Synthesis of novel 5-hydroxyalkenylphosphonates by addition of aromatic aldehydes to zirconacyclopentenylphosphonates

Novel 5-hydroxyvinylphosphonates were obtained in a regio- and stereoselective manner, by addition of aromatic aldehydes to zirconacyclopentenylphosphonates in the presence of AlMe₃, in 68-82% isolated yields. The reaction is specific for aromatic aldehydes.     

Unexpected One‐pot Synthesis of Novel 2‐Aminopyrimidine‐4‐ones under Microwave Irradiation

One‐pot, three‐component condensation of guanidine, ethylbenzoylacetate and various aromatic aldehydes in the presence of NaHCO₃ have been investigated by microwave irradiation. The aromatic aldehydes bearing electron‐withdrawing groups undergo condensation with guanidine and ethylbenzoyl‐acetate to afford ethyl‐2‐amino‐4‐aryl‐1,4‐dihydro‐6‐phenylpyrimidine‐5‐carboxylate derivatives via Biginelli reaction. However, reaction of the aromatic aldehydes having electron‐releasing groups with guanidine and ethylbenzoylacetate did not give the corresponding dihydropyrimidines. Instead, novel 2‐amino‐5‐benzoyl‐5,6‐dihydro‐6‐arylpyrimidine‐4(3H)‐ones were obtained via an unexpected mechanism.     

Nitrile oxide cycloaddition routes to 2-(isoxazolyl)-benzoates and 2-(1,2,4-oxadiazol-3-yl)benzoates

Cycloaddition of aromatic nitrile oxides to methyl o-vinylbenzoate produced methyl 2-(3-aryl-2-isoxazolin-5-yl)benzoates; the isoxazolines were converted to methyl 2-(3-arylisoxazol-5-yl)benzoates. Reaction of the nitrile oxide from o-methoxycarbonylbenzohydroximinoyl chloride ( 11 ) with phenylacetylene, styrenes, and aromatic nitriles resulted in methyl 2-(5-phenylisoxazol-3-yl)benzoate, methyl 2-(5-aryl-2-isoxazolin-3-yl)-benzoates ( 15 ), and methyl 2-(5-aryl-1,2,4-oxadiazol-3-yl)benzoates, respectively. The isoxazolines 15 were converted to the corresponding isoxazoles 16 .     

Solid state reactions of nitrogenous heterocyclic compounds (I) —Solid state reactions of 3-methyl-1-phenyl-5-pyrazolone with carbonyl compounds

The solid state reaction of 3-methyl-1-phenyl-5-pyrazolon(eM PP) with aromatic aldehydes and ketones, benzil derivatives and imides, and the solid state Michael addition reaction of MPP with 4-arylidene-3-methyl-lphenyl-5-pyrazolone2 were investigated. Some new solid state reactions between the reactants were found, from which a series of new compounds were obtained. The structures of the products were identified by IR,¹H NMR, MS, elemental analyses and also by X-ray crystal analysis, and the reaction mechanism of MPP with aromatic aldehydes and ketones was proposed. Project supported by the National Natural Science Foundation of China.     

Solid state reactions of nitrogenous heterocyclic compounds(Ⅰ)——Solid state reactions of 3-methyl-l-phenyl-5-pyrazolone with carbonyl compounds

The solid state reaction of 3-methyl-1-phenyl-5-pyrazolone (MPP) with aromatic aldehydes and ke-tones benzil derivatives and imides,and the solid state Michael addition reaction of MPP with 4-arylidene-3-methyl-1-phenyl-5-pyrnzolone 2 were investigated.Some new solid state reactions between the reactants were found,from which a series of new compounds were obtained The structures of the products were identified by IR,1H NMR,MS,elemental analyses and also by X-ray crystal analysis,and the reaction mechanism of MPP with aromatic aldehydes and ketones was proposed     

无外加催化剂条件下芳香醛与活性亚甲基化合物的缩合反应和迈克尔加成反应

在DMF溶剂中，不外加催化剂使芳香醛(1)与2,2-二甲基-1,3-二氧六环-4,6-二酮(2)发生缩合反应生成2,2-二甲基-5-芳亚甲基-1,3-二氧六环-4,6-二酮(3a～f)。在同样条件下，芳香醛与5,5-二甲基-1,3-环己二酮(4)则发生缩合和迈克尔加成反应生成2,2'-芳亚甲基双(3-羟基5,5-二甲基-2-环己烯-1-酮)(5a～h)。用单晶X-射线分析法确定了产物5b的晶体结构。     

Synthesis and stereochemistry of ω-azolylalkenes [1]

ω-Azolylalkenes 3, 4, and 5 were synthesized by N-alkylation of C-alkylation of ω-bromoalkenes 2, which were obtained either by phase transfer Wittig reactions of ω-bromoalkylphosphonium salts 1 with aldehydes or by Wittig reactions of ω-hydroxyalkylphosphonium salts 6 with aldehydes and subsequent bromination. ω-Azolylalkenes 3 were also directly prepared by the Wittig reaction of ω-azolylalkyltriphenylphosphonium salts 8 with aromatic aldehydes. The stereochemistry of these Wittig reactions was studied. © 1997 John Wiley & Sons, Inc.     

无外加催化剂条件下芳香醛与活性亚甲基化合物的缩合反应和迈克尔加成反应

在DMF溶剂中,不外加催化剂使芳香醛(1)与2,2-二甲基-1,3-二氧六环-4,6-二酮(2)发生缩合反应生成2,2-二甲基-5-芳亚甲基-1,3-二氧六环-4,6-二酮(3a～f)。在同样条件下,芳香醛与5,5-二甲基-1,3-环己二酮(4)则发生缩合和迈克尔加成反应生成2,2’-芳亚甲基双(3-羟基-5,5-二甲基-2-环己烯-1-酮)(5a～h)。用单晶X-射线分析法确定了产物5b的晶体结构。     

Preparation of 3-Aryl-4-(5-ARYL-Δ2-1,2,4-Oxadiazolin-3-YL)Sydnones and their Conversion into 3-ARYL-4-(5-ARYL-1,2,4-Oxadiazol-3-YL)Sydnones

3-Aryl-4-(5-aryl-Δ²-1,2,4-oxadiazolin-3-yl)sydnones (5) were synthesized in high yields by the reaction of 3-arylsydnone-4-carboxamide oximes (prepared from the corresponding 3-arylsydnone-4-carbonitriles) with aromatic aldehydes in the presence of acid catalysts. No reaction occurred when aliphatic aldehydes were used. The oxadiazolin-3-ylsydnones (5) were easily converted into the corresponding 3-aryl-4-(5-aryl-1,2,4-oxadiazol-3-yl)sydnones by N-bromosuccinimide oxidation. The 3-arylsydnone-4-carbonitrile oxides were synthesized in good yields by N-bromosuccinimide oxidation of the corresponding 3-arylsydnone-4-carboxaldehyde oximes.     

Synthesis of 2-(Pyrazol-1-yl)pyrimidine Derivatives by Cyclocondensation of Ethyl Acetoacetate (6-Methyl-4-oxo-3,4-dihydropyrimidin-2-yl)hydrazone with Aromatic Aldehydes

2-(4-Arylidene-3-methyl-5-oxo-4,5-dihydropyrazol-1-yl)-6-methylpyrimidin-4(3H)-ones were obtained by reaction of ethyl acetoacetate (6-methyl-4-oxo-3,4-dihydropyrimidin-2-yl)hydrazone with aromatic aldehydes. Successful cyclization occurs with aldehydes containing an auxochromic substituent in the para position.     

First Magnesium-mediated Carbonyl Benzylation in Water

Catalyzed by AgNO3, Mg was found for the first time to be able to mediate the coupling reaction between aromatic aldehydes and benzyl bromide or chloride in water. The yields were slightly higher than the recent results for Mg-mediated allylation despite the fact that aqueous benzylation is intrinsically much harder than allylation. It was also found that the coupling reaction was chemoselective for aromatic aldehydes over aliphatic aldehydes, and chemoselective for aromatic aldehydes over aromatic ketones.     

l-Proline amides catalyze direct asymmetric aldol reactions of aldehydes with methylthioacetone and fluoroacetone

Direct aldol reactions of aldehydes with methylthio- and fluoroacetone catalyzed by proline amides have been investigated. l-Prolinamide 5e was found to be the best catalyst. Under the optimized reaction conditions, a series of aromatic and aliphatic aldehydes reacted smoothly with methylthioacetone, to generate 1-methylthio-4-hydroxyketones 3 in good yields and with high regio- and enantioselectivities. Excellent enantioselectivities of up to 98% ee were observed for aromatic aldehydes and even higher enantioselectivities of >99% ee were observed for aliphatic aldehydes. Asymmetric direct aldol reactions of fluoroacetone with aldehydes in the presence of 20 mol % of 5e preferentially occurred at the fluoromethyl group, yielding products with high enantioselectivities (up to 98% ee).     

A Regioselective Biginelli‐like Reaction Controlled by the Size of Alicyclic Mono‐ketones

A regioselective Biginelli‐like reaction of alicyclic mono‐ketones, aromatic aldehydes, and urea in ionic liquid [BPY]BF₄ has been investigated. The process is controlled by the size of alicyclic mono‐ketones and the steric hindrance of aromatic aldehydes. The reaction of cyclopentanone with urea and aromatic aldehydes afforded 7‐arylidene‐3,4,6,7‐tetrahydro‐4‐aryl‐1H‐cyclopenta[d]pyrimidin‐2(5H)‐ones ( 4 ). When cyclohexanone was used as the source of active methylene to react with urea and aldehydes with slight steric hindrance groups under the same condition, 8‐arylidene‐3,4,5,6,7, 8‐hexahydro‐4‐arylquinazolin‐2(1H)‐ones ( 6 ), a homologue of 4 , were yielded, whereas 4,8‐bisaryloc‐tahydro‐1H‐pyrimido[5,4‐i]‐quinazoline‐2,10(3H,11H)‐diones ( 7 ) were obtained via the simple one‐pot reaction of cyclohexanone, urea, and aromatic aldehydes with high steric hindrance groups. The possible transitional states and mechanism of the regioselective process were discussed.     

Crown ether complex cation ionic liquids: preparation and applications in organic reactions

A series of crown ether complex cation ionic liquids (CECILs) were designed, synthesised and characterised by NMR spectroscopy, HRMS, thermogravimetric differential thermal analysis (TG-DTA) and elemental analysis. Their applications in various organic reactions were investigated: [15-C-5Na][OH], [15-C-5Na][OAc], [18-C-6K][OH] and [18-C-6K][OAc] (15-C-5=[15]crown-5; 18-C-6=[18]crown-6) efficiently catalysed the Michael addition of alkenes and relevant nucleophiles; [18-C-6K][OH] and [15-C-5Na][OH] effectively catalysed the Henry reaction of nitromethane and aromatic aldehydes; [18-C-6K][OH] has excellent catalytic efficiency for Knoevenagel condensation of aromatic aldehydes and malononitrile; PdCl(2) /[18-C-6K](3)[PO(4)]/K(2)CO(3) efficaciously catalysed the Heck reaction of olefins and aromatic halides; [18-C-6K][BrO(3)] can be used as both oxidant and solvent in the oxidation reaction of aromatic alcohols. The CECIL catalysts [15-C-5Na][OH] (Michael addition) and [18-C-6K][OH] (Henry reaction) can be recycled and reused several times without obvious loss of activity and their recovery is very simple.     

Synthesis of Heterocycles from the Products of Anionic Arylation of Unsaturated Compounds. 7. Products of Haloarylation of Acrylic Acid and Its Esters in the Synthesis of Benzo[b]thiophene Derivatives

3-Chloro-2-chlorocarbonylbenzo[b]thiophenes were obtained on oxidation of Meerwein reaction products, viz. 3-aryl-2-halopropionic acids and their esters, with thionyl chloride in the presence of N-benzyl-N-methylmorpholinium chloride. Disubstituted thioureas were synthesized by the reaction of these compounds with ammonium thiocyanate and aromatic amines, and were cyclized by interaction with iodoacetic acid with the formation of 4-thiazolidinone derivatives. The same cyclization in the presence of aromatic aldehydes leads to the formation of the corresponding 5-arylidene-substituted 4-thiazolidinones.     

One-Pot Three-Component Synthesis of 3-Methyl-4-Arylmethylene- Isoxazol-5(4H)- Ones Catalyzed by Sodium Sulfide

Abstract

3-Methyl-4-arylmethylene-isoxazol-5(4H)-ones were synthesized by the convenient three-component reaction of ethyl acetoacetate, hydroxylamine hydrochloride, and aromatic aldehydes catalyzed by sodium sulfide in the presence of ethanol at room temperature. The advantages of this procedure were mild reaction conditions, high yields, short reaction time, and operational simplicity.     

Oxidation of alcohols by transition metal complexes—iv : The rhodium catalysed synthesis of esters from aldehydes and alcohols

Both RhH(CO)PPh₃)₃ and a catalyst made in _situ from RhCl₃·3H₂O, PPh₃ and Na₂CO₃ catalyse the reaction of a range of aldehydes with simple primary alcohols to give esters together with alcohols formed by reduction of the aldehydes. The proportion of ester can be increased by adding an efficient hydrogen acceptor. The reaction can also be used to produce 5- and 7-membered lactones from aromatic dialdehydes. Propan-2-ol and the _{in situ} catalyst reduce some aromatic aldehydes to the corresponding alcohols without concomitant ester formation.     

无外加催化剂条件下邻取代芳香醛与5, 5-二甲基-1, 3-环己二 酮的反应研究

在DMF溶剂中,不外加催化剂使邻取代芳香醛(1)与5,5-二甲基-1,3-环己二酮(2)发生缩合和加成反应生成3,3,6,6-四甲基-4a-羟基-9-芳基-1,8-二氧代-2,3,4,4a,5,6,7,8,9,9a-十氢化-1H-氧杂蒽(3a-3d)。在同样条件下,邻羟基芳香醛与5,5-二甲基-1,3-环己二酮则发生缩合、加成和脱水反应生成3,3-二甲基-9-(5,5-二甲基-3-羟基-2-环己烯-1-酮-2-基)-1-氧代-2,3,4,9-四氢化-1-氧杂蒽(4a-4b)。用单晶X-射线分析法确定了产物3a和4a的晶体结构。     

Saturated heterocycles, 162 [1]. synthesis and steric structures of 3,4-disubstituted 1,6,7,11b-tetrahydropyrimido[6,1-a]isoquinolin-2-ones

The reaction of 1-(hydrazidomethyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline 3 with aromatic aldehydes yield hydrazones 4a,b or pyrimido[6,1-a]isoquinolines 5a-c depending upon the proportions of the reagents. With ketones, 3 gives only hydrazones 4a-d and 7 , which can be transformed to pyrimidoisoquinolines 10a-e and 11 with aldehydes. The ring closures are stereospecific; the relative configurations were determined by DNOE measurements.     

无外加催化剂条件下邻取代芳香醛与5,5-二甲基-1,3-环己二酮的反应研究

在DMF溶剂中,不外加催化剂使邻取代芳香醛(1)与5,5-二甲基-1,3-环己三酮(2)发生缩合和加成反应生成3,3,6,6-四甲基-4a-羟基-9-芳基-1,8二氧化-2,3,4,4a,5,6,7,8,9a-十氢化-1H氧杂蒽(3a～3d)。在同样条件下,邻羟基芳香醛与5,5-二甲基-1,3-环己三酮则发生缩合,加成和脱水反应生成3,3-二甲基-9-(5,5-二甲基-3-羟基-2-环己烯-1-酮-2-基)-1-氧代-2,3,4,9-四氢化-1 氧杂蒽(4a～4b)。用单晶X-射线分析法确定了产物3a和4a的晶体结构。