Diethyl Bromomalonate Research Articles

A simple approach to indeno-coumarins via visible-light-induced cyclization of aryl alkynoates with diethyl bromomalonate

Visible-light-induced triple-domino cyclization between aryl alkynoates and diethyl bromomalonate was developed for the synthesis of indeno-coumarins.

Synthesis, Characterization, Antimicrobial Screening of 5-Bromobenzofuranyl Aryl Ureas and Carbamates

Present work reports the biologically important benzofuran aryl ureas and carbamates. The benzofuran ring was formed by reacting bromo salicylaldehyde with diethyl bromomalonate in presence of dry acetone and anhydrous potassium carbonate to obtain 5-bromo-2-ethyl carboxylate (1). The obtained ester (1) was converted into corresponding hydrazide (2) by treating with hydrazine hydrate in ethanol. Compound 2 was then converted into 5-bromobenzofuran-2-carbonyl azide (3) by treating it with sodium nitrite in dioxane and acetic acid. The compound 3 is converted into 5-bromobenzofuranyl aryl ureas (4a-e) after treating primary amines and anhydrous toluene. 5-Bromobenzofuranyl aryl carbamate (5) and ethyl carbamate (6) were also synthesized by treating compound 3 with substituted phenol in toluene and ethanol respectively. All the compounds were characterized by NMR, IR and screened for antimicrobial activities.

Asymmetric cyclopropanation reactions catalyzed by carbohydrate-based crown ethers

Optically active cyclopropane derivatives were prepared by a novel, simple and green approach in high enantioselectivities using monosaccharide-based chiral crown ethers as phase transfer catalysts. The crown ethers having d-glucopyranoside, d-mannopyranoside and d-altropyranoside units proved to be efficient catalyst in a few asymmetric phase transfer cyclopropanation reactions. The Michael-initiated ring closure (MIRC) reactions of diethyl bromomalonate with chalcones took place with complete diastereoselectivity and up to 99% ee. Using benzylidenemalononitrile, 2-arylidenemalononitriles, 2-benzylidene-1,3-indandione, substituted 2-benzylidene-1,3-indandiones, 2-arylidene-1,3-indandiones and 2-benzylidene-1,3-diphenyl-1,3-propanediones enantioselectivities up to 92%, 99%, 54% 93%, 89% and 72%, respectively, were achieved, in the presence of chiral lariat ethers derived from different monosaccharides. The absolute configuration of a cyclopropane diester product was determined by a combined CD spectroscopic and theoretical study.

Facile synthesis of 3-aryl 2,3-dihydrobenzofurans via novel domino 1,6-addition/O-alkylation reactions of para-quinone methides

A facile K2CO3-promoted novel domino 1,6-addition/O-alkylation reaction of ortho-hydroxyphenylsubstituted p-QMs and diethyl bromomalonate is described. A variety of new 3-aryl 2,3-dihydrobenzofurans were obtained in excellent yields (up to 99%) under simple and mild conditions. The structure of the new compound 3f was determined by single crystal X-ray analysis.

Synthesis of d-mannitol-based crown ethers and their application as catalyst in asymmetric phase transfer reactions.

A few new d-mannitol-based monoaza-15-crown-5 type chiral lariat ethers and 18-crown-6 type macrocycles were synthesized. These crown compounds were used as phase transfer catalysts in asymmetric Michael addititons and in a Darzens condensation under mild conditions to afford the corresponding products in a few cases in good to excellent enantioselectivities. In the Michael addition of diethyl acetoxymalonate to trans-chalcone, in the addition of diethyl acetamidomalonate to ß-nitrostyrene, in the reaction of diethyl bromomalonate with benzylidene malononitriles, in the cyclopropanation reaction of diethyl bromomalonate and 2-benzylidene-1,3-indandione, and in the Darzens condensation of α-chloroacetophenone with benzaldehyde, maximum enantioselectivities of 39%, 65%, 99%, 56%, and 62%, respectively, were obtained in the presence of the d-mannitol-based macrocycles as the catalysts.

Synthesis of alkyl α- and β-d-glucopyranoside-based chiral crown ethers and their application as enantioselective phase-transfer catalysts

Chiral monoaza-15-crown-5-type lariat ethers annelated to alkyl 4,6-O-benzylidene-α- and β-d-glucopyranosides have been synthesized. These macrocycles generated significant asymmetric induction as phase-transfer catalysts in a few two-phase reactions. The catalytic effect of the lariat ethers with methoxy, ethoxy, and i-propoxy substituents on C-1 of the sugar unit in both α and β positions was compared. In liquid–liquid two-phase reactions, the nature and position of the substituents did not have much effect. The α-anomers were somewhat more efficient in terms of enantioselectivity than the β forms. In asymmetric Darzens condensations, in the epoxidation of trans-chalcone, in the Michael addition of β-nitrostyrene and diethyl acetamidomalonate, and in the reaction of 2-benzylidene-1,3-indandione with diethyl bromomalonate, maximum enantioselectivities of 73, 94, 78, and 72%, respectively, were obtained in presence of glucopyranoside-based lariat ethers as catalysts.

A practical and reusable catalyst for the synthesis of donor-acceptor cyclopropane

Herein, a convenient, recyclable and inexpensive Cu-based catalytic system is developed for the synthesis of donor-acceptor (D-A) cyclopropane via the cycloaddition of styrene derivatives with diethyl bromomalonate. A core-shell catalyst of Fe3O4@Cu2O is used to promote the construction of D-A cyclopropane with different functional groups in good yields. In our experiments, many harsh conditions, such as strict anhydrous and anaerobic, are avoided. The Fe3O4@Cu2O particles are easily made, air-stable and of low cost. What's more, the magnetic property makes the catalyst easy to be separated and catalytical activity has no significant change even after being recycled for five times.

Synthesis of l-threitol-based crown ethers and their application as enantioselective phase transfer catalyst in Michael additions.

A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with β-nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers.

Fabrication of assembled membrane from malonate-functionalized graphene and evaluation of its permeation performance

The increasing number of studies on graphene membranes has indicated a great potential of graphene in separation applications. For the first time, this study demonstrates liquid permeation performance of a new graphene membrane that assembled functionalized graphene sheets. Functionalized graphene was synthesized from graphene dispersion based on a Bingel reaction with diethyl bromomalonate, and employed to prepare an assembled membrane using a vacuum filtration method. Thus prepared membrane was subjected to permeation tests using four solvents (hexane, acetone, methanol and water). The chemical functionalization led to two interesting consequences: i) Even a relatively minor extent of functionalization dramatically altered the chemical selectivity of the membrane, and ii) the permeability of the membrane was greatly enhanced, which plausibly arose from the less ordered stacking of the functionalized graphene sheets as compared to the pristine ones.

Synthesis of Oxindoles by Eosin Y Catalyzed under Visible Light

A novel visible-light-introduced reaction for the construction of oxindole derivatives via tandem radical cyclization of N-aryl acrylamides with diethyl bromomalonate has been developed. The reaction has been achieved in high yield under mild conditions by using Eosin Y as photocatalyst, which is cheap, easy to handle and environmentally friendly. It might pro- vide a promising protocol for the synthesis of oxindole derivatives. Keywords eosin Y; photoredox catalysis; oxindoles; radical cyclization 吲哚酮类化合物是很多碱性天然产物和具有生物

Reaction of 5(R)-(l-Menthoxy)-2(5H)-furanone with Diethyl Bromomalonate

The reaction of 5(R)-(l-menthoxy)-2(5H)-furanone and diethyl bromomalonate was investigated in the presence of anhydrous K2CO3 and phase transfer catalyst TBAB using CH3CN as solvent at 80C. In the above condition, the expected novel chiral cyclopropane/butyrolactone derivative with two ethyl ester groups 3 was obtained, and at the same time, another chiral cycloproane/butyrolactone baring only one ethyl ester group 5, and trace amount of bromo-substitued compound 6 were also obtained. A possible mechanism was proposed based on the analysis of the products.

Reaction of 6‐Methyl‐2‐Thiouracil and 6‐Phenyl‐2‐Thiouracil with Chloro‐β‐Dicarbonyl and Bromo‐β‐Dicarbonyl Compounds and Their Nitrile Analogs

Derivatives of 2‐methylidene‐1,3‐dihydropyrimidin‐4‐ones 2a, 2b, 2c, 2d, 2e, 2f, 2g were synthesized by interaction of 6‐methyl‐2‐thiouracil and 6‐phenyl‐2‐thiouracil 1a, 1b with some activated halogenides: diethyl bromomalonate, ethyl 2‐chloro‐3‐oxobutanoate, ethyl 2‐bromocyanoacetate, 2‐bromo‐5,5‐dimethylcyclohexan‐1,3‐dione, and bromomalononitrile. The boiling of 1a with ethyl 2‐bromocyanoacetate in mixture of ethanol and EtONa results in intramolecular cyclization and formation of thiazolo[3,2‐a]pyrimidin‐5‐one 3. Interaction of 1a with 3‐chloropentane‐2,4‐dione and 2‐bromo‐1,3‐diphenylpropane‐1,3‐dione yielded corresponding S‐substituted thiopyrimidines 4a,4b. In general, the products of 1b S‐alkylation are less prone to sulfur extrusion. Reaction of 1b with diethyl bromomalonate in the absence of EtONa stops at the S‐alkylation step, while in the presence of EtONa in ethanol or PPh3 in dioxane 2‐(ethoxycarbonylmethyl)thio‐6‐phenyl‐1,3‐dihydropyrimidin‐4(1H)‐one 6 is formed exclusively. Molecular structure and crystal structure of 2‐(1,1‐diethoxycarbonylmethyliden)‐6‐methyl‐1,3‐dihydropyrimidin‐4(1H)‐one 2a are discussed.

Synthesis of Chiral Benzofuran-Derived β-Amino Esters Induced by N-tert-Butanesulfinamide

The benzofuran skeleton is commonly found in a wide variety of natural products that display a wide range of biological activities. For this reason, benzofuran has a high potential for use as a scaffold in both chemical and pharmaceutical syntheses of natural products. This work describes the development of a novel asymmetric synthetic method of benzofuran-derived β-amino esters via K2CO3-promoted domino reactions of ortho-hydroxyl aromatic N-tert-butylsulfinyl imines and diethyl bromomalonate. A small library of target compounds was prepared under optimized reaction conditions in moderate to good yields with high distereoselective and enantioselective properties. The newly generated chiral carbon center was of an (S)-configuration as determined by x-ray diffraction.

ChemInform Abstract: Zinc‐Mediated Addition of Diethyl Bromomalonate to Alkynes for the Cascade Reaction Towards Polysubstituted Pyranones and Tetracarbonyl Derivatives.

AbstractIn case of the aryl substituted products (IVb) and (IVc) partial migration of the double bond towards the Knoevenagel product occurs.

Zinc-mediated addition of diethyl bromomalonate to alkynes for the cascade reaction towards polysubstituted pyranones and tetracarbonyl derivatives

The zinc-mediated regioselective addition reactions of diethyl bromomalonate and aromatic and aliphatic alkynes were investigated for the synthesis of vinyl malonates. When the vinyl organo-zinc intermediates were reacted with acid chlorides 2H-pyran-2-ones were obtained while the application of oxalyl chloride and an amine led to tetracarbonyl derivatives in a one-pot multi-step reaction sequence.

NITROGEN AND SULFUR CONTAINING HETEROCYCLES. 50. SYNTHESIS AND REACTIONS OF 6-OXOPYRIMIDO[4,5- b ][1,4]THIAZINE-7-CARBOXYLIC ACID DERIVATIVES

Reaction of 5-amino-6 mercaptopyrimidines with diethyl bromomalonate gave ethyl 6-oxopyrimido-[4,5-b][1,4]thiazine-7-carboxylates, from which there was synthesized a series of derivatives at the carboxyl group (amides, hydrazides, and, from the latter, urethanes). Desulfurization of the 6-oxo-pyrimidothiazine-7-carboxylic acid esters gave N-(pyrimidin-5-yl)monoamides of ethyl malonate. Authors: T. S. Safonova and A. F. Keremov. English Translation in Chemistry of Heterocyclic Compounds , 1999, 35 (6), pp 733-739 http://link.springer.com/article/10.1007/BF02251635

ChemInform Abstract: KOH‐Promoted Synthesis of Oxirane Functional Derivatives from Diethyl Bromomalonate and Aldehydes under Phase‐Transfer Catalysis Conditions.

AbstractKOH‐promoted Darzens condensation of bromomalonate (II) with aromatic or isoprenoid aldehydes (I) under PTC conditions smoothly affords oxiranedicarboxylates (III) (8 examples).

Synthesis and Evaluation of Bingel-Hirsch Multiadducts of Paramagnetic Gadofullerene as Potential Magnetic Resonance Imaging Contrast Agents

Water-soluble malonate multiadducts of paramagnetic gadolinium endohedral metallofullerene, Gd@C82[C(COOH)2]6 and Gd@C82[C(COOH)2]8, were synthesized by Bingel-Hirsch reaction. Gd@C82 was firstly reacted with diethyl bromomalonate in the presence of alkali metal hydride to produce malonic ester multiadducted derivatives, Gd@C82[C(COOCH2CH3)2]x (x = 3-8), by Bingel reaction. They were isolated and purified to obtain Gd@C82[C(COOCH2CH3)2]6 and Gd@C82[C(COOCH2CH3)2]8 by silica-gel column chromatography with a gradient elution method, which were subsequently hydrolyzed to yield water-soluble Gd@C82[C(COOH)2]6 and Gd@C82[C(COOH)2]8 by Hirsch reaction. The structures of the derivatives were characterized by Fourier transform infrared spectrometry and matrix assisted laser desorption ionization time-of-flight mass spectrometry. The longitudinal relaxivities of Gd@C82[C(COOH)2]8 and Gd@C82[C(COOH)2]6, in buffer solution, were found to be 18.20 and 11.08 mM(-1) s(-1) at concentration range between 0.001-0.025 mM Gd, and to be 12.71 and 6.73 mM(-1) s(-1) between 0.050-0.200 mM Gd, respectively. The results showed that the measured relaxivities for malonate derivatives of Gd@C82 were dependent on the concentration of these solutions and the number of hydrophilic carboxyl groups appended on the surface of the Gd@C82 cage.

KOH-Promoted Synthesis of Oxirane Functional Derivatives from Diethyl Bromomalonate and Aldehydes under Phase-Transfer Catalysis Conditions

The Darzens condensation of diethyl bromomalonate with aromatic or isoprenoid aldehydes under heterogeneous conditions (KOH/MeCN) in the presence of Bu 4 NPF 6 as a recoverable phase-transfer catalyst afforded the corresponding diethyl 3-R-oxirane-2,2-dicarboxylates in high yields.

Synthesis and Aggregation Studies of Bingel-Hirsch Monoadducts of Gadofullerene

The monoadducted malonic ester derivative of paramagnetic gadofullerene, Gd@C82[C(COOCH2CH3)2], was synthesized by the Bingel reaction, which Gd@C82 was reacted with diethyl bromomalonate in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene. It was isolated and purified by high performance liquid chromatography, and subsequently hydrolyzed to yield water-soluble disodium salt form Gd@C82[C(COONa)2] by the Hirsch reaction. The disodium salt was purified by dialysis. The resulting materials were characterized by various measurements, such as matrix assisted laser desorption ionization time-of-flight mass spectrometry, ultraviolet-visible near-infrared and fourier transform infrared spectroscopy. The aggregation behavior of the newly water-soluble nanoparticles was investigated by scanning electron microscopy and dynamic light scattering analysis. This presented synthetic methodology opens the avenue for the preparation of novel water-soluble malonate derivatives of paramagnetic Gd@C82, which are expected to be useful species with potential applications in biomedicine.