Iotroridoside‐A,a Novel Cytotoxic Glycosphingolipid from the Marine Sponge Iotrochota ridley

A new cytotoxic glycosphingolipid, Iotroridoside‐A, was isolated from the marine sponge Iotrochota ridley collected from the South China Sea near Hainan Island, China. On the basis of chemical degradation method and IR, MS, ¹H NMR, ¹³C NMR and 2D NMR spectrometry, its structure was assigned as 1‐O‐β‐D‐glucopyranosyl‐2‐[(4′ Z)‐2′‐hydroxytetracosene amido]‐4‐tetradecyl‐1, 3, 4‐butantriol. The new compound exhibits strong cytotoxicity against L1210 murine leukemia cells in vitro (ED₅₀ = 0.08 μg/mL).     

Spectral study of a new dihydroisocoumarin

A novel dihydroisocoumarin, 3,4‐dihydro‐6,8‐dihydroxy‐3‐(2′‐acetyl‐3′‐hydroxy‐5′‐methoxy)methyl‐1H‐[2]benzopyran‐1‐one, was isolated from the chloroform extract of the sap of the traditional herb Aloe vera. Its structure was determined by high‐resolution negative fast atom bombardment mass spectrometry (MS), 2D NMR spectroscopy and x‐ray crystallography. The molecular structure was elucidated by 2D NMR analysis. The complete assignment of the ¹H and ¹³C NMR spectra of this compound was performed by using ¹H detected one‐bond heteronuclear multiple quantum correlation (HMQC) and long‐range (two and three bonds) heteronuclear multiple quantum bond correlation (HMBC) experiments. Detailed analyses of the one‐ and two‐dimensional NMR techniques are presented in additional to the spectral properties (MS, IR and UV). Copyright © 2003 John Wiley & Sons, Ltd.     

Annosqualine: a Novel Alkaloid from the Stems of Annona squamosa

Annosqualine (=(10′bR)‐1′,5′,6′,10′b‐tetrahydro‐9′‐hydroxy‐7′,8′‐dimethoxyspiro[cyclohexa‐2,5‐diene‐1,2′‐pyrrolo[2,1‐a]isoquinoline]‐3′,4‐dione; 1 ), a novel alkaloid with an unprecedented skeleton, and a new amide, dihydrosinapoyltyramine (=3‐(4‐hydroxy‐3,5‐dimethoxyphenyl)‐N‐[2‐(4‐hydroxyphenyl)ethyl]propanamide; 2 ), were isolated from the stems of Annona squamosa L., together with six known alkaloids. The structures of all compounds were elucidated spectroscopically by means of optical rotation, ¹H‐, ¹³C‐, and 2D‐NMR, and by EI‐MS, or by comparison with the spectral data of authentic samples. A possible biogenetical pathway towards annosqualine ( 1 ) is proposed.     

Iodine‐Catalyzed Synthesis of Spiro[1,3,4‐benzotriazepine‐2,3′‐indole]‐2′,5(1H,1′H)‐diones under Mild Conditions

The I₂‐catalyzed preparation of spiro[1,3,4‐benzotriazepine‐2,3′‐indole]‐2′,5(1H,1′H)‐diones from 2‐aminobenzohydrazide and isatins in MeCN at room temperature in good‐to‐excellent yields is described. The structure of 3 was corroborated spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS data). A plausible mechanism for this type of reaction is proposed (Scheme 2).     

Guignardic Acid,a Novel Type of Secondary Metabolite Produced by the Endophytic Fungus Guignardia sp.: Isolation,Structure Elucidation,and Asymmetric Synthesis

A UV‐guided fractionation of the AcOEt extract of the fermentation broth of Guignardia sp., an endophytic fungus from the leaves of the tropical tree Spondias mombin, resulted in the identification of the new metabolite (−)‐(2S,5Z)‐2‐(1‐methylethyl)‐4‐oxo‐5‐(phenylmethylene)‐1,3‐dioxolane‐2‐carboxylic acid ( 1 ), isolated as NH salt 1a . The metabolite 1 was designated (−)‐(S)‐guignardic acid. This first member of a new class of natural compounds contains a dioxolanone moiety formed by fusion of 2‐oxo‐3‐phenylpropanoic acid (phenylpyruvic acid) and 3‐methyl‐2‐oxobutanoic acid (dimethylpyruvic acid), products of the oxidative deamination of phenylalanine and valine, respectively. The structure of 1a was deduced from spectral data (UV, IR, MS, ¹H‐ and ¹³C‐NMR) and confirmed by asymmetric synthesis.     

A New Cyclopropyl‐Triterpenoid from Ochradenus arabicus

One new cyclopropyl‐triterpenoid ( 1 ), along with four known constituents including octacosan‐1‐ol ( 2 ), pentacosanoic acid ( 3 ), β‐sitosterol ( 4 ), and β‐sitosterol 3‐O‐β‐D ‐glucopyranoside ( 5 ) were isolated from the aerial parts of Ochradenus arabicus for the first time. These compounds were isolated by repeated column chromatography followed by further purification through recycling HPLC. The structure of the new secondary metabolite 1 was established on the basis of UV, IR, 1D‐ (¹H‐ and ¹³C‐) and 2D‐NMR (HMBC and HSQC), and MS spectral data. The molecular mass was determined by HR‐MS, and hence the molecular formula was deduced. The configurations of stereogenic centers in the molecule were assigned by NOESY experiments, along with biogenetic considerations. The structures of the known compounds were confirmed by comparison of their physical and spectroscopic data with those reported in literature.     

Novel polymeric,thio‐containing photoinitiator comprising in‐chain benzophenone and an amine coinitiator for photopolymerization

A novel thio‐containing diamine with a benzophenone structure, 4‐amino‐4′‐[4‐aminothiophenyl]benzophenone (AATBP), was synthesized. Two kinds of polymeric photoinitiators, PUPIA and PUPI, were synthesized through the polycondensation of toluene‐2,4‐diisocyanate with AATBP and/or N‐methyldiethanolamine (MDEA). A macroamine, PUPA, was also synthesized for comparison. Fourier transform infrared, ¹H NMR, and gel permeation chromatography analyses confirmed the structures of all the polymers. The ultraviolet–visible spectra of PUPIA, PUPI, and AATBP were similar, and all exhibited the maximal absorption above 325 nm. The photopolymerization of two monomers with different functionalities, poly(propylene glycol)diacrylate and trimethylolpropane triacrylate initiated by PUPIA, PUPI/MDEA, PUPI/PUPA, AATBP/MDEA, and AATBP/PUPA, was studied through differential scanning photocalorimetry. The results showed that both PUPIA and PUPI/MDEA had high photoefficiency, and their low‐molecular‐weight counterparts could hardly initiate the photopolymerization. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 576–587, 2007     

NMR assignments of selected bacterial carotenoids

Complete ¹H and ¹³C NMR assignments for selected carotenoids from purple and green phototropic bacteria are reported for the first time. Assignments are made for the all‐E isomers of OH‐rhodopin ( 1 , 1,2,1′,2′‐tetrahydro‐ψ,ψ‐carotene‐1,1′‐diol), rhodovibrin ( 2 , 1′‐methoxy‐3′,4′‐didehydro‐1,2,1′,2′‐tetrahydro‐ψ,ψ‐carotene‐1‐ol), anhydrorhodovibrin ( 3 , 1‐methoxy‐3,4‐didehydro‐1,2‐dihydro‐ψ,ψ‐carotene), 2‐ketorhodovibrin ( 4 , 1′‐hydroxy‐1‐methoxy‐3,4,3′,4′‐tetradehydro‐1,2, 1′,2′‐tetrahydro‐ψ,ψ‐carotene‐2‐one) and chlorobactene ( 5 , ?,ψ‐carotene). Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis and crystal structure of novel [1,2,4]oxadiazolo[5,4‐d][1,5]benzothiozepine derivatives containing pyrazole moiety

A series of new substituted‐[1,2,4]oxadiazolo[5,4‐d][1,5]benzothiazepine derivatives containing pyrazole ring 4 / 4′ was synthesized by substituted‐pyrazolo[1,5]benzothiazepines 2 / 2′ and substituted‐benzohydroximinoyl chlorides 3 through the 1,3‐dipolar cycloaddition reaction in the presence of Et₃N at room temperature, and characterized by MS, IR, ¹H NMR and elemental analyses. In addition, the structure of 4′l was determined by X‐ray crystallography. J. Heterocyclic Chem., 2011.     

(E/Z)‐Isomerization of 3′‐Epilutein

3′‐Epilutein (=(all‐E,3R,3′S,6′R)‐4′,5′‐didehydro‐5′,6′‐dihydro‐β,β‐carotene‐3,3′‐diol; 1 ), isolated from the flowers of Caltha palustris, was submitted to both thermal isomerization and I₂‐catalyzed photoisomerization. The structures of the main products (9Z)‐ 1 , (9′Z)‐ 1 , (13Z)‐ 1 , (13′Z)‐ 1 , (15Z)‐ 1 , and (9Z,9′Z)‐ 1 were determined based on UV/VIS, CD, ¹H‐NMR, and MS data.     

Novel PU‐type polymeric photoinitiator comprising side‐chain benzophenone and coinitiator amine for photopolymerization of PU acrylate

A novel diamine 3,5‐diamino‐4′‐phenoxylbenzophenone (DAPBP) was synthesized from the reaction of 3,5‐diamino‐4′‐chlorobenzophenone (DACBP) and phenol. Then through the polycondensation of DAPBP, toluene‐2,4‐diisocyanate (TDI), and N‐methyldiethanolamine (MDEA), we obtained a PU‐type polymeric photoinitiator containing side‐chain benzophenone (BP) and tertiary amine in the same macromolecule (PUSOA). Another polymeric photoinitiator without coinitiator amine in polymer chain (PUSO) was also synthesized for comparison. FT‐IR, ¹H NMR, and GPC analyses confirmed the structures of monomer and polymeric photoinitiators. The UV–Vis spectra of PUSOA, PUSO, and DAPBP are similar, and all exhibit the maximal absorption near 290 nm. ESR spectra indicate that PUSOA can generate active species most efficiently. The photopolymerization of PU acrylate, initiated by PUSOA, PUSO/MDEA, DAPBP/MDEA, and BP/MDEA, was studied by differential scanning photocalorimetry (photo‐DSC). The results show that the in‐chain coinitiator amine can significantly improve the photoefficiency of the polymeric photoinitiator and the PUSOA is more efficient for the polymerization of PU acrylate than its low‐molecular‐weight counterpart. Copyright © 2008 John Wiley & Sons, Ltd.     

An Efficient Synthesis of Spiro‐oxindole Derivatives by Three‐Component Reactions in Water

An efficient synthesis of (3S)‐1,1′,2,2′,3′,4′,6′,7′‐octahydro‐9′‐nitro‐2,6′‐dioxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carbonitrile is achieved via a three‐component reaction of isatin, ethyl cyanoacetate, and 1,2,3,4,5,6‐hexahydro‐2‐(nitromethylidene)pyrimidine. The present method does not involve any hazardous organic solvents or catalysts. Also the synthesis of ethyl 6′‐amino‐1,1′,2,2′,3′,4′‐hexahydro‐9′‐nitro‐2‐oxospiro[3H‐indole‐3,8′‐[8H]pyrido[1,2‐a]pyrimidine]‐7′‐carboxylates in high yields, at reflux, using a catalytic amount of piperidine, is described. The structures were confirmed spectroscopically (IR, ¹H‐ and ¹³C‐NMR, and EI‐MS data) and by elemental analyses. A plausible mechanism for this reaction is proposed (Scheme 2).     

Synthesis and Characterization of a Series of New Asymmetric Salphen Mono- and Binuclear Metal Complexes

Two novel asymmetric salen ligands H₂L¹ [N‐phenyl‐N‐(2‐hydroxy‐5‐methylphenyl)‐N′‐(2‐hydroxy‐3‐meth‐ oxylphenyl)‐o‐phenyldiamine] and H₂L² [N‐phenyl‐N‐(2‐hydroxy‐5‐chlorophenyl)‐N′‐(2‐hydroxy‐3‐methoxyl‐ phenyl)‐o‐phenyldiamine] and their metal complexes MLⁿ (M=Zn, Co, Ni, Cu; n=1, 2) have been prepared and characterized by elemental analyses, ¹H NMR, ESI‐MS, FT‐IR and UV‐Vis spectra. In particular, the complex ZnL¹, the binuclear monosalphen complex, was synthesized and studied in detail using ¹H NMR and ESI‐MS techniques. For other metal complexes under the same reaction conditions, only mononuclear complexes were obtained. The results are relevant to both the metal ions and the structure of ligands.     

Thrombin Inhibitory Constituents from Duranta repens

The C‐alkylated flavonoids 3,7,4′‐trihydroxy‐3′‐(4‐hydroxy‐3‐methylbutyl)‐5,6‐dimethoxyflavone ( 1 ), 3,7‐dihydroxy‐3′‐(4‐hydroxy‐3‐methylbutyl)‐5,6,4′‐trimethoxyflavone ( 2 ) and the trans‐clerodane diterpenoids 6β‐hydroxy‐15,16‐epoxy‐5β,8β,9β,10α‐cleroda‐3,13(16),14‐trien‐18‐oic acid ( 3 ) and 2β‐hydroxy‐15,16‐epoxy‐5β,8β,9β,10α‐cleroda‐3,13(16),14‐trien‐18‐oic acid ( 4 ) were isolated from Duranta repens. Their structures and the relative configuration of 3 and 4 were determined by spectroscopic methods (¹H‐ and ¹³C‐NMR, IR, and MS) and 2D‐NMR experiments. The known flavonoid 5 is also reported for the first time from this species. The compounds 1 , 3 , and 5 showed significant enzyme‐inhibitory activity against thrombin.     

Structure of an unexpected trimer from the reaction of ageratochromene II with aluminum chloride

A new trimer from the reaction of ageratochromene [1] (6,7‐dimethoxy‐2,2‐dimethyl‐1‐benzopyran) with anhydrous aluminum chloride was shown to be 3,4‐dihydro‐6,7‐dimethoxy‐2,2‐dimethyl‐3‐(6′,7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐4′‐yl)‐4‐(3′,4′‐dihydro‐6′, 7′‐dimethoxy‐2′,2′‐dimethyl‐2H‐1‐benzopyran‐3′‐yl)‐ 2H‐1‐benzopyran. Its structure was confirmed by NMR (¹H, ¹³C, DEPT‐135. COSY, HMBC, HSQC, TOCSY and NOESY), IR, mass spectra and elemental analysis. Copyright © 2002 John Wiley & Sons, Ltd.     

Synthesis,Crystal Structure and Hydrolysis of a Novel Anhydrogalactosucrose: 2′‐Methoxyl‐O‐1′,4′:3′,6′‐dianhydro‐β‐D‐fructofuranosyl 3,6‐anhydro‐4‐chloro‐4‐deoxy‐α‐D‐galactopyranoside

A novel anhydrogalactosucrose derivative 2′‐methoxyl‐O‐1′,4′:3′,6′‐dianhydro‐β‐D‐fructofuranosyl 3,6‐anhydro‐4‐chloro‐4‐deoxy‐α‐D‐galactopyranoside ( 4 ) was prepared from 3,6:1′,4′:3′,6′‐trianhydro‐4‐chloro‐4‐deoxy‐galactosucrose ( 3 ) via a facile method and characterized by ¹H NMR, ¹³C NMR and 2D NMR spectra. The single crystal X‐ray diffraction analysis shows that the title molecule forms a two thee‐dimensional network structure by two kinds of hydrogen bond interactions [O(2) H(2)···O(7), O(5) H(5)···O(8)]. Its stability was investigated by acid hydrolysis reaction treated with sulfuric acid, together with the formation of 1,6‐Di‐O‐methoxy‐4‐chloro‐4‐deoxy‐β‐D‐galactopyranose ( 5 ) and 2,2‐Di‐C‐methoxy‐1,4:3,6‐dianhydromannitol ( 6 ). According to the result, the relative stability of the ether bonds in the structure is in the order: C(1) O C(5)≈C(3′) O C(6′)≈C(1′) O C(4′)>C(3) O C(6)≈C(1) O C(2′)>C(2′) O C(5′).     

Practical liquid chromatography–tandem mass spectrometry method for the simultaneous quantification of amitriptyline,nortriptyline and their hydroxy metabolites in human serum

Amitriptyline (AMI) has been in use for decades in treating depression and more recently for the management of neuropathic pain. A highly sensitive and specific LC–tandem mass spectrometry method was developed for simultaneous determination of AMI, its active metabolite nortriptyline (NOR) and their hydroxy‐metabolites in human serum, using deuterated AMI and NOR as internal standards. The isobaric E‐10‐hydroxyamitriptyline (E‐OH AMI), Z‐10‐hydroxyamitriptyline (Z‐OH AMI), E‐10‐hydroxynortriptyline (E‐OH NOR) and Z‐10‐hydroxynortriptyline (Z‐OH NOR), together with their parent compounds, were separated on an ACE C₁₈ column using a simple protein precipitation method, followed by dilution and analysis using positive electrospray ionisation with multiple reaction monitoring. The total run time was 6 min with elution of E‐OH AMI, E‐OH NOR, Z‐OH AMI, Z‐OH NOR, AMI (+ deuterated AMI) and NOR (+ deuterated NOR) at 1.21, 1.28, 1.66, 1.71, 2.50 and 2.59 min, respectively. The method was validated in human serum with a lower limit of quantitation of 0.5 ng/mL for all analytes. A linear response function was established for the range of concentrations 0.5–400 ng/mL (r² > .999). The practical assay was applied on samples from patients on AMI, genotyped for CYP2C19 and CYP2D6, to understand the influence of metaboliser status and concomitant medication on therapeutic drug monitoring.     

First synthesis of dodecasubstituted porphycenes

The synthesis of dodecasubstituted porphycenes has not been reported, to date. Herein, the preparation of tetramethyloctaethylporphycene by a McMurry‐type coupling of 3,3′,4,4′‐tetraethyl‐5,5′‐diformyl‐2,2′‐bipyrrole was attempted at first, but dodecasubstituted porphycene was not successfully obtained and only pyrrolocyclophene was obtained. The structure of the pyrrolocyclophene was determined by ¹H NMR spectroscopy, FAB MS, and X‐ray crystal‐structure analysis. The pyrrolocyclophene was not successfully oxidized to porphycene. Then, the McMurry‐type coupling of bicyclo[2.2.2]octadiene (BCOD)‐fused 5,5′‐diacyl‐2,2′‐bipyrroles was performed and tetra‐meso‐octa‐β‐substituted (dodecasubstituted) porphycenes were successfully obtained for the first time. The structures were determined by ¹H NMR spectroscopy and X‐ray crystal‐structure analysis. The crystal structures and NMR spectra were compared carefully with octasubstituted porphycenes, and there was a good correlation between the position of the substituents, the N1? N2 and N1? N4 distances of the porphycene inner nitrogen atoms, and NMR chemical shifts of the inner NH protons, which expressed the strength of N? H???N hydrogen bonding between N1 and N2. These results suggested that the BCOD structure was relatively compact compared with common alkyl groups and that was why the dodecasubstituted porphycenes were available this time. UV/Vis absorption and fluorescence properties are also discussed.     

The Synthesis of N‐Glycosyl‐N′‐Pyrazolylmethylene Aminothioureas under a 4Å Molecular Sieve

A series of novel N‐glycosyl‐N′‐pyrazolylmethylene aminothioureas ( 4a‐4e, 5a‐5e ) were synthesized from N‐glycosyl‐N′‐aminothioureas ( 2a‐2d ) and 4‐formylpyrazole ( 3a‐3e ). Activated 4Å molecular sieves were adopted for dehydrated reagent to improve the reaction rate and yield. The structures of the new compounds were identified on the basis of IR, ¹H NMR and MS spectra. Simultaneously, the compounds were detected by fluorescence spectrophotometer and had preferable fluorescence activity, so they can be selected as a kind of novel fluorescence labeled derivative of sugar.     

Experimental and theoretical investigations of the antioxidant activity of 2,2′‐methylenebis(4,6‐dialkylphenol) compounds

The antioxidant activity of two primary antioxidants, 2,2′‐methylenebis(4‐methyl‐6‐tert ‐butylphenol) (MMBPH2) and 2,2′‐methylenebis(4,6‐di‐tert ‐butylphenol) (MDBPH2), has been studied using the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) method. The synthesized compounds have been successfully characterized systematically using elemental analyses, infrared, ¹H NMR and ¹³C NMR spectra and GC–MS. Importantly, it has been found that the compound MMBPH2 in particular is more active in DPPH radical scavenging. In addition, density functional theory calculations (B3LYP) have been used to predict the antioxidant activity and predict structural geometries of the compounds in the gas phase.