Metal-free propargylation/aza-annulation approach to substituted beta-carbolines and evaluation of their photophysical properties

Chada Raji Reddy (1) , Mounika Aila (2, 1) , Puppala Sathish (2, 1) , Madoori Mrinalini (2, 1) , Lingamallu Giribabu (2, 1) , Seelam Prasanthkumar (2, 1) , Rene Gree (3)

1 IICT - CSIR Indian Institute of Chemical Technology
2 CSIR - Council of Scientific and Industrial Research [India]
3 ISCR - Institut des Sciences Chimiques de Rennes

An efficient acid-catalyzed propargylation/aza-annulation sequence was developed under metal-free reaction conditions, thus leading to a one-pot synthesis of a variety of substituted beta-carbolines starting from propargylic alcohols and indole 2-carbonyls. This versatile strategy was further extended to the synthesis of 5-azaindoles and 5-azabenzothiazoles. Optical properties suggested that manipulation of electron donor and acceptor moieties on beta-carbolines has an impact on their ground and excited state electronic behavior. This leads to blue or green emission and should facilitate the development of organic light emitting diodes (OLEDs). Electrochemical and stability studies revealed that 4a-6 shows ease of redox activity and photostability during illumination.

Domains: Chemical Sciences

Chada Raji Reddy, Mounika Aila, Puppala Sathish, Madoori Mrinalini, Lingamallu Giribabu, et al.. Metal-free propargylation/aza-annulation approach to substituted beta-carbolines and evaluation of their photophysical properties. Organic & Biomolecular Chemistry, 2019, 17 (42), pp.9291-9304. ⟨10.1039/c9ob01959f⟩. ⟨hal-02391906⟩