Visible-light-promoted photocatalyst-free alkylation and acylation of benzothiazoles
Herein we report a protocol for the visible-light-mediated alkylation/acylation reaction of benzothiazoles. Alkyl/acyl substituted Hantzsch esters are easily prepared and rationally used as radical precursors. In the presence of BF3·Et2O and Na2S2O8, various benzothiazole derivatives were readily obtained in good yields. Our user-friendly protocol can proceed by simple irradiation with blue LEDs (λ = 465 nm) and without the assistance of external photocatalysts. The reaction is also characterized by mild conditions and scalability, thus offering an alternative and efficient tool for the synthesis of 2-functionalized benzothiazoles.
Visible Light-Induced Decarboxylative Alkylation of Heterocyclic Aromatics with Carboxylic Acids via Anthocyanin as a Photocatalyst
A visible light-induced decarboxylative alkylation of heterocyclic aromatics with aliphatic carboxylic acids was developed by using anthocyanins as a photocatalyst under mild conditions. A series of alkylated heterocyclic compounds were obtained in modera
Iron-catalyzed C-H alkylation of heterocyclic C-H bonds
An efficient, iron-catalyzed C-H alkylation of benzothiazoles by using alkyl diacyl peroxides and alkyl tertbutyl peresters which are readily accessible from carboxylic acids to synthesize 2-alkylbenzothiazoles is developed. This reaction is environmentally benign and compatible with a broad range of functional groups. Various primary, secondary, and tertiary alkyl groups can be efficiently incorporated into diverse benzothiazoles. The effectiveness of this method is illustrated by late-stage functionalization of biologically active heterocycles.
Babu, Kaki Raveendra,Zhu, Nengbo,Bao, Hongli
p. 46 - 49
(2017/11/28)
Silver catalyzed decarboxylative direct C2-alkylation of benzothiazoles with carboxylic acids
A novel and efficient silver catalyzed decarboxylative direct C2-alkylation of benzothiazoles with carboxylic acids for the synthesis of 2-alkyl benzothiazoles was developed.
Solvent-free synthesis of 2-aryl and 2-alkylbenzothiazoles on silica gel under microwave irradiation
2-Substituted benzothiazoles have been synthesized by the condensation of o-aminothiophenol and aromatic or aliphatic aldehydes in the presence of silica gel under microwave irradiation (MW) and solvent-free conditions. The silica gel can be easily recovered and reused for subsequent reactions without loss of the activity.
Kodomari, Mitsuo,Tamaru, Yoshimi,Aoyama, Tadashi
p. 3029 - 3036
(2007/10/03)
ALLENES-41. THE ADDITION OF THIOLS TO ALLENYL- AND PHENYLPROPYNYLNITRILE AND THE FORMATION OF THIAZOLINES AND BENZOTHIAZOLES
Thiols add to allenylnitriles to give unconjugated nitriles which may be isomerised to conjugated enesulphide nitriles either at high temperature (200o) or with base.Phenylpropynenitrile gives conjugated adducts directly.Heating the conjugated adducts from aminoethanethiols at >200o results in 5-exotrig ring closure and elimination of acetonitrile to give thiazolines and benzothiazoles.
Landor, Stephen R.,Landor, Phyllis D.,Fomum, Z. Tanee,Mbafor, J. Tanyi,Mpango, George W. B.
p. 2141 - 2149
(2007/10/02)
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