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A simple, efficient, and high yielding one-pot procedure for the formation of the title compounds (III) is reported proceeding by an iodine-catalyzed pseudo three-component domino coupling of barbituric acids and various benzaldehydes in water.

Copper or silver salts promote a domino addition–cyclization reaction between terminal alkynes, carbon disulfide, and oxiranes in a regioselective manner to afford 1,4-oxathiane derivatives in good yield.

The magnetic ionic liquid, tri(1-butyl-3-methylimidazolium) gadolinium hexachloride, ([bmim] 3 [GdCl 6 ]), has been used as an efficient green catalyst for the one-pot synthesis of 1,2,4,5-tetrasubstituted imidazoles via the condensation of benzil, an aromatic aldehyde, aniline, and ammonium acetate. Good to excellent yield, mild reaction conditions, as well as ease of operation and work-up are some advantages of the protocol.

The reaction works well in the case of 2-mono-, 3-mono- and di-substituted benzaldehydes (II) but fails with 4-substituted benzaldehydes (V) forming intermediate Knoevenagel adducta (VI) only instead.

The simple process proceeds under solvent-free conditions to give insertion products of primary and secondary amines in high yields.

Xanthenes and their derivatives as very important classes of organic compounds are key structural elements of many biologically active compounds. These materials are important heterocyclic nucleus of various dyes and drugs. Because of their wide range of pharmacological, industrial and synthetic applications, many methods for the preparation of xanthenes are reported in the literature. In recent years, among the other chemists, introduction of new methods for the preparation of these types of compounds has attracted the attention of Iranian chemists. The result of these efforts is the introduction of appropriate, effective and efficient methods. In this paper, we have a brief review on these methods and their main advantages and important applicabilities.

Some of the sydnone derivatives (II) (9 examples), especially derivatives (IId) and (IIg), show excellent antibacterial activities.

The title catalyst is successfully employed for the Strecker reaction and the Kabachnik—Fields reaction to give α-aminonitriles and phosphonates.

The three-component, one-pot-reaction between alkylidene Meldrums acid (I), isocyanide (II), aliphatic ketoxime (III), and one molecule of water (moisture) provides a simple entry into the synthesis of new derivatives of isoxazolinedione.

An efficient, safe and facile route to functionalized spiro[furo[2,3-d]pyrimidine-6,5′-pyrimidine] derivatives has been developed by a one-pot pseudo three-component domino coupling of aromatic aldehydes and (thio)barbituric acids in the presence of urotropine–bromine (UB) complex in water at room temperature. The reaction sequence consists of an initial Knoevenagel condensation of aromatic aldehydes with (thio)barbituric acids, followed by Michael addition of the second equivalent of (thio)barbituric acid derivatives, and then UB-catalyzed Williamson cycloetherification to afford the products.

The one-pot, three-component Mannich reactions of thiopyran-4-one 1 with different aromatic aldehydes and aniline derivatives in the presence of catalytic quantities of ZrOCl2.8H2O (15 mol %) led to rapid and high yield formation of various 3-methylamino substituted derivatives of 1 at room temperature. Spectroscopic and X-ray analyses of the products suggested the formation of the anti stereoisomers as the major product of the reactions.

Title thiadiazoles (II) and their Schiff base derivatives (IV) (12 examples) show significant antiproliferative activities against Mycobacterium smegmatis PTCC 1307.

Mono N-Boc protection of various amines succeeds chemoselectively in the presence of magnetically recoverable ferric oxide on silica nanoparticles.

2,3-Disubstituted quinoxalines were synthesized via condensation of α-diketones and 1,2-phenylenediamines. Nano-BF3·SiO2 as a "green" and reusable solid acid was used as the catalyst for the synthesis of quinoxalines. The reaction was carried out at room temperature under sonication with high to excellent yields.

Knoevenagel condensation of ferrocenecarboxaldehyde (I) with Meldrum′s acid (II), followed by cycloaddition with isocyanides (III) and aminolysis affords a diversity of ferrocenyltricarboxamides (V) under mild conditions.

For the presented method the use of the catalyst poly(N-bromobenzene-1,3-disulfonamid) is similarly effective and chemoselective just as the catalyst N,N,N′,N′-tetrabromobenzene-1,3-disulfonamide.

Fully substituted pyrrol-3-ol derivatives (V) are prepared via aldol reactions of propane-2-one with phenylglyoxal followed by Paal—Knorr reaction with amines.

The Mg(HSO4)2-catalyzed condensation of 2-naphthol with aldehydes can be carried out under neat conditions or in methylene chloride using ultrasound irradiation to give the title compounds in excellent yields.

Novel 2-aryl-4-chloro-3-hydroxy-1H-indole-5,7-dicarbaldehydes (III) are obtained in a three-step procedure from acetophenones.

Water was found to be a highly efficient and green catalyst and solvent for ring-opening reaction of epoxides with Na2S at room temperature to give substituted bis(hydroxyethyl)thioethers in high yields.

The series of compounds 6-carbethoxy-5-aryl-3-(3,5-dibromo-4-methoxy phenyl)-2-cyclohexenones 2a-j are obtained from the (2E)-1-(3,5-dibromo-4-methoxyphenyl)-3-aryl-prop-2-en-1-ones 1a-j by Michael addition of ethyl acetoacetate, followed by internal Claisen condensation. Reaction of 2a-j with hydrazine hydrate afforded the corresponding 6-(3,5-dibromo-4-methoxyphenyl)-4-aryl-2,3a,4,5-tetrahydro-3H-indazol-3-ones 3a-j. The constitution of all the synthesized compounds have been established by elemental analyses, IR, 1 H NMR and mass spectral data. All the compounds have been screened for their antimicrobial activities and compounds 2a-j have been tested for antitubercular activity.

A sulfonic acid functionalized ionic liquid is used as a Bronsted acid catalyst for the one-pot, three-component synthesis of α-aminophosphonates from aldehydes and ketones at room temperature in water. This homogeneous catalytic procedure is simple and efficient and the catalyst can be reused at least six times without any noticeable decrease in catalytic activity.

2-Amino-3-cyano-6-(3,5-dibromo-4-methoxyphenyl)-4-aryl-pyridines 2a-i arc synthesized by the reaction of compounds (2E)-3-(3,5-dibromo-4-methoxyphenyl)-1-arylprop-2-en-1-one 1a-i with malononitrile in the presence of ammonium acetate. Condensation of compounds 1a-i with malononitrile in pyridine has yielded 2-amino-3-cyano-6-(3,5-dibromo-4-methoxyphenyl)-4-arylpyrans 3a-i. The constitution of all the synthesized compounds have been cstablished by elemental analyses, IR, 1 H NMR, and mass spectral data. All the compounds arc screened for their antitubercular and antimicrobial activities.

2-(2,4-Dichlorophenyl)imidazo[1,2-a]pyridine-3-carbaldehyde (1) was prepared from 2-aminopyridine through multi-step reaction. Compound 1 reacts with different aryl ketones in the presence of catalytic amount of 40% KOH to give (2E)-3-[2-(2,4-dichlorophenyl)imidazo[1,2-a]pyridin-3-yl]-1-arylprop-2-en-l-ones (2a-j), which on cyclization with urea and thiourea in the presence of basic catalyst like KOH afforded 6-[2-(2,4-dichlorophenyl)imidazo[1,2-a]pyridine-3-yl]-4-aryl-pyrimidin-2(1H)-ones (3a-j) and 6-[2-(2,4-dichlorophenyl)imidazo[1,2-a]pyridine-3-yl]-4-aryl-pyrimidin-2(1H)-thiones (4a-j). The antimicrobial evaluations have been performed for their antibacterial activity and antifungal activities.

A wide range of biological activities are associated with 1,4-dihydropyridines Individually or in combination. The synthesis of N-aryl-2,6-dimethyl-3,5-dicarbmethoxy-4-[5'-(m-chloro-p-flourophenyl)-2'-furyl]-1,4-dihydropyridines (6a-J) and N-aryl-2,6-dimethyl-3,5-dicarbmethoxy-4-[5'-(m-chloro-p-flourophenyl)-2'-furyl]-1,4-dihydropyrldines (7a-j) was under-taken with hope that they may be biologically active molecules with improved activity, less toxicity and undesirable side effects. The newly synthesized compounds were characterized on the basis of elemental analysis, IR, 1 H NMR and mass spectral data. All newly synthesized compounds were tested for their antitubercular activity against Mycobacterium tuberculosis H 37 RV ATCC 27294, antibacterial activity against different Gram +ve and Gram -ve bacteria and antifungal activity.

Nano-TiO2 as an efficient, eco-friendly and reusable catalyst was applied for the one-pot synthesis of β-acetamido ketones. In this improved procedure, an aryl aldehyde, an aryl ketone, acetyl chloride and acetonitrile were condensed in the presence of the catalyst at room temperature.

The reaction of thiocarbamoylcyanoacetates with hydroxylamine in ethanol under reflux conditions has provided a convenient method for the synthesis of 5-aminoisoxazoles.

An efficient and highly chemoselective synthesis of symmetrical secondary amines via reductive amination of aldehydes with inexpensive and commercially available HMDS and sodium borohydride in high to quantitative yields is reported.

Silica-supported boron trifluoride (BF 3 ·SiO 2 ) is an efficient, readily available, and reusable catalyst for the synthesis of 14-aryl or alkyl-14 H -dibenzo[ a,j ]xanthenes by condensation of 2-naphthol and aldehydes. This reaction under heating or sonication conditions is very simple, affording good to excellent yields of products.

Various 3-(2-amino-6-arylpyrimidin-4-yl)-6-chlorocinnolin-4(3H)-one (2a-j) and 6-chloro-3-(6-aryl-2-mercapto-3,4-dihydropyrimidin-4-yl)cinnolin-4(3Η)-one (3a-j) were synthesized by the reaction of 6-chloro-3-[(2E)-3-arylprop-2-enoyl]-cinnolin-4(3H)-ones (la-j) with guanidine hydrochloride and thiourea respectively. All newly synthesized compounds were tested against different microbes for their antimicrobial activity and Mycobacterium tuberculosis for their antitubercular activity.

Cyclocondensation of hydrazine hydrate with (2E)-1-(3,5-dibromo-4-methoxyphenyl)-3-aryl-prop-2-en-l-onts (la-j) in glacial acetic acid afford corresponding l-acetyl-3-(3,5-dibromo-4-methoxyphenyl)-5-aryl-4,5-dihydro-1H-pyrazoles (2a-j). While the compounds la-j on reaction with hydroxylamine hydrochloride in presence of acetic acid and sodium acetate to give 3-(3,5-dibromo-4-methoxyphenyl)-5-aryl-isoxazoles (3a-j). All the compounds were tested against different microbes for their antimicrobial activity and compounds 2a-j were tested for antitubercular activity.

4-Amino-5-(3-pyridyl)-4H-1,2,4-triazole-3-thiol 1 is prepared from methyl nicotinate through a multi-step reaction sequence 1 . Compound 1 react with various aromatic aldehydes in the presence of gl. acetic acid to give 4-substituted-benzal-amino-3-mercapto-5-pyridin-3'yl-[l,2,4]-triazoles 2a-i, which on further cyclo-condensation with thioacetic acid afforded 3-(3'-mercapto-5'-pyridin-3"-yl-[1, 2, 4]-triazole-4'-yl)-2-aryl-1, 3-thiazolidin-4-ones 3a-i. Compounds 2a-i on reaction with formaldehyde and with different aromatic amines in dioxane yielded 2-[bis-aryl-amino-methyl]-5-pyridin-3'-yl-4-substituted-banzal-amino-2,3-di-hydro-[l,2,4]-triazlole-3-thiones 4a-i. The pharmacological evaluations have been performed for their antimicrobial and antitubercular activities.

A simple and convenient procedure for direct reductive amination of aldehydes and ketones with sodium borohydride is described. The reaction has been carried out in methanol in the presence of a catalytic amount of H 3 PW 12 O 40 (0.5 mol %). α,β-Unsaturated aldehydes and ketones can be easily converted into the corresponding allyl alcohols by reaction with H 3 PW 12 O 40 (0.5 mol %)/NaBH 4 .

Preparation methods of dibenzoxanthene derivatives are surveyed alongside the synthesis of some of the titled compounds, which are the sulfur analogues of dibenzoxanthenes. Our new procedure for the conversion of phenols to thiophenols was used to prove the structure of such sulfur analogues.