Introductory Chapter: Recent Advances on Quinazoline

1. Introduction

Quinazolines are heterocyclic systems with numerous reactive centers, which make them interesting research topics. The quinazoline molecule (1,3-diazanaphthalene) is composed of two pyrimidine and benzene rings, which are fused six-membered simple aromatic rings. Another name for it is benzopyrimidine. Along with quinoxaline, phthalazine, and cinnoline, it is isomeric. Among the heterocycles, quinazolines are widely recognized for their extensive pharmacological activity and their utility as synthetic intermediates. Many pharmacological activities, including analgesic and anti-inflammatory, antimicrobial, anti-tubercular, antihistaminic, antitussive, bronchodilator, antidiabetic, antidiuretic, antihypertensive, sedative-hypnotic activity, antidepressant, antiparkinsonian, antibacterial, anticancer, analgesic, antiallergic, anticonvulsant, antimalarial, and other effects, have been reported to be present in them [1, 2, 3, 4, 5, 6].

The purpose of heterocyclic rings with nitrogen and sulfur is significant since they are more active both pharmacologically and therapeutically. These substances serve as the foundation for numerous pharmacological products. Due to its numerous pharmacological properties and low number of side effects, quinazoline is one of the heterocyclic moieties selected for this investigation [7]. The chemical formula for quinazoline, a well-known heterocyclic molecule, is C8H6N2. Quinazoline, sometimes called 1,3-diazanaphthalene, is a light yellow crystalline substance made up of one pyrimidine and one benzene ring. In 1895, August Bischler and Lang reported on the synthesis of quinazoline by decarboxylating a 2-carboxy derivative [8]. By using Niementowski synthesis, anthranilic acid treated with amide produced 4-oxo-3,4-dihydroquinazolies [9]. Quinazoline also has other isomers, such as quinoxaline. Quinazoline also has other isomers, such as quinoxaline, cinnoline, and phthalazine [10]. Quinazolines further. the components of over 200 naturally occurring alkaloids that have been separated from microbes and plants and animals [11, 12]. In 1888, Adhatoda vasica yielded the first known quinazoline alkaloid, known as vasicine (±) or peganine. It works quite well against bronchodilators’ engagement [13].

One quinazoline derivative that is just as active as quinazoline is quinazolinone [14]. As seen in Figure 1 [15], Quinazolinones are further divided into smaller groups, such as 4-quinazolinone (a) and 2-quinazolinone (b) based on the substitution pattern.

Figure 1.

(a) 4-quinazolinone. (b) 2-quinazolinone.

Because quinazoline is a structure that is present in many medications, clinical candidates, and bioactive compounds, it is therefore of tremendous importance in the field of pharmaceutical chemistry. This introductory chapter centers on the possible biological activity of derivatives of quinazoline. The information in this chapter about the most recent advancements on quinazoline analogs with distinctly different pharmacological activity, such as anticancer, antibacterial, antimalarial, antiviral, and antidiabetic properties, will be helpful. Moreover, this chapter will be encouraging for scientists to develop, synthesize, and improve the potential of essential medication containing quinazoline moieties for the future treatment of various illnesses.

In our research project, several chapters have been included, such as Recent Approaches for the Synthesis of Imidazoquinazolines and Benzimidazoquinazolines, Triazoloquinazoline: Synthetic Strategies and Medicinal Importance, computational studies for the quinazoline derivatives, Synthesis and Antiviral activities of some Triazolo Quinazolines Derivatives, Synthetic and Kinetic study of analogues natural occurring chalcones and Flavanone and Quinazoline and its Derivatives: Privileged Heterocyclic Scaffolds in Antileishmanial Drug Discovery. These chapters included in this book concentrate on the recent advances in methods for medicinal synthesis with more important, valuable, and interested pharmacological activities such as anticancer, antibacterial, antimalarial, antiviral, antidiabetic, and antileishmanial properties to enable medicinal chemists and scientists to design novel drugs with distinctly different pharmacological activity.

In medicinal chemistry, quinazoline and quinazolinone structures are frequently encountered. Quinazolines and quinazolinones exhibit noteworthy properties, including antidepressant, antineoplastic, and antipsychotic properties, while certain quinazoline and quinazolinone compounds are shown to be useful medications with sedative, hypnotics, antimicrobial, anti-inflammatory, antifungal, antimalarial, anticonvulsant, anticoccidial, antiparkinsonian, anticancer, analgesic, and antipsychotic properties [16, 17, 18].

I am grateful to all of the authors who contributed to this book for their insightful, worthwhile, and significant discussions on Recent Advances on Quinazoline.

The book, which covers all newer medications in brief, will be very beneficial to readers. The primary goal in developing this book was to meet readers who are employed in the medical and pharmaceutical fields in particular by presenting the material in an understandable, concise, and unified manner. Additionally, I would like to express my gratitude to everyone who helped to complete the book. We greatly thank the publishers and Intech for Science, Technology, and Medicine’s collaboration in making this book possible. It would be impossible to overlook the assistance that I obtained from Mr. Tonci Lucic, the Publishing Process Manager.