Nematicidal activity of furanoeremophilenes against Meloidogyne incognita and Nacobbus aberrans.

BACKGROUND: While searching for novel small molecules for new organic pesticide agents against plant-parasitic nematodes, we found that the hexane extract from the roots of Senecio sinuatos and its main secondary metabolite, 3ß-angeloyloxy-6ß-hydroxyfuranoeremophil-1(10)-ene (1), possess nematicidal activity against the second stage juvenile (J2) of Meloidogyne incognita and Nacobbus aberrans. Both species reduce yield of various vegetable crops. These results encouraged us to synthesize esters 3-9 formed by diol 2, obtained by alkaline hydrolysis of 1 and acetic anhydride, benzoic acid, 2-nitrobenzoic acid, 2-bromobenzoic acid, 4-nitrobenzoic acid, 4-bromobenzoic acid, and 4-methoxybenzoic acid, respectively. The nematicidal activity of these esters was evaluated and compared with that of the free benzoic acids. RESULTS: Natural product 1 and derivatives 2-9 were obtained and characterized by their physical and spectroscopic properties, including one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) experiments; X-ray diffraction analysis established their absolute configuration. The nematicidal activity of compounds 1-9 was assessed in vitro against M. incognita and N. aberrans J2 and was compared to activity shown by benzoic acid, 2-nitrobenzoic acid, 2-bromobenzoic acid, 4-nitrobenzoic acid, 4-bromobenzoic acid, and 4-methoxybenzoic acid. The esters suppressed nematodes more than free benzoic acid. Nacobbus aberrans J2 were suppressed, with compounds 5, 6, and 8 being the most active. CONCLUSION: Esters formed by 3ß,6ß-dihydroxyfuranoeremophil-1(10)-ene and ortho- or para-substituted benzoic acids containing electron acceptor groups had nematicidal activity against N. aberrans. These compound can potentially serve as a model for the development of new organic nematicidal agents. © 2022 Society of Chemical Industry.

TiCl4 catalyzed cleavage of (25R)-22-oxo-23-spiroketals. Synthesis of sapogenins with furostanol and pyranone E rings on the side chain.

The regioselective opening of the F ring of 22-oxo-23-spiroketals 7a-d using TiCl4 in acetic anhydride yielded the novel furostanols 11a-d along with cholestanic derivatives 8a-d with pyranone E ring. The structures of the new derivatives thus obtained were established using one- (DEPT) and two-dimensional 1H, 13C NMR experiments (COSY, HSQC, HMBC, NOESY). The 22α-hydroxyl orientation in compounds 11a-d was proposed by comparison of the 13C chemical shifts with those of other aglycone members of this family, and confirmed by combined NOESY and X-ray diffraction analysis of compound 11a.

In search of safe pain relief: The analgesic and anti-inflammatory activity of phytosteryl ibuprofenates.

ß-Sitosteryl (S)-ibuprofenate (2), stigmasteryl (S)-ibuprofenate (3), ergosteryl (S)-ibuprofenate (4), and cholesteryl (S)-ibuprofenate (5) were prepared in 70-75% yields by Steglich esterification and were characterized by 1D and 2D NMR, as well as by MS. The new esters were evaluated in in vivo pain models of antinociception and anti-inflammation using the writhing, formalin, and carrageenan tests, in mice and rats, and the results were compared with those of (S)-ibuprofen (1). Damage to the gastric mucosa of animals was also assessed. The results indicated that 2-5 have comparable or eventually better activity than 1 at the same mg/kg doses. Since the molecular weight ratio of esters 2-5 to ibuprofen is about 3-1, the amount of truly incorporated ibuprofen was roughly one third to achieve similar effects. This resulted in minimal gastrointestinal damage in the stomach of the animals, in contrast to the large gastric injury caused by (S)-ibuprofen.

Synthesis of 2-Tetrazolylmethyl-isoindolin-1-ones via a One-Pot Ugi-Azide/(N-Acylation/exo-Diels-Alder)/Dehydration Process.

A series of fifteen 2-tetrazolylmethyl-isoindolin-1-one linked-type bis-heterocycles were synthesized in 10-76% yields under mild conditions via a one-pot Ugi-azide/(N-acylation/exo-Diels-Alder)/dehydration process from furan-2-ylmethanamine, aldehydes, isocyanides, azidotrimethylsilane, and maleic anhydride. Density functional theory calculations were performed using the polarizable continuum model (toluene)-M06-2X-D3/6-311+G(d)//M06-2X-D3/6-31G(d) level of theory to obtain the full energy profile when investigating over eight possible pathways. An anthracene-containing analogue displayed a distribution of its highest occupied molecular orbital-lowest unoccupied molecular orbital throughout both cyclic moieties.

Crystal structure of 2-(2-amino-phen-yl)-1,3-benzoxazole.

Crystals of the title compound, C13H10N2O, were grown from a di-chloro-methane/ketone/methanol solvent mixture. It crystallizes with two mol-ecules, A and B, in the asymmetric unit with very similar almost planar conformations [dihedral angles between the ring planes = 0.74 (8) and 0.67 (6)° for mol-ecules A and B, respectively; r.m.s. overlay fit = 0.019 Å]. Each mol-ecule features an intra-molecular N-H⋯N hydrogen bond, which closes an S(6) ring and therefore establishes a syn relationship for the N atoms. In the crystal, mol-ecules are linked by N-H⋯N hydrogen bonds, generating [100] chains containing alternating A and B mol-ecules. Weak aromatic π-π stacking [minimum centroid-centroid separation = 3.6212 (9) Å] links the chains into a three-dimensional network.

O-Ethyl S-{(S)-1-oxo-1-[(R)-2-oxo-4-phenyl-oxazolidin-3-yl]propan-2-yl} carbonodi-thio-ate.

In the title compound, C15H17NO4S2, synthesized by addition of O-ethylxanthic acid potassium salt to a diastereomeric mixture of (4R)-3-(2-chloro-propano-yl)-4-phenyl-oxazolidin-2-one, the oxazolidinone ring has a twist conformation on the C-C bond. The phenyl ring is inclined to the mean plane of the oxazolidinone ring by 76.4 (3)°. In the chain the methine H atom is involved in a C-H⋯S and a C-H⋯O intra-molecular inter-action. In the crystal, mol-ecules are linked by C-H⋯π inter-actions, forming chains along [001]. The S configuration at the C atom to which the xanthate group is attached was determined by comparison to the known R configuration of the C atom to which the phenyl group is attached.

π-stacking and C-X...D (X = H, NO2; D = O, π) interactions in the crystal network of both C-H...N and π-stacked dimers of 1,2-bis(4-bromophenyl)-1H-benzimidazole and 2-(4-bromophenyl)-1-(4-nitrophenyl)-1H-benzimidazole.

Molecules of 1,2-bis(4-bromophenyl)-1H-benzimidazole, C19H12Br2N2, (I), and 2-(4-bromophenyl)-1-(4-nitrophenyl)-1H-benzimidazole, C19H12BrN3O2, (II), are arranged in dimeric units through C-H...N and parallel-displaced π-stacking interactions favoured by the appropriate disposition of N- and C-bonded phenyl rings with respect to the mean benzimidazole plane. The molecular packing of the dimers of (I) and (II) arises by the concurrence of a diverse set of weak intermolecular C-X...D (X = H, NO2; D = O, π) interactions.

2-(4-Hy-droxy-phen-yl)-1H-benzimidazol-3-ium chloride monohydrate.

The title mol-ecular salt, C13H11N2O(+)·Cl(-)·H2O, crystallizes as a monohydrate. In the cation, the phenol and benzimidazole rings are almost coplanar, making a dihedral angle of 3.18 (4)°. The chloride anion and benzimidazole cation are linked by two N(+)-H⋯Cl(-) hydrogen bonds, forming chains propagating along [010]. These chains are linked through O-H⋯Cl hydrogen bonds involving the water mol-ecule and the chloride anion, which form a diamond core, giving rise to the formation of two-dimensional networks lying parallel to (10-2). Two π-π inter-actions involving the imidazolium ring with the benzene and phenol rings [centroid-centroid distances = 3.859 (3) and 3.602 (3) Å, respectively], contribute to this second dimension. A strong O-H⋯O hydrogen bond involving the water mol-ecule and the phenol substituent on the benzimidazole unit links the networks, forming a three-dimensional structure.

Coupling of internal alkynes in tp(me2)ir derivatives: selective oxidation of a noncoordinated double bond of the resulting iridacycloheptatrienes.

The reaction of different Tp(Me2)Ir derivatives and dimethylacetylene dicarboxylate (DMAD) allows the preparation of three different metallacycloheptatriene complexes and an unusual allyl-terminated metallacycle. The C atoms of distant C=C bonds in the metallacycles, including aromatic ones, can be converted selectively to the corresponding keto functionality under mild conditions.

Facile preparation of [4.4]metacyclophane- and [5.5]paracyclophane-type macrocycles from arylboronic acids and salicylideneaminoaryl alcohols.

Four different salicylideneaminoaryl alcohols have been treated with arylboronic acids in order to prepare air-stable cyclophane-type macrocyclic systems. In two cases, this objective could be realized with the high-yield formation of [4.4]metacyclophane and [5.5]paracyclophane derivatives. The skeleton in these macrocycles is held together by two chiral boron atoms. In the other two cases, monomeric boronates or polymeric material were obtained. The title structures were characterized by spectroscopic techniques and X-ray crystallography. They show transannular C-H...O hydrogen bonding, but no intramolecular pi-pi interactions. A synthetic strategy for the preparation of further boron macrocycles is presented.