324740-69-4

Upstream product

• 109-97-7 pyrrole 
• 698-69-1 4-chloro-N,N-dimethylaniline 
• 586-77-6 4-bromo-N,N-dimethylaniline 
• 1159490-62-6 4-dimethylaminoacetophenone O-vinyloxime 
• 187672-34-0 4-dimethylaminoacetophenone oxime 
• 74-86-2 acetylene 
• 2124-31-4 4'-dimethylaminoacetophenone 
• 6310-87-8 p-dimethylaminoacetophenone oxime 
• 75-20-7 calcium carbide 

Relevant academic research and scientific papers

Isomer-Specific Hydrogen Bonding as a Design Principle for Bidirectionally Quantitative and Redshifted Hemithioindigo Photoswitches

A new class of bidirectionally quantitative photoswitches based on the hemithioindigo (HTI) scaffold is reported. Incorporation of a pyrrole hydrogen-bond donor leads to a bathochromic shift allowing for quantitative bidirectional isomerization. Additionally, extending conjugation from the electron-rich pyrrole results in quantitative visible-light photoswitches, as well as photoswitches that isomerize with red and near-infrared light. The presence of the hydrogen bond leading to the observed redshift is supported by computational and spectroscopic evidence.

Direct synthesis of aryl substituted pyrroles from calcium carbide: An underestimated chemical feedstock?

In this work, a novel synthetic methodology for the preparation of aryl pyrroles directly from the reaction of calcium carbide with oxime is reported. Various pyrrole derivatives are generated from the corresponding oximes in satisfactory yields (49–88%) under the optimized conditions. The one-pot synthesis of aryl pyrrole from widely available ketone is also successfully developed. A new near-infrared fluorescent BODIPY dye containing a phenyl substitution at the C-3 position is expediently prepared from the aryl pyrrole derived from this methodology. The key benefit of this methodology is the use of an inexpensive and less hazardous primary chemical feedstock, calcium carbide, in a wet solvent without any metal catalysts. This process offers a novel cost-efficient route for the synthesis of functionalized pyrrole.

4-Dimethylaminoacetophenone O-vinyloxime: Synthesis and steric structure

4-Dimethylaminoacetophenone oxime was synthesized from 4- dimethylaminoacetophenone and hydroxylamine hydrochloride. Its reaction with acetylene in the system KOH-DMSO gave previously unknown 4- dimethylaminoacetophenone O-vinyloxime as the major product.

Palladium-catalyzed cross-coupling of pyrrole anions with aryl chlorides, bromides, and iodides

(Chemical Equation Presented) A general method for the conversion of pyrrole anions to 2-arylpyrroles has been developed. Using a palladium precatalyst and sterically demanding 2-(dialkylphosphino)biphenyl ligands, (pyrrolyl)zinc chloride may be cross-coupled with a wide range of aryl halides, including aryl chlorides and aryl bromides, at low catalyst loadings and under mild conditions. A high degree of steric hindrance is tolerated. Certain ring-substituted pyrrole anions have also been arylated with aryl bromide substrates.

Generation and reactivity of the 4-aminophenyl cation by photolysis of 4-chloroaniline

4-Chloroaniline and its N,N-dimethyl derivative are photostable in cyclohexane but undergo efficient photoheterolysis in polar media via the triplet state and give the corresponding triplet phenyl cations. CASSCF and UB3LYP calculations show that the 4-aminophenyl triplet cation has a planar geometry and is stabilized by > 10 kcal mol-1 with respect to the slightly bent singlet. The triplet has a mixed carbene-diradical character at the divalent carbon. This species either adds to the starting substrate forming 5-chloro-2,4′-diaminodiphenyls (via an intermediate cyclohexadienyl cation) or is reduced to the aniline (via the aniline radical cation) in a ratio depending on the hydrogen-donating properties of the solvent. Transients attributable to the triplet aminophenyl cation as well as to the ensuing intermediates are detected. Chemical evidence for the generation of the phenyl cation is given by trapping via electrophilic substitution with benzene, mesitylene, and hexamethylbenzene (in the last case the main product is a 6-aryl-3-methylene-1,4-cyclohexadiene). Relative rates of electrophilic attack to benzene and to some alkenes and five-membered heterocycles are measured and span over a factor of 15 or 30 for the two cations. The triplet cation formed under these conditions is trapped by iodide more efficiently than by the best π nucleophiles, However, in contrast to the singlet cation, it does not form ethers with alcohols, by which it is rather reduced.

Easy photochemical preparation of 2-dimethylaminophenylfurans, -pyrroles and -thiophenes

2-(4-N,N-dimethylaminophenyl) heterocycles are smoothly obtained from the photolysis of 4-chloro-N,N-dimethylaniline in acetonitrile in the presence of furan, pyrrole, thiophene and some of their methyl derivatives bearing a free α-position. With 2,5-dimethyl heterocycles the arylation occurs with equal efficiency in the β position. In the case of furan, when the irradiation is carried out in methanol, cis/trans 2-aryl-5-methoxy-2,5-dihydro adducts are obtained. The reaction is rationalized as involving heterolytic cleavage of the C-Cl bond in the triplet state of the aniline. The intermediacy of the thus formed triplet aryl cation explains the observed high regio- and chemo-selectivity of the process. (C) 2000 Elsevier Science Ltd.