78191-00-1Relevant articles and documents
Synthesis and characterization of benzo- and naphtho[2,1-b:3,4-b′] dithiophene-containing oligomers for photovoltaic applications
Loebert, Mirjam,Mishra, Amaresh,Uhrich, Christian,Pfeiffer, Martin,Baeuerle, Peter
, p. 4879 - 4892 (2014)
Dicyanovinyl (DCV) end-capped oligomers 1-7 containing fused benzo[2,1-b:3,4-b′]dithiophene (BDT) and naphtho[2,1-b:3,4-b′] dithiophene (NDT) as central cores have been synthesized and characterized. These oligomers show excellent thermal stability due to the insertion of the central fused ring system thus allowing purification by gradient sublimation in high yield. With respect to the reference compound, non-fused tetramer DCV4T, the new oligomers showed hypsochromic shifts in absorption and emission spectra and larger band gaps in thin films. Due to high lying LUMO energy levels, they exhibit sufficient energy offset with respect to C60 to allow for efficient charge transfer in organic solar cells. At the same time, low-lying HOMO energy levels result in high open-circuit voltages (VOC). As a result, planar heterojunction (PHJ) solar cells derived from the novel oligomers and C60 provide very high open circuit voltages (VOC) of up to 1.21 V and power conversion efficiencies (PCEs) of up to 2.7%. Bulk-heterojunction (BHJ) devices comprising oligomers 1-4 and C60 display a slightly lower VOC of 1 V leading to efficiencies as high as 3.6%. This journal is the Partner Organisations 2014.
Asymmetric Construction of Alkaloids by Employing a Key ω-Transaminase Cascade
Taday, Freya,Ryan, James,Argent, Stephen P.,Caprio, Vittorio,Maciá, Beatriz,O'Reilly, Elaine
supporting information, p. 3729 - 3732 (2020/03/11)
An ω-transaminase-triggered intramolecular aza-Michael reaction has been employed for the preparation of cyclic β-enaminones in good yield and excellent enantio- and diastereoselectivity, starting from easily accessible prochiral ketoynones and commercially available enzymes. The powerful thermodynamic driving force associated with the spontaneous aza-Michael reaction effectively displaces the transaminase reaction equilibrium towards product formation, using only two equivalents of isopropylamine. To demonstrate the potential of this methodology, this biocatalytic aza-Michael step was combined with annulation chemistry, affording unique stereo-defined fused alkaloid architectures.
One-pot method for preparing O-alkyl hydroxylamine hydrochloride and N,O-dialkyl hydroxylamine hydrochloride
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Paragraph 0032-0033, (2020/10/20)
The invention relates to the field of organic synthesis, in particular to a one-pot method for preparing O-alkyl hydroxylamine hydrochloride and N,O-dialkyl hydroxylamine hydrochloride. The method comprises the following steps: S1, acetylation: mixing hydroxylamine hydrochloride with water and methyl acetate, and dropwise adding a sodium hydroxide solution while stirring at room temperature to obtain an intermediate acetyl hydroxylamine; S2, alkylation: dropwise adding an alkylation reagent into the reaction kettle at normal temperature, and then heating the reactants for reaction; S3, hydrolysis and purification: after the reaction is qualified, adding concentrated sulfuric acid, performing heating hydrolysis, after the reaction is qualified, adding caustic soda flakes or liquid caustic soda to adjust the pH value to 12, carrying out atmospheric distillation and hydrochloric acid acidification, cooling the product for crystallization, and centrifuging and drying the crystal to obtaina final product. According to the invention, methyl acetate is used as an acetyl protective agent, and compared with ethyl acetate, methyl acetate has the advantages of good water solubility, small reaction steric hindrance, sufficient protection, few impurities, low price and cost and the like; therefore, the method has the advantages of high product purity, simple process operation, accessible raw materials, simple wastewater components and environment friendliness, and is suitable for industrial production.
Synthesis of Enantiomerically Pure β-Hydroxy Ketones via β-Keto Weinreb Amides by a Condensation/Asymmetric-Hydrogenation/Acylation Sequence
Diehl, Julian,Brückner, Reinhard
supporting information, p. 278 - 286 (2017/01/24)
An established route to enantiomerically pure β-hydroxy ketones proceeds through the asymmetric hydrogenation of β-keto esters, an ester/amide exchange, and the use of the resulting β-hydroxy amide for the acylation of an organometallic compound. We shortened this route by showing that β-keto Weinreb amides are hydrogenated with up to 99 % ee in the presence of [Me2NH2]+{[RuCl(S)-BINAP]2(μ-Cl)3}–(0.5 mol-%) at room temp./5 bar. These Weinreb amides were prepared by seemingly obvious yet unprecedented condensations of lithiated N-methoxy-N-methylacetamide with carboxylic chlorides (51–87 % yield). The resulting β-hydroxy Weinreb amides were used for the acylation of organolithium and Grignard reagents. They thus gave enantiomerically pure β-hydroxy ketones (28 examples). A selection of these compounds gave anti-1,3-diols after another C=O bond hydrogenation, or syn-1,3-diols by a Narasaka–Prasad reduction.
