One-pot synthesis of alkyl 3-aryl-2-(4-phenyl-1<Emphasis Type="Italic">H</Emphasis>-1,2,3-triazol-1-yl)propanoates

Reaction of 3-aryl-2-bromopropanoic acids esters, products of the Meerwein arylation, with sodium azide afforded alkyl 2-azido-3-arylpropanoates. The latter react with ethyl acetoacetate and phenylacetylene to form 1,2,3-triazole derivatives. A one-pot method for the synthesis of 3-aryl-2-(4-phenyl-1H-1,2,3-triazol-1-yl)-propanoic acid esters via a tricomponent reaction of alkyl 2-bromo-3-arylpropanoates, sodium azide, and phenylacetylene in the presence of CuI was developed.     

Furan derivatives. part 11 [1]. on substituent effects in the synthesis of 3,4,5,6-tetrahydrocyclohepta[cd]benzofurans

Tetrahydrocyclohepta[cd]benzofurans 7a-e were synthesized by the treatment of ( 5 -oxo-tetrahydro-5H-benzocyclohepten-4-yloxy)acetic acids 5a-e with sodium acetate in acetic anhydride or by heating of their esters 6a-e with sodium hydroxide or sodium hydride in dioxane. The yield of furans 7 decreased as a substituent R of acids 5 or esters 6 was changed from hydrogen to a methyl, ethyl, or isopropyl group. When R was a phenyl group furan 7e was always prepared in good yield. Sodium hydride was a useful base for synthesis of tetrahydrocyclohepta[cd]benzofurans.     

稳定同位素标记1,4-二氢吡啶类药剂的5,6-位及其取代基碳的合成

1,4-二氢吡啶结构是许多生物活性物以及药物分子的重要骨架,同时也是非常重要的有机合成中间体。当前并没有一种适用的方法用于¹³C标记1,4-二氢吡啶的合成.提供了一种¹³C标记1,4-二氢吡啶的合成方法以¹³C2-乙酸钠为标记原料,经磷酸酸化得到¹³C2-乙酸,羰基二咪唑酰化¹³C2-乙酸得到¹³C2-N-乙酰咪唑,随后在咪唑钠的作用下进行克莱森缩合反应获得1,2,3,4-¹³C4-乙酰乙酰咪唑的钠盐,经乙酸酸化得到1,2,3,4-¹³C4-乙酰乙酰咪唑,再通过与醇进行酯化得到1,2,3,4-¹³C4-乙酰乙酸酯,1,2,3,4-¹³C4-乙酰乙酸酯经氨基甲酸铵氨化得到1,2,3,4-¹³C4-3-氨基丁烯酸酯。随后采用Hantzsch改进法合成了5,6-位及其取代基碳标记的¹³C4-尼群地平、¹³C4-苯磺酸氨氯地平和¹³C4-马来酸氨氯地平.该方法操作简单,反应条件温和且产率高,为1,4-二氢吡啶的5,6-位及其取代基引入¹³C同位素标记合成提供了新的思路,满足中国仿制药物一致性评价的稳定同位素内标自主合成需求。     

From symmetric glycerol derivatives to dissymmetric chlorohydrins

The anticipated worldwide increase in biodiesel production will result in an accumulation of glycerol for which there are insufficient conventional uses. The surplus of this by-product has increased rapidly during the last decade, prompting a search for new glycerol applications. We describe here the synthesis of dissymmetric chlorohydrin esters from symmetric 1,3-dichloro-2-propyl esters obtained from glycerol. We studied the influence of two solvents: 1,4-dioxane and 1-butanol and two bases: sodium carbonate and 1-butylimidazole, on the synthesis of dissymmetric chlorohydrin esters. In addition, we studied the influence of other bases (potassium and lithium carbonates) in the reaction using 1,4-dioxane as the solvent. The highest yield was obtained using 1,4-dioxane and sodium carbonate.     

Nitroalkanes and ethyl glyoxalate as common precursors for the preparation of both β-keto esters and α,β-unsaturated esters

β-Nitro acrylic esters, obtained by the reaction of nitroalkanes and ethyl glyoxalate, are the key building blocks for the immediate synthesis of both the title compounds. In fact, their treatment with titanium trichloride produce the direct conversion to the β-keto esters, while their reaction with sodium boron hydride gives the one-pot synthesis of α,β-unsaturated esters through formal substitution of the vinylic nitro group with an hydrogen.     

Dynamic kinetic resolution catalyzed by Ir axially chiral phosphine catalyst: asymmetric synthesis of anti aromatic beta-hydroxy-alpha-amino acid esters

The anti selective hydrogenation of alpha-amino-beta-keto esters via dynamic kinetic resolution was achieved for the first time by using the iridium-MeOBIPHEP catalyst in asymmetric synthesis of anti aromatic beta-hydroxy-alpha-amino acid esters with excellent diastereo- and enantioslectivities. Acetic acid as a solvent and sodium acetate as an additive affected dramatically the yield and the enantioselectivity, respectively. The product anti aromatic beta-hydroxy-alpha-amino acid esters are useful for synthesis of pharmaceuticals and natural products.     

Peroxovanadium-catalyzed oxidative esterification of aldehydes

The peroxovanadium species generated from V(2)O(5) and hydrogen peroxide, which is liberated from peroxy salts such as sodium perborate (SPB) or sodium percarbonate (SPC), transform aldehydes directly into esters in an alcoholic medium. Monoesters of diols have been achieved directly in one pot from aldehydes. High catalytic turnover number combined with inexpensive, easily available reagents and innocuous side products from the reaction make it a suitable alternative for the synthesis of esters from aldehydes.     

Non-expensive,open-flask and selective catalytic systems for the synthesis of sulfinate esters and thiosulfonates

Two simple and efficient methods for the synthesis of sulfinate esters and thiosulfonates from sodium salts of sulfinic acids are described. Different alcohols were converted into the corresponding sulfinate esters in good yields and purity in an open flask. By the adjustment of the reaction conditions thiosulfonates could also be obtained in a very short reaction time.     

硫酸氢钠催化合成羧酸苄酯

讨论了一水硫酸氢钠催化合成乙酸苄酯的条件。羧酸、苄醇和硫酸氢钠的质量比为 3∶2∶0 .1 45 ,以环己烷为溶剂 ,进行回流分水 ,合成了甲酸苄酯、乙酸苄酯、丙酸苄酯和丁酸苄酯 ,其收率为 68.5 %～ 84.1 %     

Synthesis of pyridines by heterocyclization of new dienamino esters

The synthesis of pyridine derivatives is reported starting from the new dienamino esters 2 . Thermal cyclization of 2 afforded the ethyl 2-amino-3-pyridinecarboxylate derivatives 3 ; from the reaction of 2 in sodium ethoxide the 2-aminopyridines 3 and 4 , and the 1,2-dihydro-2-oxopyridines 5 and 6 were obtained.     

Polyketoetheresters from 4,4′-Dichloroacetyldiphenyl Ether and their Characterization

Benzyl chloride and phenacyl chloride are reported to condense with sodium acetate or sodium benzoate, affording the corresponding esters [1–4]. This suggested that a dichloride monomer can poly condense with a sodium dioate, affording a polyester. Akhmedzade and Yasnopolskii reported one such polyester synthesis based on polycondensation of p-xylylene dihalide with sodium terephthalate [5]. As phenacyl chloride is more reactive than benzyl chloride is more reactive than benzyl chloride [4], 4,4′-dichloroacetyldiphenyl ether (DADE) should prove even more reactive than a dichloride of the Ar(CH₂Cl)₂ type. The work presented here comprises a study of the polycondensation of DADE with sodium adipate (ADP), sebacate (SEB), or terephthalate (TER).     

A convenient procedure for the solid-phase synthesis of hydroxamic acids on PEGA resins

An efficient method for the solid-phase synthesis of hydroxamic acids is described. The method comprises the nucleophilic displacement of esters immobilized on PEGA resins with hydroxylamine/sodium hydroxide in isopropanol. The hydroxyaminolysis protocol is compatible with a broad range of PEGA-supported peptide and peptidomimetic esters. The methodology was found to be compatible with two new strategies for the synthesis of solid-supported lactams and diketopiperazines, respectively, both relying on the high inter- and intramolecular reactivity of cyclic N-acyliminium ions with electron-rich aromatics and heteroaromatics, ultimately affording hydroxamic acid derivatives in high purities.     

Pyridylethylation and Quinolylethylation of Isopropylidene Malonates

The Michael-type addition of carbanionic reagents to 2- and 4-vinylpyridines has been widely examined and utilized in organic synthesis.¹ When malonic esters are employed, the usual procedure is to reflux the reagents in ethanol containing sodium ethoxide. However, the yields of these reactions have been somewhat variable².     

Three-component condensation of 5-aminoimidazole derivatives with aldehydes and Meldrum’s acid. Synthesis of 3,4,6,7-tetrahydroimidazo[4,5-b]pyridin-5-ones

A convenient method for the synthesis of the earlier unknown substituted 3,4,6,7-tetrahydroimidazo[4,5-b]pyridin-5-ones was developed based on a three-component condensation of 5-aminoimidazole derivatives, aldehydes, and Meldrum’s acid. Unstable aminoimidazole derivatives were readily formed in situ by decarboxylation of 5-amino-4-imidazolecarboxylic acids in acidic medium at room temperature, whose sodium salts were obtained by the alkaline hydrolysis of the corresponding, readily available esters.     

Novel Stereoselective Synthesis of (E)-a,b-Unsaturated Esters by the Tandem Reaction of Deprotonation-Oxidation-Wittig Reaction from Phosphonium and Arsonium Salt

Wittigreactionisoneofthemostimportantmethodfortheformationofcarbon-carbondoublebondandhasbeenwidelyusedinthesynthesisofnaturalproducts1,2.Recentlyitwasfoundthatalcoholscanundergoinsituoxidation-Wittigreactionwithphosponiumylidestogivecorrespondingolefinationproducts,whichhasgreatpotentialutilitiesinorganicsynthesis3.Tosimplifytheprocedureofthereactionfurther,weconsideredtocombinethedeprotonationofylide,oxidationofalcoholandWittigreactionintoonetandemreaction.Weutilizedphosphoniumorarsoniumsal…     

A convenient route to 4-carboxy-4-anilidopiperidine esters and acids

The route selection and development of a convenient synthesis of 4-carboxy-4-anilidopiperidines is described. Previous routes were hampered by the low yield of the target esters as well as the inability to convert the esters to the required free acids. Considerations for large-scale production led to a modified synthesis that utilised a tert-butyl ester of 4-carboxy-4-anilidopiperidines which resulted in a dramatic increase in the overall yield of the target N-propionylated- 4-anilidopiperidine-4-carboxylic acids and their corresponding methyl esters. These compounds are now available for use as precursors and reference standards, of particular value for the production of 11C and 18F-labelled 4-carboxy-4-anilidopiperidine radiotracers.     

Novel Stereoselective Synthesis of (E)- α，β-Unsaturated Esters by the Tandem Reaction of Deprotonation-Oxidation-Wittig Reaction from Phosphonium and Arsonium Salt

Phosphonium or arsonium salt 1 can undergo the tandem reaction of deprotonation -oxidation-Wittig reaction with alcohol 2 in the presence of sodium hydroxide and manganese dioxide,which affords a general simplified method for the stereoselective synthesis of (E)- α-β-unsaturated esters 3.     

An eco-friendly procedure for one-pot synthesis of β-phosphonomalonates: micellar solution of sodium stearate catalyzes tandem Knoevenagel-phospha-Michael reaction of aldehydes, malonitrile, and phosphites in aqueous media

A new, one-pot convenient method for the synthesis of a variety of β-phosphonomalonates by a tandem Knoevenagel-phospha-Michael reaction of phosphite esters with aryl/heteroaryl/alkyl aldehydes and malonitrile in an aqueous micellar solution of sodium stearate is described. This method offers several advantages, such as using a cheap and environmentally benign reaction media, low loadings of sodium stearate as catalyst and offers good yields.     

Metal-free diastereoselective synthesis of diaza-bicyclo[3.2.0]heptan-7-one and its transformation to functionalized proline esters

A metal-free diastereoselective synthesis of novel 4-halo-3,6-di-aryl-2,6-diaza-bicyclo[3.2.0]heptan-7-one by intramolecular endo-trig haloamination of 3-amino-2-azetidinone is reported. The amidiolytic ring opening of diaza-bicyclo[3.2.0]heptan-7-one with sodium methoxide provides an easy access to previously unknown 4-halo-3-aryl amino-pyrrolidine-2-carboxylic acid methyl esters in good yields.     

3- and 4-aminocyclohexanecarboxylic acids,containing either the diethylenimidophosphoryl or the diethylimidothiophosphoryl group

Conclusions We were the first to obtain the ethyl esters of the N-dichlorophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids, the ethyl esters of the N-dichlorothiophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids, the ethyl esters of the N-diethylenimidophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids, the ethyl esters of the N-diethylenimidothiophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids, the sodium salts of the N-diethylenimidophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids, and the sodium salts of the N-diethylenimidothiophosphoryl-3(and 4)-aminocyclohexanecarboxylic acids.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 933–935, April, 1974.