Haloacetylated enol ethers. 2. Synthesis of 5-trifluoromethylpyrazoles

1-Methyl-5-(trifluoromethyl)-1H-pyrazoles 2, 3 and 4,5-dihydro-1-phenyl-5-(trifluoromethyl)-1H-pyrazol-5-ol 4 were prepared by reaction of 4-alkoxy-1,1,1-trifluoro-3-alken-2-ones 1 and hydrazine, methylhydrazine, and phenylhydrazine, respectively, in good yields. Compound 1 proved to be a versatile building block for the regiospecific construction of pyrazole rings having an 5-trifluoromethyl substituent.     

Haloacetylated enol ethers. 6 [5]. Synthesis of 4,5-trimethylene-4,5-dihydroisoxazoles

The investigation of the effect of the cyclopentane ring on the regiochemistry of the reactions of 2-acetylcyclopentanones 1a-d and β-methoxyvinyl trifluoromethyl ketone derivative 2a with hydroxylamine hydrochloride is reported. The reactions give regiospecifically the 4,5-trimethylene-4,5-dihydroisoxazoles 3a-d in good yields.     

Haloacetylated enol ethers. 7 . Synthesis of 3-aryl-5-trihalomethylisoxazoles and 3-aryl-5-hydroxy-5-trihalomethyl-4,5-dihydroisoxazoles

β-Aryl-β-methoxyvinyl trihalomethyl ketones 1a-g, 2a-g [aryl = p-YC₆H₄ where Y= H, Me, OMe, F, Cl, Br, NO₂] are cyclocondensed with hydroxylamine hydrochloride to afford the 3-aryl-5-hydroxy-5-trihalomethyl-4,5-dihydroisoxazoles 3a-g, 4a-f in good yield. The dehydratation of compounds 3a-g with concentrated sulfuric acid, led the corresponding 3-aryl-5-trichloromethylisoxazoles 5a-g . An alternative one-pot procedure yields 3-aryl-5-trihalomethylisoxazoles 5,6a-g directly by cyclocondesation of 1,2a-g with hydroxylamine hydrochloride in the presence of an excess of concentrated hydrochloric acid.     

Haloacetylated enol ethers: 3. Synthesis of 3,3a,4,5,6,7-hexahydro-3-halomethylbenzoisoxazoles

The investigation of the halomethyl group effect on the regiochemistry of the reaction of 2-acetylcyclo-hexanones 1a-d and β-methoxyvinyl trifluoro methyl ketone derivative 2a with hydroxylamine to afford 3,3a,4,5,6,7-hexahydro-3-halomethyl-3-hydroxy[2,1]benzoisoxazoles 3a-c , and the respective dehydrated compounds 4a-c , is reported. Compounds 1a-c, 2a proved to be versatile building blocks for the regiospecific synthesis of isoxazole derivatives having a 3-halomethyl substituent, in good yields.     

Synthesis of diaryl ethers based on one-pot [3+3] cyclizations of 1,3-bis(silyl enol ethers)

Functionalized and sterically encumbered diaryl ethers were prepared by [3+3] cyclization of 1,3-bis(silyl enol ethers) with 2-aryloxy-3-(silyloxy)alk-2-en-1-ones.     

新型吡唑啉酮衍生物的制备

以氢氧化钾为催化剂,1-苯基-3-甲基-吡唑啉-5-酮与取代苯甲醛亚胺反应合成了新型1-苯基-3-甲基-吡唑啉-5-酮衍生物——1-苯基-3-甲基-4-(1-N-氯乙胺基-1-取代苯基)甲基-吡唑啉-5-酮,其结构经1H NMR,IR,MS和元素分析表征。     

Haloacetylated enol ethers. 13. Synthesis of N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines and 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines

The synthesis and isolation of the intermediates N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-1-buten-1-yl]-o-phenylenediamines 2a-f and the corresponding 2-trichloromethyl-4-aryl-3H-1,5-benzodiazepines 3c-g or benzimidazoles 4a-b derivatives obtained from the intramolecular cyclization of 2a-f or from direct cyclo-condensation reaction of β-alkoxyvinyl trichloromethyl ketones 1a-g with o-phenylenediamine, is reported. Depending of the structure of the β-alkoxyvinyl trichloromethyl ketones or the N-[1-aryl(alkyl)-3-oxo-4,4,4-trichloro-buten-1-yl]-o-phenylenediamines and the reactions conditions, benzimidazoles or 3H-1,5-benzodiazepines were obtained.     

Haloacetylated enol ethers. 9. Synthesis of 4-trifluoromethyl-2-methyl[phenyl]pyrimidines and tetrahydro derivatives

The synthesis of 4-trifluoromethyl-2-methyl[phenyl]pyrimidines and the corresponding tetrahydro derivatives from the cyclo-condensation reaction of β-alkoxyvinyl trifluoromethyl ketones 1a-d with acetamidine or benzamidine hydrochloride, is reported. For the cyclo-condensation of 1a-d with acetamidine and benzamidine hydrochloride, two methods were tested: 1 M solution of sodium hydroxide (method A) and sodium alkoxide/alcohol (method B). Depending on the structure of the β-alkoxyvinyl trifluoromethyl ketones and the reactions conditions, pyrimidines or tetrahydropyrimidines or a mixture of both compounds were obtained.     

Haloacetylated enol ethers. 5 [5]. Heterocyclic ring closure reactions of β-alkoxyvinyl dichloromethyl ketones with hydroxylamine

The β-alkoxyvinyl dichloromethyl ketones 1a-d are cyclocondensed with hydroxylamine hydrochloride in pyridine to afford the 5-hydroxy-5-dichloromethyl-4,5-dihydroisoxazoles 2a-d in good yield. The cyclo-condensation of compound 1c gave, together with 2c , 3-cyano-2-hydroxy-2-dichloromethyltetrahydrofuran 5c. The dehydratation of compounds 2a,b , derived from acyclic enol ethers, with concentrated sulfuric acid at 30°, led the corresponding 5-dichloromethylisoxazoles 3a,b. The dehydratation of compounds 2c,d , derived from cyclic enol ethers, with concentrated sulfuric acid at 30°, led the bicyclic 4,5-dihydroisoxazoles 4c,d , and at 55°, a competitive rearrangement reaction gives the 3-cyano-2-hydroxy-2-dichloromethyl-2H-pyran 5d.     

Haloacetylated enol ethers: 18 : Synthesis of alkyl 6-[azol-3(5)-yl]hexanoates

A convenient method for the synthesis of eight alkyl 6-[4,5-dihydroisoxazol-3-yl(-pyrazol-3(5)-yl)]hexanoates from the cyclocondensation of methyl 10,10,10-trifluoro[chloro]-9-oxo-7-methoxydec-7-enoates and hydroxylamine hydrochloride or hydrazine hydrochloride, respectively, in ethanol as solvent is reported. The reaction of methyl 10,10,10-trichloro-9-oxo-7-methoxydec-7-enoates with hydrazines furnished the pyrazole derivatives with the simultaneous transformation of trichloromethyl to carboxyl group.     

Haloacetylated enol ethers. 14 [6]. Reaction of β-alkoxyvinyl trifluoromethyl ketones with N-methylhydroxylamine

The reaction of a series of β-methoxyvinyl trifluoromethyl ketones [CF₃COC(R²)?C(OMe)R¹, where R¹ = Me, -(CH₂)₃-C3, -CH₂)₄-C3, Ph and R² = H, Me, -(CH₂)₃-C4, -(CH₂)₄-C4] with N-methylhydroxylamine is reported. The regiochemistry of the reaction are explained by MO calculation data.     

Synthesis of tetrasubstituted and functionalized enol ethers by E-selective olefination of esters with ynolates

We have developed the E-selective olefination of ester carbonyls to afford tetrasubstituted, functionalized olefins and the C-S insertion of thiol esters to give beta-keto thiol esters via ynolates.     

Synthesis of pyrazole-3-carboxylates and pyrazole-1,5-dicarboxylates by one-pot cyclization of hydrazone dianions with diethyl oxalate

The one-pot cyclization of hydrazone dianions with diethyl oxalate allows a convenient synthesis of pyrazole-3-carboxylates and pyrazole-1,5-dicarboxylates.     

Synthesis of 7-acetyl-2,3,5,6,7,8-hexahydro-6-hydroxy-1,6-dimethyl-3-thioxo-8-phenyl(heteryl)isoquinoline-4-carbonitriles Based on 2,4-Diacetyl-5-hydroxy-5-methyl-3-phenyl(heteryl)cyclohexanones

7-Acetyl-2,3,5,6,7,8-hexahydro-6-hydroxy-1,6-dimethyl-3-thioxo-8-phenyl(heteryl)isoquinoline-4-carbonitriles were obtained by reaction of 2,4-diacetyl-5-hydroxy-5-methyl-3-phenyl(heteryl)cyclohexanones with cyanothioacetamide. Structure of 7-acetyl-5,6,7,8-tetrahydro-6-hydroxy-1,6-dimethyl-3-methylthio-8-phenylisoquinoline-4-carbonitrile was proved by X-ray diffraction method.     

A regioselective route to 5-substituted pyrazole- and pyrazoline-3-phosphonic acids and esters

The regioselective synthesis of 5-substituted-3-dimethoxyphosphono-pyrazoles and -2-pyrazolines has been accomplished through the 1,3-dipolar cycloaddition of a suitable nitrile imine to monosubstituted alkynes and alkenes. Examples of hydrolysis of the heterocyclic phosphonic esters to the corresponding acids are described.     

Haloacetylated enol ethers. 8 [12]. Reaction of β-alkoxyvinyl trihalomethyl ketones with guanidine hydrochloride. Synthesis of 4-trihalomethyl-2-aminopyrimidines

In this work the results of the reaction of β-alkoxyvinyl trihalomethyl ketones 1, 2a-e , with guanidine hydrochloride are reported. Depending on the ketone 1 or 2 and the conditions under which the reactions were carried out, 4-trihalomethyl-2-amino pyrimidines, β-alkoxyvinyl carboxylic acids, or β-acetal carboxylic esters were obtained.     

三(2-甲基-2-苯基丙基)锡芳氧乙酸酯的合成

三（２－甲基－２－苯基丙基）锡芳氧乙酸酯的合成刘宝殿,宁志刚,朱东升,包明（东北师范大学化学系,长春,１３００２４）关键词三（２－甲基－２－苯基丙基）锡芳氧乙酸酯,三（２－甲基－２－苯基丙基）氢氧化锡,芳氧乙酸,杀螨活性１９６６年Ｒｅｉｃｈｌｅ［１］...     

Synthesis of Derivatives of 3-Cyano-6-methyl-5-phenylcarbamoylpyridine-2(1H)-thione and 3-Cyano-6-methyl-5-phenyl-carbamoylpyridine-2(1H)-selenone

The reaction of ethoxymethylenacetylacetanilide with cyanothioacetamide or cyanoselenoacetamide in the presence of N-methylmorpholine and alkylating agents gave substituted 2-alkylthio- and 2-alkylselenopyridines and thieno[2,3-b]pyridines.