An eco-friendly procedure for the efficient synthesis of arylidinemalononitriles and 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) in aqueous media

Abstract

Commercially available lithium hydroxide monohydrate (LiOH·H₂O) was found to be a novel “dual activation” catalyst for Knoevenagel condensation between malononitrile (1) or 3-methyl 1-phenyl-1H-pyrazol-5-(4H)-one (6) with aromatic aldehydes 2a–e leading to an efficient and easy synthesis of arylidenemalononitriles 3a–d and 4,4′-(arylmethylene)bis(3-methyl-1-phenyl-1H-pyrazol-5-ols) 7a–c in short times. The reaction of aryl aldehydes with malononitrile afforded excellent yields after 1–6 min in aqueous media at room temperature. In case of 3-methyl-1-phenyl-1H-pyrazol-5-(4H)-one (6) and aromatic aldehydes afforded good yields after 60–75 min at 90°C.     

Vergleichende Reaktivitätsuntersuchungen am neuen Codimeren aus Malonitril und Cyanessigester an Carbonylverbindungen

The reactivity of 3-amino-2,4-dicyano-methyl-(1d) and-ethyl-crotonate (1e), resp., a new type of codimer from malononitrile and cyanoacetate, was investigated. Condensation reactions with aromatic aldehydes (2a-g), with heterocyclic aldehydes (2j-l), nitrosobenzenes (3a-c) ando-hydroxybenz-and-naphtaldehydes (4a-f), resp., are described, the differences in reactivity, compared with dimer malononitrile and dimeric forms of cyanoacetate (1a-c) are negligible. Condensation compounds of1a with cycloalkanones (5a-c) are able to cyclise with sulfur to cycloalkanonothieno-pyridines (6a-b), while the cycloalkano-derivatives of1d gave no ring closure.

Herrn Prof. Dr.O. E. Polansky zum 60. Geburtstag in Erinnerung an gemeinsame Tätigkeiten auf dem Gebiet der Nitrilchemie gewidmet.     

Microwave-Assisted Preparation of 2-Substituted Benzothiazoles

Abstract

2-Substituted benzothiazoles ( 3a–h ) were prepared from the condensation reaction of 2-aminothiophenol 1 with aldehydes 2 in the presence of P-Ts-OH and graphite on the surface of solid mineral supports without using any oxidizing agent under microwave irradiation.     

手性β-氨基醇的合成及其催化二乙基锌与醛的不对称加成反应

以烯烃为原料通过Sharpless不对称双羟化等多步反应合成7种手性β-氨基醇, 并将该类化合物用于催化二乙基锌和醛的不对称加成反应. 分别考察了影响对映选择性的催化剂结构、催化剂用量、溶剂、反应温度等各种因素. 当催化剂用量为5%、甲苯溶剂、在－10 ℃下、以(1S,2R)-(＋)-2-氨基-1,2-二苯基乙醇(1b)作催化剂时, 所得仲醇的对映体过量最高为85% ee, 产率高达100%.     

Enantioselective Addition of Diethylzinc to Aromatic Aldehydes Catalysed by Chiral Ligands Derived from L-Hydroxyproline

The Lithium salts of chiral auxiliaries 2–4 derived from L-Hydroxyprolin (2S, 4R)-1 catalysed the enantioselective addition of diethylzinc to aromatic aldehydes to afford sec alcohols in up to 80% optical purity.     

Chemistry of Ethanediyl S,S-Acetals 9-Asymmetric Synthesis of Chiral cis Allylic Alcohols

(2Z,1S)-1,3-diphenyl-2-propenol (3) is obtained from the chiral 5,6-dihydro-1,4-dithiin 1b in two steps and 60% enantiomeric excess. Combining our previously reported stereoselective double bond formation and this 1,4 asymmetric induction introduces a new route to chiral allylic alcohols with cis geometry from simple aldehydes and methyl ketones.     

MICROWAVE ASSISTED McFADYEN–STEVENS AND HUANG–MINLON REACTIONS

ABSTRACT

Microwave irradiation has been employed in McFadyen–Stevens reaction to convert p-toluenesulfonyl hydrazides 1 to the aldehydes 2. Also, microwave has been applied in Huang–Minlon reduction of carbonyl compounds 3 to the corresponding hydrocarbons 4.     

Acid‐Promoted Thioacetalization in Water using 2‐(1,3‐Dithian‐2‐ylidene)malonic Acid as an Odorless and Efficient Thioacetalization Reagent

Thioacetalization using 2‐(1,3‐dithian‐2‐ylidene)malonic acid 1 as a nonthiolic, odorless 1,3‐propanedithiol equivalent promoted by p‐dodecylbenzenesulfonic acid in water has been achieved. A range of selected carbonyl compounds 2 was converted into the corresponding dithioacetals 3 in high yields. Moreover, the thioacetalization showed high chemoselectivity between aldehydes and ketones.     

Synthesis,characterization, and biological evaluation of indole aldehydes containing N-benzyl moiety

Abstract

The present study describes the synthesis, characterization and biological evaluation of N-benzyl indole aldehydes. The biological activities of the newly synthesized compounds were examined by investigating their antioxidant and anti-inflammatory activities. The potential of these compounds as an antioxidant was determined by 2,2-diphenylpicrylhydrazyl, Nitric oxide, Superoxide, peroxide radical scavenging methods. We found that aldehydes 4a, 4b, 4c, and 4e and shows promising in vitro DPPH scavenging antioxidant activity while aldehyde 4b and 4e show good in vitro anti-inflammatory activity.     

SYNTHESIS OF 2,4-DISUBSTITUTED NORTROPINONE DERIVATIVES BY ALDOL CONDENSATION

2,4-Disubstituted nortropinone derivatives 2, with anticipated anticonvulsant activity, were synthesized by the reaction of N-substituted nortropinones, ethanol, 5N-NaOH, and aromatic aldehydes (R₁CHO).     

Synthesis and Inhibitory Activity Against Epstein-Barr Virus of Some New 1,2,3,4-Tetrahydropyrimidine-2-thiones

1,2,3,4-Tetrahydropyrimidine-2-thiones 4a–n were synthesized through the reaction of aromatic aldehydes 1a–n , ethyl acetoacetate (2) and thiourea ( 3) . The structures of all newly synthesized heterocyclic compounds elucidated by the use of IR, ¹H NMR, mass spectra, and elemental analyses. The inhibitory activity against the Epstein-Barr Virus early antigen (EBA-VA) of all newly synthesized heterocyclic compounds were evaluated.     

Water-mediated,green, and efficient synthesis of bisquinolones under catalyst-free conditions

Water-mediated, green, and efficient synthesis involving condensation of 4-hydroxy-1-methylquinoline-2(1H)-one (3) with different aromatic and heterocyclic aldehydes (4a–n) leading to 3,3′-(arylmethylene)-bis-(4-hydroxy-1-methylquinolin-2(1H)-one) 5(a–n) under catalyst-free conditions is described. This reaction has an easy workup without using column chromatography and provides excellent yields of the products in shorter reaction times. It does not require any catalyst and uses water as the medium which is the greenest solvent. 3 required in this work was itself obtained by condensation of N-methylaniline (1) with malonic acid (2) in the presence of POCl₃ using a previously reported procedure.     

1-(Cyanoacetyl)-3,5-dimethylpyrazole as Active Methylene Compound in Hantzsch-type Pyridine Synthesis: A Convenient and Highly Effective Approach to 3,5-Dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates

Summary. Reaction of 1-(cyanoacetyl)-3,5-dimethylpyrazole with (E)-2-cyano-3-(het)arylprop-2-enethioamides was used for the synthesis of N-methylmorpholinium 3,5-dicyano-4-(het)aryl-6-oxo-1,4,5,6-tetrahydropyridine-2-thiolates for the first time. The latter were also obtained in a multicomponent one-pot mode via the condensation of cyanothioacetamide with corresponding aldehydes and above 1-cyanoacetylpyrazole in the presence of N-methylmorpholine under mild conditions. Thiolates 1 exist as a pair of cis/trans-diastereomers in different ratios (from 3:4 to 2:1). Last author was Deceased on February 26, 2007     

A novel multicomponent reaction between amino acids,aromatic aldehydes and p-toluenesulfonylmethyl isocyanide: an efficient and green one-pot synthesis using nanosilica

The novel diastereomeric sulfonylamide derivatives 4a–h were synthesized by multi-component reactions between (l)-α-amino acids, 1, aromatic aldehydes, 2 and p-toluenesulfonylmethyl isocyanide, 3 in water/methanol using nanosilica as a catalyst. The one-pot green reactions were carried out at room temperature with a quantitative yield in water/methanol. The yield of the reactions and products was determined and discussed. The reusablity of the catalyst is discussed.     

Synthesis of Chiral Sulfamide–Amine Alcohol Ligands for Enantioselective Alkylation of Aldehydes

A series of chiral sulfamide–amine alcohols (SAA) (1–6) has been easily synthesized from commercially available chiral amino alcohols. In the absence of Ti(O ⁱ Pr)₄, ligand 4 catalyzed the asymmetric addition of diethylzinc to aromatic aldehydes with moderate to good yields and enantioselectivities.     

Thiazolium Salt Immobilized on Ionic Liquid: An Efficient Catalyst and Solvent for Preparation of α-Hydroxyketones

Aldehydes were efficiently converted to acyloins and benzoins using a new ionic liquid, 3-[2-(1-butyl-1H-imidazol-1,3-ium-3-yl)ethyl]-4,5-dimethyl-1,3-thiazol-3-ium dibromide 1 . This ionic liquid is introduced as a catalyst and a solvent. Acyloins and benzoins were easily isolated from the reaction mixture via simple extraction, and the ionic liquid could be recycled for further use. Also, α-hydroxy ketones with an aromatic and aliphatic substituent were prepared starting from aromatic and aliphatic aldehydes in the presence of ionic liquid 1 .     

Cascade cyclization reactions of 3,4,5-triamino-1,2,4-triazole with aromatic aldehydes and cycloalkanones

A three-component condensation of 3,4,5-triamino-1,2,4-triazole (1) with aromatic aldehydes 2a–f and dimedone (3) or cyclohexanone (8) afforded partially hydrogenated 9-aryl-[1,2,4]triazolo[5,1-b]quinazolin-8-ones. The structure of 2-amino-6,6-dimethyl-3-(4-nitrobenzylidene)amino-9-(4-nitrophenyl)-5,6,7,9-tetrahydro[1,2,4]triazolo[5,1-b]quinazolin-8-one (4e) was confirmed by X-ray diffraction data. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1178–1182, July, 2006.     

Polyethylene glycol (PEG-400): An efficient one-pot green synthesis and anti-viral activity of novel α-diaminophosphonates

Abstract

An efficient and eco-friendly protocol has been accomplished for a series of novel α-diaminophosphonates by a one-pot, three-component system via Kabachnik-Fields reaction of 4,4′-methylenedianiline, a variety of aryl/heteroaryl aldehydes and diphenylphosphite employing polyethylene glycol (PEG-400) as a green solvent at 80?°C. All products were obtained in good to excellent yields (80–95%). The identity of the new synthesized compounds was confirmed by IR, ¹H, 13C, and 31P NMR, LC-MS and elemental analysis. In vivo anti-viral activity was evaluated against tobacco mosaic virus (TMV). Compounds 4b, 4c, 4j and 4k exhibited the highest anti-viral activities against tobacco mosaic virus (TMV) when compared with the standard drug ningnanmycin.     

新型无毒离子液体催化“一锅煮”合成3,4-二氢嘧啶-2(1H)-酮

利用新型无毒离子液体(BMImSac)作催化剂, 芳香醛、1, 3-二羰基化合物和尿素或硫脲三组分“一锅煮”合成了3,4-二氢嘧啶-2(1H)-酮. 与传统方法相比, 该法是一种操作简单、产率高、用时少的环境友好方法.     

BrØnsted Reusable Acidic Ionic Liquids Catalyzed Biginelli Reaction under Solvent-Free Conditions

Abstract

2-Pyrrolidonium hydrogensulfate, N-methyl-2-pyrrolidonium hydrogensulfate, and N-methyl-2-pyrrolidonium dihydrogenphosphate as Brønsted reusable acidic ionic liquids (ILs) catalyzed the preparation of 3,4-dihydropyrimidin-2(1H)-one (thione) derivatives from ethyl/methyl acetoacetate, urea/thiourea, and aromatic aldehydes under thermal solvent-free conditions.