Rh(III)-Catalyzed One-Step Synthesis of ortho-Alkynylated Perylene Imide Dyes: Optical and Electrochemical Properties of New Derivatives

A one-step Rh-catalyzed site-selective ortho-C−H alkynylation of perylene as well as naphthalene mono- and diimides is reported. A single step regioselective access to ortho-C−H alkynylated derivatives of these ryleneimides not only increases the step economy of the ortho-functionalization on these dyes but also provides a quick access route towards highly functionalized dyes that have potential optoelectronic applications. Increased solubility of tetra(triisopropylsilyl)acetylenyl PDIs in organic solvents greatly enhances their utility for further derivatization.     

PtII-Catalyzed Hydroxylation of Terminal Aliphatic C(sp3)−H Bonds with Molecular Oxygen

The practical application of Shilov-type Pt catalysis to the selective hydroxylation of terminal aliphatic C−H bonds remains a formidable challenge, due to difficulties in replacing Pt^IV with a more economically viable oxidant, particularly O₂. We report the potential of employing FeCl₂ as a suitable redox mediator to overcome the kinetic hurdles related to the direct use of O₂ in the Pt reoxidation. For the selective conversion of butyric acid to γ-hydroxybutyric acid (GHB), a significantly enhanced catalyst activity and stability (turnover numbers (TON)>30) were achieved under 20 bar O₂ in comparison to current state-of-the-art systems (TON<10). In this regard, essential reaction parameters affecting the overall activity were identified, along with specific additives to attain catalyst stability at longer reaction times. Notably, deactivation by reduction to Pt⁰ was prevented by the addition of monodentate pyridine derivatives, such as 2-fluoropyridine, but also by introducing varying partial pressures of N₂ in the gaseous atmosphere. Finally, stability tests revealed the involvement of Pt^II and FeCl₂ in catalyzing the non-selective overoxidation of GHB. Accordingly, in situ esterification with boric acid proved to be a suitable strategy to maintain enhanced selectivities at much higher conversions (TON>60). Altogether, a useful catalytic system for the selective hydroxylation of primary aliphatic C−H bonds with O₂ is presented.     

Directing-Group-Free C7-Alkylations of N-Alkylindoles Mediated by Cationic Zirconium Complexes: Role of Brønsted Acid for Catalytic Manifold

Highly position selective alkylations of N-alkylindoles at C7-positions have been enabled by cationic zirconium complexes. The strategy provides a straightforward access to install alkyl groups at C7-positions of indoles without a complex directing group. Mechanistic studies provided support for the importance of Brønsted acids in the catalytic manifold.     

平面交叉玻璃波导型微透镜阵列光学性能研究

介绍了平面交叉玻璃光波导型半球形微透镜阵列的制作方法.利用积分形式的光线方程式讨论了半球形微透镜的光学特性,得到了半球形微透镜的光线轨迹方程式和焦距表示式,理论结果与实验数据是一致的.     

Stille Cross‐Coupling of a Racemic Planar‐Chiral Ferrocene and Crystallographic Trace Analysis of Catalysis Intermediates and By‐products

A pressure‐controlled procedure for the S_N1 reaction of rac‐1‐[(dimethylamino)methyl]‐2‐(tributylstannyl)ferrocene ( 1 ) to rac‐1‐(phthalimidomethyl)‐2‐(tributylstannyl)ferrocene ( 2 ) was developed. Pd⁰‐Catalyzed Stille coupling of 2 with iodobenzene afforded rac‐1‐phenyl‐2‐(N‐phthalimidomethyl)ferrocene ( 5 ) in 74% yield; after trace enrichment by crystallization of the combined mother liquors, one single crystal of each, 5 , catalysis intermediate trans‐iodo(σ‐phenyl)bis(triphenylarsino)palladium(II) ( 7 ), trans‐diiodobis(triphenylarsino)palladium(II) ( 8 ), and rac‐2,2′‐bis(phthalimidomethyl)‐1,1′‐biferrocene ( 9 ) could be isolated by crystal sorting under a microscope and characterized by X‐ray crystal structure analysis. Furthermore, 5 was deprotected to amine ( 11 ), which does even survive the Birch reduction to rac‐1‐(aminomethyl)‐2‐(cyclohexa‐2,5‐dienyl)ferrocene ( 12 ).     

Nitration Products of 5‐Amino‐1H‐tetrazole and Methyl‐5‐amino‐1H‐tetrazoles – Structures and Properties of Promising Energetic Materials

The nitration of 5‐amino‐1H‐tetrazole ( 1 ), 5‐amino‐1‐methyl‐1H‐tetrazole ( 3 ), and 5‐amino‐2‐methyl‐2H‐tetrazole ( 4 ) with HNO₃ (100%) was undertaken, and the corresponding products 5‐(nitrimino)‐1H‐tetrazole ( 2 ), 1‐methyl‐5‐(nitrimino)‐1H‐tetrazole ( 5 ), and 2‐methyl‐5‐(nitramino)‐2H‐tetrazole ( 6 ) were characterized comprehensively using vibrational (IR and Raman) spectroscopy, multinuclear (¹H, ¹³C, ¹⁴N, and ¹⁵N) NMR spectroscopy, mass spectrometry, and elemental analysis. The molecular structures in the crystalline state were determined by single‐crystal X‐ray diffraction. The thermodynamic properties and thermal behavior were investigated by using differential scanning calorimetry (DSC), and the heats of formation were determined by bomb calorimetric measurements. Compounds 2, 5 , and 6 were all found to be endothermic compounds. The thermal decompositions were investigated by gas‐phase IR spectroscopy as well as DSC experiments. The heats of explosion, the detonation pressures, and velocities were calculated with the software EXPLO5, whereby the calculated values are similar to those of common explosives such as TNT and RDX. In addition, the sensitivities were tested by BAM methods (drophammer and friction) and correlated to the calculated electrostatic potentials. The explosion performance of 5 was investigated by Koenen steel sleeve test, whereby a higher explosion power compared to RDX was reached. Finally, the long‐term stabilities at higher temperatures were tested by thermal safety calorimetry (FlexyTSC). X‐Ray crystallography of monoclinic 2 and 6 , and orthorhombic 5 was performed.     

Reactions of Chlorosulfanyl Derivatives of Cyclobutanones with Different Nucleophiles

The reactions of 3‐chloro‐3‐(chlorosulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one ( 2 ) with N, O, S, and P nucleophiles occur by substitution of Cl at the S‐atom. Whereas, in the cases of secondary amines, alkanols, phenols, thiols, thiophenols, and di‐ and trialkyl phosphates, the initially formed substitution products were obtained, the corresponding products with allyl and propargyl alcohols undergo a [2,3]‐sigmatropic rearrangement to give allyl and allenyl sulfoxides, respectively. Analogous substitution reactions were observed when 3‐chloro‐3‐(chlorodisulfanyl)‐2,2,4,4‐tetramethylcyclobutan‐1‐one ( 3 ) was treated with N, O, and S nucleophiles. The reaction of 3 with Et₃P led to an unexpected product via cleavage of the S? S bond (cf. Scheme 13). In the reactions of 2 with primary amines and H₂O, the substitution products react further via elimination of HCl to yield the corresponding thiocarbonyl S‐imides and the thiocarbonyl S‐oxide, respectively. Whereas the latter could be isolated, the former were not stable but could be intercepted by MeOH (Scheme 4) or adamantanethione (Scheme 5). The structures of some of the substitution products were established by X‐ray crystallography.     

Three New Lanostane Triterpenoids from Inonotus obliquus

Three new lanostane‐type triterpenoids, inonotsulides A, B, and C ( 1 – 3 , resp.) were isolated from the sclerotia of Inonotus obliquus (Pers .: Fr.) (Japanese name: Kabanoanatake; Russian name: Chaga). Their structures were determined to be (20R,24S)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide ( 1 ), (20R,24R)‐3β,25‐dihydroxylanost‐8‐en‐20,24‐olide ( 2 ), and (20R,24S)‐3β,25‐dihydroxylanosta‐7,9(11)‐dien‐20,24‐olide ( 3 ) on the basis of chemical transformation, NMR spectroscopy including 1D and 2D (¹H,¹H‐COSY, NOESY, HMQC, HMBC), EI‐MS, and single‐crystal X‐ray analysis.