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[3+2+2] Cycloaddition reactions are of key importance in organic chemistry for the synthesis of seven-membered mono- and condensed carbocycles. This review article summarises the different reports on transition-metal-catalysed [3+2+2] cycloaddition reactions since 2000. Different transitionmetals, such as Ni, Rh, Pd, Co, or Ru, which have been earlier reported for higher order [3+2+2] cycloaddition reactions are summarized in this article. The [3+2+2] cycloadditions of different functionalized substrates afford cycloheptane derivatives, 6-7,5-7 condensed bicyclic carbocycles, or 5-7-5 or 6-7-5 condensed tricyclic carbocycles. These higher order cycloaddition reactions may provide an easy route for the total synthesis of natural products, or as a preferable key synthetic step leading to final structure. [ABSTRACT FROM AUTHOR]

Acetylenic ester promoted ring opening of dienyl-thiazolidin- 4-ones and subsequent electrocyclization affords 5-phenyl-6-aryl pyridine-2-carboxylates in good to excellent yields. [ABSTRACT FROM AUTHOR]

Control over the self-assembly of bay functionalized perylene diimides and the response of these self-assembled materials towards analytes in mixed aqueous–organic media is important to consider the potential of this intriguing dye family in supramolecular chemistry. Herein, we have designed and synthesized allylcarbonate-functionalized perylene diimide AC-PDI which shows solvent dependent supramolecular nanostructures and could readily self-assemble into nanorods of tens of μm in length in CH3CN, but the length of the rods drammatically decreased to 0.8–1.2 μm in a H2O : CH3CN (1 : 1, v/v) mixture. Interestingly, AC-PDI self-assembles into nanowires of several tens of μm in length in a 30% H2O:DMSO mixture and forms only nanospheres in ethyl acetate. AC-PDI can be used as a near-infrared (NIR) colorimetric (λabs 685 nm) and fluorescent (λem 530/570 nm) probe for selective detection of Pd0 [LOD = 39 nM (UV); 45 nM (FI)]. Furthemore, TLC strips coated with the AC-PDI probe could detect 0.58 pg cm−2 of Pd0 in the solid state. The mechanism of interaction of AC-PDI with Pd0 has been confirmed by 1H NMR titration, kinetic and morphological studies. [ABSTRACT FROM AUTHOR]

In this work, we have designed and synthesized a perylene diimide based derivative PDI-SiHQ having an O-silylated-8-hydroxyquinoline group at the bay position. PDI-SiHQ is able to detect and differentiate CN− from F− in the presence of other anions. The electron transfer from cyanide ions to PDI-SiHQ leads to the emergence of panchromatic and NIR absorption bands due to the formation of a PDI-SiHQṖ− radical anion. In contrast, fluoride induced desilylation of PDI-SiHQ coupled with π–π aggregation results in a red-shifted absorption band at 730 nm. 1H NMR and cyclic voltammetry combined with the reversal of the PDI-SiHQṖ− radical anion to the PDI-SiHQ neutral form in the presence of NOBF4 or Cu2+ ions confirm the formation of the radical anion in PDI-SiHQ. Multi-channel UV-Vis-NIR absorption and emission bands and their reversibility with NOBF4/Cu2+ ions offer the possibility for fabrication of complex logic circuits such as complementary IMP/INH logic circuits, magnitude comparators and ‘set–reset’ flip flop memory elements. [ABSTRACT FROM AUTHOR]

Abstract: A novel, efficient and one‐pot multicomponent copper‐catalyzed amination of N‐pyridyl imines is described. This, one‐pot, multicomponent reaction, in which imine acts as a directing group by chelating to the metal core, affords a domino approach for the transformation of the commercial pyridinamines, aldehydes and azide into valuable imidazo[4, 5‐b]pyridines with wide substrate extent and diversity. [ABSTRACT FROM AUTHOR]

The detection and quantification of spermine in clinical practice is important for early diagnosis of many diseases. Chromatographic and immunoassay-based methods are commonly used. However, a fluorescence-based assay could provide real-time detection. Herein, the synthesis and aggregation properties of a dicationic perylene probe ( N1-dodecyl- N3-(4-phenyl)benzimidazolium-functionalized perylenediimide ( DAB-PDI)) used to develop a fluorescent 'turn-on' ensemble for the detection of spermine are discussed. The fluorescence of DAB-PDI (10 μ m, Φ=0.55) is efficiently quenched by negatively charged sodium dodecylsulfate (SDS) through the formation of ionic self-assembled aggregates (charge ratio of negative (N) in SDS to positive (P) in DAB-PDI (N/P)=9). This negatively charged ionic self-assembly between DAB-PDI and SDS has been characterized by using photophysical, microscopic, dynamic light scattering, isothermal titration calorimetry, and HRMS techniques. The addition of spermine to this ensemble solution results in the breakdown of the DAB-PDI-SDS ensemble owing to strong binding of spermine with SDS and, as a result, the fluorescence of DAB-PDI is recovered. This ensemble exhibits high sensitivity and selectivity for spermine detection in water, urine, and blood serum. The lowest limit of detection is 27.5 n m, which is at least about 36 times lower than that required for early diagnosis of cancer (1 to 10 μ m for urinary spermine). [ABSTRACT FROM AUTHOR]

Diphenylpyrimidinone–salicylideneamine DPPS-1 undergoes concentration dependent self-assembly to form aggregates with rods – mimicking a ‘coral reef’ superstructure and a spherical morphology evident from dynamic light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). DPPS-1 and DPPS-2 exhibit weak excited state intramolecular proton transfer (ESIPT) based emission in CH3CN and their binary mixtures with water, but in solutions containing ＞70% water fraction DPPS-1 and DPPS-2 molecules aggregate and ESIPT is facilitated to give a strong green ESIPT emission at 526 nm (Φ = 0.273, 0.068). The ESIPT process remains active in the solid state and solid DPPS-1 and DPPS-2 appear as fluorescent green under 365 nm light illumination. The AIE-active nature of DPPS-1 and DPPS-2 finds applications in the visualization of latent fingerprints on aluminium, steel and glass surfaces. Even 24 h after the placement of the fingerprints, up to the second level of information viz. core, lake, ridge termination and dots, delta and bifurcation in the fingerprints could be identified. [ABSTRACT FROM AUTHOR]

The manuscript describes a facile and highly diastereoselective synthesis of cis-3-(hydroxy/bromo)methyl-1-aryl-4-(-styryl)azetidin-2-ones via copper(i) mediated Kinugasa reactions of previously unexplored functionalized α,β-unsaturated nitrones. A variety of functionalized acetylenes and α,β-unsaturated nitrones were studied to yield cis-3-(hydroxy/bromo)methyl-1-aryl-4-(-styryl)azetidin-2-ones in good yields (82%). [ABSTRACT FROM AUTHOR]

The reactions of butadienylketene with variety of 1,4-diazabuta-1,3-dienes are studied. The reactions resulted in the formation of previously unknown functionalized cis butadienyl-4-iminomethyl-azetidin-2-ones and butenylidene-butadienyl-[2,2′-biazetidine]-4,4′- diones. Butadienyl ketene reacts in fashion with both iminic portion of 1,4- diazabuta-1,3-dienes and competitive [4+2] of 1,4-diazabuta-1,3-dienes as 4π component with butadienyl ketene as 2π component are not observed. [ABSTRACT FROM AUTHOR]

Herein, we report design, synthesis, and self-assembly of perylene diimide (PDI) based near-IR intracellular probe (PS-PDI). PS-PDI molecules undergo aggregation to form self-assembled nanospheres and nanorods morphology in THF : H2O (1 : 1) and DMSO : H2O (1 : 9), respectively. The nanospheres have an open hole on surface reminiscent of vesicle structure (with a diameter of internal void in the range of 20–25 nm) whereas lengths of the nanorods extended up to few μm range. The Pd0 based depropargylation leads to de-aggregation of these PS-PDI aggregates into smaller spherical aggregates as evidenced by DLS, SEM, and TEM studies. Interestingly, these aggregates of PS-PDI in solution show highly sensitive behavior in the presence of Pd0 showing absorbance changes in NIR region (λmax = 710 nm) and quenching of emission at λem 630 nm (DMSO : H2O, 1 : 9) with a limit of detection = 6.6 × 10−9 M or at λem 564 nm (THF : H2O, 1 : 1) with limit of detection = 2.1 × 10−8 M. Time and concentration dependent kinetics profiles of PS-PDI aggregates revealed an impressive rate constant value of 0.4 s−1 and 0.21 s−1 (DMSO : H2O, 1 : 9), respectively in fluorescence and UV-Vis spectroscopy using 2 × 10−5 M concentration of Pd0. PS-PDI undergoes rapid internalization into HeLa cells with low cytotoxicity and was successfully used as an intracellular imaging reagent for Pd0 in live HeLa cells. For practical applications, we exploited these nano-aggregates of PS-PDI for estimation of Pd2+ in the presence of a NaBH4–PPh3 mixture, Pd0 in drug and environmental samples, and Pd2+ in urine samples with excellent selectivity and sensitivity. [ABSTRACT FROM AUTHOR]

We designed and synthesized the mono bay functionalized perylenediimide (PDI) derivative PDI-DMEA which undergoes self-assembly to form a nanorod morphology. The diameter of these nanorods is in the range of 150–300 nm and the length extended up to the μm range. These nanorods on interaction with Cu2+ ions transformed into spherical aggregates having a diameter of 350–600 nm in accordance with DLS studies. In solution, PDI-DMEA shows a blue shift of the internal charge transfer (ICT) absorption band from 605 to 570 nm along with a hyperchromic effect at 570 nm, in the presence of 0.7 equivalents of Cu2+ ions. The addition of 2 equivalents of Cu2+ ions results in complete disappearance of the ICT band at 570 nm and appearance of a normal absorption band of PDI at 515 nm (a visual colour change from colourless to yellow). On the other hand PDI-DMEA shows a strong fluorescence ‘turn-on’ response at 537 and 573 nm on addition of higher equivalents of Cu2+ ions. Thus, PDI-DMEA represents several examples of molecular switches such as ‘OFF–ON–OFF’ and ‘ON–OFF–ON’ at 570/515 nm (Cu2+, absorbance), and ‘OFF–ON’ at 570 nm (Fe2+, absorbance) and 537 nm (Cu2+, fluorescence) and thus offers the possibility for developing NOR, OR, INH and TRANSFER logic and complimentary logic circuits. Moreover, PDI-DMEA and the PDI-DMEA–Cu2+ complex show fluorosolvatochromism which helps to develop a colour array for differentiating organic solvents. The detailed mechanism of interaction of Cu2+ and Fe2+ with PDI-DMEA, confocal laser scanning microscopic studies, dynamic light scattering, 1H NMR titration and reversibility are discussed. [ABSTRACT FROM AUTHOR]

Tandem aza-Michael addition of 3-amino-2-azetidinones with acetylenic esters and subsequent intramolecular amidic ring opening of the initially formed azetidin-3-ylaminoprop- or -but-2-enoic ester is described. The reaction provides a facile route for the formation of functionalized 4-oxo-4,5-dihydro-1H-pyrroles in good yields. [ABSTRACT FROM AUTHOR]

Chemosensor 1 shows three different responses towards Cu2+, acetate and Cu(OAc)2 ion pair at different wavelengths independently in its absorption and fluorescence behaviour following a triple-signaling mechanism, namely, internal charge transfer (ICT), C=N rotation and excited state intramolecular proton transfer (ESIPT). Chemosensor 1 shows a blue shift of the absorption band from 337 nm to 308 nm in the presence of Cu2+ ions (ICT). It exhibits a fluorescence ‘turn-off’ response at λem 458 nm in the presence of 1 equivalent of Cu2+ ions. The further addition of Cu2+ (6 equivalents) results in ∼24 times enhancement in the emission intensity at λem 427 nm, mimicking an ‘ON–OFF–ON’ molecular switch (ESIPT and C=N rotation). The addition of acetate ions to a solution of 1 results in a red shift of the absorption band from 337 to 360 nm (ICT) and ∼4 times enhancement of the emission intensity at λem 458 nm (ESIPT). On the addition of a Cu(OAc)2 ion pair, 1 shows the apparent effect of Cu2+ (blue shift, 337 to 308 nm) and acetate (red shift, 337 to 380 nm), which indicates the synergistic effect of both Cu2+ and AcO− on each other's binding. The potential application of chemosensor 1 for the construction of INHIBIT (INH), IMPLICATION (IMP), AND, NOR, YES and NOT logic gates using Cu2+ and acetate as the inputs and absorbance/emission as the outputs is elaborated. [ABSTRACT FROM AUTHOR]

Highly diastereo- and π-facially selective imino Diels–Alder cycloadditions of 3-allylideneamino-2-azetidinones having stereocentres at its α- and β-positions, with symmetrical dienophiles leading to the formation of biologically potent (2-oxo-4-styrylazetidin-3-yl)–pyridine hybrids have been reported. [ABSTRACT FROM AUTHOR]

The aggregates of perylenediimide based chemosensor (PDI 1) undergo de-aggregation induced fluorescence quenching selectively with ClO4- ions both in the solution and in the solid phase and can detect ClO4- ions in drinking water and fireworks. PDI 1 is permeable to C6 glioma cells, and ClO4- can be detected using confocal microscopy. [ABSTRACT FROM AUTHOR]

A Rh-catalyzed intramolecular [3+2+2] cycloaddition is reported. The cycloaddition affords synthetically relevant 5,7,5-fused tricyclic systems of type 2 from readily available dienyne precursors. The transformation takes place with moderate or good yields, high diastereoselectivity, and total chemoselectivity. [ABSTRACT FROM AUTHOR]

Abstract: The regioselective nitroso Diels–Alder (NDA) cycloadditions of 3-dienyl-2-azetidinones with nitrosobenzene to generate oxazine-substituted β-lactams in excellent yields are reported. The amidiolytic ring opening of the cycloadducts with sodium methoxide followed by iodocyclization using I2/K2CO3 etiquette to capitulate previously unknown, multisubstituted pyrroloxazine in outstanding yields is also accounted. [Copyright &y& Elsevier]

Polymeric membrane electrodes (PMEs) and coated graphite electrodes (CGEs) containing 1,3,4-trisubstituted-2-azetidinone derivatives as ion carriers are reported here for bismuth(III) ion selectivity. These electrodes exhibited Nernstian response for Bi3+ ions over a wide concentration range (5.0 × 10-7 M to 1.0 × 10-1 M for CGE) with a lower detection limit of 3.98 × 10-7 M (for CGE) and wide pH range (1.3-5.0). Compared to polymeric membrane electrode, the coated graphite electrode has shown better selectivity for Bi3+ ions with respect to common metal ions. Proposed electrodes have been used for the estimation of Bi3+ ions in pharmaceutical and glass samples. [ABSTRACT FROM AUTHOR]

The chemo- as well as regioselective participation of N-aryl imines as 4π component in aza-Diels-Alder reactions with 3-butadienyl-2-azetidinones in the presence of Lewis acid catalysts resulting in novel quinoline derivatives is described. [ABSTRACT FROM AUTHOR]

Abstract: The chemo- as well as regioselective aza Diels–Alder reactions of 5-dienyl pyrimidinones with N-arylimines in the presence of a Lewis acid catalyst resulting in novel quinoline derivatives are reported. [Copyright &y& Elsevier]

This paper presents novel via-only bandpass filters for a wide range of microwave/millimeter-wave frequencies. The design is based on rigorous field-theory analysis of a dielectric-loaded inductive-iris waveguide section combined with an impedance-inverter-based filter synthesis to realize maximally flat or Chebyshev characteristics. The new filter configurations are simple to realize, easy to fabricate, and highly suitable for LTCC and organic technologies. This study is carried out in order to examine the effect of the placement of continuous vias replacing the conducting side walls in iris-waveguide filters. Three bandpass filters in the new configuration are designed at center frequencies of 10, 14, and 29 GHz for the X, Ku, and Ka bands, respectively. For all the designs, the theoretical responses have been validated with commercially available full-wave electromagnetic simulation software. Since the design methodology is based on rigorous full-wave field-theory analysis, the proposed technique offers a high degree of accuracy. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 47: 215–218, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21127 [ABSTRACT FROM AUTHOR]

Abstract: The present Letter describes the use of β-lactams for the synthesis of functionalized β-amino esters and their transformation to trisubstituted octahydroisoquinolone derivatives in good yields with an extension to their one-pot synthesis. [Copyright &y& Elsevier]

We report a Pd-catalyzed intramolecular [3C + 2C + 2C] cycloaddition between alkylidenecyclopropanes, alkynes and alkenes. The method provides synthetically relevant 5-7-5 tricyclic structures, with good chemoselectivity and complete diastereoselectivity. [ABSTRACT FROM AUTHOR]

Abstract: The regioselective aza Diels–Alder reactions of isopropenyl pyrimidinone with N-arylimines in the presence of Y/Sc triflates as catalyst are described. An unprecedented oxidation of methylene to carbonyl occurred resulting in exclusive formation of 6-oxo-1,6-dihydropyrimidin-5-yl-4H-quinolin-3-one derivatives. [Copyright &y& Elsevier]

Abstract InhA is an enoyl acyl carrier reductase that catalyzes the chemo-selective reduction of its 2-trans-enoyl-ACP substrate. The pharmacological effects of the frontline medications used in the treatment of tuberculosis are elicited by inhibiting the enzyme InhA, which disrupts the mycolic acid biosynthesis pathway. The present study involves development of ligand-based pharmacophore model, docking studies, generation of 3D-QSAR model, and molecular dynamic simulation studies of virtually screened putative InhA inhibitors. The best field-based 3D-QSAR model was validated using partial least-square regression (PLS) method with high regression coefficient for training set (R 2) = 0.9256 and test set (R 2) = 0.7542, cross-validated coefficient (r cv 2) = 0.72 and R 2 pred = 0.9764. Also, virtual screening yielded compounds 4, 25, 1, and 30 exhibiting appreciable interactions (docking scores −5.972, −3.819, −3.801, and −3.701, respectively with InhA synthetase; PDB ID: 1BVR). Further, ADMET studies supported drug-like potential of compounds 25, 1, and 30 whereas compound 4 showed negligible human oral absorption. The molecular dynamic simulation studies of the top scored molecule 25 suggested stability of 25-1BVR complex over the course of simulation run. Therefore, this work can be helpful for future discovery of novel InhA inhibitors against drug-resistant tuberculosis. [ABSTRACT FROM AUTHOR]

Abstract The reported work presents the diastereo, regio-, and π-facial selective synthesis of hetero-Diels-Alder (H-DA) cycloadducts with diazene derivatives viz. di-isopropyldiazocarboxylate and diethylazodicarboxylate with cis-/trans-3-butadienyl-β-lactams having stereocentres at its α and β-position. The H-DA reactions resulted in the formation of β-lactam tethered—3,6-dihydro-pyridazines in good yields. [ABSTRACT FROM AUTHOR]

A green, sustainable, and efficient one-pot, synthetic strategy for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones (DHQs) was developed. The ZnCl2/urea used as a deep eutectic solvent (DES) not only efficiently promoted the condensation between isatoic anhydride and benzaldehyde but unexpectedly acted as a nitrogen source (like ammonia) in situ to afford DHQs in excellent yields. This approach offers remarkable advantages, involving the triple role of DES in the synthesis of DHQs, atom-economical, green organocatalysts, metal-free conditions, cost-effectiveness, and tolerance to a range of functional groups. [ABSTRACT FROM AUTHOR]