Letters in Organic Chemistry - Volume 12, Issue 1, 2015

A library of hitherto unknown functionalized and annulated spiro[indoline-3,1`-indolizin]-2-one derivatives incorporating thiophene moiety has been synthesized under conventional and microwave irradiation conditions. The structures, regio and diastereoselectivity of the synthesized cycloadducts have been confirmed using different analytical and spectral tools.

Direct preparation of 2-amino-5,6,7,8-tetrahydro-4-(4-methoxyphenyl)-7,7-dimethyl-5-oxo-4H-chromene-3- carbonitrile (2) and 1,2-diamino-1,4,5,6,7,8-hexahydro-4-(4-methoxyphenyl)-7,7-dimethyl-5-oxo-3-quinolinecarbonitrile (11) which were utilized as starting products for the synthesis of S-nucleoside analogues of kinds 10, 15 and C-nucleoside analogues of types 12, 13 is presented in the current study. The an Read More

A new one-pot three-component and highly efficient approach for the synthesis of quinoxaline derivatives was investigated. This was achieved via two methods from the reaction of α-hydroxy ketones or 1,2-dicarbonyl compounds with o-phenylenediamine in the presence of catalytic amount of many metal salt catalysts especially Zn(OAc)2 and mixture of Mn(OAc)2 and Zn(OAc)2.

Ten substituted 3-azabicyclo[3.3.1]nonan-9-one oxime ester derivatives 3-12 were synthesized from the starting material 3-azabicyclo[3.3.1]nonan-9-one oxime 2 with activated carboxylic acids in POCl3/pyridine. A wide range of carboxylic acids were used to produce the corresponding oxime esters up to 85% yield. The synthesized compounds were confirmed by FT-IR, NMR (1H, 13C and NOESY) and mass spectrometry. The ch Read More

A convenient access to some new and known bis(pyrazolyl)methanes synthesis has been successfully achieved via an alternative Knoevenagel/Michael reaction of aromatic aldehydes and pyrazole-5-one in the presence of Mohr’s salt as a green catalyst. This novel procedure has some advantages such as high efficiency, simplicity, high rate and environmental safety.

An easy and convenient direct synthesis of 2-azetidinones is described. The [2+2] cycloaddition reaction of imines and carboxylic acids using 4-(4,6-dimethoxy-1,3,5-triazin-2-yl)-4-methylmorpholinium chloride (DMTMM) has been employed to synthesize a variety of 2-azetidinones in high yields. The products were easily isolated because the byproducts are highly soluble in water.

We report the synthesis of novel alkyl 4-alkyl-2,8-dioxo-2H,8H-pyrano[2,3-f]chromene-10-carboxylates by the reaction of 7-hydroxy coumarins and dialkyl acetylenedicarboxylates in the presence of triphenylphosphine, when alkyl propiolates were employed O-vinylated coumarin derivatives were obtained.

Highly chemoselective rearrangement of chalcone epoxides to β-keto aldehydes using catalytic amount of Cu(OTf)2 (1 mol%) is presented. Copper(II)triflate is a relatively cheap, inexpensive and commercially available catalyst. In this rearrangement selective migration of the acyl group takes place. The presence of an electron donating group on either of the phenyl rings favors the reaction. However, the presence of an Read More

A facile and efficient synthesis of spiro[indoline-3,5'-pyrido[2,3-d]pyrimidine] derivatives by one-pot reactions of isatins, 2,6-diaminopyrimidin-4-one or 6-aminopyrimidine-2,4-dione and malononitrile under microwave irradiation conditions was investigated. This protocol has the virtue of short reaction time, high yields and easy work-up procedure.

We engineered, graphene based Pd -Nano composites (Pd/RGO) and tested them to catalyze the Heck reaction in [bmim] NTf2 solvent system. High yield, easy product isolation, recycling of the catalytic system and ligand free approach are the main outcomes of this proposed protocol. The proposed protocol was further exploited for the successful synthesis of 3-styryl coumarins in good yield.

A rapid, efficient method for deprotection of oximes to carbonyl compounds is demonstrated by using sodium chlorite (NaClO2) in water. The protocol has been found to be applicable to a wide range of aldoximes and ketoximes with good to excellent yields of the corresponding carbonyl compounds.