Polymerizations of methyl methacrylate and rac-lactide by zinc(II) precatalyst containing N-substituted 2-iminomethylpyridine and 2-iminomethylquinoline

The reaction of [ZnCl₂] with N-cyclopentyl-1-(quinolin-2-yl)methanimine (L_A), N-cyclohexyl-1-(quinolin-2-yl)methanimine (L_B), N-cyclohexyl-1-(pyridin-2-yl)methanimine (L_C), 2,6-diethyl-N-(pyridin-2-ylmethylene)aniline (L_D), N-cyclopentyl-1-(pyridin-2-yl)methanimine (L_E), and N-phenyl-(pyridin-2-yl)methanimine (L_F) in ethanol produced the bidentate [(NN′)ZnCl₂] complexes, [L_AZnCl₂], [L_BZnCl₂], [L_CZnCl₂], [L_DZnCl₂], [L_EZnCl₂] and [L_FZnCl₂], respectively. The molecular structures revealed that the zinc in [L_nZnCl₂] (L_n = L_A ? L_D) showed a distorted tetrahedral geometry involving two nitrogens of N,N’-bidentate ligands and two chloride ligands. Most of these initiators were effective for polymerization of methyl methacrylate (MMA) and polymerization of rac-lactide (rac-LA). [L_CZnCl₂] (with N-cyclohexyl substituted at imine-pyridine moiety) exhibited the highest catalytic activity for MMA polymerization in the presence of modified methylaluminoxane (MMAO) with an activity of 3.33 × 10⁴ g PMMA/mol·Zn·h at 60 °C, giving moderate syndiotactic poly methyl methacrylate (PMMA) with high molecular weight (9.62 × 10⁵ g/mol). The dimethyl derivatives [L_nZnMe₂] (L_n = L_A ? L_F), generated in situ, polymerized rac-LA with moderate activity and yielded a polylactide (PLA) with good number-average molecular weights and narrower polydispersity indices (PDIs). [L_AZnMe₂] effectively initiates the ring-opening polymerization (ROP) of rac-LA to attain heterotactic PLA (P_r = 0.91).     

Anti-inflammatory activities of the chemical constituents isolated from Trametes versicolor

Twenty-seven compounds including nine triterpenoids (1–9), eight sterols (10–17), two ribonucleotides (18, 19), four phenols (20–23), three glycosides (24–26), and one furan (27) were isolated from the fruiting bodies of Trametes versicolor (L.) Lloyd. This study is the first confirmation of the presence of the 11 compounds (3, 5, 6, 8, 18, 20, 21, 23–25, and 27) isolated from the Polyporaceae family, with six of these (2 and 12–16) from the genus Trametes. Compounds 3, 4, 10, 11, 16 and 17 were found to significantly inhibit the production of NO, TNF-α and IL-6 in a dose-dependent manner.     

A new 9,10-dihydrophenanthrene from Dendrobium moniliforme

A new 9,10-dihydrophenanthrene,1,5-dihydroxy-3,4,7-trimethoxy-9,10-dihydrophenanthrene (1) was isolated and identified from the whole plants of Dendrobium moniliforme, as well as 24 known compounds including hircinol (2), (2R^*,3S^*)-3-hydroxymethyl-9-methoxy-2-(4′-hydroxy-3′,5′-dimethoxyphenyl)-2,3,6,7-tetrahydro-phenanthro[4,3-b]furan-5,11-diol (3), diospyrosin (4), aloifol I (5), moscatilin (6), 3,4′-dihydroxy-3′,4,5-trimethoxybibenzyl (7), gigantol (8), 3,3′-dihydroxy-4,5-dimethoxybibenzyl (9), longicornuol A (10), N-trans-cinnamoyltyramine (11), paprazine (12), N-trans-feruloyl 3′-O-methyldopamine (13), moupinamide (14), dihydroconiferyl dihydro-p-coumarate (15), dihydrosinapyl dihydro-p-coumarate (16), 3-isopropyl-5-acetoxycyclohexene-2-one-1 (17), p-hydroxybenzaldehyde (18), vanillin (19), p-hydroxyphenylpropionic acid (20), vanillic acid (21), protocatechuic acid (22), (+)-syringaresinol (23), β-sitosterol (24) and daucosterol (25). Compounds 3, 4, 13, 16, 17 and 20 were isolated from the Dendrobium genus for the first time, and compounds 2, 5, 7, 9–12, 14, 15, 18, 21 and 22 were originally obtained from D. moniliforme.     

Selective Benzoylation of 1-(β-D-Xylopyranosyl)-3,5-dimethylpyrazole

Abstract

Selective benzoylation of l-(β-d-xylopyranosyl)-3,5-dimethylpyrazole (1) has been performed to give 2,3,4-tri- (2), 3,4-di- (3), 2,4-di- (4), 3- (5) and 4-benzoate (6). The O-acetyl derivatives of compounds 3 and 4 (7, 8), di-O-acetyl of 5 and 6 (9, 10) and O-methanesulphonyl of 3 and 4 (11, 12) have been obtained. The relative reactivity of the hydroxyl groups of 1 was HO-4 ≥ HO-3 ? HO-2. The analysis of ¹ H NMR and ¹³C NMR spectra of 1-12 is presented.     

Chemical constituents from Agrimonia pilosa Ledeb. and their chemotaxonomic significance

Phytochemical investigation of the ethanol extract from the whole plant of Agrimonia pilosa led to the isolation of 31 compounds, including 16 flavonoids (1–16), 5 triterpenes (17–21), 1 isocoumarin (22), 5 phenolic acids (23–27), 1 ceramide (28), 2 agrimols (29–30) and 1 fatty acid (31). Their structures were determined by various spectroscopic analyses. Compounds 5, 7 and 20 were firstly isolated from the genus Agrimonia, and compounds 6, 10–11, 15, 26, 28 and 31 were isolated from the family Rosaceae for the first time. Moreover, the chemotaxonomic significance of these compounds was summarised.     

Aromatische Spirane, 23. Mitt.: Darstellung von unsymmetrisch substituierten Dimethyl-2,2′-Spirobiindan-1,1′-dionen

Summary Both spirodiketones7 and8 were obtained as a mixture (56:44) by treatment of dicarbonic acid5 with polyphosphoric acid (PPA).5 was accessible from dimethylester3, synthesized byretro-Claisen reaction between1 and2. In the same way,30 was obtainedvia 27. The preparation of the pure spiro compounds7 and8, resp., was achieved by aldol reaction between9 and10 or9 and16, resp. Short treatment of the resulting compounds11 and17 with diazomethane yielded the methylbenzoates12 and18. Prolonged reaction (several hours) gave the pyrazole compounds14 and19, resp., which were also obtained (several days) from phthalides14 and20. The latter were formed from the benzylidene compounds11 and17, resp., by heating.11 and17 (after hydrogenation to15a and21a) were cyclized either withPPA or thermically to the spiro compounds7 and8. The main product20 was cyclized thermically to8 after reduction with zinc to a mixture of21a and8 (20:75).

     

NOVEL N,S-SUBSTITUTED DIENES BY THE REACTION OF 2-NITROTHIOSUBSTITUTED HALODIENES AND PRIMARY AMINES

Mono(thio)substituted 1a–c gave compounds 3a–c and 5a with o-toluidin (2) and m-toluidin (4) in ether. Compounds 9a–c and 11a, b were obtained from the reaction of compounds 1a–c with p-fluorophenylamine (8) and p-fluorobenzylamine (10). Compounds 7a and 15c were obtained from the reaction of 1a and 1c with p-phenylendiamine (6) and o-phenylendiamine (14). Compound 13c was synthesized from the reaction of compound 1c with benzidine (2).     

Acetoacetanilides in Heterocyclic Synthesis,Part 1: An Expeditious Synthesis of Thienopyridines and Other Fused Derivatives

3-Oxo-N-{4-[(pyrimidin-2-ylamino)sulfonyl]phenyl}butanamide 1 reacts with arylidinecyanothioacetamide in refluxing ethanolic TEA to give the pyridinethione 2 rather than thiopyrane 4. Compound 2 reacts with α-haloketones to give the s-alkylated derivatives 7a–e. Compound 7a–e undergoes cyclization into thieno[2,3-b]pyridine derivatives 8a–e. The saponification of 8a gives the amino acid 9, which affords 10 when refluxed in Ac₂O. The treatment of 10 with NH₄OAc/AcOH gives 11. Compound II is also obtained when 8e is refluxed in Ac₂O. The reaction of 8a with hydrazine hydrate gives 12 and with formamide gives 13. Compound 13 also is obtained from the reaction of 8e with triethylorthoformate. The acetylation of 8a with Ac₂O gives the amide derivative 14, which, on treatment with aromatic amines, affords 15a–c. Compounds 15a–c are cyclized with H₂SO₄ to 16a–c. Compound 16 is obtained also from the acetylation of compound 8c, d by Ac₂O. Reactions of compound 8e with CS₂ in refluxing dioxane afford 17. The diazotization and self-coupling of 8e give the pyridothienotriazine 18. Finally, the chloronation of compound 13 with POCl₃ affords the chloride derivative 19.     

Electronic states of XC<Subscript>3</Subscript>H<Subscript>3</Subscript>Si five-membered rings (X = CH,N, P,and As)

Stable configurations of XC₃H₃Si five-membered rings, 1 _X and 2 _X (X = CH, N, P, and As) in the singlet and triplet states are found at B3LYP/6-311++G** level of theory. All the singlet states of 1 _X and 2 _X have lower potential energy than the triplet state. The ΔG _s−t differences between the singlet and triplet states of 1 _X and 2 _X changes at the B3LYP/6-311++G** level in the order (in kcal/mol): 1 _N (−17.56) > 1 _CH (−15.26) > 1 _P (−4.96) > 1 _As (−3.45) and 2 _CH (−15.26) > 2 _N (−9.21) > 2 _P (−7.39) > 2 _As (−6.15), respectively.     

Synthesis and Antibacterial Activity of Some New S-Triazole Derivatives

Abstract

Alkylation of 4-anilino-5-phenyl-4H-1,2,4-triazole-3-thiol (1) with some halo compounds yielded the corresponding sulfides 2a–f. Some sulfides 2e,f were cyclized to give triazolothiadiazines 3 and 4. Triazolothiadiazoles 5 and 6 were prepared through the reaction of compound 1 with carbon disulfide or ethyl orthoformate, respectively. Treatment of compound 1 with ethyl chloroformate or phenyl isothiocyanate yielded triazolo-thiadiazole and triazole 9 and 10, respectively. Reaction of compound 1 with Lawesson's reagent gave triazolothiadiazaphosphole derivative 11. Also, compound 1 underwent cyclocondensation reactions with some bidentate reagents to give triazolothiazines 4, 12, and 13. Triazolo-thiazepines and triaziepine 14–16 were synthesized via the reaction of compound 1 with β-ketoesters or ethyl cyanoacetate. Tricyclic systems 19 and 20 were prepared through the reaction of compound 4 with the appropriate reagent. Some synthesized compounds were tested for antibacterial activity.

Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.     

Glycosylation of 4‐Aryl‐1‐thioxo[1,2,4] triazolo[4,3‐a] quinazolin‐5(4H)‐one

Reaction of 4‐aryl‐1‐thioxo [1,2,4] triazolo [4,3‐a] quinazolin‐5 (4H)‐ones (2a,b) with acetylated glycosyl bromides 3a–c under alkaline conditions afforded the corresponding S‐glycoside derivatives 4, 5 and N‐glycoside derivatives 6, 7. Oxidation of S‐glycosyl derivatives 4, 5 with m‐chloroperbenzoic acid yielded the corresponding sulphones 8, 9, whereas the N‐glycosyl derivatives 6, 7 yielded 1‐oxo derivatives 10, 11. However their O‐deacetylation with sodium methoxide in methanol caused cleavage of the S‐glycosyl residue and gave N ²‐glycosylated analogues 12, 13, 14 and 15.     

Three lanthanide complexes with mixed salicylate and 1,10-phenanthroline: syntheses,crystal structures,and luminescent/magnetic properties

Three new lanthanide complexes incorporating salicylate (HSA or SA) and 1,10-phenanthroline (phen), Ln₃(HSA)₅(SA)₂(phen)₃ [Ln = Ho (1) and Er (2)], and Sm₂(HSA)₂(SA)₂(phen)₃ (3), have been synthesized. X-ray structural analysis reveals that 1 and 2 are isostructural with a trinuclear pattern, and 3 exhibits a binuclear structure. Comparison of the structural differences between 1/2 and 3 suggests that the identity of metal plays an important role in construction of such complexes. The magnetic properties of 1 are discussed. Moreover, 2 and 3 are both photoluminescent materials, and their emission properties are closely related to their corresponding Ln^III centers.     

Synthesis of the [<Superscript>2</Superscript>H,<Superscript>15</Superscript>N]-labeled antiviral drug “triazavirine”

Selective methods for the incorporation of stable isotopes ¹⁵N and ²H into the structure of antiviral medicine “triazavirine” 1 were developed. The synthesized isotopically modified “triazavirine” 1– ² H ₃ , ¹⁵ N ₃ contained the labeled atoms in both the azole and the azine rings. ¹³C and ¹⁵N NMR spectra of the isotope-containing sample 1– ² H ₃ , ¹⁵ N ₃ were thoroughly analyzed.     

Synthesis and Biological Activities of Novel 1,4-Bridged Bis-1,2,4-Triazoles,Bis-1,3,4-Thiadiazoles and Bis-1,3,4-Oxadiazoles

Abstract

The terephthalic acid hydrazide(1) reacted with phenyl/benzyl isothiocyanate2a,bto yield the corresponding bis-thiosemicarbazides4a,b,viaacid hydrolysis of the intermediate 3whereas cyclization of4gave the bis-1,2,4-triazoles 5,6and bis-1,3,4-thiadiazoles7,8. Similarly, compound 1reacted with phenyl isocyanate9to give the bis-semicarbazide10, which was cyclized to the bis-oxadiazole 11and/or bis-1,2,4-triazole12in POCl_ti3and NaOH respectively.     

Synthesis and characterisation of main‐chain hydrogen‐bonded supramolecular liquid crystalline complexes formed by azo‐containing compounds

A series of azopyridine‐containing hydrogen bonding acceptors (4a–c) with flexible spacers of oligo(methylene) were synthesised. Hydrogen‐bonded polymeric complexes 4/5 and trimeric complexes 4/6₂ , where 5 and 6 are aromatic dicarboxylic acids and monocarboxylic acids, respectively, were prepared and their liquid crystallinity was examined using differential scanning calorimetry and polarising optical microscopy. The study showed that most of the complexes displayed reversible thermotropic nematic phase. The isotropic to nematic phase transition temperatures of polymeric complexes 4/5 and trimeric complexes 4/6₂ in general decreased with the increase in length of spacers and terminal groups in the corresponding proton acceptors 4 and the proton donors 5 and 6, respectively. Hydrogen bonding interactions in complexes 4/5 and 4/6₂ were studied by X‐ray photoelectron spectroscopy and Fourier transform infrared spectroscopy.     

Application of organolithium and related reagents in synthesis,Part XII. Synthesis of phenyl- and pyridylpyridopyridazinones and their derivatives

Summary The preparation of the pyridazinones10a,10b,11a,11b, and12a,12b from the ketoamides7,8, and9 and hydrazine hydrate is described. It was found that from ketoamides8b and9b in addition to the expected pyridopyridazinones11b and12b also aminopyridopyridazines14 and15 were formed and that ketoamide7b gave exclusively aminopyridopyridazine13. The pyridopyridazinones10b,11b, and12b were alkylated with alkyl iodides.

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Anwendungen von Organolithium und verwandten Reagenzien in organischen Synthesen, Teil XII. Synthese von Phenyl- und Pyridylpyridopyridazinonen und ihren Derivaten

Zusammenfassung Die Darstellung der Pyridazinone10a,10b,11a,11b und12a,12b aus Ketoamiden7,8 und9 und Hydrazinhydrat wird beschrieben. Es wurde festgestellt, daß aus Ketoamiden8b und9b außer den erwarteten Pyridopyridazinonen11b und12b auch Aminopyridopyridazine14 und15 enstanden und daß das Ketoamid7b ausschließlich ins Aminopyridopyridazin13 überführt wurde. Die Pyridopyridazinone10b,11b und12b wurden mit Alkyljodiden alkyliert.

     

SYNTHESES,STRUCTURES AND REACTIONS OF NEW AND NOVEL FOUR-, FIVEAND SIX-MEMBERED UNSATURATED N,P-HETEROCYCLE COMPLEXES

Metal-assisted heterocyclic ligand syntheses are reported using 2-H-azaphosphirene complex 1 or 7-phosphanorbornadiene complex 7 as starting material. Thermal decomposition of complex 1 led to 1,2dihydro-1,2,3-azadiphosphete complex 2, which was transformed into 2,6-dihydro-1,3,2,6-diazadiphosphinines 5a, b via ring expansion with carbonitriles 3a, b. Insertion of tert-butyl isonitrile into the P─ P bond of 2 at ambient temperature furnished the first Δ ¹ -1,3,5-azadi-phospholene complex 6─P bond of 2 using 7 failed. The 1,2,3,4-azatriphospholene complexes 9a, b were obtained by thermolysis of complex 2 in the presence of functionalized carbonitriles 8a, b.     

Chemical constituents and biological activities from branches of Colubrina asiatica

Sixteen compounds were isolated from a Thai medicinal plant, Colubrina asiatica. The isolated compounds were elucidated on the basis of spectroscopic methods (IR, 1D and 2D NMR) as six triterpene acids (1–6), five steroids (7–11), one benzoic acid derivative (12), two peptides (13 and 14), one sesquiterpenoid (15) and one jujubogenin (16). Compounds 3 and 10 showed antimalarial activity against Plasmodium falciparum. Compound 5 showed antimycobacterial activity. Moreover, compounds 3, 5, 6, 10 and 14 exhibited weak cytotoxicity against cancer cell lines. Compounds 1–15 have been isolated for the first time from this plant.     

X-ray structures of cobalt(III) complexes with bio-relevant pyrazolyl thiosemicarbazone: Indication of structural changes on the increasing bulkiness of the alkyl substituents on thiosemicarbazone moiety

X-ray crystallographic studies of cobalt(III) complexes of 5-methyl-3-formylpyrazole-N(4)-diethylthiosemicarbazone (HMP_zNEt₂), [Co(MP _z NEt ₂ ) ₂ ]Br·2H ₂ O, 5-methyl-3-formylpyrazole-N(4)-dipropylthiosemicarbazone (HMP_zNPr ₂ ), [Co(MP _z NPr ₂ ) ₂ ]Br·2H ₂ O and 5-methyl-3formylpyrazole-N(4)-dibutylthiosemicarbazone (HMP_zNBu ₂ ), [Co(MP _z NBu ₂ ) ₂ ]Br·H ₂ O, have been reported. In all the three complex species, X-ray crystallography has authenticated a CoN₄S₂ octahedral coordination with the pair of orthogonally coordinated NNS tridentate ligands in the monodeprotonated form of the ligand. The two azomethine nitrogen atoms are trans to each other, while the pyrazolyl ring nitrogens and the thiolato sulfurs are in cis positions. A gradual decrease in the dihedral angle between the coordinating ligands has been observed with increase in the bulkiness of the aliphatic side chains of the substituent on the thiosemicarbazone moieties. In all the three complexes, intraligand C–H···S contacts appear to arrest the free rotation of the side chains about the C(6)–N(5) single bond. ^†Deceased     

A new coumarin from the roots of Micromelum minutum

A new coumarin, minutuminolate (1), together with eleven known coumarins (2–12), was isolated from the roots of Micromelum minutum. The structures of these compounds were established on the basis of their 1D and 2D NMR spectroscopic data. Compounds 2, 5, 10, 11 and 12 showed cytotoxicity against KB cell line. In addition, compounds 2, 3, 4, 7, 11 and 12 also showed weak cytotoxicity against NCI-H187 cell line.