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The influence of peripheral substitution and the nature of the macroheterocyclic heteroatoms on the basicity of hydrophilic 5,10,15,20-tetraarylporphyrins in the lowest excited singlet S1 state was studied using absorption and fluorescence spectroscopies. The basicity of the porphyrins themselves in the lowest excited singlet S1 state was found to decrease as compared to the ground S0 state. The difference in basicity constants pKa depended on the nature of electronic communication between the macrocycle and peripheral substituents. In the case of an inductive effect of the substituents, the difference in the basicity constants pKa was small, while mesomeric effects led to significant differences in the pKa values. The cooperative nature of protonation, leading to almost simultaneous addition of two protons, was shown to be preserved in both cases. Replacement of a pyrrole with a thiophene in the macroheterocycle led to a decrease in cooperativity in both the ground S0 and the lowest excited singlet S1 states. The basicity constants characterizing the addition of the second and third protons by thia-substituted porphyrin differed significantly in the S1 state (pKa2 – pKa1 = 2), while they were close in the ground state. The activation entropy change ΔΔS‡ upon protonation of the porphyrins in the lowest excited S1 state was compared to that in the ground S0 state. [ABSTRACT FROM AUTHOR]

Two series of dinuclear organotin macroheterocycles of general formula [R2Sn{Ch(C6H4CH2)2}2SnR2] [Ch = O with R = n-Bu (2a), Bn (3a), Ph (4a) and Ch = S with R = n-Bu (2b), Bn (3b), Ph (4b)] were easily synthetized by a Barbier-type reaction assisted by sonochemical activation of metallic magnesium. The 119Sn{1H} NMR data for all compounds and the X-ray single-crystal diffraction studies for 2a and 4a confirmed the presence of a central Sn atom in a four-coordinate environment. The molecular structures of 2a and 4a showed puckered 16-membered macroheterocycles. The tin and oxygen atoms are in the interior of the cavity of the macrocycle, surrounded by hydrophobic C–H bonds. A Hirshfeld surface analyses of 2a and 4a showed that the macrocycles are linked by weak C–H···π, C···C, and H···H non-covalent interactions. The pairwise interaction energies showed that the cohesion between the macrocycles are mainly due to dispersion forces. [ABSTRACT FROM AUTHOR]

An effective synthesis of four potentially biologically active O- and N-containing 23-, 28-, 30-, and 31-membered macroheterocycles from undec-10-enal was carried out. First, undec-10-enal was converted to undec-10-enyl undec-10-enoate via the Tishchenko disproportionation reaction catalyzed by Al(i-PrO)3. The subsequent Wacker–Tsuji oxidation of undec-10-enyl undec-10-enoate gave 10-oxoundecanyl 10-oxoundecanoate. Finally, the [1+1]-condensation of 10-oxoundecanyl-10-oxoundecenoate with hydrazine hydrate or malonic, glutaric, or adipic acid dihydrazides resulted in the synthesis of four macroheterocycles. [ABSTRACT FROM AUTHOR]

The mini‐review is devoted to the influence of the structure and properties of chiral macroheterocyclic dopants on the induction of helical liquid‐crystalline phases. Using the example of solutions of synthetic porphyrins, camphor substituted hemiporphyrazines and tetrapyrazinoporphyrazines, as well as chemically modified natural macrocycles based on chlorin e6 derivatives and their metal complexes in nematic liquid crystals, the features of the mesomorphic, dielectric and rheological properties of induced spiral mesophases are discussed. [ABSTRACT FROM AUTHOR]

This review presents all currently known macroheterocyclic compounds that include a bispidine (3,7-diazabicyclo[3.3.1]nonane) fragment in their structure. A classification of bispidine-containing macroheterocycles, which is based on the ring size and the nature of bispidinic nitrogen atoms, is suggested. Synthetic approaches to the studied compounds are classified and considered. The features of the crystal structures and solution behavior of bispidine macroheterocycles are analyzed. Prospects for the development of these organic receptors are proposed.

(E)-16-Aryl-substituted tricyclic diterpenoids were synthesized by the cross coupling of isopimaric acid derivatives with substituted iodoarenes, catalyzed by palladium acetate in the presence of silver carbonate. The condensation of the resulting (E)-18-nor-4-(2-carboxyethyl)-16-(2-carboxyphenyl)isopimara-7,15-diene dichloride with propargylamine hydrochloride leads to the corresponding dialkyne, which readily enters a Cu(I)-catalyzed cycloaddition with 1,2-bis(2-azidoethoxy)ethane. The main product of this reaction is a macroheterocyclic compound containing a pimaran type tricyclic diterpenoid fragment and 1,2,3-triazole rings in the linker chain. The reaction of the in situ prepared (E)-18-nor-16-azido-4-(2-carboxyethyl)isopimara-7,15-dienoic acid chloride with propargylamine hydrochloride or alkynyl-substituted derivative of the protected Gly–Gly dipeptide gave the corresponding azidoalkynes. The intramolecular CuAAC reaction of azidodipeptidylalkyne resulted in the preparation of a macroheterocyclic derivative containing dipeptide and triazole fragments in the linker chain. The synthesized compounds showed a higher (compared to isopimaric acid) cytotoxicity on MCF7, U-87 MG, and DU 145 cancer cell models and were less toxic to non-cancer cells than the reference drug Doxorubicin. The GI50 of the most active compound was 6.3 μM (selectivity index >15) (MTT test). The synthesized derivatives of the tricyclic diterpenoid isopimaric acid can be used to develop new anticancer agents. [ABSTRACT FROM AUTHOR]

This review presents all currently known macroheterocyclic compounds that include a bispidine (3,7-diazabicyclo[3.3.1]nonane) fragment in their structure. A classification of bispidine-containing macroheterocycles, which is based on the ring size and the nature of bispidinic nitrogen atoms, is suggested. Synthetic approaches to the studied compounds are classified and considered. The features of the crystal structures and solution behavior of bispidine macroheterocycles are analyzed. Prospects for the development of these organic receptors are proposed. [ABSTRACT FROM AUTHOR]

The geometry and electronic structures of iron(II) complexes with porphyrin (FeP) and tetrabenzoporphyrin (FeTBP) in ground and low-lying excited electronic states are determined by DFT (PBE0/def2-TZVP) calculations and the complete active space self-consistent field (CASSCF) method, followed by the multiconfigurational quasi-degenerate second-order perturbation theory (MCQDPT2) approach to determine the dynamic electron correlation. The minima on the potential energy surfaces (PESs) of the ground (3A2g) and low-lying, high-spin (5A1g) electronic states correspond to the planar structures of FeP and FeTBP with D4h symmetry. According to the results of the MCQDPT2 calculations, the wave functions of the 3A2g and 5A1g electronic states are single determinant. The electronic absorption (UV–Vis) spectra of FeP and FeTBP are simulated within the framework of the simplified time-dependent density functional theory (sTDDFT) approach with the use of the long-range corrected CAM-B3LYP function. The most intensive bands of the UV–Vis spectra of FeP and FeTBP occur in the Soret near-UV region of 370–390 nm. [ABSTRACT FROM AUTHOR]

Methods for obtaining basic substituted gem-dichlorocyclopropanes and 1,3-dioxacyclanes based on petroleum products are considered. Separate reactions of O-, N-, C-alkylation of these compounds leading to the formation of heterocycles containing gem-dichlorocyclopropane and 1,3-dioxolane fragments are presented. Data are provided on radical polymerization, copolymerization, low-temperature ozonolysis, catalytic isomerization of vinyl-gem-dichlorocyclopropanes, as well as the study of reactions of 2,2-dimethyl-1,3-dioxolane with diazoacetoacetic ester. The possibilities of using the synthesized substances as biologically active compounds, as well as preparations capable of inhibiting the acid corrosion of metals, are shown. [ABSTRACT FROM AUTHOR]

Interatomic interactions in four zinc(II) phthalocyanine tetrafluoro derivatives with substituents in non-peripheral positions are analyzed by quantum chemistry methods. Regions of non-covalent interactions are discovered between H⋯N and F⋯N contacts; the energies of interaction between the corresponding atoms are determined. It is shown that the relative energy of considered compounds increases with the increasing number of short F⋯F contacts. [ABSTRACT FROM AUTHOR]

Structural parameters and relative Gibbs free energies are calculated by density functional theory methods for four tetrafluoro derivatives of zinc(II) phthalocyanine with substituents in non-peripheral positions. It is established that the least symmetrical isomer exhibits the highest thermodynamic stability under standard conditions. It is shown that the experimental IR spectrum of the studied compound contains contributions from the IR spectra of the corresponding isomers; a theoretical approach for the spectrum simulation is proposed. [ABSTRACT FROM AUTHOR]

The molecular structure of mononuclear noncentrosymmetric complexes of Y, La, and Lu with the ABABAB-type six-membered porphyrinoid hemihexaphyrazine H3Hhp of the composition MH2Hhp was studied using the DFT method. It was determined that the macrocyclic ligand of these complexes has a planar structure. The electronic density distribution in the MH2Hhp molecules was studied by QTAIM calculations and NBO analysis. It was shown that, in each complex, three coordination bonds are formed among the M atom and the nitrogen atom of the pyrrole fragment and two nitrogen atoms of the neighboring thiadiazole fragments. The H2Hhp ligand is quasi-tridentate, although the complexes MH2Hhp are formed by the substitution of only one hydrogen atom. It was demonstrated that the electronic structure of the complexes MH2Hhp is inconsistent with the conventional concepts of the oxidation states of the metal and the ligand in such structures (MI+H2HhpI–). Calculations by the TDDFT method determined that the electronic absorption spectra of the complexes MH2Hhp contain absorption bands in the IR region, and that the complexes can have pronounced donor properties. [ABSTRACT FROM AUTHOR]

Supramolecular complexes of proteins with macroheterocyclic compounds are unique structures that differ significantly from classical supramolecules in both complexity of organization and multiplicity of functions. Studying natural and creating synthetic supramolecular systems provide a means to control biochemical processes and also open up new prospects for practical use of macroheterocycle–protein supramolecules. Interest in supramolecular systems is annually increasing because they are highly diverse, include a variety of initial components, allow chemical and biochemical modification, and are capable of participating in photoinduced and thermally induced reactions. Macroheterocyclic components of supramolecular systems affect the affinity of the protein moiety for other ligands and may confer new properties on supramolecules. The review analyzes and summarizes the results of theoretical and experimental studies of the driving forces of molecular self-organization and the formation of supramolecular complexes. Particular attention is paid to protein–macroheterocycle supramolecules, which are of applied significance for the design of artificial photosystems and biomedical fields, such as photodynamic and photothermal therapy, photoinactivation of bacteria, and medical diagnosis. Problems in each of the fields are considered along with possible ways to solve them. [ABSTRACT FROM AUTHOR]

The title compound, C30H34N2O9 (4), is a product of the Michael reaction of azacrown ether with dimethyl acetylenedicarboxylate modified by an addition of NH3 (aq.) at 298 K. The aza-14-crown-4-ether ring adopts a bowl conformation. The dihedral angle between the planes of the benzene rings fused to the aza-14-crown-4-ether moiety is 8.65 (5)°. The tetrahydropyridine ring has a boat conformation. The molecular conformation is supported by one N—H...O and two C—H...O intramolecular hydrogen bonds. Both heterocyclic and amino N atoms have essentially planar configurations (sums of the bond angles are 359.35 and 358.00°). Compound 4 crystallizes as a racemate consisting of enantiomeric pairs of the 1R,21S diastereomer. In the crystal, molecules of 4 are connected by N—H...O hydrogen bonds, forming chains along [100]. According to the PASS program (computer prediction of biological activities), compound 4 may exhibit antiallergic (72% probability) and antiasthmatic (67%) activity, as well as be a membrane permeability inhibitor (65%).

Efficient methods have been developed for the synthesis of three potentially useful macroheterocycles containing pyridine-2,6-dicarboxylic and adipic acid ester and hydrazide fragments starting from tetrahydropyran (commercial petrochemical product) through intermediate 8-hydroxyoctan-2-one. The key stages were [2+1]-condensation of the latter with pyridine-2,6-dicarboxylic and adipic acid chlorides and [1+1]-condensation of the resulting α,ω-diketo diesters with dihydrazides derived from the same diacids. The structure of the synthesized compounds was confirmed by IR, NMR, and mass spectra. [ABSTRACT FROM AUTHOR]

The design and the preparation of a small library of optically active polyazamacrocyclic compounds with a furan bridge, connected by (4-(methylaminomethyl)-1,2,3-triazole) rings with methylene, ethyloxyethyl or ethylethoxyethyl units from natural labdanoid lambertianic acid is reported. The synthesis of the key 15,16-bis((tert-butoxycarbonyl(prop-2-ynyl)amino)methyl)labda-8(9),13,15-labdatriene from the plant diterpenoid lambertianic acid is also described. CuAAC reaction of this compounds with various diazides in the presence of Cu(II)/sodium ascorbate in methylene chloride/water reaction medium led to the mentioned chiral macrocyclic compounds with a furan bridge binding Zn2+ ions in solution. [ABSTRACT FROM AUTHOR]

The title compound, C24H29NO4, is the product of a Petrenko–Kritchenko condensation of 1,5-bis(2-formylphenoxy)-3-oxapentane, pentan-3-one and methylammonium acetate in ethanol. The molecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intramolecular C—H...O hydrogen bond. The conformation of the C—O—C—C—O—C—C—O—C polyether chain is t–g+–t–t–g−–t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitrogen atom has a trigonal–pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the molecules are linked by weak C—H...O interactions, forming zigzag chains propagating along the [100] direction.

Published data on methods for the preparation of liquid crystalline phenyl benzoate derivatives were summarized. The results of studies on the mesomorphic properties of phenyl benzoates were analyzed. The available literature and authors' research data on the application of mesogenic phenyl benzoate derivatives in medicine and in the chemistry of macroheterocyclic compounds, as well as in polymer chemistry and technology were presented. [ABSTRACT FROM AUTHOR]

Spectral and basic properties of heterosubstituted porphyrins of anionic type have studied by means of spectrophotometric titration in comparison with their structural analog — tetraphenylporphine tetrasulfonic acid. The parameters of electronic absorption spectra and concentration ranges of existence of the mono- and diprotonated forms of the studied ligands as well as the constants of basic dissociation have been determined. Comparative analysis of the effect of the reactive site modification and the medium composition on the basicity of the compounds has been performed. [ABSTRACT FROM AUTHOR]

Abstract The combination of consecutive Isocyanide-based Multicomponent Reactions (IMCRs) allowed the synthesis of a cyclic heptapeptoid in a reduced number of steps. Herein, we describe this efficient approach using four consecutive Ugi reactions, being three Ugi four-center, four-component reactions, and one Ugi four-center, three-component reaction. Our strategy involved eight steps of which seven in a row were microwave-assisted with reaction times of 3–5 min and yields ranging from 88 to 98%. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Effective syntheses of three optically active macroheterocycles with ester, azine, and dihydrazide fragments were developed from available natural L-menthol through intermediate 3R,7-dimethyl-6-oxooctanoic acid using [2 + 1]-reaction of the last with diethylene glycol and [1 + 1]-condensation of the resulting α,ω-diketodiester with hydrazine hydrate and dihydrazides of several dicarboxylic acids in the key steps. The structures of the synthesized compounds were confirmed using IR and NMR spectroscopy and GC-MS. [ABSTRACT FROM AUTHOR]

The title compound, C30H34N2O9 (4), is a product of the Michael reaction of azacrown ether with dimethyl acetylenedicarboxylate modified by an addition of NH3 (aq.) at 298K. The aza-14-crown-4-ether ring adopts a bowl conformation. The dihedral angle between the planes of the benzene rings fused to the aza-14-crown-4-ether moiety is 8.65(5)°. The tetrahydropyridine ring has a boat conformation. The molecular conformation is supported by one N--H...O and two C--H...O intramolecular hydrogen bonds. Both heterocyclic and amino N atoms have essentially planar configurations (sums of the bond angles are 359.35 and 358.00°). Compound 4 crystallizes as a racemate consisting of enantiomeric pairs of the 1R,21S diastereomer. In the crystal, molecules of 4 are connected by N--H...O hydrogen bonds, forming chains along [100]. According to the PASS program (computer prediction of biological activities), compound 4 may exhibit antiallergic (72% probability) and antiasthmatic (67%) activity, as well as be a membrane permeability inhibitor (65%). [ABSTRACT FROM AUTHOR]

An effective method has been developed for the synthesis of S,N- and S,N,O-containing cyclophanes by cyclothiomethylation reaction of primary amines with formaldehyde and aromatic dithiols. Benzene-1,2-dithiols were used in [1+2+1] cyclocondensation reaction that gave N-substituted 1,5,3-benzodithiazepines, while benzene-1,4-dithiol and 4,4'-dimercaptodiphenyl oxide participated in a [3+6+3] cyclocondensation reaction leading to cyclophanes. [ABSTRACT FROM AUTHOR]

The title compound, C24H29NO4, is the product of a Petrenko-Kritchenko condensation of 1,5-bis(2-formylphenoxy)-3-oxapentane, pentan-3-one and methylammonium acetate in ethanol. The molecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intramolecular C--H⋯O hydrogen bond. The conformation of the C--O--C--C--O--C--C--O--C polyether chain is t-g+-t-t-g---t (t = trans, 180°; g = gauche, ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitrogen atom has a trigonal-pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the molecules are linked by weak C--H⋯O interactions, forming zigzag chains propagating along the [100] direction. [ABSTRACT FROM AUTHOR]

(17R)-17,18-Dipropargyloxylabda-13,15-diene was synthesized and underwent Cu-catalyzed cycloaddition with 1,10-diazodecane or 1,2-bis(2-azidoethoxy)ethane to produce macroheterocycles of the furanolabdanoid decalin fragment. The macroheterocyclic labdanoids showed significant cytotoxicity in MEL-8, MT-4, and U-937 human tumor cell models. [ABSTRACT FROM AUTHOR]

New derivatives of 1,5,3-dithiazepanes and macroheterocycles were synthesized by a three-component cyclothiomethylation of arylamines with formaldehyde and α,ω-dithiols. The sorption properties of 3-phenyl-1,5,3-dithiazepane and 6-phenyl-1,11-dioxa-4,8-dithia-6-azacyclotridecane applicable for the extraction of Ag(I) and Pd(II) ions from nitric acid solutions at room temperature were studied by a static method. [ABSTRACT FROM AUTHOR]

A base-catalyzed reaction of 3,4-dichloro-5-methoxy- and 3,4-dichloro-5-ethoxy-2(5 H)-furanones with 2,2´-oxydiethanethiol gave thiols and bis-thioethers of 2(5 H)-furanone series. A new S, O-macroheterocyclic compound containing a 18-membered oxathiamacrocycle and two 2(5 H)-furanone fragments was synthesized based on the thiols in an aqueous solution of potassium hydroxide, which was characterized by X-ray diffraction. [ABSTRACT FROM AUTHOR]

Experimental data for the reactions of porphyrins with metal salts in various media are analyzed; possible mechanisms of the reactions are discussed. The experimental findings as well as quantum chemical calculations suggest that the most probable reaction mechanism should involve the formation of a SAT complex and a substantial deformation of the macrocycle. [ABSTRACT FROM AUTHOR]

A new efficient method for the synthesis of 3-aryl-1,5,3-dithiazacyclanes and 6-aryl-1,11-diaza-4,8-dithia-6-azacyclotridecanes by cycloaminomethylation of α,ω-dithiols (butane-1,4-, pentane-1,5-, hexane-1,6-dithiols and 3,6-dioxaoctane-1,8-dithiol) using N , N -bis(methoxymethyl)- N -arylamines and Sm- and Cu-containing catalysts is reported. [ABSTRACT FROM AUTHOR]

Luminescence properties of thiadiazole-containing compounds of cyclic and acyclic structure have been investigated. All compounds are characterized by fluorescence in the region 500-600 nm. The highest quantum yield of luminescence in the studied series is exhibited by acyclic product of the ABA type (where A is thiadiazole cycle, B is isoindole cycle) with N-pentylthiadiazoline fragments. [ABSTRACT FROM AUTHOR]

A convenient, efficient, and practical method for the synthesis of 1,3,5-thiadiazinan-4-(thi)ones via a multicomponent condensation of urea (or thiourea), formaldehyde and hydrogen sulfide in the presence of a four-fold molar excess of n-BuONa is described. It provides the novel acid- (H2SO4) and base- (n-BuONa)-promoted approach for the one-pot synthesis of the amidine containing macroheterocycles from guanidine and diphenylguanidine. X-ray powder diffraction analysis gave insight into the structure of the 4-methyl-sulfonyl-2H-1,3,5-thiadiazine hydriodide. [ABSTRACT FROM AUTHOR]

Here we provide new experimental results on multicomponent reactions of amines with aldehydes and HS in the directed synthesis of functionally-substituted 1,3-thiazetidines, 1,3,5-dithiazinanes, 1,3,5-thiadiazinanes, 1,5-dithia-3,7-diazacyclooctanes, and thioaza macrocycles. X-ray analysis gave insight into the structure of the synthesized compounds. New kinds of multicomponent reactions (MCR) have been discovered and characterized. [ABSTRACT FROM AUTHOR]

Abstract: Bis-olefinic symmetrical carbohydrate derivatives were prepared by joining two 1,2-O-isopropylidenefuranose units either through an ether linkage or by a tether of variable size. The ring-closing metathesis (RCM) of these substrates using Grubbs’ first-generation catalyst led to the synthesis of enantiopure symmetrical macroheterocycles containing nine- to twenty-five-membered rings fused to the 1,2-O-isopropylidenefuranose ring. [Copyright &y& Elsevier]

• Novel 16- and 20-membered bispidine ferrocenophanes were synthesized. Two approaches for the syntheses of bispidine-ferrocene cyclophanes were reported. Both include the acylation of 1,5-dimethylbispidin-9-one (H 2 Bp) or its pendant amino-armed derivative by 1,1'-ferrocenoyl (Fc(CO) 2) dichloride. The first approach allowed to isolate di-, tri- and pentameric cyclic oligomers of composition (BpFc(CO) 2) n. The second one included the preliminary functionalization of H 2 Bp by N-protected glycine followed by deprotection and cyclization with Fc(COCl) 2. The crystal structure of two new bispidine-ferrocene cyclophanes was established by single-crystal X-ray study. This study revealed the anti-conformation of amido-groups attached to the bispidine nitrogen atoms for both molecules. Various NMR techniques were applied to study the solution behavior of the macrocycles; the predominant anti-conformation in solution was also proved. The acyclic model compound Bp(FcCO) 2 also showed only anti-conformer as revealed by VT-NMR and X-ray studies. Cyclic voltammetry study showed the difference in oxidation potentials of the Fc moiety within the row Bp(FcCO) 2 – (BpFc(CO) 2) 2 – (BpFc(CO) 2) 3 with splitting of the oxidation curve in two later cases. The results obtained in this work will find an application in design and study of novel bispidine-ferrocene cyclophanes for the purposes of supramolecular sensing and catalysis. [Display omitted] [ABSTRACT FROM AUTHOR]

The title compound, C 30 H 34 N 2 O 9 ( 4 ), is a product of the Michael reaction of aza-crown ether with dimethyl acetyl-enedi-carboxyl-ate modified by an addition of NH 3 (aq.) at 298 K. The aza-14-crown-4-ether ring adopts a bowl conformation. The dihedral angle between the planes of the benzene rings fused to the aza-14-crown-4-ether moiety is 8.65 (5)°. The tetra-hydro-pyridine ring has a boat conformation. The mol-ecular conformation is supported by one N-H⋯O and two C-H⋯O intra-molecular hydrogen bonds. Both heterocyclic and amino N atoms have essentially planar configurations (sums of the bond angles are 359.35 and 358.00°). Compound 4 crystallizes as a racemate consisting of enanti-omeric pairs of the 1 R ,21 S diastereomer. In the crystal, mol-ecules of 4 are connected by N-H⋯O hydrogen bonds, forming chains along [100]. According to the PASS program (computer prediction of biological activities), compound 4 may exhibit anti-allergic (72% probability) and anti-asthmatic (67%) activity, as well as be a membrane permeability inhibitor (65%).

The title compound, C 24 H 29 NO 4 , is the product of a Petrenko-Kritchenko condensation of 1,5-bis-(2-formyl-phen-oxy)-3-oxa-pentane, pentan-3-one and methyl-ammonium acetate in ethanol. The mol-ecule has mirror symmetry. The aza-14-crown-3 ether ring adopts a bowl conformation stabilized by a weak intra-molecular C-H⋯O hydrogen bond. The conformation of the C-O-C-C-O-C-C-O-C polyether chain is t-g + -t-t-g - -t (t = trans , 180°; g = gauche , ±60°). The dihedral angle between the benzene rings fused to the aza-14-crown-4-ether moiety is 72.68 (4)°. The piperidinone ring adopts a chair conformation. The nitro-gen atom has a trigonal-pyramidal geometry, the sum of the bond angles being 335.9°. In the crystal, the mol-ecules are linked by weak C-H⋯O inter-actions, forming zigzag chains propagating along the [100] direction.