UJIAN KIMIA BAHAN ALAM

1.       Fats generally are solid while the oil is liquid phase, however both are equally triglyceride. Explain why the form of two different triglyceride, and point out important factors that determine the form of fat? 

Answer:  

Fats generally are solid  while the  oil is liquid phase because:

• Effect of structure on physical properties

General , as chains become longer and/ or more saturated, the triglyseride is more likely to be a fat (solid)As chains becvome shorter and/or more unsaturated, the triglyseride is more likely to be a oil ( liquid)

• Saturated fatty acids have only single bonds between its constituent carbon atoms, while unsaturated fatty acids having at least one double bond between carbon atoms of the constituent.
• oil has a chain of C1 - C10 while fat has an chain> C10
• Saturated and unsaturated fats differ in their energy content and melting point. Since unsaturated fats contain fewer carbon-hydrogen bonds than saturated fats with the same number of carbon atoms, unsaturated fats will yield slightly less energy during metabolism than saturated fats with the same number of carbon atoms
• Saturated fats can stack themselves in a closely packed arrangement, so they can freeze easily and are typically solid at room temperature

Types	Fats	Oil
Double bond	less	Many
melting point	high	low
phase	Solid	Liquid
source	the animal	The plant generally
Reactivity	not easy Easy rancid	Easy rancid

1.   

         2.    How a primary metabolite can be converted in the secondary metabolites. What is the basic idea and how the machanism could be described?

answer

The most important building blocks employed in the biosynthesis of secondary metabolites are derived from:

1. Acetyl coenzyme A (acetyl-CoA)

The form in which acetate is used in most of its important biochemical reactions is acetyl coenzyme A (acetyl-CoA).

Acetyl-CoA is formed by oxidative decarboxylation of the glycolytic pathway product pyruvic acid.

2. Shikimic acid

Shikimic acid is produced from a combination of phosphoenolpyruvate, a glycolytic pathway intermediate, and erythrose 4-phosphate from the pentose phosphate pathway. 

3. Mevalonic acid

Mevalonic acid is itself formed from three molecules of acetyl-CoA, but the mevalonate pathway channels acetate into a different series of compounds than does the acetate pathway.

4. 1-deoxyxylulose 5-phosphate

Deoxyxylulose phosphate arises from a combination of two glycolytic pathway intermediates, namely pyruvic acid and glyceraldehyde 3-phosphate 

5. Amino acids

Peptides, proteins, alkaloids and many antibiotics are derived from amino acids.

Intermediates from the glycolytic pathway and the Krebs cycle are used in constructing many of them.

the specific reasction
primary metabolite can be converted in the secondary metabolites from  the reaction the fundamental processes of photosynthesis,glycolysis, and theKrebs cycle are tapped off from energy-generating processes to provide biosynthetic intermediates.To make biosynthesis intermediets needs the buillding blocks. By far the most important building blocks employed in the biosynthesis of secondary metabolites are derived from the intermediates acetyl coenzyme A (acetyl-CoA), shikimic acid, mevalonic acid, and methylerythritol phosphate. These are utilized respectively in the acetate, shikimate, mevalonate, and methylerythritol phosphate pathways, Acetyl-CoA is formed by oxidative decarboxylation of the glycolytic pathway product pyruvic acid. It is also produced by the β-oxidation of fatty acids, effectively reversing the process by which fatty acids are themselves synthesized from acetyl-CoA. Important secondary metabolites formed from the acetate pathway include phenols, prostaglandins, and macrolide antibiotics, together with various fatty acids and derivatives at the primary–secondary metabolism interface. Shikimic acid is produced from a combination of phosphoenolpyruvate, a glycolytic pathway intermediate, and erythrose 4-phosphate from the pentose phosphate pathway. The reactions of the pentose phosphate cycle may be employed for the degradation of glucose, but they also feature in the synthesis of sugars by photosynthesis. The shikimate pathway leads to a variety of phenols, cinnamic acid derivatives, lignans, and alkaloids. Mevalonic acid is itself formed from three molecules of acetyl-CoA, but the mevalonate pathway channels acetate into a different series of compounds than does the acetate pathway. Methylerythritol phosphate arises from a combination of two glycolytic pathway intermediates, namely pyruvic acid and glyceraldehyde 3-phosphate by way of deoxyxylulose phosphate. The mevalonate and methylerythritol phosphate pathways are together responsible for the biosynthesis of a vast array of terpenoid and steroid metabolites.
In addition to acetyl-CoA, shikimic acid, mevalonic acid, and methylerythritol phosphate, other building blocks based on amino acids are frequently employed in natural product synthesis. Peptides, proteins, alkaloids, and many antibiotics are derived from amino acids, and the origins of some of the more important amino acid components of these are briefly indicated in Figure 2.1. Intermediates from the glycolytic pathway and the Krebs cycle are used in constructing many of them, but the aromatic amino acids phenylalanine, tyrosine, and tryptophan are themselves products from the shikimate pathway. Ornithine, an amino acid not found in proteins, and its homologue lysine, are important alkaloid precursors and have their origins in Krebs cycle intermediates. Of special significance is the appreciation that secondary metabolites can be synthesized by combining several building blocks of the same type, or by using a mixture of different building blocks. This expands structural diversity and, consequently, makes subdivisions based entirely on biosynthetic pathways rather more difficult. A typical natural product might be produced by combining elements from the acetate, shikimate, and methylerythritol phosphate pathways.

 3.Hormone progesterone is essential for the survival of the pregnancy. These hormones are drived from a streoid biognetically. Explain the logic of chemical reactions which may occur in the formation of progesterone. 

BIOSYNTHESIS PROGESTERONE

To get the hormone progesterone which is needed by mammals. like all other steroid hormones, synthesized from pregnenolone, which in turn comes from cholesterol. This is a step in the formation reaction of progesterone Cholesterol  undergoes double oxidation to produce 20,22-dihydroxycholesterol.

1.  This vicinal diol is then further oxidized with loss of the side chain starting at position C-22 to produce pregnenolone. This reaction is catalyzed by cytochrome P450scc.
2.  The conversion of pregnenolone to progesterone takes place in two steps. 

·         First, the 3-hydroxyl group is oxidized to a keto group  

·         second, the double bond is moved to C-4, from C-5 through a keto/enol tautomerization reaction. This reaction is catalyzed by 3beta-hydroxysteroid dehydrogenase/delta(5)-delta(4)isomerase.

Progesterone in turn  is the precursor of the mineralocorticoid aldosterone, and after conversion to 17-hydroxyprogesterone (another natural progestogen) of cortisol and androstenedione. Androstenedione can be converted totestosterone, estrone and estradiol.

 In laboratory

the synthesis begins with reacting the phosphonium salt  with phenyl lithium to produce the phosphonium ylide . The ylide  is reacted with an aldehyde to produce thealkene . The ketal protecting groups of  are hydrolyzed to produce the diketone , which in turn is cyclized to form the cyclopentenone. The ketone of  is reacted with methyl lithium to yield the tertiary alcohol , which in turn is treated with acid to produce the tertiary cation . The key step of the synthesis is the π-cation cyclization of  in which the B-, C-, and D-rings of the steroid are simultaneously formed to produce . This step resembles the cationic cyclization reaction used in the biosynthesis of steroids and hence is referred to as biomimetic. In the next step the enol orthoester is hydrolyzed to produce the ketone . The cyclopentene A-ring is then opened by oxidizing with ozone to produce . Finally, the diketone  undergoes an intramolecular aldol condensation by treating with aqueous potassium hydroxide to produce progesterone.

4. Many alkaloids are toxic to other organism. They often have pharmacological effects and are used as medications, as recreational drugs, or in entheogenic rituals. Describe in outline the process of biosynthesis of an alkalois compound and describe the functions groups which play an important role in the biological activities

.BIOSYNTHESIS OF ATROPINE

 The biosynthesis of atropine starting from L-Phenylalanine first undergoes a transamination forming phenylpyruvic acid which is then reduced to phenyl-lactic acid. Coenzyme A then couples phenyl-lactic acid with tropine forming littorine, which then undergoes a radical rearrangement initiated with a P450 enzyme forming hyoscyamine aldehyde. A dehydrogenase then reduces the aldehyde to a primary alcohol making (-)-hyoscamine, which upon racemization forms atropine.

 

Biosynthesis of atropine starting from L-Phenylalanine

steric

Steric effects arise from the fact that each atom within a molecule occupies a certain amount of space. If atoms are brought too close together, there is an associated cost in energy due to overlapping electron clouds (Pauli or Born repulsion), and this may affect the molecule's preferred shape (conformation) and reactivity.

Types of steric effects

Steric hindrance

Steric hindrance or steric resistance occurs when the size of groups within a molecule prevents chemical reactions that are observed in related smaller molecules. Although steric hindrance is sometimes a problem (it prevents SN2 reactions with tertiary substrates from taking place), it can also be a very useful tool, and is often exploited by chemists to change the reactivity pattern of a molecule by stopping unwanted side-reactions (steric protection). Steric hindrance between adjacent groups can also restrict torsional bond angles. However, hyperconjugation has been suggested as an explanation for the preference of the staggered conformation of ethane because the steric hindrance of the small hydrogen atom is far too small. [1] [2] This is the effect responsible for the observed shape of rotaxanes.

Regioselective dimethoxytritylation of the primary 5'-hydroxyl group of thymidine in the presence of a free secondary 3'-hydroxy group as a result of steric hindrance due to the dimethoxytrityl group and the ribose ring (Py = pyridine).^[3]

Other types of steric effects

Steric shielding occurs when a charged group on a molecule is seemingly weakened or spatially shielded by less charged (or oppositely charged) atoms, including counterions in solution (Debye shielding). In some cases, for an atom to interact with sterically shielded atoms, it would have to approach from a vicinity where there is less shielding, thus controlling where and from what direction a molecular interaction can take place.
Steric attraction occurs when molecules have shapes or geometries that are optimized for interaction with one another. In these cases molecules will react with each other most often in specific arrangements.
Chain crossing: A chain, ring, or a set of rings cannot change from one conformation to another if it would require a chain (or ring - a ring is a cyclic chain) to pass through itself or another chain. This is responsible for the shape of catenanes and molecular knots.
Steric repulsions between different parts of molecular system were found of key importance to govern the direction of transition metal mediated transformations and catalysis. Steric effect can even induce a mechanism switch in the catalytic reaction.^[4]

Steric effects vs. electronic effects

The structure, properties, and reactivity of a molecule is dependent on straight forward bonding interactions including covalent bonds, ionic bonds, hydrogen bonds and lesser forms of bonding. This bonding supplies a basic molecular skeleton that is modified by repulsive forces. These repulsive forces include the steric interactions described above. Basic bonding and steric are at times insufficient to explain many structures, properties, and reactivity. Thus steric effects are often contrasted and complemented by electronic effects implying the influence of effects such as induction, conjunction, orbital symmetry, electrostatic interactions, and spin state. There are more esoteric electronic effects but these are among the most important when considering structure and chemical reactivity.
A special computational procedure was developed to separate electronic and steric effects of an arbitrary group in the molecule and to reveal their influence on structure and reactivity.^[5]

Significance

Understanding steric effects is critical to chemistry, biochemistry and pharmacology. In chemistry, steric effects are nearly universal and affect the rates and energies of most chemical reactions to varying degrees. In biochemistry, steric effects are often exploited in naturally occurring molecules such as enzymes, where the catalytic site may be buried within a large protein structure. In pharmacology, steric effects determine how and at what rate a drug will interact with its target bio-molecules.

stereo alkane

Alkane conformers arise from rotation around sp³ hybridised carbon carbon sigma bonds. The smallest alkane with such a chemical bond, ethane, exists as an infinite number of conformations with respect to rotation around the C–C bond. Two of these are recognised as energy minimum (staggered conformation) and energy maximum (eclipsed conformation) forms. The existence of specific conformations is due to hindered rotation around sigma bonds, although a role for hyperconjugation is proposed by a competing theory.

The importance of energy minimum and energy maximum is seen by extension of these concepts to more complex molecules for which stable conformations may be predicted as minimum energy forms. The determination of stable conformations has also played a large role in the establishment of the concept of asymmetric induction and the ability to predict the stereochemistry of reactions controlled by steric effects.

In the example of staggered ethane in Newman projection, a hydrogen atom on one carbon atom has a 60° torsional angle or torsion angle ^[1] with respect to the nearest hydrogen atom on the other carbon so that steric hindrance is minimised. The staggered conformation is more stable by 12.5 kJ/mol than the eclipsed conformation, which is the energy maximum for ethane. In the eclipsed conformation the torsional angle is minimized.

In butane, the two staggered conformations are no longer equivalent and represent two distinct conformers:the anti-conformation (left-most, below) and the gauche conformation (right-most, below).

Both conformations are free of torsional strain, but, in the gauche conformation, the two methyl groups are in closer proximity than the sum of their van der Waals radii. The interaction between the two methyl groups is repulsive (van der Waals strain), and an energy barrier results.

A measure of the potential energy stored in butane conformers with greater steric hindrance than the 'anti'-conformer ground state is given by these values^[2]:

• Gauche, conformer - 3.8 kJ/mol
• Eclipsed H and CH₃ - 16 kJ/mol
• Eclipsed CH₃ and CH₃ - 19 kJ/mol.

The eclipsed methyl groups exert a greater steric strain because of their greater electron density compared to lone hydrogen atoms.

Relative energies of conformations of butane with respect to rotation of the central C-C bond.

The textbook explanation for the existence of the energy maximum for an eclipsed conformation in ethane is steric hindrance, but, with a C-C bond length of 154 pm and a Van der Waals radius for hydrogen of 120 pm, the hydrogen atoms in ethane are never in each other's way. The question of whether steric hindrance is responsible for the eclipsed energy maximum is a topic of debate to this day. One alternative to the steric hindrance explanation is based on hyperconjugation as analyzed within the Natural Bond Orbital framework.^[3][4][5] In the staggered conformation, one C-H sigma bonding orbital donates electron density to the antibonding orbital of the other C-H bond. The energetic stabilization of this effect is maximized when the two orbitals have maximal overlap, occurring in the staggered conformation. There is no overlap in the eclipsed conformation, leading to a disfavored energy maximum. On the other hand, an analysis within quantitative molecular orbital theory shows that 2-orbital-4-electron (steric) repulsions are dominant over hyperconjugation.^[6] A valence bond theory study also emphasizes the importance of steric effects.^[7]

[edit] Definitions

Many definitions that describe a specific conformation (IUPAC Gold Book) exist:

• a torsion angle of ±60° is called gauche ^[8]
• a torsion angle between 0° and ± 90° is called syn (s)
• a torsion angle between ± 90° and 180° is called anti (a)
• a torsion angle between 30° and 150° or between –30° and –150° is called clinal
• a torsion angle between 0° and 30° or 150° and 180° is called periplanar (p)
• a torsion angle between 0° to 30° is called synperiplanar or syn- or cis-conformation (sp)
• a torsion angle between 30° to 90° and –30° to –90° is called synclinal or gauche or skew (sc)^[9]
• a torsion angle between 90° to 150°, and –90° to –150° is called anticlinal (ac)
• a torsion angle between ± 150° to 180° is called antiperiplanar or anti or trans (ap).

Any strain resulting from torsion is also called Pitzer Strain^[10] or eclipsing strain.

In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction(s) regardless of the size of the molecule it is a part of.^[1][2] However, its relative reactivity can be modified by nearby functional groups.

The word moiety (pronounced /ˈmɔɪti/) is often used synonymously to "functional group," but, according to the IUPAC definition,^[3] a moiety is a part of a molecule that may include functional groups as substructures. For example, an ester is a functional group composed of an alcohol moiety and an acyl moiety. Also, it may be divided into carboxylate and alkyl moieties. Each moiety may carry any number of functional groups, for example, methyl parahydroxybenzoate carries a phenol functional group in the acyl moiety.

Combining the names of functional groups with the names of the parent alkanes generates a powerful systematic nomenclature for naming organic compounds.

The atoms of functional groups are linked to each other and to the rest of the molecule by covalent bonds. When the group of atoms is associated with the rest of the molecule primarily by ionic forces, the group is referred to more properly as a polyatomic ion or complex ion. And all of these are called radicals, by a meaning of the term radical that predates the free radical.

The first carbon atom after the carbon that attaches to the functional group is called the alpha carbon; the second, beta carbon, the third, gamma carbon, etc. If there is another functional group at a carbon, it may be named with the Greek letter, e.g., the gamma-amine in gamma-aminobutanoic acid is on the third carbon of the carbon chain attached to the carboxylic acid group.

Synthetic chemistry

Organic reactions are facilitated and controlled by the functional groups of the reactants. In general, alkyls are unreactive and difficult to get to react selectively at the desired positions, with few exceptions. In contrast, unsaturated carbon functional groups, and carbon-oxygen and carbon-nitrogen functional groups have a more diverse array of reactions that are also selective. It may be necessary to create a functional group in the molecule to make it react. For example, to synthesize iso-octane (the 8-carbon ideal gasoline) from the unfunctionalized alkane isobutane (a 4-carbon gas), isobutane is first dehydrogenated into isobutene. This contains the alkene functional group and can now dimerize with another isobutene to give iso-octene, which is then catalytically hydrogenated to iso-octane using pressured hydrogen gas.

Crystallography

The International Union of Crystallography in its Crystallographic Information File dictionary defines "moiety" to represent discrete non-bonded components. Thus Na₂SO₄ would contain 3 moieties (2 Na⁺ and one SO₄^2-). The dictionary defines "chemical formula moiety": "Formula with each discrete bonded residue or ion shown as a separate moiety".

Functionalization

Functionalization is the addition of functional groups onto the surface of a material by chemical synthesis methods. The functional group added can be subjected to ordinary synthesis methods to attach virtually any kind of organic compound onto the surface.

Functionalization is employed for surface modification of industrial materials in order to achieve desired surface properties such as water repellent coatings for automobile windshields and non-biofouling, hydrophilic coatings for contact lenses. In addition, functional groups are used to covalently link functional molecules to the surface of chemical and biochemical devices such as microarrays and microelectromechanical systems.

Catalysts can be attached to a material that has been functionalized. For example, silica is functionalized with an alkyl silicone, wherein the alkyl contains an amine functional group. A ligand such as an EDTA fragment is synthesized onto the amine, and a metal cation is complexed into the EDTA fragment. The EDTA is not adsorbed onto the surface, but connected by a permanent chemical bond.

Functional groups are also used to covalently link molecules such as fluorescent dyes, nanoparticles, proteins, DNA, and other compounds of interest for a variety of applications such as sensing and basic chemical research.

Table of common functional groups

The following is a list of common functional groups. In the formulas, the symbols R and R' usually denote an attached hydrogen, or a hydrocarbon side chain of any length, but may sometimes refer to any group of atoms.

Hydrocarbons

Functional groups, called hydrocarbyls, that contain only carbon and hydrogen, but vary in the number and order of π bonds. Each one differs in type (and scope) of reactivity.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Alkane	Alkyl	RH		alkyl-	-ane	Ethane
Alkene	Alkenyl	R2C=CR2		alkenyl-	-ene	Ethylene (Ethene)
Alkyne	Alkynyl	RC≡CR'		alkynyl-	-yne	Acetylene (Ethyne)
Benzene derivative	Phenyl	RC6H5 RPh		phenyl-	-benzene	Cumene (2-phenylpropane)
Toluene derivative	Benzyl	RCH2C6H5 RBn		benzyl-	1-(substituent)toluene	Benzyl bromide (1-Bromotoluene)

There are also a large number of branched or ring alkanes that have specific names, e.g., tert-butyl, bornyl, cyclohexyl, etc.

Hydrocarbons may form charged structures: positively charged carbocations or negative carbanions. Carbocations are often named -um. Examples are tropylium and triphenylmethyl cations and the cyclopentadienyl anion.

Groups containing halogens

Haloalkanes are a class of molecule that is defined by a carbon-halogen bond. This bond can be relatively weak (in the case of an iodoalkane) or quite stable (as in the case of a fluoroalkane). In general, with the exception of fluorinated compounds, haloalkanes readily undergo nucleophilic substitution reactions or elimination reactions. The substitution on the carbon, the acidity of an adjacent proton, the solvent conditions, etc. all can influence the outcome of the reactivity.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
haloalkane	halo	RX		halo-	alkyl halide	Chloroethane (Ethyl chloride)
fluoroalkane	fluoro	RF		fluoro-	alkyl fluoride	Fluoromethane (Methyl fluoride)
chloroalkane	chloro	RCl		chloro-	alkyl chloride	Chloromethane (Methyl chloride)
bromoalkane	bromo	RBr		bromo-	alkyl bromide	Bromomethane (Methyl bromide)
iodoalkane	iodo	RI		iodo-	alkyl iodide	Iodomethane (Methyl iodide)

Groups containing oxygen

Compounds that contain C-O bonds each possess differing reactivity based upon the location and hybridization of the C-O bond, owing to the electron-withdrawing effect of sp hybridized oxygen (carbonyl groups) and the donating effects of sp² hybridized oxygen (alcohol groups).

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Alcohol	Hydroxyl	ROH		hydroxy-	-ol	Methanol
Ketone	Carbonyl	RCOR'		-oyl- (-COR') or oxo- (=O)	-one	Butanone (Methyl ethyl ketone)
Aldehyde	Aldehyde	RCHO		formyl- (-COH) or oxo- (=O)	-al	Ethanal (Acetaldehyde)
Acyl halide	Haloformyl	RCOX		carbonofluoridoyl- carbonochloridoyl- carbonobromidoyl- carbonoiodidoyl-	-oyl halide	Acetyl chloride (Ethanoyl chloride)
Carbonate	Carbonate ester	ROCOOR		(alkoxycarbonyl)oxy-	alkyl carbonate	Triphosgene (Di(trichloromethyl) carbonate)
Carboxylate	Carboxylate	RCOO−		carboxy-	-oate	Sodium acetate (Sodium ethanoate)
Carboxylic acid	Carboxyl	RCOOH		carboxy-	-oic acid	Acetic acid (Ethanoic acid)
Ester	Ester	RCOOR'		alkanoyloxy- or alkoxycarbonyl	alkyl alkanoate	Ethyl butyrate (Ethyl butanoate)
Hydroperoxide	Hydroperoxy	ROOH		hydroperoxy-	alkyl hydroperoxide	Methyl ethyl ketone peroxide
Peroxide	Peroxy	ROOR		peroxy-	alkyl peroxide	Di-tert-butyl peroxide
Ether	Ether	ROR'		alkoxy-	alkyl ether	Diethyl ether (Ethoxyethane)
Hemiacetal	Hemiacetal	RCH(OR')(OH)		alkoxy -ol	-al alkyl hemiacetal
Hemiketal	Hemiketal	RCH(ORʺ)(OH)R'		alkoxy -ol	-one alkyl hemiketal
Acetal	Acetal	RCH(OR')(OR")		dialkoxy-	-al dialkyl acetal
Ketal	Ketal	RCH(ORʺ)(OR‴)R'		dialkoxy-	-one dialkyl ketal
Orthoester	Orthoester	RC(OR')(ORʺ)(OR‴)		trialkoxy-
Orthocarbonate ester	Orthocarbonate ester	C(OR)(OR')(ORʺ)(OR″)		tetralkoxy-	tetraalkyl orthocarbonate

Groups containing nitrogen

Compounds that contain nitrogen in this category may contain C-O bonds, such as in the case of amides.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Amide	Carboxamide	RCONR2		carboxamido- or carbamoyl-	-amide	Acetamide (Ethanamide)
Amines	Primary amine	RNH2		amino-	-amine	Methylamine (Methanamine)
	Secondary amine	R2NH		amino-	-amine	Dimethylamine
	Tertiary amine	R3N		amino-	-amine	Trimethylamine
	4° ammonium ion	R4N+		ammonio-	-ammonium	Choline
Imine	Primary ketimine	RC(=NH)R'		imino-	-imine
	Secondary ketimine	RC(=NR)R'		imino-	-imine
	Primary aldimine	RC(=NH)H		imino-	-imine
	Secondary aldimine	RC(=NR')H		imino-	-imine
Imide	Imide	RC(=O)NC(=O)R'		imido-	-imide
Azide	Azide	RN3		azido-	alkyl azide	Phenyl azide (Azidobenzene)
Azo compound	Azo (Diimide)	RN2R'		azo-	-diazene	Methyl orange (p-dimethylamino-azobenzenesulfonic acid)
Cyanates	Cyanate	ROCN		cyanato-	alkyl cyanate	Methyl cyanate
	Isocyanate	RNCO		isocyanato-	alkyl isocyanate	Methyl isocyanate
Nitrate	Nitrate	RONO2		nitrooxy-, nitroxy-	alkyl nitrate	Amyl nitrate (1-nitrooxypentane)
Nitrile	Nitrile	RCN		cyano-	alkanenitrile alkyl cyanide	Benzonitrile (Phenyl cyanide)
	Isonitrile	RNC		isocyano-	alkaneisonitrile alkyl isocyanide	Methyl isocyanide
Nitrite	Nitrosooxy	RONO		nitrosooxy-	alkyl nitrite	Isoamyl nitrite (3-methyl-1-nitrosooxybutane)
Nitro compound	Nitro	RNO2		nitro-		Nitromethane
Nitroso compound	Nitroso	RNO		nitroso-		Nitrosobenzene
Pyridine derivative	Pyridyl	RC5H4N		4-pyridyl (pyridin-4-yl) 3-pyridyl (pyridin-3-yl) 2-pyridyl (pyridin-2-yl)	-pyridine	Nicotine

Groups containing sulfur

Compounds that contain sulfur exhibit unique chemistry due to their ability to form more bonds than oxygen, their lighter analogue on the periodic table. Substitutive nomenclature (marked as prefix in table) is preferred over functional class nomenclature (marked as suffix in table) for sulfides, disulfides, sulfoxides and sulfones.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Thiol	Sulfhydryl	RSH		sulfanyl- (-SH)	-thiol	Ethanethiol
Sulfide (Thioether)	Sulfide	RSR'		substituent sulfanyl- (-SR')	di(substituent) sulfide	(Methylsulfanyl)methane (prefix) or Dimethyl sulfide (suffix)
Disulfide	Disulfide	RSSR'		substituent disulfanyl- (-SSR')	di(substituent) disulfide	(Methyldisulfanyl)methane (prefix) or Dimethyl disulfide (suffix)
Sulfoxide	Sulfinyl	RSOR'		-sulfinyl- (-SOR')	di(substituent) sulfoxide	(Methanesulfinyl)methane (prefix) or Dimethyl sulfoxide (suffix)
Sulfone	Sulfonyl	RSO2R'		-sulfonyl- (-SO2R')	di(substituent) sulfone	(Methanesulfonyl)methane (prefix) or Dimethyl sulfone (suffix)
Sulfinic acid	Sulfino	RSO2H		sulfino- (-SO2H)	-sulfinic acid	2-Aminoethanesulfinic acid
Sulfonic acid	Sulfo	RSO3H		sulfo- (-SO3H)	-sulfonic acid	Benzenesulfonic acid
Thiocyanate	Thiocyanate	RSCN		thiocyanato- (-SCN)	substituent thiocyanate	Phenyl thiocyanate
	Isothiocyanate	RNCS		isothiocyanato- (-NCS)	substituent isothiocyanate	Allyl isothiocyanate
Thione	Carbonothioyl	RCSR'		-thioyl- (-CSR') or sulfanylidene- (=S)	-thione	Diphenylmethanethione (Thiobenzophenone)
Thial	Carbonothioyl	RCSH		methanethioyl- (-CSH) or sulfanylidene- (=S)	-thial

Groups containing phosphorus

Compounds that contain phosphorus exhibit unique chemistry due to their ability to form more bonds than nitrogen, their lighter analogues on the periodic table.

Chemical class	Group	Formula	Structural Formula	Prefix	Suffix	Example
Phosphine (Phosphane)	Phosphino	R3P		phosphanyl-	-phosphane	Methylpropylphosphane
Phosphonic acid	Phosphono	RP(=O)(OH)2		phosphono-	substituent phosphonic acid	Benzylphosphonic acid
Phosphate	Phosphate	ROP(=O)(OH)2		phosphonooxy- or O-phosphono- (phospho-)	substituent phosphate	Glyceraldehyde 3-phosphate (suffix)
						O-Phosphonocholine (prefix) (Phosphocholine)
Phosphodiester	Phosphate	HOPO(OR)2		[(alkoxy)hydroxyphosphoryl]oxy- or O-[(alkoxy)hydroxyphosphoryl]-	di(substituent) hydrogen phosphate or phosphoric acid di(substituent) ester	DNA
						O‑[(2‑Guanidinoethoxy)hydroxyphosphoryl]‑L‑serine (prefix) (Lombricine)