Stemona alkaloids structural groups

Several other twofold cyclization strategies have been developed by Smith and coworkers, ultimately to obtain access to the cyclic framework of penitrem D with the correct stereochemistry [176]. Williams group has been interested in Stemona alkaloids, which are represented by approximately 50 structurally novel, polycyclic natu-... 

Stemona alkaloids. Root extracts of the medicinal plants Stemona japonica and S. tuberosa (Stemona-ceae) have been used in Chinese and Japanese folk medicine as insecticides, anthelmintics, and as drugs for the treatment of tuberculosis, bronchitis and pertussis. Responsible for the activities is a group of more than 20 polycyclic alkaloids with diverse structures, e.g. protostemonine CjsHsiNOj, Mr 417.50, mp. 172-173 °C, [alD +148° (CH3OH) and stemofoline. 

Xu and coworkers have previously suggested that the Stemona alkaloids can be separated into eight structural groups according to the sites of connection between the... 

The stemofoline group comprises some of the structurally more complex representatives of the Stemona alkaloids, and currently ten alkaloids have been described stemofoline (48) 17,22,53,54), oxystemofoline (49) (77), methoxystemofline (50) (77), 2 -hydroxystemofoline (51) 22,36), 16,17-didehydro-16( )-stemofoline (52) 22,54), also named as didehydrostemofoline, l, 2 -didehydrostemofoline or asparagamine A (5,55),... 

The first total synthesis of stemospironine (30), a structurally complex Stemona alkaloid, was accomplished by Williams and coworkers (75) (Scheme 18), using the same strategy successfully applied by the same group for the total synthesis of croomine and... 

The second chapter is on a group of alkaloids, the Stemona, which, considering its overall size, possesses a remarkable number of complex alkaloid skeleta. This area was last reviewed in 1967, and the tremendous changes in this field are presented by Pilli, Rosso, and de Oliveira, from the perspectives of their isolation, structure determination, and biological activity. 

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