Definition: What is Hinsberg Test? Hinsberg test is a chemical reaction that can distinguish between primary, secondary, tertiary amines. The amine is shaken well with Hinsberg reagent in the presence of aqueous alkali (e.g., KOH or NaOH). The Hinsberg reagent is a solution of aqueous sodium hydroxide and benzenesulfonyl chloride. In this test, the amine… Continue reading Hinsberg Test

Definition: What is Benzoin Condensation? The benzoin condensation is the condensation between two molecules of benzaldehyde to form benzoin in the presence of a cyanide catalyst (e.g., NaCN and KCN) or thiamine (vitamin B). The structure of benzoin is that of a ketone. It consists of acetophenone bearing hydroxy and phenyl substituents at the alpha-position… Continue reading Benzoin Condensation

Definition: What is Schmidt Reaction? The Schmidt reaction is the reaction of hydrazoic acid or an alkyl azide with a carbonyl compound, alkene, or alcohol, often in the presence of a Brønsted or Lewis acid. The product is an amine, imine, or amide, with the expulsion of nitrogen [1-5].

Definition: What is Aldol Reaction? Aldol reaction is an essential class of chemical reaction, occasionally encountered in biochemistry. In an aldol reaction, new carbon-carbon bonds are forms due to the reaction between two carbonyl compounds. The product formed is a β-hydroxy carbonyl compound, also called an aldol product (aldehyde + alcohol). The aldol reaction is… Continue reading Aldol Reaction

Definition: What is Wolff-Kishner Reduction? The Wolff-Kishner reduction is an organic reaction used to convert an aldehyde or ketone to an alkane using hydrazine, base, and heat (~200 °C). Aldehydes and ketones are first converted to a hydrazine derivative by reaction with hydrazine. These hydrazones can be further converted to the corresponding alkane by reaction… Continue reading Wolff–Kishner Reduction

Definition: What is Curtius Rearrangement? The Curtius rearrangement is a versatile reaction that converts a carboxylic azide to an isocyanate under thermal conditions with the loss of nitrogen gas. Isocyanates can be isolated during azide decomposition in inert solvents. By adding various nucleophiles, isocyanates can be transformed into other useful species [1-4].

Definition: What is Knoevenagel Condensation? Knoevenagel condensation is a nucleophilic addition of an activated methylene compound to an aldehyde or ketone using an amine base (e.g., pyridine or piperidine) as a catalyst followed by a dehydration reaction in which a molecule of water is eliminated (condensation). The product is often an α,β-unsaturated carbonyl compound (enone).… Continue reading Knoevenagel Condensation

Definition: What is Fischer Indole Synthesis? The Fischer indole synthesis is an organic reaction used to convert a phenylhydrazine and an aldehyde or ketone to an indole using an acid catalyst, like Brønsted or Lewis acids. An application of this reaction is the synthesis of antimigraine drugs belonging to the triptan class [1-8].

Definition: What is Haloform Reaction? The Haloform reaction is a chemical reaction where haloforms (CH3X) are produced by the complete halogenation of acetone (CH3COCH3), acetophenone (PhCOCH3), or acetaldehyde (HCOCH3) in the presence of a base. The aldehyde or ketone must have a methyl group next to the carbonyl since methyl has three alpha-hydrogen atoms. The… Continue reading Haloform Reaction

Definition: What is Finkelstein Reaction? Finkelstein reaction is used in the preparation of alkyl halides using metal halides. It is an SN2 reaction that involves the exchange of one halogen atom for another. In the reaction, newly formed metal halides like sodium chloride and sodium bromide are not soluble in a polar aprotic solvent such… Continue reading Finkelstein Reaction

Definition: What is Hofmann Rearrangement? Hofmann rearrangement, also known as Hofmann degradation, is the reaction of a primary amide with a halogen (chlorine or bromine) in a strongly basic (sodium or potassium hydroxide) aqueous medium to convert the amide into a primary amine. The reaction results in one carbon degradation [1-5].

Definition: What is Claisen Rearrangement? A rearrangement is a reaction in which a molecule changes its bonds by transferring one atom or group from one position to another within the molecule. The Claisen rearrangement is an organic reaction in which an allyl vinyl ether or an allyl aryl ether undergoes a 3,3-sigmatropic rearrangement to produce… Continue reading Claisen Rearrangement

Definition: What is McLafferty Rearrangement? Mass spectrometry is a technique used to determine the mass of a given molecule. The molecule is placed inside the spectrometer and ionized by high-energy electrons. After the molecules are ionized, they become radical cations that can then be sorted and weighed. When hydrogen is available at the gamma position… Continue reading McLafferty Rearrangement

Definition: What is Molisch’s Test? Molisch test is a chemical test to detect carbohydrates (monosaccharide, disaccharide, and polysaccharide) and glycoprotein in an analyte. It can be used to differentiate proteins and amino acids from carbohydrates. The test has been named after Czech-Austrian botanist Hans Molisch [1,2].

Definition: What is Malonic Ester Synthesis? Malonic ester is a diester molecule that can undergo hydrolysis to produce 1,3-dicarboxylic acid. The dicarboxylic acid, if gently heated, can undergo a decarboxylation reaction to produce carbon dioxide and an enol molecule. The enol then interconverts into a more stable carboxylic acid, like acetic acid.  This reaction is… Continue reading Malonic Ester Synthesis

Definition: What is Suzuki Reaction? A coupling reaction in organic chemistry is a general term for a variety of reactions where two fragments are joined together with the aid of a metal catalyst. The Suzuki reaction, or Suzuki-Miyaura coupling reaction, is an organic coupling reaction of an organohalide with an organoborane to give a coupled… Continue reading Suzuki Reaction

Definition: What is Oxymercuration Demercuration? Oxymercuration demercuration is an addition reaction that can be used to turn an alkene into alcohol. In this reaction, an alkene reacts with mercury (II) acetate (Hg(OAc)2) in aqueous THF, followed by reduction with sodium borohydride (NaBH4). The reaction is not stereoselective and not subject to rearrangements, as the intermediate… Continue reading Oxymercuration Demercuration

Definition: What is Ozonolysis? Ozonolysis is an organic reaction where the pi bonds of unsaturated olefins like alkenes and alkynes are cleaved with ozone (O3). It is a type of cycloaddition that destroys bonds. Ozone is a very reactive allotrope of oxygen and reacts readily with alkenes. Alkenes form organic compounds in which a carbonyl… Continue reading Ozonolysis

Definition: What is Heck Reaction? A cross-coupling reaction in organic chemistry is a reaction where two fragments are joined together (eg., C-C bonding) with the aid of a metal catalyst. The Heck reaction (also called Mizoroki-Heck reaction) is a cross-coupling reaction of an organohalide with an alkene to make a substituted alkene using palladium as… Continue reading Heck Reaction

Definition: What is Baeyer-Villiger Oxidation? The Baeyer-Villiger oxidation is the oxidative cleavage of a carbon-carbon bond that is adjacent to a carbonyl functional group. This reaction is used to convert ketones to esters and cyclic ketones to lactones. It can be carried out with peroxy acids (also called peracid) like MCPBA, or with hydrogen peroxide… Continue reading Baeyer-Villiger Oxidation

Definition: What is Schiff Reagent? Schiff reagent is the product formed in some dye formulation reactions, such as the reaction between sodium bisulfite and fuchsine. It is used to check for the presence of aldehyde in an analyte. It can be used to differentiate between aldehydes and ketones. Fuschsine or rosaniline hydrochloride is a magenta-colored… Continue reading Schiff Reagent

Definition: What is Simmons-Smith Reaction? Simmons-Smith reaction is an asymmetric reaction in which a carbenoid adds to an alkene or alkyne to form a cyclopropane. It is an essential reaction involving an organozinc reagent. The reaction is typically conducted using diiodomethane in combination with metallic zinc and copper (Zn(Cu)). The iodomethyl zinc iodide is usually… Continue reading Simmons-Smith Reaction

Definition: What is Addition Reaction? Addition reaction occurs when two or more reactants combine to form a product without the loss of any atoms present in the reactants. Addition reaction is common in compounds that have unsaturated C-C bond, like double (alkene) and triple (alkyne) bonds. The weaker π bond is converted into two new… Continue reading Addition Reaction

Definition: What is Huckel’s Rule? Pi electrons are defined as electrons that participate in pi bonds or lone pairs within p orbitals. In order to be aromatic, a molecule must have a certain number of pi electrons within a closed loop of parallel, adjacent p orbitals. The pi-electron count is defined by the series of… Continue reading Huckel’s Rule

Definition: What is Fries Rearrangement? The Fries rearrangement is an organic reaction used to convert a phenyl ester to a hydroxy aryl ketone using a Lewis acid catalyst and Brønsted acid work-up. In this reaction, an acyl group belonging to phenol ester migrates to the aryl ring either in the ortho or para position, depending… Continue reading Fries Rearrangement

Definition: What is Dieckmann Condensation? The Dieckmann condensation is an organic reaction which is used to form a carbon-carbon bond between two tethered ester groups using an alkoxide base in alcohol. The resulting product is a cyclic β-ketoester. This reaction is an intermolecular form of Claisen condensation [1-3].

Definition: What is Birch Reduction? Birch reduction is an organic redox reaction that is used to convert aromatic compounds into dienes. The reaction is carried out by sodium or potassium metal dissolved in liquid ammonia in the presence of alcohol. Two hydrogen atoms are added at the opposite ends of the molecule at 1,4 positions.… Continue reading Birch Reduction

Definition: What is Pinacol Rearrangement? Pinacol is a compound which has two hydroxyl groups, each attached to a vicinal carbon atom. Its IUPAC name is 2,3-dimethyl-2,3-butanediol. Pinacol rearrangement is a 1,2-rearrangement of pinacol via carbon group migration to produce a ketone, often with acid catalysis. The resulting ketone is known as pinacolone or 3,3-dimethyl-2-butanone. Pinacol… Continue reading Pinacol Rearrangement

Definition: What is Beckmann Rearrangement? Beckmann rearrangement is an acid-catalyzed reaction of ketoximes into amides. The yield of this reaction increases at elevated temperatures. The reaction is named after German pharmacist and chemist Ernst Otto Beckmann [1-2].

Definition: What is Nessler’s Reagent? Nessler’s reagent, or potassium tetraiodomercurate, is an organic compound and consists of potassium cations and tetraiodomercurate (II) anion. The molecular formula is given by [K2(HgI4)]. It is used to detect ammonia. The reagent has been named after German chemist Julius Nessler [1].

Definition: What is the Fenton Reaction? The oxidation of organic substrates by iron (II) and hydrogen peroxide (typically iron (II) sulfate, FeSO4) is called the Fenton reaction. The reagent used for this purpose is known as Fenton’s reagent, which is accepted as one of the most effective methods for the oxidation of organic pollutants. Fenton’s… Continue reading Fenton Reaction

Definition: What is Gilman Reagent? Gilman reagent is an organocuprate reagent consisting of lithium, copper, and alkyl group with the molecular formula [R-Cu-R]+Li– (lithium dialkylcuprate). It is used to synthesize new compounds consisting of carbon-carbon bonds from alkyl, aryl, and vinyl halides. Typically, the SN2 reaction method is employed to obtain the final product. The… Continue reading Gilman Reagent

Definition: What is Clemmensen Reduction? Clemmensen reduction is a chemical reaction used to reduce an aldehyde or ketone to an alkane using zinc amalgam and concentrated hydrochloric acid. The process is carried out by replacing the double bond between carbon and oxygen by two hydrogen atoms. The zinc dissolves during the process, and hence, this… Continue reading Clemmensen Reduction

Definition: What is Mannich Reaction? The Mannich reaction is an organic reaction, which is used to convert a primary or secondary amine and two carbonyl compounds (one non-enolizable and one enolizable) to a β-amino carbonyl compound. Usually, an acid or base is used as a catalyst. Generally, formaldehyde is used as the non-enolizable carbonyl compound,… Continue reading Mannich Reaction

Definition: What is PCC Reagent? PCC (pyridinium chlorochromate) reagent is used in the organic synthesis of aldehyde and ketone from primary and secondary alcohols, respectively. It is a yellow-orange colored salt with the formula [C5H5NH]+[CrO3Cl]–. PCC oxidizes the alcohol (OH) group and does not affect any other functional group or double bond present in the… Continue reading PCC Reagent

Definition: What is Marquis Reagent? Marquis reagent is composed of a mixture of formaldehyde and concentrated sulfuric acid. It is used as a simple spot-test to identify illicit drugs belonging to the alkaloid family and other compounds. Alkaloids are natural substances typically containing basic nitrogen atoms. The test employed for this purpose is called the… Continue reading Marquis Reagent

Definition: What is Ehrlich Reagent? Ehrlich reagent contains p-dimethylaminobenzaldehyde (DMAB), which is used to test for indoles and urobilinogen. This reagent is employed for the Ehrlich test, also known as the Ehrlich aldehyde test. This test diagnoses liver diseases, hemolytic processes, occlusion of the common bile duct, and carcinoid syndrome. It is also used as… Continue reading Ehrlich Reagent

Definition: What is Gabriel Synthesis? The Gabriel synthesis is a chemical reaction that transforms primary alkyl halides into primary amines. It is a type of SN2 reaction, except that it does not produce any ammonium salts. Gabriel synthesis is also called Gabriel phthalimide synthesis because phthalimide is used in this reaction along with a base… Continue reading Gabriel Synthesis

Definition: What is Electrophilic Aromatic Substitution? Electrophilic aromatic substitution is a chemical reaction in which a hydrogen atom or a functional group from an aromatic compound is substituted with another functional group, which is an electrophile [1-3].

Definition: What is Electrophilic Substitution? Electrophilic substitution is a chemical reaction in which a functional group from a compound is substituted with an electrophilic species. There are two main types of electrophilic substitution reactions – electrophilic aromatic substitution and electrophilic aliphatic substitution. In the former, a functional group is added to an aromatic compound like… Continue reading Electrophilic Substitution

Definition: What is SN2 Reaction? Nucleophiles, typically, have a lone pair of electrons in them. As the name suggests, they are attracted to the nucleus of an atom. The SN2 reaction is a type of nucleophilic substitution in which an electron-rich nucleophile displaces the halogen atom bonded to the central carbon of an alkyl halide… Continue reading SN2 Reaction

Definition: What is SN1 Reaction? Nucleophiles, typically, have a lone pair of electrons in them. As the name suggests, they are attracted to the nucleus of an atom. The SN1 reaction is a type of nucleophilic substitution reaction in which an electron-rich nucleophile displaces the halogen atom bonded to the central carbon of an alkyl… Continue reading SN1 Reaction

Definition: What is Nucleophilic Substitution? Nucleophiles, typically, have a lone pair of electrons in them. As the name suggests, they are attracted to the nucleus of an atom. Nucleophilic substitution is a substitution reaction in which an electron-rich nucleophile displaces the halogen atom bonded to the central carbon of an alkyl halide molecule. The halide… Continue reading Nucleophilic Substitution

Definition: What is Fehling’s Solution? Fehling’s solution, or Fehling’s reagent, is a chemical reagent that is used to distinguish between an aldehyde and a ketone other than α-hydroxy ketone. Practically, it is used for the determination of reducing and non-reducing sugars that are present in carbohydrates. The test employed for this purpose is known as… Continue reading Fehling’s Solution

Definition: What is Tollens’ Test? Tollens’ test, also known as a silver-mirror test, is a qualitative laboratory test that is used to differentiate between an aldehyde and a ketone. It uses the fact that aldehydes can be more easily oxidized than ketones. This test cannot distinguish between an aldehyde and an α-hydroxy ketone (e.g., hydroxy… Continue reading Tollens’ Test

Definition: What is Hydroboration-Oxidation? The hydroboration-oxidation reaction is an organic chemical reaction that is used for the conversion of alkene into alcohol. In this reaction, borane (BH3) is added across the carbon‐carbon double bond of an alkene resulting in an organoboron compound. This organoboron compound reacts with hydrogen peroxide in a basic medium (e.g., NaOH)… Continue reading Hydroboration-Oxidation

Definition: What is Fischer Esterification? Fischer Esterification or Fischer–Speier Esterification is an organic reaction that is used to convert carboxylic acid into an ester. The reaction takes place in the presence of excess alcohol and an active acid catalyst. During the reaction, the products and the reactants are in equilibrium. This ester is formed along… Continue reading Fischer Esterification

Definition: What is Robinson Annulation? Robinson annulation is an organic chemical reaction used to construct a six-membered ring structure. This method uses a ketone and an α, β-unsaturated ketone to form a bicyclic system containing a substituted cyclohexenone system in a sequential combination of Michael addition and intramolecular aldol condensation. The word ‘annulation’ means ‘building… Continue reading Robinson Annulation

Definition: What is Michael Addition? Michael addition, also known as the Michael reaction, is one of the most well-known reactions in organic synthesis. It is a nucleophilic addition reaction. It is immensely useful for the formation of a carbon-carbon bond when a carbon nucleophile adds to an α, β-unsaturated carbonyl compound through a 1,4-addition mechanism.… Continue reading Michael Addition

Definition: What is the Diels-Alder Reaction? The Diels-Alder reaction is an organic reaction that is used to convert a conjugated diene (a molecule with two alternating double bonds) and a dienophile (an alkene) to a cyclic olefin. This process is concerted, where bonds form and break at the same time, and the entire reaction takes… Continue reading Diels-Alder Reaction

Definition: What is Strecker Synthesis? Strecker synthesis is a method for the synthesis of amino acids from the reaction of an aldehyde with ammonium chloride in the presence of sodium cyanide. The procedure is carried out in two steps, during which several intermediates are formed. A wide variety of amino acids can be synthesized through… Continue reading Strecker Synthesis