Bifunctional chelators for copper radiopharmaceuticals: the synthesis of [Cu(ATSM)-amino acid] and [Cu(ATSM)-octreotide] conjugates

Two new bifunctional chelators that are derivatives of the bis(thiosemicarbazone) ATSMH(2) proligand have been prepared, one with two phenyl carboxylate substituents on the exocyclic nitrogens (L(1)H(2)) and one with a single phenyl carboxylate (L(2)H(2)). The new ligands have been characterised by NMR spectroscopy, mass spectrometry and in the case of L(1)H(2) by X-ray crystallography. The copper, nickel and zinc complexes of the new ligands have been synthesised and characterised. Electrochemical measurements show that the copper(II) complexes undergo a reversible reduction attributable to a Cu(II)/Cu(I) process. The new proligands have been tethered to the N-alpha-Boc-protected amino acids lysine and ornithine using solution and solid phase methods. The new amino acid conjugates form copper complexes and the complexes have been characterised by mass spectrometry and electronic spectroscopy. The bifunctional chelator L(2)H(2) has been conjugated to the tumour targeting peptide octreotide and the new ATSMH(2)-octreotide conjugate and its copper complex have been characterized by mass spectrometry. These new systems have the potential to be used for new targeted copper radiopharmaceuticals for imaging and therapy.     

New sesquiterpenes and calebin derivatives from Curcuma longa

One novel sesquiterpene with new skeleton, (6S)-2-methyl-6-(4-hydroxyphenyl-3-methyl)-2-hepten-4-one (1), two new bisabolane sesquiterpenes, (6S)-2-methyl-6-(4-hydroxyphenyl)-2-hepten-4-one (2), (6S)-2-methyl-6-(4-formylphenyl)-2-hepten-4-one (3), and two calebin derivatives, 4'-(4'-hydroxyphenyl-3'-methoxy)-2'-oxo-3'-butenyl-3-(4'-hydroxyphenyl)-propenoate (4) and 4'-(4'-hydroxyphenyl)-2'-oxo-3'-butenyl-3-(4'-hydroxyphenyl-3'-methoxy)-propenoate (5) were isolated along with five known bisabolane sesquiterpenes from Curcuma longa. 1-4 were new compounds and 5 was a new natural product. Their structures were established by spectral methods.     

2-酰肼基-5-(2,4-二氯苯基)-1,3,4-噁二唑的合成及环化反应研究

二唑衍生物具有抗菌、消炎和调节植物生长等活性［１～５］．二唑硫醚衍生物也具有一定抗菌活性［６］．为筛选具有生物活性的新化合物和研究亲核取代反应的规律,我们设计和合成了新的２－酰肼基－５－（２,４－二氯苯基）－１,３,４－二唑２,研究了２在Ｋ２Ｃ...     

Vibrational infrared intensities and polar tensors of 1,2-difluoroethylenes

The polar tensors of cis and trans-1,2-difluoroethylenes have been determined with new normal modes based in a reassignment of nu(7) and nu(12) bands of the trans isomers and frequency values corrected for Fermi resonances and phase shifts. The signs of the dipole moment derivatives (and its directions, for B(u) symmetry species) were considered to be those of MP2/6-31G** estimates. Root mean square errors calculated for the new tensor element values from each pair of isotopomers (trans-1,2-C(2)H(2)F(2)/trans-1,2-C(2)D(2)F(2) and cis-1,2-C(2)H(2)F(2)/cis-1,2-C(2)D(2)F(2)) show that the new polar tensor sets fit the isotopic invariance criterion better than previously reported sets. The accuracy of polar tensor transference procedures was tested by calculating the infrared intensities of trans-1,2-C(2)H(2)F(2) through the new polar tensors of the cis isomer. The resulting estimates are very accurate and also support the new band assignment, though the A(6) intensity remains still somewhat underestimated.     

Synthesis and magnetic properties of new mono- and binuclear iron complexes with salicyloylhydrazono dithiolane ligand

We report here experimental evidence for the formation in the solid state of a new binuclear Fe (III) 2(mu-OMe) 2(HL) 4 complex (H 2L is 2-salicyloylhydrazono-1,3-dithiolane). The isostructural Mn (III) 2(mu-OMe) 2(HL) 4 complex has provided the strongest ferromagnetic interaction value (J approximately 20 cm (-1)) between Mn (III) ions to date. The new iron binuclear compound presented in this study shows antiferromagnetic intramolecular coupling, which agrees with the theoretical study that we previously proposed. During our synthetic work, we also observed an unexpected spontaneous reduction of the new Fe (III)(HL) 2Cl,S complex to the new Fe (II)(H 2L) 2Cl 2 high-spin mononuclear complex. This process has been checked by cyclo-voltammetry as well as pseudosteady voltammetry.     

Synthesis, characterization and some properties of mononuclear Ni and trinuclear NiFe2 complexes related to the active site of [NiFe]-hydrogenases

The [N(2)S(2)]-type ligand 1,2-(2-C(5)H(4)NCH(2)S)(2)C(6)H(4) (L) is prepared in 84% yield by a new method and its structure has been confirmed by X-ray crystallography. The new synthetic method involves sequential reaction of 1,2-phenylenedithiol with EtONa followed by treatment of the resulting disodium salt of 1,2-phenylenedithiol with in situ generated 2-(chloromethyl)pyridine from its HCl salt. Further treatment of ligand L with NiCl(2)·6H(2)O or NiI(2) affords the expected new mononuclear Ni complexes Ni[1,2-(2-C(5)H(4)NCH(2)S)(2)C(6)H(4)]Cl(2) (1) and Ni[1,2-(2-C(5)H(4)NCH(2)S)(2)C(6)H(4)]I(2) (3) in 87-88% yields, whereas reaction of L with NiBr(2) under similar conditions results in formation of the expected new mononuclear complex Ni[1,2-(2-C(5)H(4)NCH(2)S)(2)C(6)H(4)]Br(2) (2) and one unexpected new mononuclear complex Ni[1-(2-C(5)H(4)NCH(2)S)-2-(2-C(5)H(4)NCH(2)SC(6)H(4)S)C(6)H(4)]Br(2) (2*) in 82% and 5% yields, respectively. More interestingly, the ligand L-containing novel trinuclear NiFe(2) complex Ni{[1,2-(2-C(5)H(4)NCH(2)S)(2)C(6)H(4)}Fe(2)(CO)(6)(μ(3)-S)(2) (4) is found to be prepared by sequential reaction of (μ-S(2))Fe(2)(CO)(6) with Et(3)BHLi, followed by treatment of the resulting (μ-LiS)(2)Fe(2)(CO)(6) with mononuclear complex 1, 2, or 3 in 12-20% yields. The new complexes 1-4 and 2* are fully characterized by elemental analysis and various spectroscopies, and the crystal structures of 1, 2* and 3 as well as some electrochemical properties of 1-4 are also reported.     

Chiral molecular switches based on binaphthalene molecules with anthracene moieties: CD signal due to interchromophoric exciton coupling and modulation of the CD spectrum

By coupling the features of binaphthalene and anthracene, new binaphthalenes with two anthracene moieties were designed and synthesized, aiming at developing chiral molecular switches. A strong CD signal with negative sign due to the interchromophoric exciton coupling was observed for (S)-1 with -(CH2)2 as the linker. This new CD signal became weak and the sign reversed by changing the linker to -(CH2)3 in (S)-2 and -(CH2)6 in (S)-3. For (S)-4 with -(CH2)11 as the linker, no such CD signal was detected. Photodimerization of two anthracene moieties in these binaphthalene molecules can occur. The results show that the CD spectra of (S)-1, (S)-2, (S)-3, and (R)-1 can be reversibly modulated by alternating UV light irradiation and heating. Therefore, chiral molecular switches based on new binaphthalenes with two anthracene moieties are achieved.     

Sesquiterpenes, nortriterpenes and other constituents from Ligularia tongolensis

Two new eremophilane-type sesquiterpenes, 3beta-(2'-methylbutanoyloxy)-8betaH-eremophil-7(11)-ene-12,8alpha-(14,6alpha)-diolide (1) and 8betaH-eremophil-3,7(11)-diene-12,8alpha(14,6alpha)-diolide (2), and two new norursane-type triterpenes, 2alpha,3beta,19alpha-trihydroxy-28-norurs-12-ene (7) and 2alpha,3alpha,19alpha-trihydroxy-28-norurs-12-ene (8), were isolated from the roots of Ligularia tongolensis, together with nine known compounds. The structures of the new compounds were elucidated by spectroscopic methods.     

Addition of dioxygen to an N4S(thiolate) iron(II) cysteine dioxygenase model gives a structurally characterized sulfinato-iron(II) complex

The non-heme iron enzyme cysteine dioxygenase (CDO) catalyzes the S-oxygenation of cysteine by O(2) to give cysteine sulfinic acid. The synthesis of a new structural and functional model of the cysteine-bound CDO active site, [Fe(II)(N3PyS)(CH(3)CN)]BF(4) (1) is reported. This complex was prepared with a new facially chelating 4N/1S(thiolate) pentadentate ligand. The reaction of 1 with O(2) resulted in oxygenation of the thiolate donor to afford the doubly oxygenated sulfinate product [Fe(II)(N3PySO(2))(NCS)] (2), which was crystallographically characterized. The thiolate donor provided by the new N3PyS ligand has a dramatic influence on the redox potential and O(2) reactivity of this Fe(II) model complex.     

N1-Substitution in 2-methyl-4(5)nitroimidazole. III. New syntheses of 1-(2′-(ethylsulfonyl)ethyl)-2-methyl-5-nitroimidazole

Some new syntheses of 1-[2′-(ethylsulfonyl)ethyl]-2-methyl-5-nitroimidazole (IV), a new antitrichomonal agent are described. The most successful method proved to be alkylation of sodium ethanesulfinate (XXI) with 1-(2′-haloethyl)-2-methyl-5-nitroimidazoles (1a,b) in dimethylformamide.     

A unique approach to development of near-infrared fluorescent sensors for in vivo imaging

Near-infrared (NIR) fluorescent sensors have emerged as promising molecular tools for imaging biomolecules in living systems. However, NIR fluorescent sensors are very challenging to be developed. Herein, we describe the discovery of a new class of NIR fluorescent dyes represented by 1a/1c/1e, which are superior to the traditional 7-hydroxycoumarin and fluorescein with both absorption and emission in the NIR region while retaining an optically tunable hydroxyl group. Quantum chemical calculations with the B3LYP exchange functional employing 6-31G(d) basis sets provide insights into the optical property distinctions between 1a/1c/1e and their alkoxy derivatives. The unique optical properties of the new type of fluorescent dyes can be exploited as a useful strategy for development of NIR fluorescent sensors. Employing this strategy, two different types of NIR fluorescent sensors, NIR-H(2)O(2) and NIR-thiol, for H(2)O(2) and thiols, respectively, were constructed. These novel sensors respond to H(2)O(2) or thiols with a large turn-on NIR fluorescence signal upon excitation in the NIR region. Furthermore, NIR-H(2)O(2) and NIR-thiol are capable of imaging endogenously produced H(2)O(2) and thiols, respectively, not only in living cells but also in living mice, demonstrating the value of the new NIR fluorescent sensor design strategy. The new type of NIR dyes presented herein may open up new opportunities for the development of NIR fluorescent sensors based on the hydroxyl functionalized reactive sites for biological imaging applications in living animals.     

Comparison of liquid chromatographic behaviors on N-methylimidazolium functionalized ZrO(2)/SiO(2)-4 and N-methylimidazolium functionalized SiO(2) stationary phases

A new stationary phase N-methylimidazolium functionalized ZrO(2)/SiO(2)-4 (Zr/SilprMim) has been prepared. The chromatographic property of this stationary phase is investigated by ion chromatography (IC) with inorganic and organic anions, and normal phase HPLC with basic compounds and hydroxybenzenes. The effects of pH and the strength of Lewis base of eluent on separation of anions are studied. This new stationary phase is also compared with a N-methylimidazolium functionalized SiO(2) stationary phase (SilprMim). The results show that this new stationary phase can be used in analysis of inorganic anions with great prospects. At the same time, successful separations of some organic anions can be obtained by using phosphate buffer solution as mobile phase. This new stationary phase also has a distinct advantage in the separation of basic compounds in normal phase. But due to the presence of Lewis acid sites on the surface of ZrO(2)/SiO(2)-4, Lewis bases such as hydroxybenzenes adsorb very strongly on this new stationary phase, and Lewis acid sites can be masked or modified by the eluent that contain Lewis base groups.     

Naphthalene-1,8-diyl bis(halogenophosphanes): novel syntheses and structures of useful synthetic building blocks

A series of new bay region disphospha-functionalised naphthalenes is reported. The reduction of ylidic phosphonium phosphoride NapP(2)Cl(6) (1) (Nap=naphthalene-1,8-diyl) with MeOPCl(2) gives the important synthon Nap(PCl(2))(2) (2) in nearly quantitative yield. Reaction of 1 with magnesium metal affords (NapP(2))(n) (3), which reacts with Br(2) and I(2), yielding Nap(PBr(2))(2) (4) and Nap(PI)(2) (5), respectively. X-ray structure determinations reveal a twisted geometry of the naphthalene ring in sterically strained 2 and 4, whilst the presence of a P-P bond in 5 results in the release of the steric strain and generation of the planar NapP(2) moiety. Although the tetrahedral P environments are severely distorted the sigma(3)P-sigma(3)P bonding in 5 represents a new type of P-P bonding environment in 1,8-diphosphanaphthalenes. Compounds 1, 4 and 5 each represent the highest coordination, achievable by direct halogenation. The new compounds 2-5 were fully characterised by NMR, IR, and Raman spectroscopy, mass spectrometry, and elemental analysis.     

Medicinal flowers. VI. Absolute stereostructures of two new flavanone glycosides and a phenylbutanoid glycoside from the flowers of Chrysanthemum indicum L.: their inhibitory activities for rat lens aldose reductase

Two new flavanone glycosides, (2S)- and (2R)-eriodictyol 7-O-beta-D-glucopyranosiduronic acids, and a new phenylbutanoid glycoside, (2S, 3S)-1-phenyl-2,3-butanediol 3-O-beta-D-glucopyranoside, were isolated from the flowers of Chrysanthemum indicum L. cultivated in China together with eight flavonoids. The absolute stereostructures of the new compounds were determined on the basis of chemical and physicochemical evidence. Both of the new flavanone glycosides were found to show inhibitory activity for rat lens aldose reductase.     

New sesquiterpenoid and triterpenoids from the fruits of Rhizophora mucronata

A new sesquiterpene (1) and two new pentacyclic triterpenoid esters (2, 3) together with three known compounds (4-6) were isolated from the fruits of Rhizophora mucronata. Their structures were elucidated by analysis of their spectroscopic data. The new compounds were characterized as 3-hydroxy-3,7,11-trimethyl-9-oxododeca-1,10-diene (mucronatone, 1), 3beta-E-caffeoyltaraxerol (2) and 3beta-Z-caffeoyltaraxerol (3).     

Synthesis and Characterization of new Monomers and Polymers Containing Hindered Piperidine Groups

Abstract

Two new methacryloyl ureas, 1-(2-methylacryloyl)-3-(2,2,6,6-tetra-methylpiperidin-4-yl)-urea and 1-butyl-3-(2-methylacryloyl)-1-(2,2,6,6-tetramethylpiperidin-4-yl)-urea (monomer I and monomer II), were prepared by the addition reaction of 2-methylacryloyl iso-cyanate with 2,2,6,6-tetramethylpiperidin-4-yl-amine or butyl-(2,2,6,6-tetramethylpiperidin-4-yl)-amine in a molar ratio of 1:1 at low or room temperature. In a similar way, the syntheses of two new methacryloyl carbamates, 1-(2,2,6,6-tetra-methylpiperidin-4-yl)-3-(2-methylacryloyl)-carbamate and l-(1,2,2,6,6-pentamethyl-piperidin-4-yl)-3-(2-methylacryloyl)-carbamate (monomer III and monomer IV), were completed by the reaction of 2,2,6,6-tetra-methylpiperidin-4-ol or 1,2,2,6,6-pentamethylpiperidin-4-ol with 2-methylacryloyl isocyanate in the presence of dibutyltin dilaurate as catalyst at 60°C. The four new monomers were homopolymerized, and copolymerized with styrene by AIBN as initiator at 70°C. The structures of the new monomers and their polymers were characterized by FT-IR and NMR spectroscopy and by GPC.     

Two minor diterpene glycosides from the leaves of Stevia rebaudiana

Two new new diterpene glycosides, 13-[(2-O-(6-O-beta-D-glucopyranosyl)-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (1) and 13-[(2-O-beta-D-glucopyranosyl-3-O-beta-D-fructofuranosyl-beta-D-glucopyranosyl)oxy] kaur-16-en-18-oic acid beta-D-glucopyranosyl ester (2) were isolated from the leaves of Stevia rebaudiana, along with the known steviol glycosides stevioside, rebaudiosides A-F and dulcoside A. The structures of the two new compounds were established on the basis of extensive 2D NMR (COSY, HSQC, and HMBC), MS and chemical studies.     

Selective reductive transformations using samarium diiodide-water

Samarium diiodide (SmI(2)) is one of the most important reductive electron transfer reagents available in the laboratory. Key to the popularity of SmI(2) is the ability of additives and co-solvents to tune the properties of the reagent. Over the last decade water has emerged as a particularly valuable additive, opening up new chemical space and leading to the discovery of unprecedented selectivity and new reactions promoted by SmI(2). In this Feature Article we review recent progress in the application of SmI(2)-H(2)O systems, with an emphasis on mechanistic considerations and the development of new transformations.     

马来酸罗格列酮的核磁共振谱分析

利用NMR、2D NMR及IR、UV、MS等实验技术详细研究了胰岛素增敏剂马来酸罗格列酮的波谱学特征。借助马来酸罗格列酮及罗格列酮的DEPT谱和罗格列酮的二维^1H--^1H COSY、^13C-^1H COSY对马来酸罗格列酮氢谱和碳谱进行了完全的归属，为该类化合物的结构解析提供了有益的分析依据。     

Ring-A hydroxylated dolastanes from the marine brown alga Dictyota dichotoma (Huds.) Lamour

Marine brown alga Dictyota dichotoma (Dictyotaceae) collected from Karachi coast of Arabian Sea yielded two new dolastane-diterpenoids named: dichototetraol (1) and dichotopentaol (3) along with 2 of the same skeleton as a new source. Their structures have been characterized with the aid of 2D-NMR spectroscopic techniques.