具有亲油性及近红外光吸收特性的金属细菌卟吩的合成与表征

在四氢呋喃中加入金属卟吩、 强碱(无水氢化钠)和金属盐MX_n(M=Cu, Ni, Pd), 合成了细菌卟吩的5种过渡金属配合物, 该方法减少了反应时间, 提高了反应产率. 通过紫外-可见光谱、 核磁共振氢谱、 质谱等方法对所合成的化合物进行了表征, 并研究了其光学性质. 结果表明, 细菌卟吩在近红外区有明显的吸收峰, 且具有较高的强度, 相比于细菌卟吩配体, 金属配合物吸收光谱中的Q_x和Q_y带均发生了明显的红移. 细菌卟吩配体与锌配合物具有发光性质, 为Q_y(0,0)荧光, 而铜、 镍等金属配合物并没有检测到荧光峰.     

Selectivity of Organosamarium （Ⅲ） Hydridein Reducing Unsaturated Carbonyl Compounds

IntroductionOrganolanthanidehydrideswhichhaveboththepropertyofnegativehydrogenandthespecialpropertyofhydridesoff blockelementscannotonlycatalyzethehydrogenationandpolymerizationofalkenesoralkynes[1] butalsoreducemanyunsaturatedfunctionalgroups[2 ,3] .Qianetal.[4 ] hasfoundthatthecy clopentadienylsamarium NaHsystemcouldreduceterminalcarbon carbondoublebondsindieneswitha10 0 %selectivity ,andproposedapossiblemechanismbywhichthealkeneinsertsintotheM—Hbondoforganolanthanidehydrideformedinsitutog…     

Synthesis and photophysical characterization of stable indium bacteriochlorins

Bacteriochlorins have wide potential in photochemistry because of their strong absorption of near-infrared light, yet metallobacteriochlorins traditionally have been accessed with difficulty. Established acid-catalysis conditions [BF(3)·OEt(2) in CH(3)CN or TMSOTf/2,6-di-tert-butylpyridine in CH(2)Cl(2)] for the self-condensation of dihydrodipyrrin-acetals (bearing a geminal dimethyl group in the pyrroline ring) afford stable free base bacteriochlorins. Here, InBr(3) in CH(3)CN at room temperature was found to give directly the corresponding indium bacteriochlorin. Application of the new acid catalysis conditions has afforded four indium bacteriochlorins bearing aryl, alkyl/ester, or no substituents at the β-pyrrolic positions. The indium bacteriochlorins exhibit (i) a long-wavelength absorption band in the 741-782 nm range, which is shifted bathochromically by 22-32 nm versus the analogous free base species, (ii) fluorescence quantum yields (0.011-0.026) and average singlet lifetime (270 ps) diminished by an order of magnitude versus that (0.13-0.25; 4.0 ns) for the free base analogues, and (iii) higher average yield (0.9 versus 0.5) yet shorter average lifetime (30 vs 105 μs) of the lowest triplet excited state compared to the free base compounds. The differences in the excited-state properties of the indium chelates versus free base bacteriochlorins derive primarily from a 30-fold greater rate constant for S(1) → T(1) intersystem crossing, which stems from the heavy-atom effect on spin-orbit coupling. The trends in optical properties of the indium bacteriochlorins versus free base analogues, and the effects of 5-OMe versus 5-H substituents, correlate well with frontier molecular-orbital energies and energy gaps derived from density functional theory calculations. Collectively the synthesis, photophysical properties, and electronic characteristics of the indium bacteriochlorins and free base analogues reported herein should aid in the further design of such chromophores for diverse applications.     

Reaction of InCl3 with various reducing agents: InCl3-NaBH4-mediated reduction of aromatic and aliphatic nitriles to primary amines

While alternative methods of preparing dichloroindium hydride (HInCl(2)) via the in situ reduction of InCl(3) using lithium amino borohydride (LAB) were explored, generation of HInCl(2) from the reduction of InCl(3) by sodium borohydride (NaBH(4)) was also re-evaluated for comparison. The reductive capability of the InCl(3)/NaBH(4) system was found to be highly dependent on the solvent used. Investigation by (11)B NMR spectroscopic analyses indicated that the reaction of InCl(3) with NaBH(4) in THF generates HInCl(2) along with borane-tetrahydrofuran (BH(3)·THF) in situ. Nitriles underwent reduction to primary amines under optimized conditions at 25 °C using 1 equiv of anhydrous InCl(3) with 3 equiv of NaBH(4) in THF. A variety of aromatic, heteroaromatic, and aliphatic nitriles were reduced to their corresponding primary amine in 70-99% isolated yields. Alkyl halide and nitrile functional groups were reduced in tandem by utilizing the reductive capabilities of both HInCl(2) and BH(3)·THF in a one-pot reaction. Finally, the selective reduction of the carbon bromine bond in the presence of nitriles was achieved by generating HInCl(2) via the reduction InCl(3) with NaBH(4) in CH(3)CN or with lithium dimethylaminoborohydride (MeLAB) in THF.     

Metal bacteriochlorins which act as dual singlet oxygen and superoxide generators

A series of stable free-base, Zn(II) and Pd(II) bacteriochlorins containing a fused six- or five-member diketo- or imide ring have been synthesized as good candidates for photodynamic therapy sensitizers, and their electrochemical, photophysical, and photochemical properties were examined. Photoexcitation of the palladium bacteriochlorin affords the triplet excited state without fluorescence emission, resulting in formation of singlet oxygen with a high quantum yield due to the heavy atom effect of palladium. Electrochemical studies revealed that the zinc bacteriochlorin has the smallest HOMO-LUMO gap of the investigated compounds, and this value is significantly lower than the triplet excited-state energy of the compound in benzonitrile. Such a small HOMO-LUMO gap of the zinc bacteriochlorin enables intermolecular photoinduced electron transfer from the triplet excited state to the ground state to produce both the radical cation and the radical anion. The radical anion thus produced can transfer an electron to molecular oxygen to produce superoxide anion which was detected by electron spin resonance. The same photosensitizer can also act as an efficient singlet oxygen generator. Thus, the same zinc bacteriochlorin can function as a sensitizer with a dual role in that it produces both singlet oxygen and superoxide anion in an aprotic solvent (benzonitrile).     

A Dieckmann cyclization route to piperazine-2,5-diones

Piperazine-2,5-diones are formed by Dieckmann cyclization (NaH, THF) of substructures of the type CH(2)-N(R)C(O)CH(2)N(R')CO(2)Ph in which the terminal methylene (CH(2)) that is adjacent to nitrogen closes onto the carbonyl group of the phenyl carbamate unit at the other end of the chain. R and R' are alkyl groups, and the terminal methylene is activated by a ketone carbonyl, a nitrile, an ester, or a phosphoryl group. The starting materials are assembled by standard acylation and oxidation processes, starting from a β-(alkylamino)alcohol, an (alkylamino)acetonitrile, an (alkylamino) ester, or an (alkylamino)methyl phosphonate.     

Preparation of Functionalized Diaryl‐ and Diheteroaryllanthanum Reagents by Fast Halogen–Lanthanum Exchange

Aryl and heteroaryl halides (X=Br, I) undergo a fast and convenient halogen–lanthanum exchange with nBu₂LaMe, which leads to functionalized diaryl‐ and diheteroaryllanthanum derivatives. Subsequent trapping reactions with selected electrophiles, such as ketones, aldehydes, or amides, proceeded smoothly at −50 °C in THF, affording polyfunctionalized alcohols and carbonyl derivatives. Kinetic competition experiments revealed a similar reactivity trend as for Br/Mg exchange, but 10⁶‐times higher rates, making it comparable to Br/Li exchange.     

Harnessing anionic rearrangements on the benzenoid ring of quinoline for the synthesis of 6,6'-disubstituted 7,7'-dihydroxy-8,8'-biquinolyls

7,7'-Bis(((dimethylamino)carbonyl)oxy)-8,8'-biquinolyl (5) was prepared in 71% yield by regioselective directed ortho metalation (DoM) of N,N-dimethyl O-quinol-7-yl carbamate (2) with LDA followed by oxidation with anhydrous ferric chloride. DoM of 5 with excess LDA induced double anionic ortho-Fries rearrangement and gave 6,6'-bis((dimethylamino)carbonyl)-7,7'-dihydroxy-8,8'-biquinolyl (8). Treatment of N,N-diethyl O-(8-iodoquinol-7-yl) carbamate (16) with LDA in THF solvent at -78 degrees C, followed by addition of anhydrous ferric chloride, resulted in an efficient tandem halogen-dance dimerization process which afforded 7,7'-bis(((diethylamino)carbonyl)oxy)-6,6'-diiodo-8,8'-biquinolyl (17) directly in 54% yield.     

A novel rearrangement of alkyl (n-alkylamido) methyl sulfides

The finding of a new rearrangement of alkyl (N-alkylamido) methyl sulfides promoted by strong bases such as NaH, LDA, and t-BuLi is described. The reaction induces a migration of the alkyl group linked to the sulfur to the amide carbonyl giving the corresponding ketone.     

Understanding the Origins of Nucleophilic Hydride Reactivity of a Sodium Hydride–Iodide Composite

Sodium hydride (NaH) has been commonly used as a Brønsted base in chemical syntheses, while it has rarely been employed to add hydride (H^?) to unsaturated electrophiles. We previously developed a procedure to activate NaH through the addition of a soluble iodide source and found that the new NaH–NaI composite can effect even stereoselective nucleophilic hydride reductions of nitriles, imines, and carbonyl compounds. In this work, we report that mixing NaH with NaI or LiI in tetrahydrofuran (THF) as a solvent provides a new inorganic composite, which consists of NaI interspersed with activated NaH, as revealed by powder X‐ray diffraction, and both solid‐state NMR and X‐ray photoelectron spectroscopies. DFT calculations imply that this remarkably simple inorganic composite, which is comprised of NaH and NaI, gains nucleophilic hydridic character similar to covalent hydrides, resulting in unprecedented and unique hydride donor chemical reactivity.     

Photochemical C2-C6 cyclization of enyne-allenes: detection of a fulvene triplet diradical in the laser flash photolysis

A series of enyne-allenes, with and without benzannulation at the ene moiety and equipped with aromatic and carbonyl groups as internal triplet sensitizer units at the allene terminus, was synthesized. Both sets, the cyclohexenyne-allenes and benzenyne-allenes, underwent thermal C(2)-C(6) cyclization exclusively to formal ene products. In contrast, the photochemical C(2)-C(6) cyclization of enyne-allenes provided formal Diels-Alder and/or ene products, with higher yields for the benzannulated systems. A raise of the temperature in the photochemical cyclization of enyne-allene 1b' led to increasing amounts of the ene product in relation to that of the formal Diels-Alder product. Laser flash photolysis at 266 and 355 nm as well as triplet quenching studies for 1b,b' indicated that the C(2)-C(6) cyclization proceeds via the triplet manifold. On the basis of a density functional theory (DFT) study, a short-lived transient (tau = 30 ns) was assigned as a triplet allene, while a long-lived transient (tau = 33 micros) insensitive to oxygen was assigned as fulvene triplet diradical. An elucidation of the reaction mechanism using extensive DFT computations allowed rationalization of the experimental product ratio and its temperature dependence.     

Synthese und Charakterisierung von Fluorenylgallaten und Fluorenylindaten

Synthesis and Characterization of Fluorenyl Gallates and Fluorenyl Indates GaCl₃ reacts with Fluorenyllithium (LiFl) in the ratio 1:4 in Et₂O to [Li(THF)₄][GaFl₄] ( 1 ). The addition of DME (1,2-dimethoxyethane) to solutions of 1 in THF leads to [Li(DME)₃][GaFl₄] ( 2 ) under replacement of THF molecules by DME molecules in the coordination sphere of the Li⁺ ions. Treatment of InCl with LiFl in Et₂O and recrystallization from THF gives [Li(THF)₄][ClInFl₃] ( 3 ), which is formed by an disproportionation reaction. 3 can also be obtained by the reaction of InCl with FlZnCl/LiCl in Et₂O and recrystallization from THF. 1 and 2 crystallize from THF and THF/DME as [Li(THF)₄][GaFl₄] · THF ( 1 · THF) and [Li(DME)₃][GaFl₄] · THF ( 2 · THF), respectively. Crystalline 3 is isolated from the reaction of InCl and FlZnCl/LiCl, while the reaction mixture of InCl and LiFl gives after recrystallization in THF 3 · 1,5 THF. The gallate ions in 1 and 2 differ mainly in the position of the fluorenyl ligands. The unit cells of 3 and 3 · 1,5 THF contain two crystallographic unique ion pairs of [Li(THF)₄][ClInFl₃].     

A convenient route to diverse heterocycles through an addition of beta-amino carbonyl compounds to 3-halogeno-4-methoxybenzynes

[reaction: see text] 3-Halogeno-4-methoxybenzynes 5 generated from 5-(3-halogeno-4-methoxyphenyl)thianthrenium perchlorates 1 and LDA in THF at reflux reacted with various beta-amino carbonyl compounds and 2-aminophenyl benzenesulfonate etc. to give diverse heterocyclic compounds.     

Tailoring a bacteriochlorin building block with cationic, amphipathic, or lipophilic substituents

Bacteriochlorins are attractive candidates for photodynamic therapy (PDT) of diverse medical indications owing to their strong absorption in the near-infrared (NIR) region, but their use has been stymied by lack of access to stable, synthetically malleable molecules. To overcome these limitations, a synthetic free base 3,13-dibromobacteriochlorin (BC-Br(3)Br(13)) has been exploited as a building block in the synthesis of diverse bacteriochlorins via Pd-mediated coupling reactions (Sonogashira, Suzuki, and reductive carbonylation). Each bacteriochlorin is stable to adventitious dehydrogenation by virtue of the presence of a geminal dimethyl group in each pyrroline ring. The target bacteriochlorins bear cationic, lipophilic, or amphipathic substituents at the 3- and 13- (beta-pyrrolic) positions. A dicarboxybacteriochlorin was converted to amide derivatives via the intermediate diacid chloride. A diformylbacteriochlorin was subjected to reductive amination to give aminomethyl derivatives. A set of 3,5-disubstituted aryl groups bearing lipophilic or amphipathic groups was introduced via Suzuki coupling. Altogether 22 free base bacteriochlorins have been prepared. Eight aminoalkylbacteriochlorins were quaternized with methyl iodide at two or four amine sites per molecule, which resulted in water solubility. Each bacteriochlorin exhibits a Q(y) absorption band in the range of 720-772 nm. The ability to introduce a wide variety of peripheral functional groups makes these bacteriochlorins attractive candidates for diverse applications in photomedicine including PDT in the NIR region.     

含萘结构的新型苦参碱衍生物的合成

以二异丙基氨基锂和氢化钠为亲核试剂,THF为溶剂,苦参碱和萘类化合物为原料,设计并合成了10个含萘结构的新型苦参碱衍生物［14-萘羟次甲基苦参碱(3a~3c), 14-萘甲酰基苦参碱(3g~3j)和14-萘甲烯基苦参碱 (3d~3f)］,其结构经¹H NMR, ¹³C NMR, FT-IR和ESI-MS表征。     

Generation of Allylmagnesium Reagents by Hydromagnesiation of 2-Aryl-1,3-dienes

A protocol for the generation of allylmagnesium reagents from 2-aryl-1,3-dienes was developed using magnesium hydride (MgH₂) that is generated in situ by solvothermal treatment of sodium hydride (NaH) and magnesium iodide (MgI₂) in tetrahydrofuran (THF). Downstream functionalization of the resulting allylmagnesium reagents with carbonyl compounds or alkyl (pseudo)halides delivers branched products having an allylic quaternary carbon center, whereas that with chlorosilanes resulted in formation of linear allylsilanes in regio and stereoselective manners. Further derivatizations of the homoallylic alcohols and allylsilanes were also demonstrated.     

Coordination chemistry of diselenophosphinate complexes: the X-ray single-crystal structures of [K(Se2PPh2)(THF)2]2 and [In(Se2PPh2)3].L (L = THF, PhMe)

Reaction of potassium diphenylphosphide with elemental selenium is shown to give [K(Se(2)PPh(2))(THF)(2)](2) 1, which further reacts with InCl(3) to yield [In(Se(2)PPh(2))(3)] 2. Crystallization of 2 from either THF or PhMe gave 2.THF or 2.PhMe, respectively, both of which form loosely linked dimers in the solid state via Se...Se intermolecular van der Waals interactions. Decomposition of 2 has been studied by TGA.     

Simple and rapid p-methoxybenzylation of hydroxy and amide groups at room temperature by NaOt-Bu and DMSO

The p-methoxybenzylation of hydroxy and amide groups by p-methoxybenzyl chloride utilizing NaOt-Bu in DMSO is described. p-Methoxybenzylation of sterically hindered menthol using NaOt-Bu in DMSO proceeded faster than the commonly used methods which use NaH in THF or DMF for p-methoxybenzylation of hydroxy and amide groups. The described method was applicable for sterically hindered substrates at room temperature without adding any activating reagents such as tetrabutylammonium iodide.     

Efficient synthesis of (1R,4S,6R)-4-Isopropenyl-1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one

A simple and convenient one-pot synthesis of (1R,4S,6R)-4-isopropenyl-1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-2-one was developed consisting in a thermodynamic methylation of carvone (NaH, MeI, THF, 20°C) followed by the epoxidation with alkalinized hydrogen peroxide. The reduction of the obtained epoxyketone with sodium borohydride proceeded stereoselectively to give a β-alcohol. The attempts to convert its isopropenyl fragment into an acetate group by a rearrangement of products or intermediates of the oxidative fragmentation resulted only in obtaining intermediate acyl derivatives.     

Application of Organolithium and Related Reagents in Synthesis. Part 111. Metallation of 2-Methyl- and 4-Methylnicotinic Acids. A Useful Method for Preparation of AZA-Isocoumarins

The metallation (LDA/THF) of 2-methyl- and 4-methylnicotinic acids (1) and (2), and the subsequent reaction of the lithiated species (3) and (4) with carbonyl electrophiles as a synthetic route of 5-aza- and 7-aza-isocoumarins (7), (8), (9) and (10), is described. The isocoumarins (9) and (10) appeared to be readily transformable into the corresponding naphthyridines (11) and (12).