Products 3a Research Articles

Phosphorus-nitrogen compounds. Part 40. The syntheses of (4-fluorobenzyl) pendant armed cyclotetraphosphazene derivatives: Spectroscopic, crystallographic and stereogenic properties, DNA interactions and antimicrobial activities

The Cl substitution reaction of octachlorocyclotetraphosphazene, N4P4Cl8 (1), with 1.2 equimolar amounts of sodium salt of N/O donor-type bidentate ligand (2) gave four different new (4-fluorobenzyl) pendant armed cyclotetraphosphazene derivatives; namely, mono-(4-fluorobenzyl)-spiro- (spiro; 3), mono-(4-fluorobenzyl)-2-cis-4-dichloro-ansa- (2,4-ansa; 4), bis-(4-fluorobenzyl)-2-trans-6-dispiro (5) and bis-(4-fluorobenzyl)-2-trans-4-dispiro (6) cyclotetraphosphazenes of which 3 was the major product (yield 55%). Compound 3 was treated with mono and difunctional reagents to prepare the fully substituted products (3a-3j) due to its very high yield. However, tetrapyrrolidino-2-cis-4-dichloro-ansa- product (4a) was obtained from the reaction of 2,4-ansa (4) with excess pyrrolidine. The new cyclotetraphosphazenes were characterized by elemental analyses, mass spectrometry (ESI-MS), Fourier transform infrared (FTIR), 1H, 13C, and 31P NMR techniques. The structures of 3 and 3g were determined by X-ray crystallography. 2,4-Ansa compounds (4 and 4a) have two stereogenic P atoms. The stereogenic property of 4 was identified by 31P NMR spectra in the addition of the chiral solvating agent, (R)-(+)-2,2,2-trifluoro-1-(9′-anthryl)-ethanol (CSA). The tetraspiro compounds (3i and 3j) look similar to a propeller, and they may have P and M atropisomers. The antimicrobial activities of the compounds were screened against some G(−)/G(+) bacteria and yeast strains. The interactions of the compounds with supercoiled plasmid pBR322 DNA and their inhibited DNA restriction were examined.

An access to a library of novel triterpene derivatives with a promising pharmacological potential by Ugi and Passerini multicomponent reactions

The promising combination of natural product leads and their derivatization by isocyanide-based multicomponent reactions (IMCRs) has gained interest in accessing diversity-oriented libraries with auspicious pharmacological potential. Therefore, a set of 34 Ugi and 3 Passerini products was successfully synthesized starting from naturally occurring triterpenoids, i.e. oleanolic acid (OA) and maslinic acid (MA), followed by a biological evaluation of the novel α-acylamino carboxamides and the α-acyloxy carboxamides in colorimetric SRB assays to determine their cytotoxic potential. Especially, the MA-Ugi products 6a, 6b and 7b showed a remarkable cytotoxicity for A2780 ovarian carcinoma cells in a low μM range. Compounds 6a and 7b induced programmed cell death in part through the apoptosis pathway.

Formation of Reactive π-Conjugated Frustrated N/B Pairs by Borane-Induced Propargyl Amine Rearrangement

N-Propargyltetramethylpiperidine reacts with a series of trans-alkenyl-B(C6F5)2 compounds to give the substituted alkenyl-bridged frustrated N/B Lewis pairs 5. Their structures and spectroscopic features indicate a pronounced participation of the mesomeric s-trans-iminium/borata-alkene resonance form. The compounds are thought to be formed in a stepwise addition/rearrangement process which is initiated by a trans-1,2-amine/borane FLP addition to the carbon-carbon triple bond to generate a reactive zwitterionic aziridinium/alkenylborate intermediate. Subsequent alkenylborate attack leads to opening of the activated three-membered heterocycle with clean formation of the products 5a-c. Treatment of the propargyl-TMP substrate with B(C6F5)3 gave a stable example of such an aziridinium/borate betaine, which was isolated and amply characterized. The products 5a-c are active N/B FLPs. They split dihydrogen heterolytically under mild conditions to give the respective NH+/BH- products 9a-c. These contain Z-configurated core C═C double bonds, which indicates rotational equilibration around the central C-C bond of 5a-c during this reaction. Structural and chemical features of the 5c system were analyzed by DFT calculations.

Synthesis, Substitution, and Oxidation of Imidazole‐2‐thione Based Tricyclic 1,4‐Dihydro‐1,4‐diphosphinines

Herein, the synthesis and chemistry of P‐functional tricyclic 1,4‐dihydro‐1,4‐diphosphinines is described, following a recent communication on their use as precursors of 1,4‐diphosphinines. In particular, ring formation of imidazole‐2‐thione‐based tricyclic 1,4‐dihydro‐1,4‐diphosphinines 4a,b {–[P(Me2N)IMSR,R]2–; IMSR,R = 1,3‐dialkylimidazole‐2‐thione‐4‐yl}, first detected as side products, has been optimized to access 4d–f {–[P(Et2N)IMSR,R]2–; IMSR,R = 1,3‐dialkylimidazole‐2‐thione‐4‐yl}. The 1,4‐dihydro‐1,4‐dichloro‐1,4‐diphosphinines 8a,b {–[P(Cl)IMSR,R]2–; IMSR,R = 1,3‐dialkylimidazole‐2‐thione‐4‐yl}, easily obtained from 4, are ideal starting materials for P‐substituted products 9a–c (P–R; R = nBu, TMSC2–). The P‐diorganoamino derivatives 4d–f are used to synthesize bis(P–oxides) 10a–c and bis(P‐sulfides) 11a–c, and similarly, the bis(P–borane) adducts 13a–c. The first examples of bis(spirophosphorane) derivatives 12a–c, featuring two benzodioxaphosphole units, are synthesized by the reaction of 4d–f with o‐chloranil. Attempts to access bis(phosphonium) derivatives using methyl trifluoromethanesulfonate have resulted in S‐methylation of 4d–f, and hence, have furnished the first examples of tricyclic 1,4‐dihydro‐1,4‐diphosphinines possessing two imidazolium units 14a,b {[–{P(Me2N)‐IMSMeR,R}2–](CF3SO3)2; IMSMeR,R = 1,3‐dialkyl‐2‐thiomethyl‐imidazolium‐4‐yl}.

Design and synthesis of novel bis-hydroxychalcones with consideration of their biological activities

In the present study, eight new substituted bis-hydroxychalcones for the first time were designed, synthesized, purified and fully characterized. Then their inhibitory effects on the diphenolase activity of mushroom tyrosinase were evaluated. The concentration of compounds to scavenge 50% of ABTS (IC50) values were calculated for all the synthesized compounds. IC50 values for 2,2-azinobis (3-ethylbenzothiazoline-sulfonate) assay (ABTS) were in the range of 0.130–0.39 mM. Synthesized compounds possessed an inhibitory effect on tyrosinase activity, too. All of the products were much more active than E and C vitamins. The high antioxidant activity of products could be due to the longer conjugated system which can stabilize the free radical by resonance through a longer system. The concentration of compounds to scavenge 50% of LDOPA (IC50) values were in the range of 0.2–0.6 mM for the tyrosinase inhibition screening Products 4a, 4c, 4d, 4e and 4g which have inhibitory properties comparable to kojic acid (KA). Molecular modeling studies have been performed to achieve insight into the binding mode of the synthesized compounds to the tyrosinase enzyme active site.

Synthesis of 8',11'-dihydrospiro[cyclohexane-1,2'-oxepino[2,3-h] chromen]-4'(3'H)-ones with ring closing metathesis as a key step.

A series of novel hybrid molecular entities incorporating various spiro chromanone scaffolds onto the benzannulated oxepine core moiety were synthesised using allylation, Claisen rearrangement, Kabbe condensation and Ring Closing Metathesis (RCM) as a key step. During the synthesis we found that the nitrogen functionality in the substrate influences significantly the catalyst load due to electronic effects. Several iterations have been carried out to achieve complete conversion to products 6a–6e.

A novel one-step synthesis of alkenylated 1,4-benzoquinone natural products

Event Abstract Back to Event A novel one-step synthesis of alkenylated 1,4-benzoquinone natural products Zhenyu Han1 and Dana Lashley1* 1 College of William & Mary, United States Naturally occurring quinones have widely exhibited therapeutic properties due to their bioactivity. In this work, we present a short and efficient one-step synthesis of benzoquinone derivatives based on alkenylation of 2-methyl-1,4-benzoquinone. An alkene side chain was introduced at C-6 and/or C-5 position, from the corresponding alkenylated bromide under zinc catalyst. Synthesized natural products 1a, 1b, and 2 were confirmed by 1H and 13C NMR spectroscopy and 1,1-ADEQUATE experiment. Figure 1 Acknowledgements We wish to express our thanks to William & Mary Charles Center and Chemistry Department for funding support. Keywords: Natural products (NPs), Quinone (C6H 4O2), 1,4-benzoquinone (BZQ), one-step synthesis, Alkenylations, Concise synthesis, Biochemistry, Organic synthesis and medicinal chemistry, Ubiquinone derivatives Conference: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference , Orlando, Florida, United States, 17 Sep - 20 Sep, 2018. Presentation Type: Poster Presentation Topic: Medicinal Chemistry Citation: Han Z and Lashley D (2019). A novel one-step synthesis of alkenylated 1,4-benzoquinone natural products. Front. Chem. Conference Abstract: National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE) 45th Annual Conference . doi: 10.3389/conf.fchem.2018.01.00001 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 02 Oct 2018; Published Online: 17 Jan 2019. * Correspondence: Dr. Dana Lashley, College of William & Mary, Williamsburg, United States, dlashley@wm.edu Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Zhenyu Han Dana Lashley Google Zhenyu Han Dana Lashley Google Scholar Zhenyu Han Dana Lashley PubMed Zhenyu Han Dana Lashley Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Synthesis of Some New Polyfunctionalized Pyridines

5‐Methyl‐2,4‐dihydro‐3H‐pyrazol‐3‐one and/or 5‐methyl‐2‐phenyl‐2,4‐dihydro‐3H‐pyrazol‐3‐one was reacted with arylidenemalononitrile in the presence of sodium alkoxide to give 2‐amino‐6‐alkoxy‐4‐arylpyridine‐3,5‐dicarbonitrile 4a–e instead of the reported pyrazolo[3,4‐b]pyridine‐5‐carbonitriles. The same products 4a–e were prepared via reaction of arylidenemalononitrile with sodium alkoxide in an appropriative alcohol. However, the new synthetic route for preparation of their positional isomer 4‐amino‐6‐alkoxy‐2‐arylpyridine‐3,5‐dicarbonitrile 7a–j has been achieved via reaction of 2‐aminoprop‐1‐ene‐1,1,3‐tricarbonitrile with different aromatic aldehydes under the same conditions.

Synthetic zeolites as potential sorbents of mercury from wastewater occurring during wet FGD processes of flue gas

This paper evaluates the suitability of fly ash-derived zeolites as sorbents of mercury in water and wastewater. The tested materials were type X and type A synthetic zeolites obtained by hydrothermal synthesis of Class F fly ash. Silver-modified type X fly ash-derived zeolites were also used to check the need for structural modification. The commercial products 4A and 13X zeolites were used as reference materials. Mercury sorption experiments were carried out under static conditions in an artificial solution with an Hg concentration in the range of 13.20–575 mg dm−3. In each case, the sorption efficiency was achieved at a level of above 90%. A second experiment involved the removal of mercury from real wastewater using the wet desulphurization process for flue gas. The results for the tested samples show extremely high sorption efficiency at a level of 99%. Based on these results, it can be stated that fly ash-derived zeolites have similar sorption properties to commercial products in terms of their used as mercury sorbents for liquid waste and are therefore a cost-effective substitute for commercially available products. The X and A types of the zeolite structure were found to remove mercury at a similar level.

Utility of chloroacetonitrile in construction of some hitherto novel pyrazole and thiazole derivatives

2-(-Piperidin-1-yl) acetamide (2) was easily prepared by reacting chloroacetonitrile with piperidine. Furthermore, (2) was allowed to react with different aromatic aldehydes to afford novel arylidene derivatives (3a,b). Unexpectedly, 2-oxo-4-hydroxy-thiazole (5) was obtained instead of 2-(piperidin-1-yl-methylene) thiazolidin-4-one (4) when (2) was treated with mercaptoacetic acid under fusion conditions. Subsequent treatment of (5) with aromatic aldehydes and either malononitrile or cyanoacetamide (1:1:1 molar ratios) produced the hitherto unknown pyrano[2,3-d] thiazole derivatives (6a,b) and (7). Novel pyrazole derivatives (8a, b) and (9) were synthesized upon cyclocondensation of (2) with aromatic aldehydes and hydrazine hydrate. Unfortunately, attempts to prepare novel isoxazole derivatives by utilizing hydroxylamine instead of hydrazine hydrate following the previous procedure were failed. Surprisingly, the uncyclized products (10a,b) were obtained rather than 3-hydroxy-4-piperidinyl-isoxazole (11a,b). Upon refluxing thiosemicarbazide with (2) and aromatic aldehydes under the same conditions, pyrazolinone carbothioamides (12), (13) and (14a-c) were obtained.

Synthesis of Novel Diverse Methoxybenzenes‐substituted 2H/4H‐chromene Derivatives in the Presence of InBr3 (5 mol%) and their Cytotoxic Activity

A series of novel 2‐(trifluoromethyl)‐2H/4H‐chromene‐3‐carboxylate isomers 3 and 4 functionalized with diverse methoxybenzenes 2 at position 4 in compound 3 and position 2 in compound 4 were prepared in different proportions by nucleophilic substitution on ethyl 2‐hydroxy‐2‐(trifluoromethyl)‐2H‐chromene‐3‐carboxylate 1 in single step promoted by Indium (III) bromide (5 mol%) a Lewis acid. Regiospecific isomers 3k, 3l, 3m, and 3n prepared by using sterically bulk 1,3,5‐trimethoxy benzene substrate 2e in this reaction. Further, isomers 3a and 4a independently on reaction with amines, only compound 3a could give Michael addition products 5a–c. All the compounds 3a–n, 4a–j, and 5a–c were screened for cytotoxic activity against four human cancer cell lines and found to show high activity at micromolar concentration. The compounds 4h and 5a–c showed promising cytotoxic activity against the tested cancer cell lines. Further, these compounds 4h and 5a–c were docked with protein (1SA0) on colchicine‐binding site of β tubulin suggesting that tubulin inhibition could be the possible mechanism of action for these compounds.

Synthesis of novel triazolothione, thiadiazole, triazole-functionalized furo/thieno[2,3-b]pyridine derivatives and their antimicrobial activity

ABSTRACTA series of novel triazolothione, thiadiazole, triazole-functionalized furo/thieno[2,3-b]pyridine derivatives 9a–l, respectively, were prepared starting from 2 (1H) pyridone 3 through selective O/S-alkylation followed by Thorpe–Ziegler cyclization to form furo/thieno[2,3-b]pyridine derivatives 6. Compounds 6 on reaction with hydrazine hydrate resulted carbohydrazide derivatives 7 and further reacted with diverse substituted phenyl isothiocyanates to form phenyl hydrazine carbothiamide derivatives 8. Each compound 8 is independently reacted in presence of NaOH, H2SO4, and N2H4.H2O to form triazolothione, thiadiazole, triazole-functionalized furo/thieno[2,3-b]pyridine derivatives 9a–l, respectively. All the products 9a–l were screened against Gram +ve, Gram –ve bacteria and fungal strains. Compounds 9c–h showed high activity against Bacillus subtilis microbial-type culture collection (MTCC) 121 at <8.0 micromolar concentration. Promising compounds further screened for minimum bactericidal concentration against B. subtilis MTCC 121 using ciprofloxacin as standard and found to show very good activity. These compounds also screened for biofilm inhibition activity against B. subtilis MTCC 121 using erythromycin as standard and confirmed the high activity.

Organocopper-based magnetically recoverable and reusable nanocatalyst for efficient synthesis of novel 1,2,3-triazole-based sulfonamides in green medium

We report robust green synthesis of novel 1,2,3-triazole-based sulfonamides bearing different motifs such as fluorine under click conditions in presence of a copper-based magnetically recoverable and reusable heterogeneous nanocatalyst. The organocopper catalyst at 0.5 mol.% was highly recyclable (up to five times) when recovered using an external magnet without significant loss in catalytic activity. The mild reaction conditions and excellent yields (69–95 %) make this protocol an attractive method for efficient synthesis of the title compounds. The structure of product 3a was determined by Rontgen crystal structure analysis.

Synthesis and stereogenic properties of N,N-spiro bridged bis(cyclotriphosphazene) compounds containing two equivalent chiral centres

The stereogenic properties of N,N-spiro bridged bis(cyclotriphosphazene) compound having four potential stereogenic phosphorus centres have been investigated. Two reaction pathways, in which same reactions were done in different order, were used to determine the isomer variety and to compare them. When the first route included unsymmetrically substitution (2-methylaminoethanol), aminolysis (n-butylamine) and deprotonation (sodium hydride) reaction steps, respectively, the second route consisted of aminolysis (n-butylamine), deprotonation (sodium hydride) and unsymmetrically substitution (2-methylaminoethanol) reaction steps, respectively. Both routes resulted in formation of the same products (4a and 4d) containing two equivalent chiral centres. The structures and stereogenic properties of the products, 4a and 4d were characterized by X-ray crystallography and 31P NMR spectroscopy on addition of the chiral solvating agent which is (R)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol. These new di-spiro derivatives (4a and 4d) bring about trans–trans and cis–cis geometric isomers and they are meso due to centre of the symmetry and plane of the symmetry.

Utility of 2-thioxo-pyrido[2,3-d]pyrimidinone in synthesis of pyridopyrimido[2,1-b][1,3,5]-thiadiazinones and pyridopyrimido[2,1-b][1,3]thiazinones as antimicrobial agents

BackgroundPyridopyrimidines are of current interest because of their extensive variety of biological and pharmacological activities.ResultsA series of pyrido[2′,3′:4,5]pyrimido[2,1-b][1,3,5]thiadiazinones was obtained by aminomethylation of pyridopyrimidinethione with formaldehyde solution (37%) and different primary aromatic amines. Another series of pyrido[2′,3:4,5]pyrimido[2,1-b][1,3]thiazinones was prepared by Michael addition reaction of pyridopyrimidinethione to the activated double bond of a number of arylidene malononitrile and 2-(benzo[d][1,3]dioxol-5-ylmethylene)malononitrile. The mechanisms of formation of the synthesized compounds were discussed and the assigned structure was established via microanalysis and spectral data (IR, 1H NMR, and Ms.). A comparative study of the biological activity of the synthesized compounds with chloramphenicol and trimethoprim/sulphamethoxazole is shown in Table 1. Generally, all synthesized compounds showed adequate inhibitory effects on the growth of Gram-positive and Gram-negative bacteria.ConclusionsIn this study, we use a simple (synthetic) strategy for the synthesis of pyrimidothiadiazines, based on their aminomethylation through the Mannich reaction; they have also been synthesized by the application of the Michael addition to activated nitriles. Mechanisms and structures of the newly synthesized compounds were examined: the antimicrobial activity of some selected compounds was evaluated, which demonstrated adequate inhibitory effects. Graphical abstractThe strategic structures of the products (7a–g).

Synthesis of Novel 3-chloro-3-(4-oxo-4H-pyrido[1,2-a]pyrimidin-3yl)acrylaldehydes and their Subsequent Knoevenagel Condensation with Various Active Methylene Compounds

Background: Simple and efficient method has been developed for the Knoevenagel condensation of novel 3-chloro-3-(4-oxo-4H-pyrido[1,2-a]pyrimidin-3yl)acrylaldehyde (5) with active methylene compounds such as malononitrile (6), 3-methyl-1-phenyl-pyrazole-5(4H)-one (7), 3-methyl-1Hpyrazole- 5(4H)-one (8), Meldrum’s acid (9), Barbituric acid (10) and 4-hydroxycoumarin (11) by stirring in ethanol at room temperature for 2 h in the presence of L-proline as a catalyst yielding the products 12a, b to 17a, b respectively. Methods: In this article, we reported a new synthesis of 3-chloro-3-(4-oxo-4H-pyrido[1,2-a]pyrimidin- 3yl)acrylaldehyde (5) which was prepared from the 2-aminopyridine 1 condensed with ethyl ethoxymethyleneacetoacetate (2) in ethanol under refluxing conditions for 4 h giving a product which has been characterized as ethyl 3-oxo-2-((pyridin-2-ylamino)methylene)butanoate 3 on the basis of its spectral data. On thermal cyclization, in diphenyl ether for 30 min at 255oC, 3a gave a product 4. Vilsmeier-Haack formylation of 4 at RT for 4 h gave a product 5. Condensation of 5 with malononitrile, 3-methyl-1-phenyl-pyrazole-5(4H)-one, 3-methyl-1H-pyrazole-5(4H)-one, Meldrum’s acid, Barbituric acid and 4-hydroxycoumarin (11) by stirring in ethanol at room temperature for 2 h in the presence of L-proline as a catalyst yielding the products 12a, b to 17a, b respectively. Result: A novel preparation of 3-chloro-3-(4-oxo-4H-pyrido[1,2-a]pyrimidin-3yl)acrylaldehyde (5) method is reported in this article, along with the condensation of 5 with various active methylene compounds by stirring in ethanol at room temperature for 2 h in the presence of L-proline as a catalyst yielding the products 12a, b to 17a, b respectively. The structures of the synthesized compounds were confirmed by 1H-NMR, 13C-NMR, GC-MS and IR spectral data. All of the intermediates were structurally characterized IR (KBr): 1747 and 1697 cm-1 (strong, sharp of absorptions due to the -CHO and -N-CO-). 1H-NMR (DMSO-d6/TMS): δ 7.4-7.8 (t, 3H, Ar-H), 8.7 (s, 1H, α-H to the enamine nitrogen), 9.2 (q, pyridine ring proton), 10.2 (s, 1H, -CHO). LC-MS (HR-MS): m/z 235.0271, [(C12H14N2O3) +H]+. Conclusion: In conclusion, L-proline has been employed as an efficient catalyst for the preparation of a simple, efficient method for the synthesis of condensed compounds and a novel synthetic route to 3- chloro-3-(4-oxo-4H-pyrido[1, 2-a]pyrimidin-3yl)acrylaldehyde(5), whose condensation with active methylene compounds (6-11) reactions at RT, led to products 12-17. Keywords: Active methylene compounds, Knoevenagel condensation, L-proline, Pyridopyrimidines, Vilsemeier-Haack formylation.

A theoretical study on platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene

Density functional theory calculations are carried out to explore the reaction mechanism for the cycloisomerization of 2-ethynyl-1-ferrocenylbenzene by using PtCl2 as a catalyst at the M06-2X/6-31G (d, p) (LanL2DZ (f) for Pt, Fe) level. The calculation results prove that the platinum-catalyzed cycloisomerization of 2-ethynyl-1-ferrocenylbenzene includes two possible pathways and three steps to afford naphthalene fused ferrocene. One reaction pathway is based on the 6-endo-dig cyclization mechanism, and another pathway is on the alkyne-vinylidene rearrangement mechanism. The channel 1 has a lower activation free energy by 17.0kcal/mol, which is more favorable to obtain the major product 2a. However, the activation barrier for the channel 2 is relatively high by 22.7kcal/mol. Through the detailed computational study, the results show that the platinum-catalyzed cycloisomerization has the good reactivity and high yield, giving a good explanation for the experimental observed major product.

Design, synthesis and antibacterial evaluation of 2-alkyl- and 2-aryl-3-(phenylamino)quinazolin-4(3H)-one derivatives

Abstract 2-Alkyl and 2-aryl-3-(phenylamino)quinazolin-4(3H)-ones 4a–h were synthesized in a one-pot three-component condensation of an isatoic anhydride 1a–h, ethyl or methyl ortho ester and phenylhydrazine in the presence of KAl(SO4)2·12H2O (alum) as a nontoxic, reusable, inexpensive and easily available catalyst. The synthesis was conducted under microwave irradiation or classical heating. Products 4a and 4b show good antimicrobial activities.

Kinetic Resolution of Planar-Chiral (η5-Bromocyclopentadienyl)manganese(I) Complexes by Molybdenum-Catalyzed Asymmetric Ring-Closing Metathesis

Kinetic resolution of racemic planar-chiral (η5-1-alkenyl-2-bromocyclopentadienyl)manganese(I) complexes 1 was realized by the molybdenum-catalyzed asymmetric ring-closing metathesis. While vinyl-Cp derivative 1a was resolved in excellent enantioselectivity with the krel values of up to 127, the selectivity in the ARCM reaction of allyl-Cp derivative 1b was modest (krel = 3.0). ARCM product 2a, which was obtained in an enantiomerically pure form by the two successive ARCM reactions or recrystallization of the enantiomerically enriched products, was found to be a versatile synthetic precursor to various planar-chiral cymantrene derivatives.

Evidence of Oxygen Activation in the Reaction between an N-Heterocyclic Carbene and M3N@Ih(7)-C80: An Unexpected Method of Steric Hindrance Release.

We herein demonstrate for the first time the unexpected oxygen-involving reaction between M3N@Ih(7)-C80 (M = Sc, Lu) and 1,3-bis(diisopropylphenyl)imidazol-2-ylene (1). By introducing a tiny amount of oxygen into the reaction, unprecedented products (2a for Sc3N@C80 and 3a for Lu3N@C80) with the normal carbene center C2 singly bonded to a triple hexagonal junction (THJ) cage carbon together with an oxygen atom bridging the same THJ carbon atom and a neighboring carbon atom forming an epoxy structure are obtained. In situ mechanism study, in combination with theoretical calculations, reveals that the bond-breaking peroxidation facilitates the formation of the unexpected products 2a and 3a, providing new insight into fullerene chemistry.