Neelam P. Prajapati

Recent advances in the synthesis of 2-substituted benzothiazoles: a review

Benzothiazole can serve as unique and versatile scaffolds, especially in synthetic and pharmaceutical chemistry because of their potent and significant pharmacological activities. This important class of derivatives possess numerous pharmacological activities like antitumor, antimicrobial, anti-inflammatory, anticonvulsant, antidiabetic activities and so on. Many scientists have developed a wide range of methodologies for the synthesis of the 2-substituted benzothiazole nucleus and its derivatives using different types of catalysts to improve the selectivity, purity and yield of the products. Thus, the present review article focuses mainly on the different kind of reactions involved in synthesis of the 2-substituted benzothiazole nucleus and its derivatives.

Review of Synthesis of Multispiro Heterocyclic Compounds from Isatin

Abstract Because of its various biological activities, isatin plays important roles in organic chemistry. The C-3 carbonyl group of the isatin possesses very high reactivity and thus isatin possesses many diverse applications in organic synthesis. This carbonyl group reacts like a prochiral center. For the organic synthetic chemist, the conception of a spiroheterocyclic building block has always been interesting, as it often requires synthetic design based on specific strategies. This review summarizes the synthesis of various multispiro heterocyclic compounds by using isatin through 1,3-dipolar cycloaddition reactions and multicomponent reactions. GRAPHICAL ABSTRACT

Ceric Ammonium Nitrate (CAN)–Catalyzed Multicomponent Reactions: An Efficient Catalyst for Green Organic Synthesis

Abstract Multicomponent reactions (MCRs) consist of two or more synthetic steps carried out without isolation of any intermediate, which reduces time and saves money, energy, and raw materials. The development of MCRs in the presence of ceric ammonium nitrate (CAN) is an efficient approach that meets with requirements of sustainable chemistry. The aim of this review is to highlight the interactive effect of the combined use of MCRs and CAN for the development of new ecofavorable methodologies for synthetic organic chemistry. There are many advantages to the use of CAN as a catalyst in organic synthesis, including the very small amount of this catalyst needed to complete reactions in most cases, lower costs, ecofriendly nature, ease of handling, nontoxicity, and high reactivity. GRAPHICAL ABSTRACT

Silica-supported polyphosphoric acid (PPA-SiO2): An efficient and reusable heterogeneous catalyst for ecofriendly organic synthesis

ABSTRACT This review discusses the advances in the use of silica-supported polyphosphoric acid (PPA-SiO2) as a green and reusable heterogeneous catalyst in the preparation of various organic compounds and pharmaceutical intermediates. PPA-SiO2 could be recovered and reused several times without significant loss of their efficiency. In this review, we attempt to give an overview of the applications of PPA-SiO2 as a catalyst in condensation, cyclization, and addition reactions for the preparation of various organic compounds. GRAPHICAL ABSTRACT

MCM-41-anchored sulfonic acid (MCM-41-SO3H): An efficient heterogeneous catalyst for green organic synthesis

ABSTRACT MCM-41-anchored sulfonic acid (MCM-41-SO3H) used as a solid acid catalyst has been reported in recent years for various synthetic protocols. The superior advantage of MCM-41-SO3H is that it can be recovered and reused several times without loss of its efficiency. In this tutorial review, we attempt to give an overview of the use of MCM-41-SO3H as a solid and heterogeneous catalyst in the synthesis of various organic compounds that have industrial and pharmaceutical applications. GRAPHICAL ABSTRACT

Phenacyl Bromide: A Versatile Organic Intermediate for Synthesis of Heterocyclic Compounds

ABSTRACT Phenacyl bromides are used as a building blocks in synthetic organic chemistry, which serves as a key model for the development of various biologically important heterocyclic compounds and other industrially important scaffolds. This review covers recent synthetic advances in the preparation of heterocyclic compounds utilizing various phenacyl bromides. A wide range of five- and six-membered heterocyclic compounds as well as fused heterocyclic compounds were synthesized efficiently from the phenacyl bromide precursors through one-pot multicomponent reactions. GRAPHICAL ABSTRACT