An aerobic visible-light driven photoredox catalytic formation of 2-substitutedbenzothiazoles through radical cyclization of thioanilides has been accomplished. The reaction features C–H functionalization and C–S bond formation with no direct metal involvement except the sensitizer. The reaction highlights the following: (1) visible-light is the reaction driving force; (2) molecular oxygen is the
Riboflavin as Photoredox Catalyst in the Cyclization of Thiobenzanilides: Synthesis of 2-Substituted Benzothiazoles
作者:Lydia M. Bouchet、Adrián A. Heredia、Juan E. Argüello、Luciana C. Schmidt
DOI:10.1021/acs.orglett.9b04384
日期:2020.1.17
Benzothiazoles are synthesized from thiobenzanilides using riboflavin as a photosensitizer and potassium peroxydisulfate as a sacrificial oxidizing agent under visible light irradiation. The methodology accepts a broad range of functional groups and affords the 2-substitutedbenzothiazoles by transition-metal-free organic photoredoxcatalysis under very mild conditions.
One-Pot Preparation of 2-(Alkyl)arylbenzothiazoles from the Corresponding <i>o</i>-Halobenzanilides
作者:Dan Bernardi、Gilbert Kirsch、Lalla Ba
DOI:10.1055/s-2007-984544
日期:——
: Thionation of o-halobenzanilides was carried out in the presence of Lawesson's reagent. Subsequently, the formed thio-amides reacted with cesium carbonate to give the corresponding benzothiazole derivatives in the same pot.
Intramolecular aromatic substitution (SRN1) reactions; use of entrainment for the preparation of benzothiazoles
作者:W.Russell Bowman、Harry Heaney、Philip H.G. Smith
DOI:10.1016/s0040-4039(00)85581-1
日期:1982.1
The process of entrainment (catalytic chain initiation) with the enolate-anion of acetone has been used in intramolecular aromaticSRN1 subsitution for the preparation of 2-phenyl- and 2-methyl-1,3-benzothiazole in high yield from o-iodothiobenzanilide and o-iodothioacetanilide.
The present invention relates to compounds of formula (I)
1
wherein R
1
, R
2
, R
3
, R
4
, R
5
, R
6
and R
7
are as defined in the description and claims, and pharmaceutically acceptable salts thereof. The compounds are useful for the treatment and/or prophylaxis of diseases which are associated with the modulation of CB1 receptors.