J.S. Calderón

Montafrusin, a new germacrolide from Montanoa frutescens

Abstract The investigation of Montanoa frutescens afforded a new sesquiterpene lactone of the germacrolide type, montafrusin, besides the known diterpenes kaurenic acid and its 15α-isovalerate.

Highly oxygenated flavonoids from Ageratum corymbosum

Abstract The investigation of Ageratum corymbosum resulted in the isolation of four new highly oxygenated flavonoids, and their structures established by spectroscopic and degradative evidence as 5,6,7,5′-tetramethoxy-3′,4′-methylenedioxyflavanone; 5,6,7,8,5′-pentamethoxy-3′,4′-methylenedioxyflavanone; 5,6,7,8,2′,4′,5′-heptamethoxy-flavone and 5,2′,4′-trihydroxy-6,7,8,5′-tetramethoxyflavone. The recently reported gardenin A monomethyl ether and 5′-methoxylucidin dimethyl ether (eupalestin) were also isolated.

Zoapatanolide A and B, two new heliangolides from Montanoa tomentosa☆

Abstract The re-investigation of Montanoa tomentosa afforded, in addition to known diterpenoids of the kaurene class, two new sesquiterpene lactones, zoapatanolide A and B, of the heliangolide type.

An unusual prenyl biflavanol from Tephrosia tepicana

Abstract The roots and aerial parts of Tephrosia tepicana afforded a prenyl biflavanol. The structure and stereochemistry were established by spectroscopic methods, some chemical transformations and confirmed by X-ray diffraction. Tepicanol A is the first biflavanol with a 4,4″biflavanyl ether group to be isolated from the genus Tephrosia.

TWO POLYMETHOXYFLAVONES FROM AGERATUM HOUSTONIANUM

Abstract Besides agecorynin C, eupalestin and lucidin dimethyl ether, two new highly oxygenated flavones were isolated from Ageratum houstonianum . Their structures were established by spectroscopic and degradative evidence as 5, 6, 7, 8, 2′, 3′, 4′, 5′-octamethoxyflavone and 5, 6, 7, 2′, 3′, 4′, 5′-heptamethoxyflavone.

Abietane and icetexane diterpenoids from Salvia ballotaeflora and Salvia axillaris

From the aereal parts of Salvia ballotaeflora three new icetexane diterpenoids were isolated besides anastomosine and conacytone. The structure of these compounds were established as 19-deoxyicetexone, 19-deoxyisoicetexone and 7,20-dihydroanastomosine by spectroscopic means. Cryptotanshinone was the sole diterpenoid isolated from both aerial parts and roots of S. axillaris.

A prenylated flavan from Tephrosia madrensis

Abstract 5,7-Dimethoxy-8-prenylflavan has been isolated and identified from aerial parts of Tephrosia madrensis .

Deltoidin A and B, two new germacrolides from Eupatorium deltoideum☆

Abstract Investigation of E. deltoideum provided two new germacrolide-type sesquiterpene lactones, deltoidin A and B, besides the known guaianolide ligustrin, and diterpenes and triterpenes.

Labdane diterpenes from brickellia veronicaefolia

Abstract The aerial parts of Brickellia veronicaefolia afforded two new labdane type diterpenes, the structures and stereochemistries of which were established by spectroscopic methods and chemical transformations.

Four flavonoids from Ageratum strictum

Abstract Four new flavonoids, three flavanones and one chalcone, were isolated from aerial parts of Ageratum strictum. Their structures were establised as 3′6′-dihydroxy-2′, 4′-dimethoxy- 3, 4-methylenedioxy-chalcone, 6-hydroxy-5,7-dimethoxy-3′,4′-methylenedioxyflavanone, 6-hydroxy- 5,7,3′,4′-tetramethoxyflavanone and 6,4′-dihydroxy-5,7,3′-trimethoxyflavanone on the basis of spectral data and chemical degradation.