Pyrrole

Our initial investigation of the asymmetric Mannich reaction of indole 2a with phenyl α-amidosulfone 3a is summarized in Table 1. The effect of catalyst structure on the reaction outcome was first investigated at 10 mol% catalyst loading in toluene (Table 1, Entries 1–5). As we expected, based on our knowledge of the catalytic performance of chiral oligoEG 1,[7] the ether chain length (Entries 1–3) as well as suitable acidity of the phenolic protons (Entry 2 vs. Entries 4 and 5) are critical for the catalytic performance in this reaction. Consistently, catalyst 1b bearing iodine atom at the 3 and 3′ positions of the binaphthyl scaffold showed the best results in terms of catalytic activity (70% yield) and enantioselectivity (98% ee) (Entry 2, Table 1). In further experiments using (R)-1b as the optimal catalyst, different solvents were examined (Entries 6–10). In general, excellent enantioselectivity was obtained in all the solvents tested in this study. Among them, m-xylene proved to be the best in terms of yield (75%) and asymmetric induction (99% ee) (Entries 8–10). Further improvement of the yield was achieved by increasing the equivalents of indole (83% yield and 99% ee, Entry 11). Table 1. Optimization of the BINOL-based polyether catalyzed asymmetric Friedel-Crafts (FC) reactions of indole [a] Entry Catalyst Indole 2a (equiv.) Solvent Yield (%)[b] ee (%)[c] 1 (R)-1a 1.0 Toluene 68 61 2 (R)-1b 1.0 Toluene 70 98 3 (R)-1c 1.0 Toluene 59 80 4 (R)-1d 1.0 Toluene 24 1…

Basicity of Pyridine vs Pyrrole The lower the pKb value of a compound, the stronger a base it is. Since pyridine has a lower pKb value, it is a stronger base than pyrrole. In this example, we cannot use either the steric factor or inductive factor to explain their basicity. Instead, we have to look at the hybridization state of the respective nitrogen atoms. The nitrogen atoms in pyrrole and pyridine are sp2 hybridized because they satisfy the following two conditions: 1) the atom has at least…

(PPy-Au NCs) by the chemical oxidative polymerization of pyrrole with ferric chloride as an oxidizing agent, in the presence of a colloidal suspension of gold nanoparticles. Gold nanoparticles (Au NPs) were synthesized by standard citrate reduction method. Au NPs and PPy-Au NCs were characterized by Transmission Electron Microscopy (TEM), Atomic Forced Microscopy (AFM), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray diffraction (XRD)…

atom must still be trigonal with the lone pair in a p orbital so the N–H bond is in the plane of the five-membered ring. The NMR of pyrrole is slightly less convincing as the two types of proton on the ring resonate at higher field (6.5 and 6.2 p.p.m.) than those of benzene or pyridine but they still fall in the aromatic rather than the alkene region. Pyrrole is also more reactive towards electrophiles than benzene or 1148 43 . Aromatic heterocycles 1: structures and reactions replace one CH…

My plan includes functional group conversions of a benzyl ester Knorr pyrrole using various organic reactions (Figure 3), while using mass spectroscopy (MS), thin-layer chromatography (TLC) and proton nuclear magnetic resonance (HNMR) to track the development of DHP. After the coupling of DHP into the tripyrrole, I plan on using various starting materials to adjust the functional groups to find the most suitable variant of tripyrrole by using NMR, TLC and MS to detect potential collapses in…

not increase even at 70 °C.[17] Thus at 70 °C, the reaction was completed within 10 h, affording the product in 79% and 99% ee. Thus, the substrate scope was then investigated at 70 °C. Substituted indoles 2, containing either electron-donating groups or electron-withdrawing groups at the ortho, meta and para-position of the phenyl ring, were tested in the reaction with α-amidosulfone 8 (Scheme 5). In all the cases, moderate yields and excellent ees were achieved for the desired…

discovered, most of these enzymes catalyze degradation of environmental pollutants. Chlorophenol 4-monooxygenase was isolated from Burkholderia cepacia AC1100 catalyzes hydroxylation and de-chlorination of 2, 4, 6-trichlorophenol (30, 31). Hydroxylation of p-nitrophenol is carried out by the two-component monooxygenase in Bacillus sphaericus JS905 (32). Degradation of metal chelators such as oxidation of EDTA is carried out by the enzyme isolated from bacterial strains DSM9103 and BNC1 (33, 34)…

indicating possibly a longer reaction time especially during dione formation. The researchers also looked regiospecificity with the Lewis acids and they found that most acids except for TsOH were able to deliver a regiospecific manner. Observing their many attempts to produce the desired product and good yields gave a picture as to what was the recipe/requirement for this reaction to take place. All successful reactions had electron donating group on aromatic nucleophile, ideal reaction…

Experimental Section - Chemicals Pyrrole, substituted benzaldehydes (p-anisaldehyde, p-nitrobenzaldehyde, 2,6-dichlorobenzaldehyde and benzaldehyde), triethylamine (TEA), p-terphenyl (TP) and ferrocene (Fc) were purchased from Sigma-Aldrich. Tetraphenylporphyrin (TPP) was purchased from Frontier Scientific. Acetonitrile (MeCN), dichloromethane (DCM), 1,4-dioxane, and other organic solvents used were spectroscopic grade. These solvents were distilled from appropriate drying agents under argon…

of hemoglobin which is a protein in red blood cells that carries oxygen from the lungs to the rest of the body. It also is an iron-containing compound used throughout the body in the role of breaking down chemicals so they can be removed from your body. (Kujtan 2005). Heme is made mainly in the bone marrow and the liver through the production of porphyrin and link with iron. The process of making heme is called the heme biosynthecic pathway. One of eight enzymes controls each step of the…