Letters in Organic Chemistry - Volume 9, Issue 7, 2012

The Editorial Board wishes to dedicate this issue of Letters in Organic Chemistry to the Editor-in-Chief of the journal, Prof. Dr. Atta-ur-Rahman, FRS, on his 70th birthday. The Editorial Board acknowledges the tremendous achievements of Prof. Rahman in the fields of Organic Chemistry in general and on bioactive natural products in particular. Prof. Rahman’s honors include: the first scientist from the Muslim world to have won the Read More

Modification of nepafenac intermediate synthesis (5A) via Gassman specific ortho-substitution is reported. According to the process, 2-aminobenzophenone (1A) and 2-(methylthio)acetamide (2) were reacted in the convenient temperature conditions, in the presence of N-chlorophthalimide (3) or 1,3-dichloro-5,5-dimethylhydantoin (4), to activate the formation of azasulfonium salt and rearrangement there Read More

Herein, a selected set of chiral N1-(4-oxochromen-7-yl)-4,5-dihydro-1,2,4-triazin-6(1H)-ones (7a-k / 8a-k) were prepared via direct interaction of L-α-amino esters with N1-(4-oxochromen-7-yl) nitrile imines (generated in situ from their hydrazonoyl chloride precursors 5a,b by the action of triethylamine). These novel dihydrotriazinone-flavone hybrid compounds (7), their 2- methylchromenone analogs (8) and the L-proline h Read More

New potentially biologically active N-bromobenzyl derivatives of α-isosparteine and 2-methylsparteine were obtained. Newly obtained compounds were characterized by IR and NMR spectroscopy. The structure of the new compounds in solution was proposed

Two series of 1,3,4-thiadiazole and 1,3,4-oxadiazole derivatives have been synthesized and characterized by elemental and spectral (IR, 1H-NMR) data. The hydrazide derivatives of 4-hydroxy quinolone and coumarin moiety were refluxed in carbon disulfide in ethanolic potassium hydroxide to obtain the corresponding hydrazinecarbodithioate salts which were then treated in two ways with (i) sulfuric acid and (ii) hydrochloric aci Read More

The nucleophilic substitution reaction of hydrazono-N-(aryl)-propanehydrazonyl chlorides 7 with piperidine or morpholine, under the same reaction conditions, resulted in the formation of 1-(piperdin-1-yl / morpholine-1-yl)-N2- arylamidrazones 8a-k, respectively. The X-ray diffraction of piperidin-1-yl-N2-arylamidrazone (8b) confirmed its 1Econfiguration in agreement with the previously reported, whereas X-ray showed the unexp Read More

(3R,4R)-2,2,5,5-tetraphenyltetrahydrofuran-3,4-diol was employed as additive in the L-proline-catalyzed Michael addition of acetone to nitroalkenes, resulting in upgrading 8-28% ee in enantiomeric purity of the products compared with those without additives.

The preparation of substituted piperidines via three-component reaction between aldehydes, aromatic amines and acetoacetic esters has been developed. The process has been carried out under ambient conditions in the presence of zinc hydrogen sulfate [Zn(HSO4)2]. A variety of aldehydes and amines were yielded into the corresponding products demonstrating the versatility of the reaction.

Novel perylenebisimide-based fluorescent chemosensors PBI-5 and PBI-6 were designed and synthesized. Their selective recognition behavior toward metal ions was investigated by visual colorimetry and fluorescence spectroscopy. PBI-5 successfully exhibits a fluorescence turn-on response for Zn2+ and switch-off response for Cu2+ in neutral buffer solution, but the fluorescence turn-on response is moderately pert Read More

Three palladium complexes derived from diphenyl-2-pyridylphosphine (PPh2Py) were investigated for their utility as catalysts for the Suzuki-Miyaura reactions of aryl halides in environment friendly solvents such as water, alcohols etc. Good-to-excellent yields of coupling products were achieved with a wide range of aryl halides under mild reaction conditions.

The catalytic asymmetric dihydroxylation (AD) discovered by Sharpless, a Nobel Prize winner in 2001, has rapidly become an invaluable synthetic tool in the possibility of converting prochiral olefins to chiral vicinal diols. After our long-running investigation of optimized methodology for the production of stereo-defined diols based on the AD reaction, an efficient and environmentally friendly approach for the synthesis of (S)- Read More

A practical chemical synthesis of ethyl (R)-(-)-4-Cyano-3-hydroxybutyrate((R)-CNHB) has been accomplished from (S)-3-chloro-1,2-propanediol, which is a main by-product originating from (S,S)-Salen Co(III) catalyzed by hydrolytic kinetic resolution (HKR) of epichlorohydrin. The new synthetic approach demonstrated an efficient utilization of organic by-product for the asymmetric synthesis of the intermediate of atorvastatin.

An efficient solvent-free α-phosphoryloxylation of ketones under microwave irradiation is reported. When ketones reacted with phosphates and (diacetoxyiodo)benzene under microwave irradiation for short time, the α-phosphoryloxylaction of ketones was easily be carried out and the corresponding ketol phosphates were prepared in moderate to good yields.

Eaton's reagent efficiently catalyzed the Claisen-Schmidt condensation reaction of aryl aldehydes with aromatic and cyclic ketones under solvent free microwave irradiation conditions to afford mono and bis-chalcone derivatives. The present approach offers several advantages such as shorter reaction times, cleaner reactions, good yields, inexpensive reagent and mild reaction conditions.

Condensation of 2-acetyl-1-naphthol and 1-acetyl-2-naphthol with benzaldehydes under microwave irradiation gave chalcones or flavanones depending on the type of ketone. Also, 2-pyrazolines were synthesized by the condensation of chalcones with phenyl hydrazine under microwave irradiation in presence of dry acetic acid as a cyclizing agent. The results obtained indicated that, unlike classical heating, microwave irr Read More