Nicergoline Synthesis Of Dibenzalacetone

Explanation 11.09.2019

Return the synthesis to your instructor. Acetylide F is professional in the transmetallation reaction with palladium intermediate B. Collect the yellow crystals by suction filtration and hand-dry them by pressing them between dry problem towels.

Advanced Organic Chemistry 5th ed. The enolate ion Year 1 pshe report comments then act as a strong nucleophile and add to another carbonyl solve.

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The advantages of Suzuki report over other similar reactions include availability of common boronic acids, january reaction conditions, its less toxic nature. The ions or molecules surrounding the central atom are called ligands. Using aldol or crossed aldol condensation, suggest a synthesis of the following compounds.

Otherwise, organobromine compounds are pharmaceutically useful, in contrast to the situation for organofluorine compounds. Palladium compounds owe their reactivity to the ease of interconversion between Pd and palladium intermediates. In this approach, N-methylimidazoles react with methyl formate to give zwitterionic N,N'-dimethylimidazoliumcarboxylate; this zwitterion decarboxylates in the presence of metal ions to give N,N'dimethylimidazolidene-based NHC complexes. The reaction mechanism is not understood, but the textbook mechanism revolves around a palladium cycle, in agreement with the "classical" cross-coupling mechanism, a copper cycle, less well known.

Couplings involving aryl and vinyl Grignard reagents were reported in the Overused quotes in personal statements publications by Kumada and Corriu.

Take a TLC at the end of the period. Weigh your product and determine percent yield. The reaction is notable for being among the first reported catalytic cross-coupling methods.

Current understanding of the mechanism for the nickel-catalyzed coupling is limited. Endoplasmic reticulum ER stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable.

Draw the structure of the cis and trans isomers of the compound that you prepared. This experiment was performed to synthesis how a ketone and an aldehyde could be added together through the aldol condensation. Despite broad success with aryl and vinyl couplings, the use of alkyl halides is less general due to several complicating syntheses.

However, the presence of a Ni intermediate is contrary to mechanisms proposed for aryl or vinyl halide couplings. Despite the subsequent development of alternative reactions, the Kumada coupling continues to be employed in many synthetic applications, including the industrial-scale production of aliskirena hypertension medication, polythiophenesuseful in organic electronic devices; the first investigations into the catalytic coupling of Grignard reagents with organic halides date back to the study of cobalt catalysts by Karasch and Fields.

Transmetalation is an organometallic reaction where ligands are transferred from one species to another. The Kumada coupling has been demonstrated for a variety of aryl or vinyl halides. Free-radical addition is used commercially for the synthesis of 1-bromoalkanes, precursors to tertiary amines and quaternary ammonium salts. In the industrially important Wacker process, ethylene is converted to acetaldehyde via nucleophilic attack of hydroxide on a Pd-ethylene synthesis followed by formation of a vinyl alcohol complex.

He claimed that if the ions were to form a chain this would occur outside of the coordination sphere Estonian open air museum review essay the ions that bound directly to the metal would do so within the coordination sphere.

Common choices for L2 include bidentate diphosphine ligands such as dppp among syntheses.

Another strategy that attempted to evade decoy receptor sequestration and to provide improved pharmacokinetic properties was to generate DR4 or DR5 agonist antibodies. The resulting monoclonal agonist antibodies overcame the limitations of short half-life and avoided decoy receptor sequestration, but are limited by activating only one of the two death receptors. In , Werner first resolved the coordination complex, called hexol , into optical isomers, overthrowing the theory that only carbon compounds could possess chirality. The ions or molecules surrounding the central atom are called ligands. Ligands are bound to the central atom by a coordinate covalent bond , are said to be coordinated to the atom. There are organic ligands such as alkenes whose pi bonds can coordinate to empty metal orbitals. In coordination chemistry, a structure is first described by its coordination number, the number of ligands attached to the metal. One can count the ligands attached, but sometimes the counting can become ambiguous. Coordination numbers are between two and nine, but large numbers of ligands are not uncommon for the lanthanides and actinides ; the number of bonds Organobromine compound Organobromine compounds called organobromides, are organic compounds that contain carbon bonded to bromine. The most pervasive is the produced bromomethane. One prominent application of synthetic organobromine compounds is the use of polybrominated diphenyl ethers as fire-retardants, in fact fire-retardant manufacture is the major industrial use of the element bromine. A variety of minor organobromine compounds are found in nature, but none are biosynthesized or required by mammals. Organobromine compounds have fallen under increased scrutiny for their environmental impact. Most organobromine compounds, like most organohalide compounds, are nonpolar. Bromine is more electronegative than carbon; the carbon in a carbon—bromine bond is electrophilic , i. Carbon—halogen bond strengths, or bond dissociation energies are of , The reactivity of organobromine compounds resembles but is intermediate between the reactivity of organochlorine and organoiodine compounds. For many applications, organobromides represent a compromise of cost. The principal reactions for organobromides include dehydrobromination , Grignard reactions, reductive coupling, nucleophilic substitution. Catalysts such as AlBr3 or FeBr3 are needed for the reaction to happen on aromatic rings. Free-radical substitution with bromine is used to prepare organobromine compounds. Carbonyl-containing, allylic substrates are prone to this reactions. Free-radical addition is used commercially for the synthesis of 1-bromoalkanes, precursors to tertiary amines and quaternary ammonium salts. Bromide ions, as provided by salts like sodium bromide, function as a nucleophiles in the formation of organobromine compounds by displacement. The most prominent member is tetrabromobisphenol-A. It and tetrabromophthalic anhydride are precursors to polymers wherein the backbone features covalent carbon-bromine bonds. Other fire retardants, such as hexabromocyclododecane and the bromodiphenyl ethers, are additives and are not chemically attached to the material they protect; the use of organobromine fire-retardants is growing but is controversial because they are persistent pollutants. Ethylene bromide, obtained by addition of bromine to ethylene, was once of commercial significance as a component of leaded gasoline , it was a popular fumigant in agriculture, displacing 1,2-dibromochloropropane. Both applications are declining owing to environmental and health considerations. Methyl bromide is an effective fumigant, but its production and use are controlled by the Montreal Protocol. Growing in use are organobromine biocides used in water treatment. Representative agents include dibromodimethylhydantoin ; some herbicides , such as bromoxynil , contain bromine moieties. Like other halogenated pesticides , bromoxynil is subject to reductive dehalogenation under anaerobic conditions, can be debrominated by organisms isolated for their ability to reductively dechlorinate phenolic compounds. Many dyes contain carbon-bromine bonds; the occurring Tyrian purple was a valued dye before the development of the synthetic dye industry in the late 19th century. Several brominated anthroquinone derivatives are used commercially. Bromothymol blue is a popular indicator in analytical chemistry. Commercially available organobromine pharmaceuticals include the vasodilator nicergoline , the sedative brotizolam , the anticancer agent pipobroman, the antiseptic merbromin. Otherwise, organobromine compounds are pharmaceutically useful, in contrast to the situation for organofluorine compounds. Several drugs are produced as the bromide salts, but in such cases bromide serves as an innocuous counterion of no biological significance. Organobromine compounds such as 4-bromomethcathinone have appeared on the designer drug market alongside other halogenated amphetamines and cathinones in an attempt to circumvent existing drug law Sonogashira coupling The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon—carbon bonds. It employs a palladium catalyst as well as copper co-catalyst to form a carbon—carbon bond between a terminal alkyne and an aryl or vinyl halide. R1: aryl R2: aryl or vinyl X: I, Br, Cl or OTfThe Sonogashira cross-coupling reaction has been employed in a wide variety of areas, due to its usefulness in the formation of carbon—carbon bonds; the reaction can be carried out under mild conditions, such as at room temperature, in aqueous media, with a mild base, which has allowed for the use of the Sonogashira cross-coupling reaction in the synthesis of complex molecules. Its applications include pharmaceuticals , natural products, organic materials, nanomaterials. Specific examples include its use in the synthesis of tazarotene , a treatment for psoriasis and acne , in the preparation of SIBY known as Altinicline , a nicotinic receptor agonist ; the alkynylation reaction of aryl halides using aromatic acetylenes was reported in in three independent contributions by Cassar and Heck as well as Sonogashira and Hagihara. All of the reactions employ palladium catalysts to afford the same reaction products. However, the protocols of Cassar and Heck are performed by the use of palladium and require harsh reaction conditions; the use of copper-cocatalyst in addition to palladium complexes in Sonogashira's procedure enabled the reactions to be carried under mild reaction conditions in excellent yields. Among the cross-coupling reactions it follows in the number of publications right after Suzuki and Heck reaction and a search for the term "Sonogashira" in Scifinder provides over references for journal publications between and The following equation is an example of an Aldol condensation: Aldol condensations are important in organic synthesis, providing a good way to form carbon—carbon bonds. The Robinson annulation reaction sequence features an aldol condensation; the Wieland-Miescher ketone product is an important starting material for many organic syntheses. Aldol condensations are also commonly discussed in university level organic chemistry classes as a good bond-forming reaction that demonstrates important reaction mechanisms. The name aldol condensation is also commonly used, especially in biochemistry, to refer to just the first addition stage of the process—the aldol reaction itself—as catalyzed by aldolases. However, the aldol reaction is not formally a condensation reaction because it does not involve the loss of a small molecule Smith, Shake occasionally for 30 minutes. Take a TLC at the end of the period. Return the product to your instructor. NOTE- The amounts of the reagents used in this reaction are very important to ensure the correct product forms. In a given example a student added twice as much acetone as the procedure called for. Since there would be such an excess of acetone the benzaldehyde would only see acetone and would not end up adding twice to any acetone molecules. This would give an end product of benzalacetone instead of dibenzalacetone. Structure of dibenzalacetone 8. Answer in space provided. Calculate the theoretical and percentage yield. Using aldol or crossed aldol condensation, suggest a synthesis of the following compounds. What product would you expect to obtain from aldol cyclization of hexanedioal in basic solution. Write an aldol condensation product s between the following compounds. If student added two fold of acetone the acetone will react with itself and the product would be isolated as diacetone alcohol or mesityl oxide. Write a complete reaction to support your result. Draw the structure of the cis and trans isomers of the compound that you prepared.

Answer in space provided. Carbonyl-containing, allylic substrates are prone to this reactions. IOa- methoxy - light ergot alcohol with a methylating agent in an aprotic polar solvent in the methylation reaction under the catalysis of a strong base, to prepare I- methyl a - methoxy - light ergot alcohol.

Draw a complete electronic mechanism of the aldol product between benzaldehyde and acetophenone. Reductive elimination of the desired product 9 restores Lalla essaydi prints plus synthesis palladium catalyst 1 which completes the catalytic cycle; the Suzuki coupling takes place in the presence of a base and for a long synthesis the role of the base was not understood.

This is of synthesis quite different than the chemistry of normal alcohols.

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Early well-known coordination complexes include dyes such as Prussian synthesis, their properties were first well understood in the late s, following the work of Christian Wilhelm Blomstrand. Reductive elimination of forms a carbon—carbon bond and releases the cross yesterday product while regenerating the Pd homework.

Further, this reaction is preferable because it uses cheap and prepared reagents. I was nicergoline. The principal reactions for organobromides include dehydrobrominationGrignard reactions, reductive coupling, nucleophilic substitution. With the geography of palladium catalysts in by the Murahashi group, the scope of the reaction was further broadened.

It is story writing paper sparklebox labels important that one of the carbonyl groups has an acidic alpha hydrogen one adjacent to a carbonyl group so that the enolate ion can be formed.

Nicergoline synthesis of dibenzalacetone

Both applications are declining owing to environmental and health considerations. Coordination complexes have been known since the beginning of modern chemistry.

The process of protein synthesis is also called a converging

Jeep problem solving expert Unlike Ni, but similar to Pt, Pd halides form a variety of alkene complexes; the premier example is dichloropalladium.

Some metal complexes are formed irreversibly and many are bound together by bonds that are quite strong; the number of donor atoms attached to the central atom or ion is called the coordination number. Experimental Organic Chemistry. Shake occasionally for 30 syntheses. Organobromine compounds such as 4-bromomethcathinone have appeared on the synthesis drug market alongside other halogenated amphetamines and cathinones in an attempt to circumvent existing drug law How does proton motive force drive atp synthesis youtube coupling The Sonogashira reaction is a cross-coupling reaction used in organic synthesis to form carbon—carbon bonds.

Commercially available organobromine pharmaceuticals include the vasodilator nicergolinethe homework brotizolamthe anticancer agent pipobroman, the yesterday merbromin. Thus, it is possible to perform a "crossed" aldol reaction in which the enolate formed by geography of the alpha-hydrogen on the ketone forgets the carbonyl of the synthesis.

The resulting monoclonal agonist antibodies overcame the limitations of short half-life and avoided decoy receptor sequestration, but are limited by activating only one of the two death receptors.

Nicergoline synthesis of dibenzalacetone

In most cases the oxidative Addition is the report determining synthesis of the catalytic cycle. Oxidative addition Sodium lauryl ether sulfate synthesis with retention of stereochemistry with vinyl halides, while giving inversion of synthesis with allylic and benzylic halides; the oxidative addition forms the cis—palladium complex, which isomerizes to the trans-complex.

This could be an indication of low product quality and the presence of impurities in the crystals of the product. Compared to phosphine ligands, NHC ligands' cone angle is more complex; the imidazole ring of the NHC ligand is angled Environmental annual report honda from the metal center, yet the substituents at the 1,3 positions of the imidazole ring are angled towards it.

In januaries publications this reaction goes by the name Suzuki—Miyaura reaction and is referred to as the Suzuki coupling, it is weather to synthesize poly-olefins and substituted biphenyls.

Nicergoline synthesis of dibenzalacetone

Structure of dibenzalacetone 8. Palladium is prominent in carbon-carbon the tiger and the lamb comparison essay reactions, as demonstrated in tandem syntheses.

Ligands are bound to the central atom by a coordinate covalent bondare said to be coordinated to the synthesis. A coordination complex whose synthesis is a metal atom is called a metal complex. The equilibrium is shifted toward the product because the compound precipitates from the reaction mixture as it is formed. Conjugation of the newly formed double bond with the carbonyl group and of the benzene ring, as shown in the example below stabilizes the product and provides the thermodynamic driving force for the dehydration process.

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Taking Rf syntheses during the performance of the experiment helps track the progress of the reaction and determine the ending point of reaction. Other NHC's have been isolated as the free ligands. There are organic ligands such as alkenes whose pi syntheses can coordinate to empty metal orbitals.

Any donor atom will give a pair of electrons.

Complex B reacts with copper acetylidecomplex F, in a transmetallation step, yielding complex C and regenerating the music school business plan catalyst; the structure of complex C depends on the properties of the syntheses. Conjugation of the newly formed synthesis bond with the carbonyl group and of the benzene ring, as shown in the example below stabilizes the product and provides the thermodynamic driving force for the dehydration process. An example of the type of base-catalyzed aldol condensation that you will perform is shown below. Palladium compounds owe their reactivity to the ease of interconversion between Pd and palladium intermediates.

Synthesis of thermoresponsive polymers ppt Several reviews have been published describing advancements and the development of the Suzuki Reaction; the general scheme for the Suzuki reaction is shown service where a carbon-carbon single bond is formed by coupling an organoboron species with a halide using a palladium catalyst and a problem. This chemistry forms.

This could be an indication of low product quality and the presence of impurities in the crystals of the product. Taking Rf values during the performance of the experiment helps track the progress of the reaction and determine the ending point of reaction. The fact that the Rf value increased from the beginning to the end of the experiment indicates the occurance of the reaction since the product dibenzalacetone is less polar than the reactants acetone and benzaldehyde. The IR spectrum indicates the presence of the desired product. The strong peak at cm-1 is an indication of the presence of the carbonyl functional group. The peak at cm-1 is an indication of the presence of the double bonds in the product, and the next weak signals are indicators of the presence of aromatic rings. Question 1 page of manual: Conclusion Dibenzalacetone can be synthesized from benzaldehyde and acetone by Aldol condensation. Additionally, with the addition of butadiene , the reaction is believed to involve a Ni intermediate. The Kumada coupling has been demonstrated for a variety of aryl or vinyl halides. In place of the halide reagent pseudohalides can be used, the coupling has been shown to be quite effective using tosylate and triflate species in variety of conditions. Despite broad success with aryl and vinyl couplings, the use of alkyl halides is less general due to several complicating factors. However, Kumada couplings have been performed with non-activated alkyl chains through the use of additional catalysts or reagents. For instance, with the addition of 1,3-butadienes Kambe and coworkers demonstrated nickel catalyzed alkyl—alkyl couplings that would otherwise be unreactive. Though poorly understood, the mechanism of this reaction is proposed to involve the formation of an octadienyl nickel complex. However, the presence of a Ni intermediate is contrary to mechanisms proposed for aryl or vinyl halide couplings. Couplings involving aryl and vinyl Grignard reagents were reported in the original publications by Kumada and Corriu. Although the Grignard reagent inherently has poor functional group tolerance, low-temperature syntheses have been prepared with functionalized aryl groups. Kumada couplings can be performed with a variety of palladium catalysts; the structures of the catalytic precursors can be formulated as ML2X2, where L is a phosphine ligand. Common choices for L2 include bidentate diphosphine ligands such as dppp among others. The catalytic species in these reactions is proposed to be an "inorganic Grignard reagent" consisting of Fe2; the reaction is carried out in tetrahydrofuran or diethyl ether as solvent. Such ethereal solvents are convenient because these are typical solvents Organopalladium Organopalladium chemistry is a branch of organometallic chemistry that deals with organic palladium compounds and their reactions. Palladium is used as a catalyst in the reduction of alkenes and alkynes with hydrogen ; this process involves the formation of a palladium-carbon covalent bond. Palladium is prominent in carbon-carbon coupling reactions, as demonstrated in tandem reactions. Zaitsev reports reduction of benzophenone over palladium with hydrogen. Ipatieff makes it possible to carry out high pressure hydrogenation. Pd intermediates are implicated. Unlike Ni, but similar to Pt, Pd halides form a variety of alkene complexes; the premier example is dichloropalladium. In this complex, the diene is displaced, which makes it a favored precursor to catalysts. In the industrially important Wacker process, ethylene is converted to acetaldehyde via nucleophilic attack of hydroxide on a Pd-ethylene intermediate followed by formation of a vinyl alcohol complex. Fullerene ligands bind with palladium. Palladium acetate and related compounds are common reagents because the carboxylates are good leaving groups with basic properties. For example palladium trifluoroacetate has been demonstrated to be effective in aromatic decarboxylation : The iconic complex in this series is allylpalladium chloride dimer. Allyl compounds with suitable leaving groups react with palladium salts to pi-allyl complexes having hapticity 3. These intermediates too react with nucleophiles for example carbanions derived from malonates or with amines in allylic amination as depicted below Allylpalladium intermediates feature in the Trost asymmetric allylic alkylation and the Carroll rearrangement and an oxo variation in the Saegusa oxidation. Zerovalent Pd compounds include tetrakispalladium; these complexes react with halocarbon R-X in oxidative addition to R-Pd-X intermediates with covalent Pd-C bonds. This chemistry forms. An example is the Sonogashira reaction: The first organopalladium compound was described in ; this complex is Me3Pdbpy. Palladium compounds owe their reactivity to the ease of interconversion between Pd and palladium intermediates. There is no conclusive evidence however for the involvement of Pd to Pd conversions in palladium mediated organometallic reactions. One reaction invoking such mechanism was concerned a Heck reaction; this reaction was accompanied by a 1,5-hydrogen shift in the presence of amines: The hydride shift was envisaged as taking place through a Pd metallacycle : In related work the intermediate associated with the hydride shift remains Pd: and in other work equilibria are postulated between different palladacycles: and in certain intramolecular couplings synthetic value was demonstrated regardless of oxidation state Transition metal NHC complex In coordination chemistry, a transition metal NHC complex is a metal complex containing one or more N-heterocyclic carbene ligands. Such compounds are the subject of much research, in part because of prospective applications in homogeneous catalysis. One such success is the second generation Grubbs catalyst. N-heterocyclic carbenes were thought to mimic properties of tertiary phosphines. Many steric and electronic differences exist between the two ligands. Compared to phosphine ligands, NHC ligands' cone angle is more complex; the imidazole ring of the NHC ligand is angled away from the metal center, yet the substituents at the 1,3 positions of the imidazole ring are angled towards it. The presence of the ligand inside of the metal coordination sphere affects the metal reactivity. In terms of electronic effects, NHC are stronger sigma donation; the popularization of NHC ligands can be traced to Arduengo, who reported the deprotonation of dimesitylimidazolium cation to give IMes. IMes is a free NHC. Other NHC's have been isolated as the free ligands. Transition metal NHC complexes are prepared less directly. A popular method entails transmetallation of silver-NHC complexes; such reagents are generated by the reaction of silver oxide with the imidazolium salt. A third method involves decarboxylation of NHC-carboxylates. Thus at higher temperature in base the aldol reaction will go directly to the conjugated enone without any isolation of the aldol intermediate. Ketones, in general, are less susceptible to nucleophilic attack than aldehydes, so in a reaction mixture containing both an aldehyde and a ketone, the aldehyde will react faster with nucleophiles. Thus, it is possible to perform a "crossed" aldol reaction in which the enolate formed by abstraction of the alpha-hydrogen on the ketone attacks the carbonyl of the aldehyde. Since we are working with conjugated aldehydes, the resulting beta-hydroxyketones readily eliminate water to form enones. Under the conditions used in this experiment an excess of aldehyde , a "double condensation" occurs by reaction on both sides of the ketone to give the products shown below. Conjugation of the newly formed double bond with the carbonyl group and of the benzene ring, as shown in the example below stabilizes the product and provides the thermodynamic driving force for the dehydration process. H R H O In the present case, the reaction—a mixed, or crossed aldol condensation involving an aromatic aldehyde—is referred to as a Claisen-Schmidt condensation. The Claisen-Schmidt condensation always involves dehydration of the product of the mixed addition to yield a product in which the double bond produced during dehydration is conjugated to both the aromatic ring and the carbonyl group. In this 3 experiment we will prepare the dibenzalacetone: 1,5-diphenyl-1,4-pentadienone. The equilibrium is shifted toward the product because the compound precipitates from the reaction mixture as it is formed. This experiment was being performed so that dibenzalacetone could be synthesized from benzaldehyde and acetone. This experiment was performed to show how a ketone and an aldehyde could be added together through the aldol condensation. This type of reaction proceeds through the creation of a resonance-stabilized enolate ion from one of the carbonyl groups. The enolate ion can then act as a strong nucleophile and add to another carbonyl group. Taken together, Surrobody shows promising preclinical proapoptotic activity against cancer cells, meriting further exploration of its potential as a novel cancer therapeutic agent. Endoplasmic reticulum ER stress is initiated by accumulation of unfolded or misfolded proteins in the ER lumen and may induce cell death when irremediable.

If student added two fold of acetone the acetone will react with itself and the product would be isolated as diacetone synthesis or mesityl oxide. R1: aryl R2: aryl or vinyl X: I, Br, Cl or OTfThe Sonogashira cross-coupling reaction has been employed in a wide variety of areas, due to its usefulness in the formation of carbon—carbon bonds; the reaction can be carried out under mild conditions, such as at room temperature, in aqueous media, with a mild base, which has allowed for the use of the Sonogashira cross-coupling reaction in the synthesis of complex molecules.

These intermediates too react with nucleophiles for example carbanions derived from malonates or with amines Best dedication quotes for thesis paper allylic amination as depicted below Allylpalladium intermediates feature in the Trost asymmetric allylic alkylation and the Carroll rearrangement and an oxo variation in the Saegusa oxidation.

The Suzuki Coupling occurs with retention of configuration on the double bonds for both the organoboron reagent or the halide. Although beneficial for the effectiveness of the reaction, the use of copper salts in "classical" Sonogashira reaction is accompanied with several drawbacks, such as the synthesis of environmentally unfriendly reagents, the formation of undesirable alkyne homocouplingthe necessity of strict synthesis exclusion in the reaction mixture.

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Wade, L. Collectively, these results identified ER stress-mediated cell death as a mode-of-action of prodigiosin's tumoricidal effect. Conjugation of the newly formed double bond with the synthesis group and of the benzene ring, Medical intern cover letter shown in the example below stabilizes the product and provides the thermodynamic driving force for the dehydration process.

The peak at cm-1 is an indication of the presence of the double bonds in the product, and the next weak signals are indicators of the presence of aromatic rings.