3-甲基-4-乙氧甲酰-2-环己烯酮合成方法的改进

甲基乙氧羰基环己烯酮;多聚甲醛;3-甲基-4-乙氧甲酰-2-环己烯酮合成方法的改进     

2-甲基-9-芴酮的合成

对甲苯胺与苯甲酰氯经酰胺化反应制得N-对甲苯基苯甲酰胺(1);1经傅克酰基化反应和脱酰胺保护制得2-氨基-5-甲基二苯甲酮(2);2经Pschorr环合反应合成了2-甲基-9-芴酮,总收率64%,其结构经1H NMR和HR-ESI-MS确证。     

4—甲基—7—巯基—2（1H）—喹啉酮的合成

以间氨基苯硫酚为起始原料,与乙酰乙酸乙酯一步环合得目标产物4－甲基－7－巯基－2（1H)-喹啉酮（4）,收率：22％;以间苯二胺为起努原料,经乙酰乙酸乙酯环合,重氮化,二硫化合物的形成及盐酸锌和粉还原获得目标产物4,收率：59％。     

New method for synthesis of 3-pyrrolin-2-one derivatives

We propose a method for synthesis of derivatives of pyrrolinone by reaction of the methyl ester of 3-substituted 2-oxo-3-pentonoic acid with primary amines or acetylhydrazine.Institute of Organic Chemistry, National Academy of Sciences of the Armenian Republic, Yerevan 375094. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1345–1350, October, 1994. Original article submitted July 4, 1994.     

Efficient Synthesis of 3-Methyl-2H-chromen-2-one: Classic Versus Microwave Conditions

The reaction of salicylaldehyde with propionic anhydride in the presence of anhydrous K₂CO₃ as catalyst afforded 3-methyl-2H-chromen-2-one (3-methylcoumarin) in good yields depending on the reaction conditions. The reaction was performed under classic thermal (55% yield) and microwave conditions (91–97% yield).

2－甲基－2－甲氧基羰基－5－次甲基－1，3－二氧环戊－4－酮的合成和阴离子聚合

本文报导了一种环状新单体，２－甲基－２－甲氧基羰基－５－次甲基－１，３－二氧环戊－４－酮的合成，并用红外、核磁及元素分析对单体和中间体的结构进行了鉴定．在－７０℃及干燥氮气保护下，用９－芴锂作阴离子５：发剂对此新单体进行了阴离子开环聚合反应的研究．聚合物的红外和核磁谱图表明：在聚合物中存在两种结构单元，这说明在聚合过程中同时存在开环和不开环的两种情况。虽然在聚合物中，这两种结构单元的量应取决于两种相应的碳阴离子的相对稳定性，但是开环聚合在热力学上是有利的，因为开环的结果形成了更稳定的羰基．用粘度法测定了聚合物的特性粘数。     

Synthesis of 5-Aryl-4-aroyl-3-hydroxy-1-cyanomethyl-3-pyrrolin-2-ones

5-Aryl-4-aroyl-3-hydroxy-1-cyanomethyl-3-pyrrolin-2-ones were synthesized by a three-component reaction of methyl aroylpyruvate with a mixture of aromatic aldehyde and 2-aminoacetonitrile sulfate in glacial acetic acid in the presence of anhydrous sodium acetate.     

Photochemical Synthesis of 2-Alkylidene-4-pyrrolin-3-ones

Irradiation (λ =313 nm) of the 4-pyrrolin-3-ones 1a–1c in acetone-, 3-pentanone-and cyclopentanone solution affords the title compounds 2 , formally via H-abstrac-tion by the excited ketone and recombination of the radical pair formed.     

Synthesis of 1-Bromo-3-butyn-2-one and 1,3-Dibromo-3-buten-2-one

Synthetic procedures for the preparation of 1-bromo-3-butyn-2-one and 1,3-dibromo-3-buten-2-one are given. These compounds are prepared from 2-bromomethyl-2-vinyl-1,3-dioxolane, which can readily be prepared from 2-ethyl- 2-methyl-1,3-dioxolane. The synthetic routes are as follows: 2-bromomethyl-2-vinyl-1,3-dioxolane is converted to 2-(1,2-dibromoethyl)-2-bromomethyl-1,3-dioxolane. Double dehydrobromination with ^tBuOK affords 2-ethynyl-2-bromomethyl-1,3-dioxolane. Formolysis with formic acid gives 1-bromo-3-butyn-2-one. Deacetalized 2-bromoethyl-2-vinyl-1,3-dioxolane was treated with Br₂ and Li₂CO₃/12-crown-4 in tetrahydrofuran to give 1,3-dibrom-3-buten-2-one in moderate yield.     

Base-catalyzed reaction between isatins and N-Boc-3-pyrrolin-2-one

The base-catalyzed reaction between isatins and N-Boc-3-pyrrolin-2-one yields Morita–Baylis–Hillman (MBH) adducts instead of the expected aldol products in good to high yields (up to 97%). Various organic and inorganic bases are efficient catalysts for this reaction. Our study excluded the Morita–Baylis–Hillman mechanism for the formation of the MBH-type products. The MBH products are most likely formed as a result of the subsequent isomerization of the original aldol products between isatins and N-Boc-3-pyrrolin-2-one.     

Synthesis of 3-pyrrolin-1-yloxy and 1-pyrrolidinyloxy free radicals

Summary By the use of reactions which do not affect the free valence a number of substituted 3-pyrrolin-1-yloxy and 1-pyrrolidinyloxy free radicals were synthesized.This article is published in accordance with a resolution of the Conference of Chief Editors of Journals of the Academy of Sciences of the USSR of July 12, 1962, as a dissertation paper by L. A. Krinitskaya.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 1, pp. 115–118, January, 1965     

The Synthesis of 1-Methyl-6,7,8,8a-tetrahydro-5H-indolizin-3-one by the Palladium-Catalyzed Cyclization of N-Bromoacetyl-2-vinylpiperidine

N-Bromoacetyl-2-vinylpiperidine underwent cyclization to give indolizidine derivative in the presence of a base and a catalytic amount of palladium trifluoroacetate.     

Improved Synthesis of 1-Bromo-3-buten-2-one

A convenient procedure for the synthesis of 1-bromo-3-buten-2-one, 4, from commercially available 2-ethyl-2-methyl-1,3-dioxolane, 1, is described. The procedure involves three reaction steps: (1) The acetal 1 is converted to 2-(1-bromoethyl)-2-bromomethyl-1,3-dioxolane, 2, by reacting 1 with elemental bromine in dichloromethane to yield 98% of 2. (2) Dehydrobromination of 2 with potassium tert-butoxide in tetrahydrofuran gives 2-bromomethyl-2-vinyl-1,3-dioxolane, 3, in 84–93% yield. (3) Removal of the acetal protection from 3 by formolysis for 6–10 h afforded 1-bromo-3-buten-2-one, 4, in 85–94% yield. A more rapid method is acid hydrolysis of 3 under microwave activation (100 °C, 8–10 min), by which 4 was obtained in 75% yield. Full experimental details are given.

Synthesis of 3-(3-Methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one Derivatives via a One-Pot,Three-Component Reaction

An efficient synthesis of 3-(3-methyl-1-aryl-1H-pyrazol-5-yl)-2H-2-chromen-2-one derivatives by the reaction of salicylaldehydes, 4-hydroxy-6-methyl-2H-pyran-2-one, and arylhydrazine in acetonitrile under reflux condition and in the presence of piperidine is reported. This three-component reaction has some advantages such as ease of handling, good yields, and easy purification. All structures were confirmed by infrared, mass, ¹H NMR, and ¹³C NMR spectroscopy.     

Stereoselective synthesis of tricyclic derivatives of 2-amino-1-pyrrolin-5-one dimethyl acetals

Reactions of a tetracyanobicycloalkene (1) with methanol and ethylene glycol give derivatives of 2-aminopyrrolin-5-one (2 and 3), and acid hydrolysis of3 gives an imide (4). According to an X-ray structural investigation, acis orientation of the heterocycle (with respect to the C=C bond) is realized in2; in the case of4, thecis/trans ratio of the isomers in the crystal and solution is 21.Signals overlap and are lost in the background noise.Translated fromIzvestiya Akademii Nauk. Seriya Khimlcheskaya, No. 3, pp. 534–538, March, 1993.     

Synthesis of amino derivatives of 5-aralkylidene-3-pyrrolin-2-ones

Preparation of some derivatives of 5-aralkylidene-3-pyrrolin-2-ones is reported. Compounds with an amino group on the phenyl ring at the 3-position of the pyrrolinone ring showed suitable properties as potential UV-A filters. Some of the compounds were quaternarized to enhance their solubility in aqueous solvents.