Efficient synthesis of methyl 4-chloro-6-fluoro-3-formyl-2H-chromene-2-carboxylate and its derivatives

Abstract  

Methyl 4-chloro-6-fluoro-3-formyl-2H-chromene-2-carboxylate was synthesized conveniently using Vilsmeier reagent. A series of new 2H-chromenes was prepared in high yields by introducing a corresponding β-halovinylaldehyde into condensation and cyclization reactions with active methylene compounds.     

One-pot, three-component reaction of isocyanides, dialkyl acetylenedicarboxylates, and non-cyclic anhydrides: synthesis of 2,5-diaminofuran derivatives and dialkyl (E)-2-[(N-acyl-N-alkylamino)carbonyl]-2-butenedioates

Abstract  

Isocyanides, dialkyl acetylenedicarboxylates, and non-cyclic anhydrides, for example acetic anhydride or benzoic anhydride, react in one-pot to afford 2,5-diaminofuran derivatives and dialkyl (E)-2-[(N-acyl-N-alkylamino)carbonyl]-2-butenedioates in fairly good yields at room temperature.     

CaO solubility and activity coefficient in molten salts CaCl2–x (x = 0, NaCl, KCl, SrCl2, BaCl2 and LiCl)

CaO solubility in equimolar molten salts CaCl₂–x (x = 0, NaCl, KCl, SrCl₂, BaCl₂ and LiCl) was determined at 873–1223 K and activity coefficient calculated. CaO solubility in the binary salts is less than in CaCl₂, and the activity coefficient is greater than one. With increasing temperature CaO solubility increases and the activity coefficient decreases. The dependency of CaO activity coefficient on temperature in equimolar molten salts CaCl₂–x is

CaCl2	RTln γCaO = 6961 + 5.06 T (K)	1123–1223 K
CaCl2–NaCl	RTln γCaO = 3985 + 17.67 T (K)	923–1123 K
CaCl2–KCl	RTln γCaO = 2384 + 22.72 T (K)	1073–1223 K
CaCl2–SrCl2	RTln γCaO = 27245–1.13 T (K)	1073–1223 K
CaCl2–BaCl2	RTln γCaO = 17068 + 10.19 T (K)	1223–1273 K
CaCl2–LiCl	RTln γCaO = 14724 + 0.72 T (K)	923–1073 K

Full-size table

     

Biochemical characterization of Cdk2-Speedy/Ringo A2

Background  

Normal cell cycle progression requires the precise activation and inactivation of cyclin-dependent protein kinases (CDKs), which consist of a CDK and a cyclin subunit. A novel cell cycle regulator called Speedy/Ringo shows no sequence similarity to cyclins, yet can directly bind to and activate CDKs. Speedy/Ringo proteins, which bind to and activate Cdc2 and Cdk2 in vitro, are required for the G2 to M transition during Xenopus oocyte maturation and for normal S-phase entry in cultured human cells.     

Synthesis of arylaminotetrazoles by ZnCl2/AlCl3/silica as an efficient heterogeneous catalyst

Abstract  

Arylaminotetrazoles were efficiently synthesized from secondary arylcyanamides by application of ZnCl₂/AlCl₃/silica as a reusable heterogeneous Lewis acid catalyst. 5-Arylamino-1H-tetrazoles can be obtained from arylcyanamides carrying electron-withdrawing substituents on the aryl ring, while with electron-releasing groups 1-aryl-5-amino-1H-tetrazoles will be produced. The former isomer is also produced within longer reaction times (~20 h) even with electron-releasing groups.     

Design and synthesis of 3-acyl-2(3H)-benzoxazolone and 3-acyl-2(3H)-benzothiazolone derivatives

Abstract  

A simpler and efficient “green” method using solid sodium hydroxide in a solvent mixture of acetone/water was found to catalyze N-acylation of 2(3H)-benzoxazolones and 2(3H)-benzothiazolones for facile and rapid synthesis of N-acyl derivatives in excellent yields. This method was applied to the synthesis of a series of 132 compounds employing a variety of acyl chlorides.     

Synthesis, chemical properties, and antimicrobial activity of 2- and 2,3-substituted [(tetrahydro-2,4-dioxopyrimidin-1(2H)-yl)phenoxy]naphthalene-1,4-diones

Abstract  

Mono- and disubstituted [(tetrahydro-2,4-dioxopyrimidin-1(2H)-yl)phenoxy]naphthalene-1,4-diones were synthesized by the reaction of dihydro-1-(3-hydroxy- and 4-hydroxyphenyl)pyrimidine-2,4(1H,3H)-diones and their 5- and 6-methyl derivatives with 2,3-dichloro-1,4-naphthoquinone. Their stability in alkaline and acidic media was investigated. Four of the compounds exhibited good antimicrobial activity against Staphylococcus aureus, Mycobacterium luteum, Candida tenuis, and Aspergillus niger.     

Solvent-free, one-pot synthesis of amidoalkyl naphthols by a copper p-toluenesulfonate catalyzed multicomponent reaction

Abstract  

An efficient synthesis of amidoalkyl naphthols using copper p-toluenesulfonate (CPTS) as catalyst for the three-component condensation reaction of 2-naphthol, aldehydes, and amides under thermal, solvent-free conditions is described. This new approach has advantages such as short reaction time, high yield, simple work-up, and reusable catalyst.     

A facile and efficient method for synthesis of xanthone derivatives catalyzed by HBF4/SiO2 under solvent-free conditions

Abstract  

HBF₄/SiO₂ was used as an efficient, green, and inexpensive catalytic system for synthesis of 12-aryl or 12-alkyl-8,9,10,12-tetrahydro-11H-benzo[a]xanthen-11-one derivatives via a one-pot three-component reaction of aldehydes, 2-naphthol, and cyclic 1,3-dicarbonyl compounds. The reactions proceeded rapidly at 80 °C under solvent-free conditions and the desired products were obtained in good to excellent yields.     

Derivatives of 5-nitro-1H-benzo[de]isoquinoline-1,3(2H)-dione: design, synthesis, and biological activity

Abstract  

A series of mono and bis-2-(2-(dimethylamino)-ethyl)-5-nitro-1H-benzo[de]isoquinoline-1,3(2H)-diones with different amino side chains, a novel family of antitumor agents, has been designed and synthesized. Their antitumor activity was evaluated against HeLa, A549, P388, HL-60, MCF-7, HCT-8, and A375 cancer cell lines in vitro. Preliminary results showed that most of the derivatives had antitumor activity comparable with that of mitonafide, with IC ₅₀ values of 10⁻⁶–10⁻⁵ M. More importantly, the derivatives had distinct antitumor selectivity against different cancer cell lines. This work provided a novel class of mitonafide-based lead compounds with improved antitumor selectivity against cancer cell lines for further optimization.     

Synthesis of flavanones, azaflavanones, and thioflavanones catalyzed by PMA-SiO2 as a mild, efficient, and reusable catalyst

Abstract  

Cyclization of a variety of chalcones to flavanones catalyzed by 1 mol% phosphomolybdic acid (PMA) supported on silica as a mild, efficient, and reusable catalyst was carried out in high yields. PMA-SiO₂ is an efficient, inexpensive, and green catalyst which gave high conversion yields and could be recycled up to three times without significant loss in activity.     

A highly selective method for the synthesis of 1,3-diarylbenzo[f]quinoline derivatives catalyzed by silver triflate

Abstract  

The three-component reactions of aromatic aldehydes, naphthalen-2-amine, and phenylacetylene catalyzed by AgOTf in toluene selectively gave 1,3-diarylbenzo[f]quinolines in high yields. This procedure provides an efficient method for the synthesis of benzo[f]quinolines under mild reaction conditions and with high yields, high selectivity, and operational simplicity.     

1,3-Dibromo-5,5-dimethylhydantoin as an efficient homogeneous catalyst for synthesis of benzoxazoles, benzimidazoles, and oxazolo[4,5-b]pyridines

Abstract  

A simple and highly efficient method for synthesis of benzoxazoles, benzimidazoles, and oxazolo[4,5-b]pyridines is described. Condensation of orthoesters with o-substituted anilines or 2-amino-3-hydroxypyridine was performed in the presence of catalytic amounts of commercially available, inexpensive, and moisture-stable 1,3-dibromo-5,5-dimethylhydantoin under solvent-free conditions. The corresponding heterocycles were obtained in good to excellent yields. The main advantages of the present procedure are mild reaction conditions, short reaction times, high yields of products, easy work-up, and absence of solvent.     

R22(8) motifs in Aminopyrimidine sulfonate/carboxylate interactions: Crystal structures of pyrimethaminium benzenesulfonate monohydrate (2:2:1) and 2-amino-4,6-dimethylpyrimidinium sulfosalicylate dihydrate (4:2:2)

Background  

Pyrimethamine [2,4-diamino-5-(p-chlorophenyl)-6-ethylpyrimidine] is an antifolate drug used in anti-malarial chemotherapy. Pyrimidine and aminopyrimidine derivatives are biologically important compounds owing to their natural occurrence as components of nucleic acids.     

La6Pd13Cd4 and Ce6Pd13Cd4 with palladium-centred rare earth octahedra: synthesis, structure, and chemical bonding

Abstract  

The palladium-rich cadmium compounds La₆Pd₁₃Cd₄ and Ce₆Pd₁₃Cd₄ were synthesized by induction melting the elements in sealed tantalum ampoules and subsequent annealing. They were characterized by X-ray powder and single-crystal diffraction: Na₁₆Ba₆N type, Im[`3] mIm\overline{3} m, a = 988.12(9) pm, wR2 = 0.0463, 225 F ² values, and 12 variables for La₆Pd₁₃Cd₄, and a = 982.1(2) pm, wR2 = 0.0521, 215 F ² values, and 12 variables for Ce₆Pd₁₃Cd₄. The striking structural motifs are palladium-centred La₆ and Ce₆ octahedra, which are packed in a bcc fashion. Further palladium and cadmium atoms built up three-dimensional [Pd₃Cd] networks in which the La₆Pd and Ce₆Pd octahedra are embedded. Chemical bonding analyses show that the dominant interaction occurs within the palladium-centred RE ₆ octahedra, while weaker bonding exists between them.     

Extraction and DFT study on the complexation of H3O+ ion with tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene

Abstract  

Extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements were used to determine the stability constant of protonated tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene in nitrobenzene saturated with water. Density functional theory (DFT) calculations were applied to derive the most probable structure of the tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene·H₃O⁺ complex species.     

Synthesis of sterically congested 1,3,4-oxadiazole derivatives from aromatic carboxylic acids, acenaphthoquinone, and (N-isocyanimino)triphenylphosphorane

Abstract  

Reactions of (N-isocyanimino)triphenylphosphorane with acenaphthoquinone in the presence of aromatic carboxylic acids proceed smoothly at room temperature and under neutral conditions to afford sterically congested 1,3,4-oxadiazole derivatives in high yields. The reaction proceeds smoothly and cleanly under mild conditions and no side reactions are observed.     

Light-induced dehydrogenation of 3,4-dihydropyrimidin-2(1H)-ones

Abstract  

UV light irradiation of Biginelli 3,4-dihydropyrimidin-2(1H)-ones in chloroform in an argon atmosphere leads to dehydrogenation of these compounds to their corresponding pyrimidin-2(1H)-ones in excellent yields. Irradiation in the same solvent under an oxygen atmosphere generates, in addition, various hitherto unidentified products. A light-induced electron transfer from the substrate to the solvent is proposed as the initial event, supported by the detection of dichloromethane and hydrogen chloride in the photolysate.     

FeNH4(SO4)2·12H2O (alum)-catalyzed preparation of 1,4-dihydropyridines: improved conditions for the Hantzsch reaction

Abstract  

FeNH₄(SO₄)₂·12H₂O (alum) efficiently catalyzes the one-pot three-component reaction of dimedone, aldehydes, and 3-aminocrotonate to afford 1,4-dihydropyridines. The work-up is easy, and the products are obtained in good to excellent yields and high purity.