Chemistry
Heterocyclic Chemistry
Heterocyclic chemistry is the study of organic compounds containing at least one ring structure with atoms other than carbon. These atoms are typically nitrogen, oxygen, or sulfur, and the presence of heteroatoms imparts unique chemical and biological properties to these compounds. Heterocyclic compounds are widely used in pharmaceuticals, agrochemicals, and materials science due to their diverse reactivity and functional diversity.
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2 Key excerpts on "Heterocyclic Chemistry"
eBook - PDF- Ramesh Chandra, Snigdha Singh, Aarushi Singh(Authors)
- 2020(Publication Date)
- Arcler Press(Publisher)
In addition to this, a latest article or book with respect to the Heterocyclic Chemistry is consisting of the significance of the heterocyclic compounds in the context of medicinal chemistry and natural products. Synthesis of Five- and Six-Membered Heterocyclic Compounds 211 7.3. COMPARISON WITH CARBOCYCLIC COMPOUNDS The molecules of the organic chemical compounds are developed from a backbone or framework of carbon atoms to which are attached oxygen, hydrogen (H), or the other kind of heteroatoms. Atoms of the carbon have distinctive properties of having the potential to combine with one another in order to form chains of atoms. When the tails of the chains are combined together into a ring, consequences of the cyclic compounds such as substance every so often are referred to as carbocyclic compounds or alicyclic compounds. Substitution of one or more of the ring carbon atoms in the molecules of a carbocyclic compound with a heteroatom given a heterocyclic compound. A conventional carbocyclic compound is cyclopentane (C 5 H 10 ), the molecular structure of which is shown by the formula: In which the chemical symbols that shows the atom of the elements and the lines shows the bonds among the atoms. In order to ease these kinds of formula every so often written in the simplified polygonal form, like: With respect to cyclopentane, in which each of the edge of the polygon shows a carbon atom (it is being acknowledged that the atoms of the hydrogen are linked to the atoms of carbon as needed). When one of the atoms of carbon of cyclopentane is substituted with the help of an atom of nitrogen, then the compound pyrrolidine, a chemical relative of pyrrole is created. The structural formula of the pyrrolidine can be written as shown below:
eBook - PDFFundamentals of Heterocyclic Chemistry
Importance in Nature and in the Synthesis of Pharmaceuticals
- Louis D. Quin, John A. Tyrell(Authors)
- 2010(Publication Date)
- Wiley(Publisher)
This is the case for rings with the H¨ uckel number (4n + 2, where n is a small whole number) of pi-electrons. All 6-membered rings where n = 1 containing one or more nitrogen or phosphorus atoms meet this specification, although P- containing rings are rare and exhibit special properties. Six-membered rings containing oxygen or sulfur can only have two double bonds and are not aromatic, although as will be discussed, the rings do have some characteristics of aromaticity if the heteroatom is positively charged (as in the oxonium ion). Five-membered rings with N, O, or S have four pi-electrons from the two double bonds and have two more non-bonded pi-electrons on the heteroatom. These rings are also considered to meet the H¨ uckel specification. Larger rings where n = 2, 3, 4, etc., can also be considered to possess aromaticity. Aromaticity can be defined in several ways. We will consider this point in connection with a review of benzene aromaticity in section 6.2. Suffice it to say that aromaticity has a profound effect on the proper- ties of cyclic systems, controlling many aspects of their chemistry. In Fundamentals of Heterocyclic Chemistry: Importance in Nature and in the Synthesis of Pharmaceuticals, By Louis D. Quin and John A. Tyrell Copyright 2010 John Wiley & Sons, Inc. 131 132 AROMATICITY AND OTHER SPECIAL PROPERTIES OF HETEROCYCLES this chapter, we will examine the properties of some fundamental aro- matic heterocyclic systems. When rings are saturated or only partly unsaturated, their chemistry is much like that of nonaromatic carbo- cyclic counterparts. The features of stereochemistry become important in such heterocyclic systems; they will be considered mostly from this standpoint in Chapter 10. There is a very convenient description of heterocycles as being pi-deficient or pi-excessive.
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