The reaction between barbituric acid or 2-thiobarbituric acid and different benzaldehydes, dependent upon the applied reaction conditions, selectively yields three different product types, i.e. 5-benzylidene(thio)barbituric acids II, symetric Michael adducts III or 5-phenyl-1H-pyrano[2,3-d]pyrimidine-2,4(3H,5H)-diones and 5-phenyl-2-thioxo-2,3-dihydro-1H-pyrano[2,3-d]pyrimidin-4(5H)-ones IV. Th...

A range of enethioate derivatives of 1,3-diones underwent reductive aldol cyclizations catalyzed by a chiral copper hydride generated in situ from 5 mol% TaniaPhos (SL-T001-1), 5 mol% Cu(OAc)(2)·H(2)O, 5 mol% bipyridine and 2.0 equiv. of PhSiH(3), to furnish polycyclic β-hydroxythioester products bearing three newly established contiguous stereocenters, with >98:2 dr and in up to 94% yield and ...

This article reviews the surface adsorption of p-benzoquinonemonoimine zwitterions from the class of N-alkyldiaminoresorcinones (or 4,6-bis-dialkylaminobenzene-1,3-diones, i.e. C6H2(.. .NHR)2(. . .O)2), where R = H, R = C2H5, n-C4H9), on a variety of conducting surfaces. These small molecules with a large electrical dipole exhibit molecular orientation and packing on surfaces depending on the d...

A novel series of 1,3,4-thiadiazoles, 5-arylazothiazoles and hexahydropyrimido-[4,5-d][1,2,4]triazolo[4,3-a]pyrimidines were synthesized via reaction of hydrazonoyl halides with each of alkyl carbothioates, carbothioamides and 7-thioxo-5,6,7,8-tetrahydropyrimido-[4,5-d]pyrimidine-2,4(1H,3H)-diones in the presence of triethylamine. The structures of the newly synthesized compounds were establish...

Small molecule diversity can be achieved in a single synthetic operation from bifunctional substrates in the absence of additives and under the influence of microwaves with complete control of pathway selectivity. The preliminary Ugi four-component coupling products give rise to three structurally distinct scaffolds that are dependent on solvent effects and sterics. 2,5-Diketopiperazines (Type ...

Several l,3,5-triaza-2-boracyclohexa-4,6-diones have been prepared by condensation reactions of boranes with biurets; N-methylated species could be characterized by their 1H, U B and 13C NMR spectra. Some data are also reported on bicyclic bis(N,N',N"trimethylbiuret-l,5-diyl)borate(l-) salts and on a betaine consisting of two N,N',N"-trimethylbiuret moieties bonded to a central four-coordinate ...

N-Aryl-C-ethoxycarbonylnitrile imines (3a-g) react with ethyl cyanoacetate 1 in 1,3-dipolar cycloaddition to yield novel pyrazole-3,4-dicarboxylates (4a-g) in moderate yields. The reaction of pyrazole-3,4-dicarboxylates (4a, d) with hydrazine afforded pyrazolo[4,3-d]pyridazine-4,7-diones (5a, d) in good yields. All compounds were fully characterized by spectroscopic methods. Some of the newly s...

Synthesis and anticonvulsant potential of certain new 6-aryl-9-substituted-6,9-diazaspiro[4.5]decane-8,10-diones (6a-l) and 1-aryl-4-substituted-1,4-diazaspiro[5.5] undecane-3,5-diones (6m-x) are reported. The intermediates 1-[(aryl)(cyanomethyl)amino] cycloalkanecarboxamides (3a-f) were prepared via adopting Strecker synthesis on the proper cycloalkanone followed by partial hydrolysis of the o...

Multi drug resistance (MDR) is a serious obstacle in the management of breast cancer. Therefore, overcoming MDR using novel anticancer agents is a top priority for medicinal chemists. It was found that dihydropyridines lacking calcium antagonistic activity (e.g acridinediones) possess MDR modifier potency. In this study, the capability of four novel acridine-1,8-diones derivatives 3a-d were eva...