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.     

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.     

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.     

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.     

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.     

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.     

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.     

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.     

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     

New cytotoxic and anti-inflammatory compounds isolated from Morus alba L.

Six Diels–Alder adducts (1–6) and nine prenylated flavanones (7–15) were isolated from the root bark of Morus alba L. Among them, soroceal B (1) and sanggenol Q (7) were new compounds. Their structures were elucidated on the basis of extensive spectroscopic methods, including 1D and 2D NMR techniques. Compounds 1–3, 9, 10, 12, 13 and 15 exhibited cytotoxic activity against five human tumour lines and compound 2 inhibited significantly selective cytotoxic activities towards HL-60 and AGS cells with IC₅₀ of 3.4 and 3.6 μM. Compounds 3, 5, 9 and 12 exhibited moderate inhibitory activity against nitric oxide production in LPS-activated RAW264.7.     

Cyanothioacetanilide Intermediates in Heterocyclic Synthesis,Part 1: Synthesis and Biological Evaluation of Some Novel Thiazole,Thiophene, Pyrazole,and Pyrazolo[1,5-a]Pyrimidine Derivatives

Some novel thiophenes (4a,b, 5, and 9a,b) were obtained from the cycloalkylation of the thiocarbamoyl group in the cyanothioacetanilide derivative (1) with α-halocarbonyl compounds. Also, the reaction of cyanothioacetanilide derivative with phenyl isothiocyanate in the presence of potassium hydroxide followed by in situ heterocyclization of the resulting adduct with α-halocarbonyl compounds furnished the corresponding thiazole (12, 14, and 15), pyrazole (19), and pyraozlo[1,5-a]pyrimidine (22, 25, and 26) derivatives. Compounds (4b, 5, 9a, 12, 13, 18, 22, 25, and 26) were tested to evaluate their antimicrobial 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.     

Intermolecular cyclization of cinnamoyl isothiocyanate: A new synthetic entry for pyrimidine,triazine, and triazole candidates

An efficient and facile protocol for the synthesis of azine and azole ring systems was reported. Whereas, reaction of cinnamoyl isothiocyanate with N-nucleophile containing compounds (namely, p-aminophenol (2), N¹-phenylbenzene-1,4-diamine (5) and p-aminoacetophenone (8)) tolerated thiourea derivatives 3, 6, and 9, respectively. The later compounds underwent intramolecular cyclization upon treatment with EtONa to give pyrimidinethiones 4, 7, and 10, respectively, in moderate yield (74–79%). Compound 9 underwent intramolecular cyclization and condensation upon reaction with NaOH and benzaldehyde to give pyrimidinethione 12. Thiosemicarbazides 14 and 19 were obtained through reaction of heteroallen 1 with 2,4-dinitrophenylhydrazine 13 and hydrazone 18, respectively. Compound 14 was cyclized to pyrimidinethione 15 and triazine derivatives 17 through its reaction with EtONa at room temperature and refluxing temperature, respectively. Finally, base mediated and oxidative cyclization of thiourea derivative 19 with EtONa, Br₂/AcOH, and Pb(OAc)₂ afforded thiadiazole 20, benzothiazolotriazole 21, and triazolethione 22 derivatives, 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.     

Novel Syntheses and Reactions of Polynuclear Heterocyclic Derivatives Derived From Thioxopyridopyrimidine,With a New Ring System

Pyridopyrimidine derivatives 2 reacted with hydrazonoylchloride derivatives and yielded triazolopyridopyrimidines 6a–f. Compound 4b reacted with aliphatic acids and afforded triazolo-pyridopyrimidines 7a,b, and the reaction with carbon disulfide afforded 10-mercapto-triazolopyridopyrimidine (10). Moreover, the reaction of 4b with β -ketoesters afforded 10-pyrazolyl-pyridopyrimidines derivatives 11, 13, 14, and 15. Compound 4b reacted with nitrous acid to give tetrazolopyridopyrimidine 16, which reduced to 10-amino-derivative 17. On the other hand, the reaction of 4b with aromatic aldehydes afforded arylidines derivatives 18a–c, which were later cyclized to triazolo-pyridopyrimidines deivatives 19a–c. Finally, 4b reacted with α-haloketones to give triazines derivativrs 20, with new ring systems.     

白藜芦醇类似物的合成

3,5-二甲氧基苄溴(4)与NaCN反应生成3,5-二甲氧基苄腈(5), 5经水解得到3,5-二甲氧基苯乙酸(6). 5与苯甲醛或取代苯甲醛发生Knoevenagel反应生成化合物2a～2d, 为Z式构型. 6与苯甲醛或取代苯甲醛发生Perkin反应得到化合物3a～3c, 为E式构型. 2a～2d和3a～3c均为白藜芦醇类似物. 给出了各步反应产物的IR, ¹H NMR, ¹³C NMR和MS数据, 讨论了影响反应的因素, 并给出了化合物2a～2d和3a～3c对乳腺癌细胞MCF-7、肺癌细胞H446、乳腺癌细胞231的体外生理活性和对正常肝细胞L02体外毒性的半致死浓度.     

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.     

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.     

Secoiridoids and other chemotaxonomically relevant compounds in Pedicularis: phytochemical analysis and comparison of Pedicularis rostratocapitata Crantz and Pedicularis verticillata L. from Dolomites

We compared the respective metabolite patterns of two Pedicularis species from Dolomites. Seven phenylethanoid glycosides, i.e., verbascoside (1), echinacoside (2), angoroside A (3), cistantubuloside B1 (4), wiedemannioside C (5), campneoside II (11) and cistantubuloside C1 (12), together with several iridoid glucosides as aucubin (6), euphroside (7), monomelittoside (8), mussaenosidic acid (9) and 8-epiloganic acid (13) were identified. Pedicularis verticillata showed also the presence of greatly unexpected secoiridoids, ligustroside (14) and excelside B (15), very rare compounds in Lamiales. Both PhGs and iridoids are considered of taxonomical relevance in the Asteridae and their occurrence in Pedicularis was discussed. In particular, the exclusive presence of several compounds such as 8-epiloganic acid (13), campneoside II (11), cistantubuloside C1 (12), ligustroside (14) and excelside B (15) in Pedicularis rostratocapitata, and angoroside A (3), cistantubuloside B1 (4) and wiedemannioside C (5) in P. verticillata could be considered specific markers for the two botanical entities.     

Solution structure and equilibrium of new calix[4]resorcinarene complexes—prototype of molecular machines. NMR data

Association properties and molecular machine application of water soluble calix[4]resorcinarene (1) with two aromatic guests (2-naphthol (2) and 1,5-naphthalenediamine (3)) have been investigated by various NMR methods (chemical shift, nOe and diffusion measurements) in aqueous solution at different concentrations and pH range. In neutral solution 1 strongly associates with 2, while only moderately associating with 3. Increase in concentration causes an increase in the stability of 1 + 3 and 1 + 2 + 3 complexes and produces high order complexes. The decrease of pH does not have an influence on 1 + 2 association, but disrupts 1 + 3 assembly. 1 can be used for the separation of 2 + 3 mixture in aqueous solution at moderate concentrations. The pH dependency of the association properties of the 1 + 3 system makes these compounds prime candidates for pH-responsive molecular machines applications.