New Triterpenes from Machaerocereus eruca

Abstract

Four triterpenes, three lupanes, and a germanicane were isolated from Machaerocereus eruca. The germanicane derivative (1) was determined to be 3β,19α-dihydroxygermanican-28-oic acid and named machaeroceric acid. The three new lupane derivatives were identified as 21-ketobetulinic acid (2), 16β-hydroxybetulinic acid (3), and 22β-hydroxystellatogenin (4), respectively, on the basis of their spectroscopic data.

Thiophenes, polyacetylenes and terpenes from the aerial parts of Eclipata prostrata

“…Compound 13 was obtained as a white amorphous powder, with the molecular formula C 36 (Table 4) 23 showed that they had the same olean-18-ene skeleton. The signals of C-3 and C-28 were observed at d C 89.3 and 175.8, respectively, which implied that compound 15 must be a bisdesmosidic triterpene saponin.…”

“…18 As part of an ongoing search for bioactive natural products from traditional folk medicine, the aerial parts of E. prostrata were investigated. Twentyfour compounds, including eight mono-, di-, and trithiophene derivatives (1-7), two polyacetylenic glucosides (8 and 9), and fifteen mono-, sesqui-, and triterpenoid glycosides (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24), were isolated from E. prostrata. Herein, we report the isolation and structural elucidation of one new bithiophenes (2), two new polyacetylenic glucosides (8 and 9), and six new terpenoid glycosides (10)(11)(12)(13)(14)(15) from E. prostrata.…”

“…HMBC correlation between d H 5.37 (H-1 00 ) and d C 83.7 (C-2 0 ) indicated Glc II was connected to C-2 0 of Glc I. Hence, the structure of 15 was identified as 3-O-b-D-glucopyranosyl-(1?2)-b-D-glucopyranosyl oleanlic-18-ene acid-28-O-b-Dglucopyranoside.Fifteen known compounds, including six thiophene derivatives (1 and 3-7) and nine terpenoid glycosides(16)(17)(18)(19)(20)(21)(22)(23)(24), were isolated and identified as 2-(penta-…”

Synthesis and cytotoxicity of allobetulin derivatives

“…Allobetulin (3β hydroxy 19β,28 epoxy 18α ole ane) (I) and its derivatives belong to the group of trit erpenoids of the germanican family, a very rare class of natural compounds [1,2]. Allobetulin and related compounds (e. g., 28 oxoallobetulon [3] and 3β ace toxy 18α oleanan 28,19β lactam [4]) can be synthe sized from widely occurring natural lupane triterpe noids (e.g., betulin) using the Wagner-Meerwein rearrangement in the presence of acids [5][6][7][8].…”

“…These are allobetulin derivatives: 3β О cinnamate (XI), 1 oxo 2 ene (XII), 5β methyl 25 nor 9 ene (XIII), (3R,5R) and (3S,5S) 1,2,4 trioxolanes (XIV) and (XV), 3α,5α epoxide (XVI), [3,2 d] [1,2,3]thiadiazole (XVII), 3 oxime (XVIII), and 3 semicarbazone (XIX).…”