Introduction to Quinolines 1.1 General: Quinoline [1] or 1-aza-napthalene or benzo[b]pyridine is nitrogen containing heterocyclic aromatic compound [1]. Quinoline is a weak tertiary base [1]. It can form salt with acids and displays reactions similar to those of pyridine and benzene [1]. It shows both electrophilic and nucleophilic substitution reactions [1]. It is nontoxic to humans on oral absorption and inhalation [1]. Runge was discovered quinolines first time in 1834 by the distilled coal tar and gave the substance the name Leukol/quinoline [1]. Then in 1842 Gerhardt discovered "chinolein" or "chinolin" by alkaline distillation of quinine, cinchonine and strychnine [2]. However, it was not, until 1882 that Hoogewerff and von Dorp determined …show more content…
Although it has known for more than a century, it is still the most useful method for the preparation of quinolines [22]. Genereally, this reaction is carried out by refluxing an aqueous or alcoholic solution of reactants in the presence of base at convenient temperatures [22]. O-Aminobenzophenone fails to react with simple ketones such as cyclohexanone and β-ketoesters under thermal or base catalysis conditions [23]. Recently, modified methods employing znCl2, Phosphoric acid, Bi(OTf)3, silver phosphotungstate and AuCl3, have been reported for the synthesis of quinolines …show more content…
reported that the reaction of propargylic anilines (XXVI) with a appropriate electiphiles leading to 3-iodo or phenylseleno substituted quinolines (XXVII) (Scheme 1.4) [28]. Miller et al. developed a mild, efficient, high-yielding one-pot synthesis of quinolines by employing SnCl2 and ZnCl2. Substituted-o-nitrobenzaldehyde (XXVIII) on condensation with dialkyl ketones (XXIX) in presence of stannous chloride and zinc chloride in refluxing ethanol led to 2, 3-dialkylquinoline (XXX) (scheme 1.5) [29]. Scheme 1.5 Sweson et al. reported the regiocontrolled synthesis of 2, 4, 6-trisubstituted quinolines from bromomethyl ketones, aldehydes and anilines. Michael addition of the dianion of N-Boc-anilines in the presence of CuCN and LiCl with the α-tolysulfonyl-α, β-unsaturated ketones derived from Knovengal condensation of the β-keto sulphones with an aldehyde, generated a 1, 4-adduct, which after deprotection of the Boc group and thermal elimination of tolyl sulfone provided the quinoline (scheme
This week’s lab was the third and final step in a multi-step synthesis reaction. The starting material of this week was benzil and 1,3- diphenylacetone was added along with a strong base, KOH, to form the product tetraphenylcyclopentadienone. The product was confirmed to be tetraphenylcyclopentadienone based of the color of the product, the IR spectrum, and the mechanism of the reaction. The product of the reaction was a dark purple/black color, which corresponds to literature colors of tetraphenylcyclopentadienone. The tetraphenylcyclopentadienone product was a deep purple/black because of its absorption of all light wavelengths. The conjugated aromatic rings in the product create a delocalized pi electron system and the electrons are excited
The primary goal of this laboratory project was to identify an unknown compound and determine its chemical and physical properties. First the appearance, odor, solubility, and conductivity of the compound were observed and measured so that they could be compared to those of known compounds. Then the cation present in the compound was identified using the flame test. The identity of the anion present in the compound was deduced through a series of chemical tests (Cooper, 2009).
Wittig reactions allow the generation of an alkene from the reaction between an aldehyde/ketone and a ylide (derived from phosphonium salt).The mechanism for the synthesis of trans-9-(2-phenylethenyl) anthracene first requires the formation of the phosphonium salt by the addition of triphenylphosphine and alkyl halide. The phosphonium halide is produced through the nucleophilic substitution of 1° and 2° alkyl halides and triphenylphosphine (the nucleophile and weak base) 4 An example is benzyltriphenylphosphonium chloride which was used in this experiment. The second step in the formation of the of the Wittig reagent which is primarily called a ylide and derived from a phosphonium halide. In the formation of the ylide, the phosphonium ion in benzyltriphenylphosphonium chloride is deprotonated by the base, sodium hydroxide to produce the ylide as shown in equation 1. The positive charge on the phosphorus atom is a strong EWG (electron-withdrawing group), which will trigger the adjacent carbon as a weak acid 5 Very strong bases are required for deprotonation such as an alkyl lithium however in this experiment 50% sodium hydroxide was used as reiterated. Lastly, the reaction between ylide and aldehyde/ketone produces an alkene.3
The alcohol starting material, 2-methylcyclohexanol, was dehydrated through an E1 elimination by using of phosphoric acid as a catalyst. After a purification by simple distillation, which removed the alkene product and the by-product water from the reaction mixture, the methylcyclohexene products were analyzed by percent yield, boiling point, IR spectroscopy, and two chemical tests, Br2 in CCl4 and Jones test. By performing the simple distillation using pyrolysis, 85% of phosphoric acid and 2-methylcyclohexanol were added into the boiling flask, where the product from the collecting flask was condensed by the ice, and washed with the saturated sodium chloride. The weight of the product was determined and the percent yield of the product was
The goal of this lab is to exemplify a standard method for making alkyne groups in two main steps: adding bromine to alkene groups, and followed by heating the product with a strong base to eliminate H and Br from C. Then, in order to purify the product obtained, recrystallization method is used with ethanol and water. Lastly, the melting point and IR spectrum are used to determine the purity of diphenylacetylene.
Discussion and Conclusions: Interpreting these results have concluded that relative reactivity of these three anilines in order of most reactive to least reactive go; Aniline > Anisole > Acetanilide. Aniline, has an NH2 , the most active substituent , and adds to any ortho/para position available on the ring. This data is confirmed with the product obtained, (2,4,6 tribromoaniline, mp of 108-110 C). As for anisole, it has a strongly activating group attached, OMe an alkoxy group, and it added in two of the three available spots, both ortho. The results conclude: (2,4-Dibromoanisol mp 55-58 C ). Acetanilide has a strong activating group attached, acylamino group, but this group is large and the ortho positions are somewhat hindered so the majority of the product obtained added at the para position, results conclude: (p-bromoacetanilide mp 160-165 C). Since all the substituents attached to the aromatic rings were activators the only products able to be obtained were ortho/para products.
By comparing the overall percent yields based upon pathway, the statistically superior pathway proved to be the Red pathway, which also happens to be the synthesis pathway I implemented. I determined that this was the best pathway based on the mean, median, and maximum overall percent yields of each pathway and are shown on Table 2. I hypothesize that this pathway was most successful because of the order of the reagents used, specifically that the nitration was the second step. I hypothesize that the addition of the nitro group to the benzoic acid was more successful than other reaction pathways because the attached carboxylic acid group is a moderate deactivator and meta director, more so than the attached ketone in the Blue pathway or the attached ester in the Green
The purpose of the experiment was to study the kinetics of the hydrolysis of ester, p-nitrophenyl acetate (NPA) that is catalyzed by the buffer imidazole (Im). In terms of kinetics, specifically speaking, the rate of reaction as determined by the concentration, reaction orders, and rate constant with each species in a chemical reaction. By using the concentration of the catalyst and the temperature, the overall reaction rate was determined. The rate constants of K0, Kobs, and Kcat can be derived via the plotting of the absorbtion at 400nm of p-nitrophenol vs. the concentration of the catalyst imidazole. Lastly, the free energy of activation, ΔGǂ, that is necessary to force the reactant’s transformation of the reactants to the transition state structure will be determined by using the equation ΔGǂ = ΔHǂ – TΔSǂ derived from the Eyring plot.
The article, “Asymmetric one-pot Robinson annulations” (Rajagopal et al., 2001) describes the procedure of a Robinson Annulation Reaction that converts a five-membered cyclic ketone to a two-ring, bicyclic compound. In this reaction, 1.12 g of 0.01 mol dione was added to a solution of 1.15 g of 0.01 mol S-proline in dry DMSO and mixed in a beaker, followed by 0.7 g of 0.01 mol methyl vinyl ketone. This mixture was stirred for 145 ...
The three butene products have been verified to elute in the following order: 1-butene, trans-2-butene, and cis-2-butene. Theory: The dehydration of 2-butanol, a secondary alcohol, progresses readily in the presence of a strong acid like concentrated sulfuric acid (H2SO4). The reaction is completed via the E1 mechanism. Initially, the hydroxyl group is a poor leaving group, but that is remedied by its protonation by the acid catalyst (H2SO4) converting it to a better leaving group, H2O. The loss of this water molecule results in a secondary carbocation intermediate that continues to form an alkene in an E1 elimination.
Ensure gloves are worn at all times when handling strong acids and bases within the experiment of the preparation of benzocaine. 4-aminobenzoic acid (3.0g, 0.022 moles) was suspended into a dry round-bottomed flask (100cm3) followed by methylated sprits (20 cm3). Taking extra care the concentrated sulphuric acid of (3.0 cm3, 0.031 moles) was added. Immediately after the condenser was fitted on, and the components in the flask were swirled gently to mix components. It should be ensured that the reactants of the concentrated sulphuric acid and the 4-aminobenzoic acid were not clustered in the ground glass joint between the condenser itself and the flask. In order to heat the mixture to a boiling point, a heating mantle was used and then further left for gently refluxing for a constituent time of forty minutes. After the duration of the consistent forty minutes the rou...
In a small reaction tube, the tetraphenylcyclopentadienone (0.110 g, 0.28 mmol) was added into the dimethyl acetylene dicarboxylate (0.1 mL) and nitrobenzene (1 mL) along with a boiling stick. The color of the mixed solution was purple. The solution was then heated to reflux until it turned into a tan color. After the color change has occurred, ethanol (3 mL) was stirred into the small reaction tube. After that, the small reaction tube was placed in an ice bath until the solid was formed at the bottom of the tube. Then, the solution with the precipitate was filtered through vacuum filtration and washed with ethanol. The precipitate then was dried and weighed. The final product was dimethyl tertraphenylpthalate (0.086 g, 0.172mmol, 61.42%).
Product 3 was isolated in a low yield of 27% and with some solvent impurities as shown by the analytical techniques but it was indeed synthesised successfully.
These were all naturally occurring substances. No refinement had occurred, and isolation of specific compounds (drugs) had not taken place.
Development of specific ethers has been inactive and fruitful area of investigation in the past few decades.2The strategy of ether catalysis General encompasses synergistic activation of a ethers an electrophile by two or more reactive centers through the combination of a Lewis acid and Lewis base working in concert. Such approach results in high reaction rates and excellent ethers. Hydrogen bonding plays a crucial role in this catalysis. Hydrogen bonding to an electrophile decreases the electron density of this species, activating it toward nucleophilic attack. Recently chemists have begun to appreciate the tremendous potential offered by hydrogen bonding as a tool for electrophile activation in synthetic catalytic systems. In particular, ethers donors have emerged as a broadly applicable class of catalysts for ethers synthesis. An amide unit, the key functional group of peptides, plays an important role in catalyst design and modification. Based on the understanding of different asymmetric catalytic reaction mechanisms, the creation of amide structure-based ether and was realized by rational arrangement of hydrogen-bond networks. According to their model, two water molecules simultaneously establish H-bonds to the carbonyl oxygen of the substrate for optimal transition state stabilization. The concept of explicit double H-bonding activation was no longer restricted to one type of reaction or catalyst, but became a generally applicable principle. The simultaneous donation of two hydrogen bonds has proven to be a highly successful strategy for electrophile activation. Such interactions benefit from increased strength and directionality compared to a single hydrogen bond. Ethers containing double hydrogen bond ethers are capable of directing the assembly of molecules with similar control as