The invention relates to small, conjugatable, orthogonal and tunable fluorophores for imaging of small bioactive molecules. The invention further relates to processes for the preparation of the compounds, and uses of the compounds in therapeutic, diagnostic, surgery and analytical applications. The invention provides a compound of formula (I), a derivative or a salt thereof. Wherein X is selected from the group consisting of NH, O, S, SeR5R6, CR7R8; R1 is selected from the group consisting of amines, alcohols, thiols, thiophenols, selenols, selenophenols and aryl groups; R2 and R3 are independently H or a halogen; R4 tis either H, nitro or cyano; R5 is either absent or methyl or oxygen; R6 is either absent or methyl or oxygen; and R7 and R8 are independently selected from the group consisting of linear or cyclic alkyl groups containing halogen, amino, cyano or carboxylic ester substituents, and alkyl aryl groups. ##STR00001##

The present invention provides covalent fluorescent probes for cannabinoid receptor 2 (CB2) having the general formula (I)

##STR00001##

wherein X, n, p, and R.sup.1 to R.sup.4 are as described herein, compositions including the compounds, processes of manufacturing the compounds and methods of using the compounds.

The present invention provides covalent fluorescent probes for cannabinoid receptor 2 (CB2) having the general formula (I)

##STR00001##

wherein X, n, p, and R.sup.1 to R.sup.4 are as described herein, compositions including the compounds, processes of manufacturing the compounds and methods of using the compounds.

The present invention discloses the synthetic methods and the corresponding applications of a benzothiaselenazole-1-oxide compound and derivatives thereof, in which with sulfoximine and elemental selenium as starting materials, a series of benzothiaselenazole-1-oxide compounds has been synthesized through rhodium-catalyzed direct CH functionalization reaction. Furthermore, with sulfoximine and elemental selenium as starting materials, a chiral benzothiaselenazole-1-oxide compound is synthesized through direct CH functionalization reaction by virtue of a chiral phosphoric acid ligand. The present invention can allow specific labeling of sulfydryl structures in polypeptides, carbohydrates, drug molecules, and proteins, as well as in proteins and other biomacromolecules, exhibiting good anti-SARS-CoV-2 activity; and a bioconjugate with trastuzumab according to the present invention can effectively image HER.sup.2 receptors on the cell surface and show intense fluorescence, and is applicable to the preparation of an imaging reagent for the HER.sup.2 receptors on the cell surface.

The present invention discloses the synthetic methods and the corresponding applications of a benzothiaselenazole-1-oxide compound and derivatives thereof, in which with sulfoximine and elemental selenium as starting materials, a series of benzothiaselenazole-1-oxide compounds has been synthesized through rhodium-catalyzed direct CH functionalization reaction. Furthermore, with sulfoximine and elemental selenium as starting materials, a chiral benzothiaselenazole-1-oxide compound is synthesized through direct CH functionalization reaction by virtue of a chiral phosphoric acid ligand. The present invention can allow specific labeling of sulfydryl structures in polypeptides, carbohydrates, drug molecules, and proteins, as well as in proteins and other biomacromolecules, exhibiting good anti-SARS-CoV-2 activity; and a bioconjugate with trastuzumab according to the present invention can effectively image HER.sup.2 receptors on the cell surface and show intense fluorescence, and is applicable to the preparation of an imaging reagent for the HER.sup.2 receptors on the cell surface.