Synthesis of 6-substituted pyrimidines by the wittig reaction. II . Via 2-acetamido-4-hydroxy-5-phenylbutylpyrimidine-6-carboxaldehyde

Wittig condensations of both stabilized and unstabilized ylides were successfully achieved with 2-acetamido-4-hydroxy-5-phenylbutylpyrimidine-6-carboxaldehyde (XI); functionalized Wittig reagents derived from dichloroacetone, ethyl 4-iodobutyrate, 4-bromobutyronitrile, phenylpropyl bromide, 3-bromopropylphthalimide, p - nitrobenzyl bromide, and p-nitrocinnamyl bromide were used. The resultant 6-substituted pyrimidines could be further transformed by reduction of the 6-side-chain double bond. Successful Wittig reactions were achieved with XI where the corresponding 2-amino-4-hydroxy-5-phenylbutylpyrimidine-6-carboxaldehyde (X) with its less electrophilic aldehyde group failed to give isolable yields of condensation products.     

Synthesis of 6-substituted pyrimidines by the wittig reaction. III . Via 2-amino-4-hydroxy-5-phenylbutyl-6-pyrimidylmethyl triphenyl phosphonium bromide

2-Amino-6-bromomethyl-5-phenylbutyl-4-pyrimidinol (IV) smoothly alkylated triphenyl phosphine, resulting in a 95% yield of the phosphonium salt (V). This Wittig reagent (V) readily condensed with p-nitrobenzaldehyde, p-nitrocinnamaldehyde, or cinnamalde-hyde in N,N-dimethylformamide to give the 6-(p-nitrostyryl) (X), 6-(p-nitrophenyl-1,3-butadien-1-yl) (VIH), and 6-(phenyl-1,3-butadien-1-yl) (IX) pyrimidinols in 72, 67 and 44% yields, respectively. Catalytic reduction of VIII and IX afforded the corresponding 6-(p-aminophenylethyl) (XII) and 6-(p-aminophenylbutyl) (XI) 4-pyrimidinols.     

Amino-functionalized SBA-15 catalyzed one-step synthesis of 2-amino-5-cyano-4-hydroxy-6-aryl pyrimidines

A simple and efficient approach towards one-step synthesis of 2-amino-5-cyano-4-hydroxy-6-aryl pyrimidines has been developed. It is based on three-component condensation of aliphatic, aromatic or heterocyclic aldehydes, ethyl cyanoacetate and guanidinium carbonate in the presence of amino-functionalized SBA-15 catalyst in ethanol. In this chemical process, the tautomeric interconversion of pyrimidine derivatives has been observed. This efficient technique has the advantage to give 2-amino-pyrimidine derivatives using a heterogeneous catalyst in high yields, to be completed in short reaction times and to offer a simple product isolation procedure.     

Synthesis of 6-substituted 5-cyano-7-hydroxy-2-carboxybenzofurans

Methods for the synthesis of 5-cyano-7-hydroxy-2-carboxybenzofurans bearing a variety of substituents at the 6-position are outlined. The scope and limitations of lithiation processes, electrophilic substitutions, and pericyclic reactions are investigated.     

3-氨基-5-取代苯氨基-6-苯基-1,2,4-三嗪的合成

3-氨基-1,2,4-三嗪化合物具有广泛的生理活性,如:治疗支气管扩张、抑制乳酸菌和症原虫繁殖杀菌等,因此,研究这类化合物合成方法应运而生。本文以苯甲酰基硫代甲酰胺为原料,进一步合成了氨基-5-取代苯氨基-6-苯基-1,2,4-三嗪。     

Novel reaction of carbon suboxide. Synthesis of 6-amino-4-hydroxy-2(1H)-pyridone derivatives

The reaction of 2-cyanoacetamidines 1 with carbon suboxide 2 afforded 6-amino-4-hydroxy-2(1H)-pyri-dones 4 . Compounds 4 were also obtained by reaction of amidines 1 and 2,4,6-trichlorophenylmalonates 3 .     

Synthesis of 2-amino-4-hydroxy-1,3,5-triazanaphthalenes

The synthesis of 2-amino-4-hydroxy-6-amyl-1,3,5-triazanaphthalene (8) is described as a model sequence pertinent to preparation of 8-deazafolic acid and its analogs. Condensation of 2-acet-amido-4-hydroxy-6-pyrimidinealdehyde (3) with dimethyl 2-oxoheptylphosphonate afforded 1-(2′-acetamido-4′-hydroxy-6′-pyrimidinyl)-1-octene-3-one (4) as a key intermediate. Conversion of 4 to 1-(2′-amino-4′-hydroxy-5′ -phenylazo-6′ pyrimidinyl)-3-octanone (7) followed by reductive cyclization yielded 8 or its tetrahydro derivative (9) .     

Non-steroidal antiinflammatory agents. 1. Synthesis of 4-hydroxy-2-oxo-1,2-dihydroquinolin-3-yl alkanoic acids by the wittig reaction of quinisatines

The Wittig reaction of quinisatines ( 1a,b ) with 1-ethoxycarbonylethyliden- ( 2a ) and ethoxycarbonylmeth-ylenetriphenylphosphorane ( 2b ) has been investigated. In both cases unusual reaction products ( 3a,b and 12a,b respectively) were isolated in high yields and converted to potential antiinflammatory acids 6, 8, 15 and lactones 4 , 7.     

Synthesis of methyl -substituted 4-amino methyl-4-butanolides and 5 -hydroxy-2-piperidones

Esters of 5-amino-4-hydroxy-3-methylvaleric acids, which exist as pairs of diastereomers and are readily converted to the corresponding methyl-substituted 4-aminomethyl-4-butanolides or 5-hydroxy-2-piperidones, are obtained by reaction of esters of 3-methyl-4, 5-epoxy-2-pentenoic acid with amines and subsequent hydrogenation of the resulting esters of 5-amino-4-hydroxy-3-methyl-2-pentenoic acids.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 594–598, May, 1975.     

Synthesis of 2-hydroxy-3-substituted naphthoquinones using the Heck reaction

An efficient Heck coupling of 2-hydroxy-3-iodo-naphthoquinone with a series of electron-deficient alkenes in aqueous solution has been accomplished. The method is characterized by simple conditions and facile work-up to isolate the products in good to excellent yields. The products contain the motif present in several naphthoquinone pigments but with enhanced polarity.     

Synthesis of 4(5)-substituted 2-amino-5(4)-hydroxyimino-5(4)H-imidazoles and their transformation into the corresponding 3-substituted 5-amino-1,2,4-oxadiazoles

Treatment of 4(5)-phenyl(or alkyl)-2-aminoimidazoles with isoamyl nitrite in acetic acid afforded the corresponding 4(5)-substituted 2-amino-5(4)-hydroxyimino-5(4)H-imidazoles which by heating in water were transformed into 3-benzoyl(or acyl)-5-amino-1,2,4-oxadiazoles.     

5-vinyl pyrimidines. I. Synthesis

A total synthesis of 5-vinyl pyrimidine and some of its substituted derivatives is described. The following vinyl pyrimidines have been prepared: 5-vinyl pyrimidine, 5-vinyl-4,6-dimethoxy pyrimidine, 5-(α-bromo) vinyl-4,6-dimethoxy pyrimidine.     

Synthesis of 5-substituted pyrimidines. ortho-directed lithiation of pyrimidine derivatives

ortho-Directed lithiation of some pyrimidines has been investigated. Treatment of 2- and/or 4-alkoxy or acylaminopyrimidine with lithium 2,2,6,6-tetramethylpiperidide in ether at 0°, followed by quenching with various electrophiles afforded the corresponding 5-substituted pyrimidines.     

Synthesis of 4-hydroxy- and 3-aryl-4-amino- 2-trifluoromethylpyridines

Schemes for synthesizing 3-acyl-4-amino(hydroxy)-2-trifluoromethylpyridines from 3-acyl 4-amino-5,5,5-trifluoro-3-penten-2-ones via their diphenylboron chelate complexes have been suggested.Translated fromlzvestiyn Akademii Nauk. Seriya Khimicheskaya, No. 11, pp. 2715–2718, November, 1996,     

A convenient synthesis of 2-substituted 4-amino-5-pyrimidinecarbonitriles

Synthesis of the novel 2-halogenated 4-amino-5-pyrimidinecarbonitriles 3a,b starting from ethoxy-methylenemalononitrile 1 and cyanamide is described. Nucleophilic substitution of the reactive halogen atom leads to the derivatives 5a-g, 6 and 7a-h.     

Synthesis, NMR and X-ray characterisation of 6-substituted 4-amino-5-aryldiazenyl-1-arylpyridazinium salts

A new simple method has been used to prepare 6-substituted 4-(subst. amino)-5-aryldiazenyl-1-arylpyridazinium salts from N-methyl- or N-aryl-3-amino-1-phenylbut-2-en-1-ones and 4-aminopent-3-en-2-ones and substituted benzenediazonium tetrafluoroborates or hexafluorophosphates. The structure of selected derivatives was studied by means of ¹⁵N NMR spectra and X-ray.     

Synthesis of 4-amino-6-hetarylthieno[2,3-d]pyrimidines from 5-acetyl-6-aminopyrimidine-4(3H)-thiones

Russian Chemical Bulletin - An efficient method for the synthesis of functionalized thieno[2,3-d]pyrimidines and 2-(thieno[2,3-d]pyrimidin-6-yl)pyrido[2,3-d]pyrimidines from...