Recent Advances in the Application of 2-Aminobenzothiazole to the Multicomponent Synthesis of Heterocycles

Abstract

Heterocycles are a vital class of compounds in numerous fields, including drug discovery, agriculture, and materials science. Efficient methods for the synthesis of heterocycles remain critical for meeting the demands of these industries. Recent advances in multicomponent reactions (MCRs) utilizing 2-aminobenzothiazole (ABT) have shown promising results for the formation of heterocycles. The versatility of 2-aminobenzothiazole in this context has enabled the rapid and efficient construction of diverse heterocyclic structures. Various synthetic methodologies and reactions involving 2-aminobenzothiazole are discussed, highlighting its importance as a valuable building block in the synthesis of complex heterocycles. The potential applications of these heterocycles in drug discovery and material science are also explored. Overall, this review provides a comprehensive overview of the current state of research in the field and offers insights into the future directions of this promising area of study. We highlight the potential of ABT as a versatile and sustainable starting material in heterocyclic synthesis via MCRs, with significant implications for the chemical industry.

Keywords: 2-aminobenzothiazole; heterocycles; multicomponent reactions; synthesis.

Figure 1

Structure of 2‐aminobenzothiazole.

Figure 2

2‐Aminobenzothiazoles containing bioactive molecules.

Figure 3

Reactions of 2‐aminobenzothiazole.

Figure 4

Synthesis of 2‐aminobenzothiazole.

Scheme 1

Synthesis of 13‐aryl‐13H‐benzo[g]benzothiazolo [2,3‐b]quinazoline‐5,14‐diones.

Scheme 2

Synthesis of tetrahydrobenzo[g]benzo[4,5]thiazolo[2,3‐b]quinazolin‐14‐ium hydroxides.

Scheme 3

Synthesis of various pyrimidine derivatives.

Scheme 4

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazole derivatives.

Scheme 5

A proposed mechanism for preparation of 4H‐pyrimido[2,1‐b]benzothiazole derivatives.

Scheme 6

Synthetic procedure for 4H‐benzo[4,5]thiazolo[3,2‐a]pyrimidine‐3‐carboxylates.

Scheme 7

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles derivatives.

Scheme 8

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazole derivatives.

Scheme 9

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles.

Scheme 10

Synthesis of tricyclic 4H‐pyrimido[2,1‐b]benzothiazoles derivatives.

Scheme 11

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles.

Scheme 12

Synthesis of pyrimido[2,1‐b][1,3]benzothiazole (PBT) scaffolds.

Scheme 13

Synthesis of pyrimidine derivatives.

Scheme 14

Synthesis of pyrimido[1,2‐b]benzazole derivatives.

Scheme 15

Suggested mechanism for the model reaction.

Scheme 16

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazole derivatives.

Scheme 17

Synthesis of benzothiazolo quinazolinones.

Scheme 18

Synthesis of tetraheterocyclicbenzothiazolo quinazolin‐1‐ones.

Scheme 19

Synthesis of tetrahydro‐1H‐benzo[4,5]thiazolo [2,3‐b]quinazolin‐1‐one.

Scheme 20

Synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles.

Scheme 21

Synthesis of quinazoline analogs.

Scheme 22

Synthesis of thiazolo[3,2‐a]pyrimidine.

Scheme 23

Synthesis of 2,3‐dihydroquinazolin‐4(1H)‐one derivatives and benzothiazolo[2,3‐b]quinazolin‐1‐one derivatives.

Scheme 24

Synthesis of mono‐ and bis‐4H‐pyrimido[2,1‐b]benzothiazoles.

Scheme 25

Synthesis of pyrimido[4,5‐d]pyrimidine derivatives.

Scheme 26

Synthesis of benzo[4,5]thiazolo[3,2‐a]chromeno[4,3‐d]pyrimidin‐6‐one derivatives.

Scheme 27

Synthesis of fused pyrimidine derivatives.

Scheme 28

Synthesis of N‐methyl‐3‐nitro‐4H‐pyrimido[2,1‐b] benzothiazole‐2‐amine derivatives.

Scheme 29

Synthesis of 3‐benzothiazol‐2‐yl‐2‐phenyl‐thiazolidin‐4‐one.

Scheme 30

Plausible mechanistic pathway of reaction.

Scheme 31

Synthesis of N,1‐bis(benzo[d]thiazol‐2‐yl)‐6‐hydroxy‐2,4‐diaryl‐1,4‐dihydropyridine‐3‐carboxamides.

Scheme 32

Synthesis of (benzo[d]imidazo[2,1‐b]thiazol‐3‐yl)‐2H‐chromen‐2‐one derivatives.

Scheme 33

Synthesis of benzo[d]imidazo[2,1‐b]thiazoles.

Scheme 34

Synthesis of 2‐(1H‐indol‐3‐yl)‐N‐(phenyl)imidazo[2,1‐b][1,3]benzothiazol‐3‐amine derivatives.

Scheme 35

Synthesis of tricyclic fused imidazoles.

Scheme 36

Synthesis of benzo[d]imidazo[2,1‐b]thiazoles.

Scheme 37

Plausible one‐pot GBBR/S_NAr/ring‐chain azido‐tautomerization mechanism.

Scheme 38

Synthesis of a new series of benzo[d]imidazo[2,1‐b]thiazole‐1‐ium hydroxides.

Scheme 39

Synthesis of 2‐arylbenzo[d]imidazo[2,1‐b]thiazoles.

Scheme 40

Synthesis of benzo[d]imidazo[2,1‐b]thiazole derivatives.

Scheme 41

Synthesis of imidazo[2,1‐b]benzothiazoles.

Scheme 42

Synthesis of benzo[d]imidazo[2,1‐b]thiazol‐2‐yl)‐2,3‐dihydropyrimidin‐4(1H)‐ones.

Scheme 43

Synthesis of 2′‐aminobenzothiazolomethylnaphthol derivatives.

Scheme 44

Synthesis of 1‐(benzothiazolylamino)methyl‐2‐naphthol derivatives.

Scheme 45

Synthesis of 1‐(benzothiazolylamino)phenylmethyl‐2‐naphthol derivatives.

Scheme 46

Proposed mechanism for the synthesis of 1‐(benzothiazolylamino) phenylmethyl‐2‐naphthols.

Scheme 47

Different methods for the synthesis of 1‐(benzothiazolylamino)phenylmethyl‐2‐naphthol derivatives.

Scheme 48

Synthesis of spiroheterocycles.

Scheme 49

Plausible mechanism for the synthesis of spiroheterocycles.

Scheme 50

synthesis of spirooxindoles.

Scheme 51

Synthesis of novel bis‐thiazole derivatives.

Scheme 52

Synthesis of 2‐pyrrolidinone derivatives.

Scheme 53

The proposed mechanism for the synthesis of polyfunctionalized 2‐pyrrolidinones.

Scheme 54

Synthesis of 3‐(benzo[d]thiazol‐2‐yl)‐2‐alkyl‐4(3H)‐quinazolinones.