-6-methyl-2-thioxo-1,2,3,4-tetrahydropyrimidin-5-yl)ethan-1-one was efficiently synthesized by Biginelli reaction of 1,3-diphenyl-1H-pyrazole-4-carbaldehdye, acetylacetone, and thiourea and submitted to react with ethyl chloroacetate and chloroacetyl chloride under different conditions to afford some N-heterocycles integrated with pyrazole scaffold. Hydrazinolysis of the pyrimidinethione was studied under different conditions. The insecticidal activity for these compounds, DFT calculations, and docking were run and discussed. Some of them exhibited 100% mortality against Nilaparvata lugens and Mythimna separata.     

A novel access to pyrido[4,3-d]pyrimidine scaffold via Staudinger/intramolecular aza-Wittig reaction of 5-acyl-4-(β-azidoalkyl)-1,2,3,4-tetrahydropyrimidin-2-ones

A general four-step approach to 1,2,3,7,8,8a-hexahydropyrido[4,3-d]pyrimidin-2-ones via Staudinger/intramolecular aza-Wittig reaction of 5-acyl-4-(β-azidoalkyl)-1,2,3,4-tetrahydropyrimidin-2-ones promoted by PPh₃ was developed. Synthesis of the starting pyrimidinones included preparation of 3-azidoaldehydes by the addition of hydrazoic acid to α,β-unsaturated aldehydes, transformation of 3-azidoaldehydes into N-[(3-azido-1-tosyl)alkyl]ureas followed by the reaction with enolates of dibenzoylmethane, benzoylacetone, acetylacetone, or ethyl 2,4-dioxo-4-phenylbutanoate and dehydration of the resulting products under acidic conditions.