Paul M. Baker

Neolignans of Virola surinamensis

Abstract Elemicin, galbacin, veraguensin and two new neolignans, surinamensin and virolin, were isolated and characterized from the leaves of Virola surinamensis.

The major component of the trail pheromone of the leaf-cutting ant,Atta sexdens rubropilosa forel

The major component of the trail pheromone of the South American leaf-cutting ant,Atta sexdens rubropilosa Forel, is 3-ethyl-2,5-dimethylpyrazine (II). Methyl and ethyl phenylacetate and methyl 4-methylpyrrole-2-carboxylate (I), which is the major component of the trail pheromone ofA. texana (Buckley) andA. cephalotes (L.), were also identified and may be minor components. The pheromone is stored in the poison gland.Atta sexdens sexdens (L.) also responds strongly to the pyrazine, which in large amounts evokes a weak response fromA. texana, A. cephalotes, andAcromyrmex octospinosus (Reich). Foraging workers ofAtta sexdens rubropilosa did not preferentially pick up baits impregnated with the pyrazine. The pyrazine was puffed into the nests ofA. cephalotes, and a particular response called “milling” was noted.

Tetracyclic triterpenes of Barbacenia bicolor

Abstract The isolation of 3β,20(R)-dihydroxydammer-24-ene and 20(R)-hydroxydammar-24-en-3-one from Barbacenia bicolor Mart. is described.

Vellozone, a tetracyclic triterpene from Vellozia stipitata

Abstract The isolation of (20 R )-20-hydroxy-24-methylenedammar-3-one from Vellozia stipitata is described.