Solvent Free Synthesis of Novel Mono- and Bis-Benzoxazines from Cashew Nut Shell Liquid Components

Cashew nut shell liquid (CNSL) is a largely available by-product of the cashew agro-industry. In this paper, the main constituents (cardanol, cardol and methylcardol) obtained after separation of the CNSL mixture have been used as starting material to prepare a variety of novel mono- and bis-benzoxazines via cyclization reactions with formaldehyde and aromatic amine derivatives under mild conditions. These model reactions were successfully extended to the cardanol and cardols mixture affording the one pot synthesis monoand bis-benzoxazines.