Organic Chemistry: Functional Groups, Structures, and Heterocycles

Vocabulary practice flashcards defining core functional groups, organic derivatives, alkyl/aryl substituents, simple carboxylic acids and carbonyls, amino acids, sugars, and aromatic/saturated heterocycles directly from the lecture notes.

Alkane

A saturated hydrocarbon containing only single covalent bonds between carbon atoms with the general structure $R'-CH_2-CH_2-R'$, where $R$ is an alkyl group and $R'$ is an alkyl group or $H$.

(Z)-isomer (cis)

A stereoisomeric alkene configuration in which the higher-priority substituent groups (or identical alkyl groups $R$) are located on the same side of the carbon-carbon double bond ($C=C$).

(E)-isomer (trans)

A stereoisomeric alkene configuration in which the substituent groups (or identical alkyl groups $R$) are located on opposite sides of the carbon-carbon double bond ($C=C$).

Cycloalkane

A monocyclic saturated hydrocarbon containing single bonds arranged in a ring, including cyclopropane, cyclobutane, cyclopentane, and cyclohexane.

Cycloalkene

A cyclic hydrocarbon containing at least one carbon-carbon double bond within the ring, such as cyclopropene, cyclobutene, cyclopentene, and cyclohexene.

Hydroxyl group (Alcohol)

A functional group consisting of a hydrogen atom covalently bonded to an oxygen atom ($-OH$); compounds where it is bonded to an aliphatic carbon group are designated as alcohols ($R-OH$).

Thiol (Mercaptan)

A sulfur analogue of an alcohol containing a sulfhydryl group attached to an alkyl or aryl carbon chain, represented by the formula $R-SH$.

Phenols and Thiophenols

Aromatic compounds in which a hydroxyl group ($-OH$) or a thiol group ($-SH$) is directly bonded to an aromatic benzene ring, yielding phenols and thiophenols respectively.

Alcoholate and Thiolate

Deprotonated organic salts paired with metal cations: an alcoholate has the formula $R-O^-M^+$ (such as sodium alcoholate when $M = Na$), while a thiolate has the formula $R-S^-M^+$.

Peroxide and Disulfide

Compounds containing divalent heteroatom-heteroatom single bonds: peroxides possess an oxygen-oxygen bond ($R-O-O-R'$), and disulfides possess a sulfur-sulfur bond ($R-S-S-R$).

Ether

An organic compound characterized by an oxygen atom bonded to two alkyl or aryl groups, represented as $R-O-R$.

Aldehyde

A carbonyl compound containing a carbonyl group ($C=O$) bonded to at least one hydrogen atom and an alkyl group or hydrogen, represented as $R'-CHO$.

Ketone

A carbonyl compound containing a carbonyl group ($C=O$) flanked by two carbon-containing alkyl or aryl groups, represented as $R-CO-R$.

Carboxylic acid (Carboxyl group)

An organic compound containing a carboxyl functional group consisting of a carbonyl linked to a hydroxyl group ($R'-COOH$).

Carboxylic acid ester (Alkyl/aryl carboxylate)

A carboxylic acid derivative where the hydroxyl hydrogen is replaced by an alkyl or aryl group, represented by the general structure $R'-COOR$.

Acyl chloride

A reactive carboxylic acid derivative containing a carbonyl group bonded to a chlorine atom, represented as $R'-COCl$.

Amide (Amide bound / Peptide bound)

A carboxylic acid derivative containing a carbonyl group linked directly to a nitrogen atom, having the general structure $R'-CON(R')_2$.

Carboxylic acid anhydride

A compound containing two acyl groups joined by a central oxygen bridge, having the structure $R'-CO-O-CO-R'$.

$\beta$-lactone

A four-membered cyclic ester formed from a hydroxy acid where cyclization occurs at the $\beta$-carbon.

$\delta$-lactone

A six-membered cyclic ester where ring closure links the carbonyl carbon through an ester bond to the $\delta$-position.

$\beta$-lactam

A four-membered cyclic amide where the nitrogen atom is bonded directly to the $\beta$-carbon relative to the carbonyl group.

$\delta$-lactam

A six-membered cyclic amide formed by intramolecular cyclization involving the nitrogen atom and the $\delta$-carbon.

Carboxylic acid salt (Metal carboxylate)

An ionic compound resulting from the neutralization or deprotonation of a carboxylic acid, represented as $R'-COO^-M^+$.

Thioester

A carboxylic acid derivative in which the ester oxygen is replaced by a sulfur atom, represented as $R'-CO-SR$.

Amidine

A nitrogen derivative of a carboxylic acid containing both an imino and an amino group on the same carbon, represented as $R'-C(=NR')-NH_2$.

Hemiacetal

A functional group derived from an aldehyde containing a central carbon bonded to one $R$ group, one hydrogen ($H$), one hydroxyl group ($-OH$), and one alkoxy group ($-OR$).

Acetal

A functional group derived from an aldehyde containing a central carbon bonded to one $R$ group, one hydrogen ($H$), and two alkoxy groups ($-OR$).

Hemiketal

A functional group derived from a ketone containing a central carbon bonded to two $R$ groups, one hydroxyl group ($-OH$), and one alkoxy group ($-OR$).

Ketal

A functional group derived from a ketone containing a central carbon bonded to two $R$ groups and two alkoxy groups ($-OR$).

Monothioacetal and Dithioacetal

Sulfur analogues of acetals: monothioacetals feature one $-OR$ and one $-SR$ attached to the central carbon, whereas dithioacetals feature two $-SR$ groups attached to the central carbon.

Hydrazines

Compounds containing a nitrogen-nitrogen single bond, ranging from the parent inorganic molecule $H_2N-NH_2$ to tetra-substituted organic derivatives ($R'_2N-NR'_2$).

Schiff base (imine)

A functional group containing a carbon-nitrogen double bond formed by condensation of an aldehyde or ketone with an amine, represented as $R'R-C=N-R$.

Hydrazone

A condensation product of a carbonyl compound and hydrazine containing the $R'R-C=N-NH_2$ group.

Aldoxime

An oxime derived from an aldehyde containing a carbon-nitrogen double bond where the carbon is bonded to hydrogen and an $R$ group ($R-CH=N-OH$).

Ketoxime

An oxime derived from a ketone containing a carbon-nitrogen double bond where the carbon is bonded to two alkyl/aryl $R$ groups ($R_2C=N-OH$).

Semicarbazone

A crystalline condensation derivative of an aldehyde or ketone formed with semicarbazide, having the general structure $R'R-C=N-NH-CO-NH_2$.

Nitrile ((carboxylic acid) nitrile)

An organic compound containing a cyano group characterized by a carbon-nitrogen triple bond ($R-C ≡ N$).

Cyanate, Isocyanate, and Isothiocyanate

Related pseudohalide and heterocumulene derivatives: cyanate has the connectivity $R-O-C ≡ N$, isocyanate is $R-N=C=O$, and isothiocyanate is $R-N=C=S$.

Carbonic acid

The diprotic oxoacid of carbon with the chemical formula $HO-CO-OH$ ($H_2CO_3$).

Carbamic acid

The monoamide of carbonic acid with the formula $H_2N-COOH$.

Carbamate (Carbamic acid ester)

An ester of carbamic acid with the general formula $R'_2N-CO-OR$.

Urea (Carbamide)

The diamide of carbonic acid with the structure $H_2N-CO-NH_2$.

Thiourea (Thiocarbamide)

The sulfur analogue of urea in which the carbonyl oxygen is replaced by sulfur, represented as $H_2N-CS-NH_2$.

Guanidine

A nitrogen-rich derivative of carbonic acid with the structural formula $(H_2N)_2C=NH$.

Alkyl chloroformate (Chloroformic acid ester)

An ester of chloroformic acid containing both a carbonyl chloride and an ester group, represented as $Cl-CO-OR$.

Primary amine (primer amine / primer amino group)

An amine derivative in which one hydrogen atom of ammonia is replaced by an alkyl or aryl group ($R-NH_2$).

Secondary amine (secunder amine / secunder amino group)

An amine derivative in which two hydrogen atoms of ammonia are replaced by carbon substituents ($R_2NH$).

Tertiary amine (tertier amine / tertier amino group)

An amine derivative in which all three hydrogen atoms of ammonia are replaced by carbon substituents ($R_3N$).

Quaternary ammonium salt (quaterner ammonium salt)

A positively charged nitrogen atom bonded to four organic substituents paired with an anion ($R_4N^+X^-$).

Nitroso group

A nitrogen-containing functional group consisting of a nitrogen monoxide moiety bonded to carbon ($R-NO$).

Nitro group

A functional group composed of a nitrogen atom bonded to two oxygen atoms ($-NO_2$), forming nitroalkanes or nitroarenes ($R-NO_2$).

Nitrite and Nitrate ester

Esters of nitrogen oxoacids: nitrous acid esters (nitrites) have the formula $R-O-N=O$, while nitric acid esters (nitrates) have the formula $R-O-NO_2$.

Diazo compound

An organic compound containing two linked nitrogen atoms bonded to a single carbon atom ($R=N^+=N^-$).

Diazonium salt

An organic salt containing an aryl group attached to a terminal dinitrogen cation ($Ar-N^+ ≡ N$).

Azo compound and Azide

Nitrogen-linked compounds: azo compounds contain the $R-N=N-R$ linkage, whereas azides contain the linear triazo group ($R-N_3$).

Sulfoxide and Sulfone

Organosulfur compounds with varying sulfur oxidation states: sulfoxides contain a sulfinyl group ($R-SO-R$), while sulfones contain a sulfonyl group ($R-SO_2-R$).

Sulfonic acid and Sulfonic acid ester

Sulfur oxoacid derivatives: sulfonic acids contain a sulfonate group bonded to hydrogen ($R-SO_2-OH$), while sulfonic acid esters contain an alkyl/aryl group ($R-SO_2-OR$).

Sulfuric acid ester (Sulfate)

An ester derived from sulfuric acid with the general formula $R-O-SO_2-O-R$.

Sulfonamide

An amide derivative of a sulfonic acid having the general structure $R-SO_2-NR'_2$.

Sulfamate and Sultame

Sulfur-nitrogen compounds: sulfamates are sulfuric acid monoester monoamides ($R-O-SO_2-NH_2$), and sultames are cyclic sulfonamides ($HN-SO_2-(CH_2)_n$).

Phosphoric acid, Phosphonic acid, and Phosphonate

Phosphorus oxoacids and derivatives: phosphoric acid is $HO-PO(OH)_2$, phosphonic acid contains a direct $C-P$ bond ($R-PO(OH)_2$), and phosphonates are phosphonic acid esters ($R-PO(OR)_2$).

Propyl groups (n-propyl and isopropyl)

Three-carbon alkyl substituents: n-propyl is a straight-chain group ($-CH_2CH_2CH_3$), while isopropyl is a branched secondary group attached at the central carbon ($-CH(CH_3)_2$).

Butyl groups (n-butyl, sec-butyl, isobutyl, tert-butyl)

Four-carbon alkyl substituents: n-butyl (linear), sec-butyl (secondary carbon attachment), isobutyl (branched primary group), and tert-butyl (branched tertiary group, $-C(CH_3)_3$).

Phenyl and Benzyl groups

Aromatic substituents: phenyl is derived directly from benzene ($-C_6H_5$), whereas benzyl contains an intervening methylene unit ($-CH_2-C_6H_5$).

Naphthalene, $\alpha$-naphthyl, and $\beta$-naphthyl

A bicyclic aromatic hydrocarbon ($C_{10}H_8$) consisting of two fused benzene rings; substitution at the 1-position gives the $\alpha$-naphthyl group, and at the 2-position gives the $\beta$-naphthyl group.

Vinyl, Allyl, and Propargyl groups

Unsaturated hydrocarbon groups: vinyl is the ethenyl group ($-CH=CH_2$), allyl is the 2-propenyl group ($-CH_2-CH=CH_2$), and propargyl is the 2-propynyl group ($-CH_2-C ≡ CH$).

Acetyl, Benzoyl, and Acyl groups

Acyl groups derived by removing the hydroxyl group from carboxylic acids: generic acyl is $R-CO-$, acetyl is derived from acetic acid ($-COCH_3$), and benzoyl is derived from benzoic acid ($-COC_6H_5$).

Methoxy and Phenoxy groups

Ether-type substituents: methoxy consists of a methyl group attached to oxygen ($-OCH_3$ or $-OMe$), while phenoxy consists of a phenyl ring attached to oxygen ($-OC_6H_5$).

Simple Aldehydes (Formaldehyde to Butyraldehyde)

Homologous straight-chain aldehydes: formaldehyde ($HCHO$), acetaldehyde ($CH_3CHO$), propionaldehyde or propanal ($CH_3CH_2CHO$), and butyraldehyde or butanal ($CH_3(CH_2)_2CHO$).

Simple Monocarboxylic Acids (Formic to Butyric acid)

Short-chain carboxylic acids: formic acid ($HCOOH$), acetic acid ($CH_3COOH$), propionic acid ($CH_3CH_2COOH$), and butyric acid ($CH_3CH_2CH_2COOH$).

Dicarboxylic acids (Oxalic, Malonic, Succinic, Glutaric)

Straight-chain terminal dicarboxylic acids: oxalic acid ($HOOC-COOH$), malonic acid ($HOOC-CH_2-COOH$), succinic acid ($HOOC-(CH_2)_2-COOH$), and glutaric acid ($HOOC-(CH_2)_3-COOH$).

$\alpha$-Amino acid and $\beta$-Amino acid

Amino acids classified by amine placement: in $\alpha$-amino acids (such as glycine, alanine, serine, phenylalanine), the amino group is attached to the carbon adjacent to the carboxyl group; in $\beta$-amino acids, it is attached to the second carbon from the carboxyl group.

Dipeptide

A molecule formed by two amino acids joined through an amide bond, specifically designated as a peptide bond.

D-Glucose and Glucopyranose Anomers

An aldohexose carbohydrate represented in Fischer projection as D-glucose, which cyclizes into six-membered hemiacetal rings ($\alpha$-D-glucopyranose and $\beta$-D-glucopyranose) depicted in Haworth or chair conformations.

Oxirane (Ethylene oxide)

A three-membered saturated cyclic ether containing two carbon atoms and one oxygen atom.

Aziridine (Ethylene imine)

A three-membered saturated heterocycle containing two carbon atoms and one nitrogen atom ($NH$).

Oxetane and Azetidine

Four-membered saturated heterocycles: oxetane contains one oxygen atom, and azetidine contains one nitrogen atom ($NH$).

Azetidine-2-on

A four-membered cyclic amide ($\beta$-lactam) composed of an azetidine ring with a carbonyl oxygen at position 2.

Furan and its Hydrogenated Derivatives

Five-membered oxygen heterocycles: furan is aromatic with two double bonds; partially hydrogenated forms are 2,3-dihydrofuran and 2,5-dihydrofuran; the fully saturated form is tetrahydrofuran (THF).

Pyrrole and Pyrrolidine (Tetrahydropyrrole)

Five-membered nitrogen heterocycles: pyrrole is an aromatic ring with two double bonds and an $NH$ group, while pyrrolidine (tetrahydropyrrole) is its fully saturated four-carbon analogue.

Thiophene

A five-membered aromatic heterocyclic compound containing four carbon atoms and one sulfur atom.

1H-Imidazole and 1H-Pyrazole

Five-membered diazole isomers: 1H-imidazole has nitrogen atoms at positions 1 and 3 (1,3-diazole), whereas 1H-pyrazole has adjacent nitrogen atoms at positions 1 and 2 (1,2-diazole).

Tetrazole, Thiazole, and Oxazole

Five-membered aromatic azoles: tetrazole contains four nitrogens; thiazole contains one sulfur and one nitrogen; oxazole contains one oxygen and one nitrogen.

Pyridine and Piperidine

Six-membered mononitrogen heterocycles: pyridine is an aromatic ring containing one nitrogen atom, while piperidine is its fully saturated hexahydropyridine counterpart.

Diazines (Pyridazine, Pyrimidine, Pyrazine)

Six-membered aromatic dinitrogen heterocycles: pyridazine (1,2-diazine), pyrimidine (1,3-diazine), and pyrazine (1,4-diazine).

Morpholine and Piperazine

Six-membered saturated heterocycles: morpholine contains one oxygen and one nitrogen in 1,4-positions, while piperazine contains two nitrogen atoms at 1,4-positions.

Azepine

A seven-membered unsaturated nitrogen-containing heterocyclic ring.

Quinoline and Isoquinoline

Bicyclic aromatic heterocycles composed of a benzene ring fused to a pyridine ring, differing in whether nitrogen is at position 1 (quinoline) or position 2 (isoquinoline).

Indole

A fused bicyclic aromatic heterocycle consisting of a six-membered benzene ring fused to a five-membered pyrrole ring.

Purine

A heterocyclic aromatic bicyclic compound consisting of a six-membered pyrimidine ring fused to a five-membered imidazole ring.

Acridine

A tricyclic aromatic heterocycle containing a central pyridine ring fused between two outer benzene rings.

Benzoxazole and Benzimidazole

Fused bicyclic heterocycles where a benzene ring is fused to a five-membered azole ring: benzoxazole features a fused oxazole ring, while benzimidazole features a fused imidazole ring.