Novel synthesis and biological activity of 2‐substituted derivatives of 3‐cyano‐4‐imino‐2‐methylthio‐8‐methoxy‐4H‐pyrimido[2,1‐b][1,3]benzothiazole and 3‐amino‐4‐imino‐8‐methoxy‐2H‐pyrazolo[3′,4′:4,5]pyrimido[2,1‐b][1,3]benzothiazole

Abstract

2‐Amino‐6‐methoxybenzothiazole 1 on reaction with bis(methylthio)methylene malononitrile 2 in the presence of dimethyl formamide and catalytic amount of anhydrous potassium carbonate afforded 3‐cyano‐4‐imino‐8‐methoxy‐4H‐pyrimido[2,1‐b][1,3]benzothiazole 3. Under similar experimental conditions, compound 3 on treatment independently with arylamines/heterylamines/phenols/compounds containing active methylene group yielded corresponding 2‐substituted derivatives of compound 3 (4a, 4b, 4c, 4d, 5a, 5b, 5c, 6a, 6b, 6c, 6d, 6e, and 7a, 7b, 7c, 7d, 7e). Similarly, novel heterocyclic compounds, 3‐amino‐4‐imino‐8‐methoxy‐2H 8a/aryl 8b–c/heteryl 8d, 8e, 8f/pyrazolo[3′,4′:4,5]pyrimido[2,1‐b][1,3]benzothiazoles, were prepared by heating compound 3 independently with hydrazine hydrate/arylhydrazines/heterylhydrazines, respectively. All these newly synthesized compounds were screened for antimicrobial activity. J. Heterocyclic Chem., (2011).

Importance of Fluorine in Benzazole Compounds

“…Moreover, the benzothiazole core is a widespread scaffold that has been extensively studied [ 54 , 55 , 56 , 57 , 58 , 59 ] and many derivatives are found to be antimicrobial [ 49 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 ], anticancer [ 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 ], anti-Alzheimer’s [ 92 , 93 ], anti-inflammatory [ 94 , 95 , 96 ], anti-HIV [ 97 , 98 , 99 ] anticonvulsant [ 100 , 101 , 102 ], antioxidant [ 39 , 103 ], anti-tuberculosis [ 104 ...…”

Cu(II)‐supported graphene quantum dots modified NiFe2O4: A green and efficient catalyst for the synthesis of 4H‐pyrimido[2,1‐b]benzothiazoles in water

“…[ 9 ] Among fused benzothiazoles, pyrimido[2,1‐b]benzothiazoles have fascinated significant attention due to their effective pharmaceutical actions. An overview of the literature indicated that pyrimido[2,1‐b]benzothiazoles show several biological operations such as anti‐tumoral agents, [ 10 ] anti‐allergic, [ 11 ] antimicrobial, [ 12 ] and anticonvulsant. [ 13 ] Given the significance of pyrimido[2,1‐b]benzothiazoles, the advancement of efficient policies for the synthesis of these condensed heterocycles will be noteworthy in both medicinal and organic chemistry.…”