Biomimetic Dimerisation

On refluxing murrayafoline A (12) and girinimbine (3) in aqueous methanol solution fot 48 hours in the presence of Nafion 117, Furukawa et al obtained three dimeric products (157,157A, 158) 44). 

Chakrabarti and Chakraborty 16) have reported the Bp3-Etherate catalysed synthesis of biscarbazoles (158,162,163) starting with girinim-bine (3) and its derivatives (159-160). Mechanistically the dimer formation has been envisaged as proceeding through the adduct (161). 

Mahanimbine (10) on heating at 200°C in a sealed tube for a short time is transformed to dl-mahanimbine first and then to murrayazoline (164) and murrayazolidine (165). On further heating for 3 hrs more only dl-murrayazolidine is obtained 87). 

On passing mahanimbine (10) over a column of Dowex 50 x 8 (H ) resin dl-murrayazolidine (165) is obtained (5). 

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