Letters in Organic Chemistry - Volume 10, Issue 5, 2013

A mild, efficient and straightforward method has been developed for the synthesis of novel bis-Betti bases via a pseudo five-component, one-pot condensation reaction of heteroaryl amines, terephthaldehyde and naphthols under solvent- free conditions. The salient features of this protocol are: simple reaction procedure, shorter reaction time, high to excellent yields, avoidance of aqueous work-up, and column chromatogra Read More

The stereoselective synthesis of the unsaturated lactone intermediates, (S) - and (R)-2-(6-oxo-3, 6-dihydro-2Hpyran- 2-yl) acetaldehydes has been accomplished from propane 1,3 diol employing Maruoka asymmetric allylation and ring closing metathesis reaction. The intermediates were converted into two natural dihydropyranones, 6 (R)-4-oxopent-2- enyl 5,6-dihydro-2H-pyran-2-one and (R)- rugulactone and their enanti Read More

In the present work, L-pyrrolidine-2-carboxylic acid-4-hydrogen sulfate, supported on silica gel was prepared and characterized by Mass spectroscopy, 1H NMR, 13CNMR, FT IR and elemental analysis (CHN) methods. This heterogenized catalyst can be used as an efficient catalyst for the acylation of alcohols, phenols, and amines with acetic anhydride under mild and solvent-free conditions. Simple work-up, stability of Read More

The microwave promoted alkylation of 1- and 2-naphthols with benzyl, butyl, ethyl and isopropyl halides in the presence of an alkali carbonate may result in O- and C-alkylated products. The alkylations were O-selective in the presence of K2CO3 in acetonitrile as the solvent and in the absence of phase transfer catalyst. The alkylations utilizing butyl and ethyl halides were also O-selective in solventless accomplishment and in the pr Read More

A series of pyrazolo[3,4-b]pyrrolo[3,4-d]pyridine derivatives was synthesized via catalyst-free bi-component and one-pot reactions of 5-aminopyrazoles, DMF-DMA (or TMOF) and N-arylmaleimides in xylene as solvent. This protocol showed advantages of milder reaction conditions, easier work-up, shorter reaction times and good yields, over other approaches tested.

Polyethylene glycol (PEG) encapsulation of porphyrin was designed and synthesized by introducing branched PEG substituents to the porphyrin core. Fluorescence imaging of cells was conducted to investigate the cellular uptake of these PEPPs. Results suggest that the porphyrin compound with 16 triethylene glycol chains exhibits increased cellular uptake and/or efficiency for emitting fluorescence inside the cells. The singlet oxy Read More

The practical synthesis of 3-(trifluoromethyl)-triazolopiperazine the key intermediate of Sitagliptin and 3- (trifluoromethyl)-triazolopyridine was carried out employing industrially feasible transformations. The other advantage of this method is the new environment friendly approach to synthesize triazolopiperazine and triazolopyridines by eliminating the commonly used trifluoroacetic anhydride and polyphosphoric acid.

Montmorillonite K-10 clay catalyzes the reaction of different anhydrides with semicarbazide under microwave irradiation. The corresponding carboxamide derivatives are obtained in high yield and short reaction times.

A facile synthesis of symmetric diaryldisulfides in 55-75% yield by nucleophilic ring opening of benzo[b]thiophene-2,3-diones is described.

An improved and efficient synthetic process developed for an endothelin receptor antagonist, bosentan monohydrate by condensing a key intermediate 4-tert-butyl-N-(6-hydroxy-5-(2-methoxyphenoxy)-2,2’-bipyrimidine-4- yl)benezenesulfonamide 5 with commercially cheaper chloro acetonitrile and α-halo esters. This synthetic approach efficiently provides highly pure bosentan without formation of the major impurity Read More

In the absence of any additional catalysts, a series of aromatic amines were alkylated with a range of aromatic and aliphatic aldehydes. Moderate to excellent isolated yields (up to 94%) were obtained under mild conditions. Simultaneously, the reaction time dramatically shortened from hours to minutes when the Microwave technique was used.

A new series of pyrimidinesulfamoyl-1H-pyrrole-3-carboxamides (3a-e) and pyrimidinesulfamoyl-1Hpyrazole- 3-carboxamides (4a-e) moiety was prepared using intermediate compounds pyrimidinesulfamoyl cinnamamides (2a-e). On the basis of the FT-IR, 1H NMR, 13C NMR, LCMS spectral results and elemental analysis data, the structures of newly synthesized compounds were confirmed. Based on results of their in-vitro a Read More

An O-aminated naphthol AS-E was designed as a prodrug to achieve reductive activation and improved aqueous solubility. During the synthesis of this designed compound, a novel transformation from aryl triflates and ethyl acetohydroximate to oxazoles was discovered. Although the initially designed O-amino naphthol AS-E was not made successfully, the eventually synthesized O-tert-butylamino derivative was found to be bi Read More