Versatile Synthesis of Fused Tricyclic 1,2,4-Triazole Derivatives

ABSTRACT

A rapid and general method for the synthesis of symmetrical disulfides involves reaction of sulfur with sodium hydroxide under PTC-microwave irradiation condition to give sodium disulfide, which reacts with alkyl halides to afford the disulfides in good to excellent isolated yields.     

Phase Transfer Catalysed N-Monoalkylation of Amino Anthraquinones

1-Alkylaminoanthraquinones ( 2 a-f) and 1,4-bisalkylaminoanthraquinones ( 4 a-c) were prepared from aminoanthraquinones ( 1,3 ) by alkylation with alkyl sulphate/alkyl halide in presence of powdered sodium hydroxide, potassium carbonate and phase transfer catalyst.     

Organic Reactions in Ionic Liquids: A New Method for the Synthesis of Alkyl Aryl Sulfones by Alkylation of Sodium Arenesulfinates with Unactivated Alkyl Chlorides

Abstract

A new method is reported for the synthesis of alkyl aryl sulfones by alkylation of sodium arenesulfinates with unactivated alkyl chlorides using ionic liquid based on 1‐butyl‐3‐methylimidazolium tetrafluoroborate (BmimBF₄) mixed with water (2:1) as reaction media. The ionic liquid can be reused and the procedure gives the sulfones in moderate yields.     

A RAPID SYNTHESIS OF ALKYL α-CYANOACETYL GLYCOLATES UNDER MICROWAVE IRRADIATION IN DRY MEDIUM

ABSTRACT

Alkyl α-cyanoacetyl glycolates (3) are effectively synthesized in few minutes by reaction of alkyl chloroacetates with sodium cyanoacetate absorbed on silica gel in the presence of tetrabutylammonium bromide under microwave irradiation without solvent.     

Investigation of Complexation of Sodium Cation by Anthracene Crown Ethers

Abstract

Formation constants for complexes of sodium and anthracene crown ethers were determined using spectrophotometry and cyclic voltammetry. The complexation properties of the ligands examined depend significantly on alkyl substituents at 9 and 10-positions of the anthracene group and are strongly influenced by the solvent.     

Microwave assisted efficient synthesis of β-keto-sulfones in aqueous medium

Abstract

An efficient synthesis of β-keto-sulfones is described. The reaction of α-haloketones with sodium alkyl/aryl sulphinates in aqueous medium under microwave irradiation afforded the corresponding β-keto-sulfones in excellent yields.     

A Simple and Convenient Synthesis of HEPT Analogues via a One‐Pot Reduction–Sulfenylation Reaction

Abstract

The one‐pot reduction–sulfenylation of 5‐alkyl‐6‐chlorouracils (1) with diaryl disulfides (2) and sodium borohydride in methanol was carried out to afford 1‐[(2‐hydroxyethoxy)methyl]‐6‐(phenylthio)thymine HEPT analogues in good to excellent yields.     

Ion-Pair Liquid Chromatography of Alkylanilines

Abstract

The optimization of ion-pair liquid chromatography of structural isomers of carbon number two alkyl anilines has been studied.

The shorter alkyl cha in bonded silica gel demonstrated the stereo selectivity. the alkyl chain length of ion-pair reagent ruled the equilibration of ion-pair formation. the longer chain of ion-pair reagent formed hydrophobic ion-pair and the shorter chain could not form ion-pair, and ionized solute formed ion-pair with polar ion which was a component of eluent. Three ethylanilines and six xylidines mixture was separated on an octadecyl-bonded silica gel column using an eluent containing methanol/water mixture with sodium 1-dodecanesul-fonate.     

New Approach to Synthesize Symmetrical and Unsymmetrical 6-(N-Alkyl(Aryl)Amino)- and 6-(N,N-Dialkyl(Aryl)Amino)-2,4-Bis(Alkyl(Aryl)Thio)Pyrimidines as anti-Platelet Agents

Abstract

A new and straightforward procedure has been developed for the preparation of symmetrical and unsymmetrical 6-(N-alkyl(aryl)amino)- and 6-(N,N-bisalkyl(aryl)amino)-2,4-bis(alkyl(aryl)thio)pyrimidines. The two identical or different alkylthio groups were successfully introduced into the pyrimidine ring of 4-amino-6-hydroxy-2- mercaptopyrimidine via S-alkylation with alkyl halides, and via a nucleophilic displacement with sodium alkylmercaptides, affording the key intermediate symmetrical and unsymmetrical 2,4-bis(alkyl(aryl)thio)-6-aminopyrimidines. Subsequently, N-alkylation of the 2,4-bis(alkyl(aryl)thio)-6-aminopyrimidines with alkyl halides conveniently gave the desired products. The human anti-platelet activities of all the synthesized new compounds were also evaluated.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Separation of Sulphonium Salts by Ion Chromatography: Five- and Six-Membered Cyclic Sulphonium Salts

Abstract

Several cyclic 5-and 6-membered sulphonium compounds were separated by ion pair chromatography on a opti-dbb ion pair column. The salts show specific retention behavior when using different mixtures of acetonitrile and aqueous sodium perchlorate solutions as eluents. The increase of retention times with extending chain length of the alkyl group R and with ring size is due to an increase of the solute molecular surface areas which were also calculated. The obtained retention parameters give additional information for structural determination.     

Synthesis and Investigation of 1,2,3,4-Thiatriazol-5-ylcarbamates

Methyl 1,2,3,4-thiatriazol-5-ylcarbamate (2a), ethyl 1,2,3,4-thiatriazol-5-ylcarbamate (2b), 2-butyl 1,2,3,4-thiatriazol-5-ylcarbamate (2c), allyl 1,2,3,4-thiatriazol-5-ylcarbamate (2d), and 3-(1,2,3,4-thiatriazol-5-yl)oxazolidin-2-one (2e) were synthesized with high yields by the reaction of the corresponding carbon(isothiocyanatidic) acid, alkyl esters, and sodium azide in aqueous solution. The compounds were characterized by ¹H, ¹³C, and ¹⁵N NMR, vibrational spectroscopy (IR), and single crystal X-ray diffraction. The thermal stability was investigated by differential scanning calorimetry.     

3-Hydroxy- and 3-alkoxy-2-sulfanylquinazolin-4(3H)-ones: synthesis and reactions with alkylating and acylating agents

Reactions of methyl 2-isothiocyanatobenzoate with hydroxylamine and alkoxyamines afforded earlier unknown 3-hydroxy-2-sulfanylquinazolin-4(3H)-one (1a) and 3-alkoxy-2-sulfanylquinazolin-4(3H)-ones (1b,c). Base-catalyzed reactions of compound 1a with alkyl halides were not regioselective, yielding O,S-dialkylation products. In the presence of acetic acid and sodium acetate, compound 1a was alkylated only at the S atom to give 2-alkylsulfanyl-3-hydroxyquinazolin-4(3H)-ones. Selective O-acylation of compound 1a at position 3 yielded 3-acyloxy-2-sulfanylquinazolin-4(3H)-ones.     

Three-Component,Four-Molecule,Ru-Catalyzed Cascade Reactions of Indoles and Alkyl Bromides with Sodium Nitrite

Abstract

An operationally simple domino approach for the ruthenium-catalyzed synthesis of (E)-2,3′-bi(3H-indol)-3-one O-alkyl oximes by the region- and stereoselective three-component, four-molecule reactions of indoles with sodium nitrite and alkyl bromides under mild reaction condition in dimethylformamide is described. Remarkably, multiple bonds including C?C, C=N, and C?O bonds were conveniently formed in one pot. The reaction is tolerant to air and is atom economical, in accordance with the concept of modern green chemistry.     

SYNTHESIS OF BENZO[1,2-b: 5,4-b′]- DIFURANYL-TRIAZOLES, -OXADIAZOLES, -THIAZOLIDINONES, -THIADIAZOLES,AND THE USE OF DNA IN EVALUATION OF THEIR BIOLOGICAL ACTIVITY

Benzo[1,2-b:5,4-b′]difuran-2-carbohydrazides 5a, b were reacted with aryl or alkyl isothiocyanates to give the corresponding thiosemicarbazides 6a–h. Cyclization of the substituted thiosemicarbazides with sodium hydroxide led to the formation of benzo[1,2-b:5,4-b′]difuranyl-1,3,4-triazoles 7a–f. Desulfurization of thiosemicarbazides by mercuric oxide gave benzo[1,2-b:5,4-b′]difuranyl-1,3,4-oxadiazoles 8a–f. Treatment of thiosemicarbazides with ethyl bromoacetate or α-bromopropionic acid yielded benzo[1,2-b:5,4-b′]difuranyl-carbonyl-hydrazono-4-thiazolidinones 9a–f and 10a–f, respectively. Furthermore, the reaction of the thiosemicarbazides with phosphorus oxychloride gave benzo[1,2-b:5,4-b′]difuranyl-1,3,4-thiadiazoles 11a–f. Some compounds in this study were biologically evaluated for their ability to bind to DNA.     

TRANSESTERIFICATION OF TRIS(p-NITROPHENYL) PHOSPHATE WITH SODIUM ALKOXIDES: BIS(p-NITROPHENYL) METHYL PHOSPHATE,BIS(p-NITROPHENYL) BENZYL PHOSPHATE,BIS(p-NITROPHENYL) n-BUTYL PHOSPHATE

Abstract

Transesterification of tris(p-nitrophenyl) phosphate by sodium alkoxides, in dichloromethane at 0°, provides a convenient synthetic route to diaryl alkyl phosphates which are produced in a high state of purity and in moderate to high yields. The procedure is used to prepare bis(p-nitrophenyl) methyl phosphate, bis(p-nitrophenyl) benzyl phosphate and bis(p-nitrophenyl) n-butyl phosphate.     

Preparation of Alkyl Carbamate of 1‐Protected Indole‐3‐methylamine as a Precursor of Indole‐3‐methylamine

A series of alkyl carbamates 3 of 1‐protected indole‐3‐methylamines, alkyl carbamates 6 of thiophenylmethylamines, and pyrrolylmethylamines were prepared from the corresponding acetamides 2 and 5 in good to excellent yields via diacetoxyiodobenzene‐promoted Hofmann rearrangement. For a successful Hofmann rearrangement, an electron‐withdrawing group on position 1 of indolylacetamide and pyrrolylacetamide was required. The alkyl carbamate 3g was demonstrated to serve well as a stable precursor of 1‐protected indole‐3‐methylamine 1.     

Novel near-infrared fluorescent liquid crystal: Bodipy bearing multiple alkyl chains with columnar mesophase

By the typical Knoevenagel condensation of Bodipy with aldehyde derivatives, two novel Bodipy derivatives 3 and 6 with symmetric three and six alkyl chains were designed and prepared. The Bodipy derivative 3 with three alkyl chains showed no mesophase but the Bodipy derivative 6 with six alkyl chains possessed the orderly hexagonal columnar mesophase at room temperature. Both samples 3 and 6 exhibited the near-infrared fluorescence with high fluorescence quantum yields and larger Stokes shifts than their Bodipy precursors. Sample 6 was the first near-infrared fluorescent columnar liquid crystal with Bodipy core. This research presented a good strategy on constructing the near-infrared columnar Bodipy liquid crystal.     

Tailoring of ionic supramolecular assemblies based on ammonium carboxylates toward liquid‐crystalline micellar cubic mesophases

Ionic liquid crystals based on ionic complexation of tris(2‐aminoethyl)amine (1) with 3,4,5‐tris(7,7,8,8,9,9,10,10,11,11,12,12,12‐tridecafluorododecyloxy)benzoic acid (2) and with 3,4,5‐tris(2‐octyldodecyloxy)benzoic acid (3) were investigated. The ionic complex with the partially fluorinated alkyl chains (1·2) exhibited a morphological transition from a hexagonal columnar mesophase to a Pm3n micellar cubic phase upon increasing the molar ratio of 2 to 1. For the complex with the branched alkyl chains (1·3) a micellar cubic mesophase was exclusively generated at appropriate composite ratios. The generation of the micellar cubic mesophases is attributed to the introduction of the laterally expanded volume of the alkyl chains compared with the corresponding normal dodecyl chains. Their thermal stabilities were most enhanced at a specific molar ratio of 1:5 for 1·2 and 1:4 for 1·3. This result corresponds to the most suitable chain volume for the stable micellar cubic mesophase.     

Poly-α-n-alkyl Acrylic Derivatives: Synthesis,Influence of Molecuur Weight and n-Alkyl Group Length on Physical and Physicochemical Properties

Abstract

A series of α-n-alkyl acrylic acid monomers was synthesized and homopolymerized by a radical route. Methylation of polyacids using diazomethane led to the corresponding methyl esters and allowed physicochemical analysis. The thermal stability of polyacids and polymethyl esters is insensitive to the nature of the alkyl group and to the molecular weight. The glass transition temperature, T _g, classically decreases with increases in alkyl group length such as alkyl polymethacrylates. Molecular weight has a drastic influence on T _g for short alkyl groups.     

A SIMPLE STEREOSELECTIVE ONE POT CONVERSION OF COMPOUNDS WITH A DIMETHYLAMINOMETHYLENE GROUP INTO ENOL ESTERS

A simple stereoselective synthesis of 2Z and 2Z,1′E alkyl 3-acyloxy-2-(2,2-disubstituted ethenyl) aminopropenoates 4 from alkyl 2-(2,2-disubstituted ethenyl)amino-3-dimethylaminopropenoates 1 in 12–91% yield is presented.