**Abstract**

Drug discovery and optimization comprise one of the most significant targets in medicinal chemistry. Quinazoline and quinazolinone derivatives and nitrogencontaining heterocycles have received significant attention due to their widely and distinct biopharmaceutical activities. Quinazolines and quinazolinones are considered as noteworthy chemical for the synthesis of diverse physiological significance and pharmacological utilized molecules. Quinazolines are building blocks for about 150 naturally occurring alkaloids with a broad range of biological activity. The various substituted quinazolines and quinazolinones displayed important, for example, sedative hypnotics, antibacterial, anti-inflammatory, analgesic, antipsychotic, antifungal, antimalarial, anticonvulsant, anti-Parkinsonism, cancer, and other activities. This chapter aims to highlight the latest evidence of quinazolinone and quinazoline derivatives as a privileged scaffold in medicinal chemistry.

**Keywords:** quinazoline, quinazolinones, antioxidant and anticancer, antibacterial, structure-activity relationship

### **1. Introduction**

Emergence of drug resistance has created a critical and unmet medical requirement for the innovation and development of novel classes of antibacterial agents [1–4]. Due to the appearance of drug resistance bacterial strains, there is an escalating need for the development of novel antibiotics to treat the resistant bacteria stain. Diverse set of biological activities of quinazolinones (fused heterocyclic system) such as anti-inflammatory, anticonvulsant, anticancer, antibacterial, antifungal, anti-HIV and anti-analgesic [5–16], have encouraged to abundant of medicinal chemists to investigate this fused heterocycles as a novel drug molecules. Several research groups have successfully investigated and reported the promising antimicrobial properties and structure-activity relationships (SAR) of various quinazolinone derivatives.

Quinazolines and quinazolinones emerged as a privileged class of nitrogen containing heterocyclic scaffolds; exhibits a broad spectrum of pharmacological activities, viz. anti-inflammatory, antitubercular, and antiviral activities [17]. Number of quinazoline derived compound have been approved as a drug; for example prazosin and doxazosine are used to treat benign prostatic hyperplasia and post-traumatic stress disorder [18], and erlotinib and gefitinib both are used for the curing of lung and pancreatic cancers (**Figure 1**) [19].

**Figure 1.** *Quinazoline and quinazolinone-based drugs.*

Several quinazolinone-based drugs including idelalisib and fenquizone have been shown to exhibit a broad spectrum of antimicrobial, antitumor, antifungal, and cytotoxic activities [20]. Lapatinib has been displayed to be effective in combination therapy for breast cancer [21]. In the recent years, various synthetic strategies for the synthesis of quinazolines and quinazolinones derivatives have

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*Quinazolinone and Quinazoline Derivatives: Synthesis and Biological Application*

**2. Synthesis of quinazoline and quinazolinone derivatives**

been developed to accomplish the budding requirements of medicinal chemist [22]. Many research groups have successfully utilized copper catalyzed Ullmanntype coupling procedures of aryl bromides and benzamidines for the synthesis of

1.Synthesis of 4(3H)-quinazolinone using anthranilic acid or formyl anthranila-

2.Via condensation reaction of 4-chloroanthranilic acid amide with triethyl orthoformate, the 7-chloro-substituted derivative has been prepared [25].

3.Quinazolin-4(3H)-one was synthesized by the reaction of anthranilic acid with excess formamide at 120°C in an open air. This is also known as Niementowski

4. 2-styryl-4(3H)-quinazolinone derivatives were prepared using starting substrate 2-aminobenzonitrile with 3-phenyl cinnamoyl chloride. Under alkaline conditions, intramolecular cyclization of cinnamamide derivative was carried out to afford 2-styryl-4(3H)-quinazolinone. This procedure was tolerated to a

wide range of different substituted benzene rings [27].

*DOI: http://dx.doi.org/10.5772/intechopen.89203*

quinazoline derivatives [23].

mide [24].

reaction [26].

*Quinazolinone and Quinazoline Derivatives: Synthesis and Biological Application DOI: http://dx.doi.org/10.5772/intechopen.89203*

been developed to accomplish the budding requirements of medicinal chemist [22]. Many research groups have successfully utilized copper catalyzed Ullmanntype coupling procedures of aryl bromides and benzamidines for the synthesis of quinazoline derivatives [23].
