Letters in Organic Chemistry - Volume 6, Issue 7, 2009

In the presence of platinum on carbon (Pt/C), diarylmethanols and donor substituted 1-phenylalkan-1-ols undergo cross-etherification with primary and secondary alcohols.

An efficient protocol for the synthesis of pyrimido[5',4'p:5,6]thiopyrano[2,3-b]indoles by the cyclocondensation of 1,3-dihydro-2H-indole-2-thione with 6-chloropyrimidine-5-carbaldehydes has been developed. 4-Chloro-2- methylthiopyrimido[5',4':5,6]thiopyrano[2,3-b]indole was found to undergo smooth nucleophilic substitution with various nucleophiles to give 4-substituted pyrimido[5',4':5,6]thiopyrano[2,3-b]indoles.

The effect of triethylbenzylammonium chloride (TEBAC) was studied on the outcome of the microwaveassisted solid-liquid phase N-alkylation of amides, imides and N-heterocycles using benzyl halides and K2CO3. It was found that while the benzylation of amides may be somewhat promoted by the presence of TEBAC, succinimide and benzimidazole are so reactive that there is no need to use the catalyst. At the same time, th Read More

The benzylation of cresol was studied under liquid-liquid and solid-liquid phase transfer catalytic conditions. Microwave irradiation was useful only in the solid-liquid phase benzylations. Using acetonitrile as the solvent, the benzylations were fully O-selective, but complete conversions were obtained only in the presence of Cs2CO3. There was no need to use an onium salt. In the absence of solvent, an O-selectivity of ca. 90% Read More

We describe synthesis of a chain-terminating mRNA cap dinucleotide m2 7, 2'OG[5']ppp[5']m7G analog. A new dinucleotide cap analog was synthesized with methyl groups on the both N7 guanine moieties, as well as the 2'-OH of one of the ribose moiety is reported. The biological validation of triple methylated cap analog was done with respect to their effects on capping efficiency, yield of RNAs during in vitro trans Read More

3-Amino-8-methyl pyrimido [4,5-b] quinoline (1) in N,N-dimethyl formamide (DMF) and anhydrous potassium carbonate reacted with ethyl-2-cyano-3,3-bismethyl thioacrylate 2 to afford novel heterocyclic compound 3- cyano-9-methyl-2-methylthio-4-oxo-4H-pyrimido [4,5-b] quinoline 3. The latter were further reacted with selected N-, Oand C- nucleophiles such as arylamines, substituted phenols, heterylamines and compoun Read More

The reaction of the primary amine species with the carbohydrate's reducing end moieties is a kind of special reductive amination reactions which need acid catalysis. The rate equation and selectivity equation of this kind of reactions were given by the kinetic and thermodynamic theories, which can predict the influence of the reaction temperature, pKa of used amine and pH on the reaction rate and yield. Based on this the Read More

N,N-Diaryl α-haloamides undergo Darzens condensations with aldehydes induced by metal hydroxides. The diastereoselectivity of epoxide formation is strongly influenced by the electronic properties of the arylamide, which can be rationalised on the basis of the acidity of the substrate hydrogens and hence on reaction occurring under kinetic or thermodynamic control.

A simple, efficient and green procedure has been developed for the synthesis of octahydroquinazolinone derivatives by Biginelli-type three-component cyclocondensation reactions of cyclic β-diketones, aldehydes and (thio)urea with p-TsOH catalysis in water.

A cycloaddition of aldehydes and acetylenic ketones mediated by 4-dimethylaminopyridine and 2,4- pentanedione is reported. The method supplies a facile way to synthesize 3,4,5-trisubstituted-4H-pyrans in moderate to good yields under mild conditions.

A simple methodology for Cu-catalyzed cyanation of aryl halides with K4[Fe(CN)6] was developed with water as the solvent in conjunction with ligand-free Cu(OAc)2·H2O as the catalyst. The suggested methodology is applicable to cyanation of a wide range of aryl iodides and activated aryl bromides, and allows the catalyst to be reused six times with a very slight change in the catalytic activity.

Acyclic or cyclic O,O-acetals and O,S-acetals underwent reductive cleavage to give primary alcohols efficiently on treatment with Zn-CoCl2.6H2O-bimetal redox system in dry tetrahydrofuran at ambient temperature to give good to excellent yields.

Fe(acac)3 has been used as the catalyst in cross-coupling reactions of aryl Grignard reagents with 1,4-bis(2- bromovinyl)benzenes affording bis(2-arylvinyl)benzenes. Effects of alkoxy substituents on both reactants and of the temperature on the reaction outcome are investigated.

The bioactive 3-(chlorophenylethyl)- and 3-(chlorophenylethenyl)-isocoumarins were synthesized by the condensation of simple homophthalic acid with 3-chlorophenylpropionoyl chlorides and chlorocinnamoyl chlorides, respectively. Alkaline hydrolysis of these isocoumarins gave the respective keto-acids. (dl)-3,4-Dihydroisocoumarins were obtained by the reduction of the keto-acids to racemic hydroxyl-acids, followed by cyclod Read More

In this presentation the novel regioselective halogenation of arenes or phenols with dimethyldioxirane and Bu4NX is described. The results showed that a new, versatile and mild method can be utilized for preparation of aryl halides starting with arenes or phenols. Finally, this aryl halide forming methodology is applicable to structurally more complex flavonoids.

Guest molecules (benzene and 1,4-dioxane) can be incorporated into 9,10-dipentafluorophenylanthracene (DPFPA) by tuning the arrangement of its one-dimensional (1D) column-like structure with CF-π interactions of its pentafluorophenyl group in the solid state. The two guest molecules are trapped in cavities due to benzene-anthracene edge-to-face and CH-π interactions with DPFPA, respectively.