Synthesis of β-nitramino derivatives ofgem-dinitroalkanes

A method for the synthesis of β-nitramino derivatives ofgem-dinitroalkanes by nitration of the products of condensation of sulfamic acid derivatives with the correspondinggem-dinitroalkanes was proposed.     

Clean synthesis and antibacterial activities of spiro[pyrimido[4,5-b]quinoline-5,5'-pyrrolo[2,3-d]pyrimidine]-pentaones

A simple, clean and efficient method for the synthesis of spiro[pyrimido[4,5-b]quinoline-5,5'-pyrrolo[2,3-d]pyrimidine]-pentaone derivatives by condensation reaction of 6-amino-uracils and isatins in aqueous media is reported. These products were evaluated in vitro for their antibacterial activities.     

Hydrogen bond assisted synthesis of azacyclophanes from l-tyrosine derivatives

Spectroscopic and computational studies reveal that a dimer of two units of l-tyrosine derivatives, joined by intermolecular hydrogen bonds, acts as a template in the synthesis of azacyclophanes from l-tyrosine derivatives and formaldehyde via double Mannich type reaction. When the reaction is performed with l-tyrosine, the absence of this template leads to linear products. A new azacyclophane (benzoxazinephane) was synthesized by condensation of l-tyrosine isopropyl ester and formaldehyde.     

Synthesis and characterization of a compact tricyclic resorcinol from (+)- and (−)-3-pinanol

Resorcinol derivatives are important building blocks in the synthesis of natural products and pharmaceutical compounds including cannabinoids. Here we describe the synthesis and the structural characterization of a key resorcinol which carries a fully restricted bridged bicyclic group. We also report a potential mechanism for the acid catalyzed condensation of (+)- or (−)-3-pinanol with 2,6-dimethoxyphenol. The synthesized resorcinol facilitates the development of novel conformationally restricted cannabinoid analogs.     

Synthesis and analysis of 1,2,3,4-tetrahydro-(9H)-pyrido[3,4-b]indole

The synthesis of 1,2,3,4-tetrahydro-(9H)-pyrido[3,4-b]indole derivatives was carried out in one pot, by condensation of tryptamin with cycloalkanones in the presence of a polyphosphate ester as the catalyst in moderate to low yields, the aldol condensation being the main products. Reaction of tryptamine and cyclic ketones was also carried out in two stage through the imine intermediate with protic catalysis giving the tetrahydro-β-carbolines 8–14 , in good yields. 2-Methyl derivatives 15–21 , of the tetrahydro-β-carbolines, were obtained in good yields, using methyl iodide in dimethyl sulphoxide-potassium carbonate.     

A convenient and efficient synthesis of heteroaromatic hydrazone derivatives via cyclization of thiosemicarbazone with ω‐bromoacetophenone

The synthesis of hydrazone derivatives containing thiazole unit was achieved with condensation of thiosemicarbazones and ω‐bromoacetophenone at room temperature. This mild, convenient, and efficient method affords the desired products with good to excellent yields. Their structures have been determined by X‐ray diffractional analysis, ¹H‐NMR, MS, elemental analysis, and IR. Thiosemicarbazones were prepared by the condensation of thiosemicarbazide with aldehydes or ketones. J. Heterocyclic Chem., (2011).     

Regiocontrolled dieckmann condensation of 3,4-Bis(methoxycarbonylmethyl) levoglucosenone derivative

The Dieckmann condensation of 3,4-bis(methoxycarbonylmethyl) levoglucosenone derivative afforded two regioisomeric 9,11-dioxatricyclo[6.2.1.0^2,6]undecane derivatives at a ratio of 5: 3. The products can be used in the synthesis of iridoids.     

Application of divergent multi-component reactions in the synthesis of a library of peptidomimetics based on γ-amino-α,β-cyclopropyl acids

The multi-component condensation of organozirconocene, aldimine and zinc carbenoid was applied to the stereoselective synthesis of cyclopropane amino acid derivatives. These compounds served as scaffolds for the preparation of a 46-member library. The C- and N-termini of the cyclopropane amino acid derivatives were diversified by condensations with ten amines and ten acylating agents, respectively. To improve yields and accelerate library synthesis, most products were prepared under microwave irradiation and purified by polymer-bound scavengers and SPE methodology. All compounds were analyzed by LC-MS and a representative selection was fully characterized.     

Efficient Synthesis of Fully Substituted and Diversely Functionalized Pyrazoles through p-TSA Catalyzed One-Pot Condensation of Cyclic β-Diketones,Arylglyoxals and Arylhydrazones

A one-pot, three-component, and atom economic synthesis of biologically and pharmaceutically important fully substituted and functionalized pyrazole derivatives has been accomplished under metal-catalyst-free benign conditions. The strategy involves early condensation of readily available cyclic β-diketones (dimidone, 4-hydroxycoumarin and 2-hydroxy-1,4-naphthoquinone) and arylglyoxals to generate a chalcone type intermediate which upon acid catalyzed condensation with ambident nucleophile arylhydrazones produces various aryl and cyclic β-diketone substituted pyrazole derivatives. The synthesis embraces high functional group tolerance, broad substrate scope, excellent yield of the products, short reaction time and operationally simple and mild reaction conditions. The synthesis provides an easy opportunity of incorporating biologically important N-diarylsulfide/selenide functionality, various enolisable cyclic β-diketones and other bioactive heterocycles concurrently to pyrazole, which may help in designing and development of pyrazole derivatives of pharmacological significance.     

Rutile phase nanoTiO2 as an effective heterogeneous catalyst for condensation reaction of isatin derivatives with 1,2-diaminobenzene under solvent free conditions: A greener “NOSE” approach

Rutile phase of TiO₂ nanoparticles were readily prepared and identified as an efficient heterogeneous catalyst for the synthesis of a library of quinoxaline derivatives by condensation reaction of isatin derivatives with o-phenylenediamine under solvent-free conditions. The presented method is mild, environmentally friendly, inexpensive and highly effective to give the products in good to excellent yields. The recyclability of the catalyst is another emphasis of proposed methodology.     

二氧化钛纳米粒子催化合成Hantzsch酯和多氢喹啉衍生物(英文)

1,4-Dihydropyridine and polyhydroquinoline derivatives have been prepared efficiently in a one-pot synthesis via Hantzsch condensation using nanosized titanium dioxide as a heterogeneous catalyst.The present methodology offers several advantages such as excellent yields,short reaction times (30-120 min),environmentally benign,and mild reaction conditions.The catalyst can be readily separated from the reaction products and recovered in excellent purity for direct reuse.     

Uncatalyzed,One-pot Synthesis of 3,3'-(Benzylene)bis(4-hydroxy-2H-chromen-2-one)Derivatives under Thermal Solvent-free Conditions

A series of 3,3′‐(benzylene)bis(4‐hydroxy‐2H‐chromen‐2‐one) derivatives have been synthesized from condensation reactions of 4‐hydroxycoumarin with benzaldehydes under thermal solvent‐free conditions. This environmentally friendly synthesis is uncatalyzed and affords the desired products in excellent yields.     

pTSA-catalyzed condensation of xylenols and aldehydes under solvent-free conditions: One-pot synthesis of 9H-xanthene or bisphenol derivatives

A simple and efficient procedure for the synthesis of 9H-xanthene or bisphenol derivatives has been developed by one-pot condensation of xylenols with aromatic aldehydes in the presence of p-toluenesulfonic acid (pTSA) as a catalyst under solvent-free conditions at 100 °C. It is noteworthy that the condensation reaction of 3,5-xylenol with aldehydes produces 9H-xanthene derivatives, while the reaction with other xylenols leads to the corresponding bisphenol derivatives. Different types of aromatic aldehydes are used in the reaction and in every case the products were obtained in good to excellent yields. The structures of these compounds were established on the basis of IR, ¹H NMR, ¹³C NMR and CHN data.     

A Convenient and Efficient Synthesis of 2‐Thioxoquinazolinone Derivatives via Microwave Irradiation

The synthesis of 2‐thioxoquinazolinone derivatives was achieved by condensation of isatoic anhydride, primary amine, and carbon disulfide under microwave irradiation. This convenient and efficient method affords the desired products with good to excellent yields. Satisfactory infrared spectroscopy, ¹H NMR, and high‐resolution mass spectrometry (electrospray ionization) spectra were obtained for all compounds described.     

N,N′-Alkylidenpeptide: Peptidsynthese-Nebenprodukte bei Einwirkung von Carbonylverbindungen

Byproducts of peptide synthesis, formed in the course of accidental attack by Pd-activated oxygen on ethanol and triethylamine in reaction media, have been identified as products of condensation between peptides and acetaldehyde, and demonstrated to represent N,N′-alkylidenepeptides, i.e. derivatives of 4-imidazolidinones. The same products are obtained by direct action of acetaldehyde on the respective peptides, and analogs resulted in some cases when acetaldehyde was replaced by formaldehyde or acetone. The condensation is reversible, imidazolidinone stability depending on structural features of both the involved peptide and carbonyl compound. There are evidently implications of these findings with respect to the chemistry and biochemistry of peptides and proteins.     

Synthesis and nitration of condensation products of sulfamates with aliphatic amines and formaldehyde

A method for the synthesis of 5-alkyl-1,3-dinitro-1,3,5-triazacyclohexanes and linear polynitramines was proposed. It includes the reaction of aliphatic amines with sulfamates and formaldehyde and nitration of the reaction products. The yield and composition of nitramino derivatives depend on the conditions of the condensation and nitration. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1088–1091, June, 2000.     

Biginelli 3,4-二氢嘧啶-2-酮衍生物的合成研究新进展

1893年, 意大利化学家Biginelli首次利用芳香醛、乙酰乙酸乙酯和尿素三组分“一锅煮法”合成了3,4-二氢嘧啶-2(1H)-酮. 此类化合物具有良好的生物活性和反应活性, 对近几年来有关Biginelli 3,4-二氢嘧啶-2(1H)-酮的衍生化反应、Biginelli不对称合成和Biginelli反应在天然产物合成中的应用研究进行了综述.     

Diazatruxenes from the Condensation Reaction of Indoles with Ninhydrin

The reaction of indoles with ninhydrin has been reported to provide only 1:1 condensation products (cf. A or 8 ) that show good antioxidant and anti‐inflammatory activity. In the present work, our synthetic challenge for the synthesis of innovative, highly substituted tetra‐indole indanes of type 1 via a 4:1 condensation reaction in acetic acid gave two unexpected new products, the diazatruxene derivatives 3 and 4 . The novel structures have been characterized by their analytical and spectral data including 1D‐ and 2D‐NMR. With 5‐chloroindole, only the known 1:1 reaction.     

A domino N-amidoacylation/aldol-type condensation approach to the synthesis of the topo-I inhibitor Rosettacin and derivatives

The pot, atom, and step-economic synthesis of Rosettacin topo-I poison and its derivatives has been achieved using a novel domino N-amidoacylation/aldol-type condensation, followed by decarboxylation of the ester function. The key domino procedure simply involves mixing HOBt ester as new reagent with lactam and NaH together in THF or THF/ DMF. The reaction seems to be general and led to suitable N-heterocyclic products in moderate to good yields.     

Structure elucidation of a condensation product of 4-aminopyrrole derivatives and dicyclohexylcarbodiimide

The chemical structure of the two condensation products of dicyclohexylcarbodiimide (DCC) with the precursors of the mono-pyrrole homologues of distamycin and with the mono and tri-pyrrole homologues of congocidine were established. The two products isolated were proven to be condensation products between 4-aminopyrrole derivatives and dicyclohexylcarbodiimide (DCC).