Zur Kenntnis der Triterpene. (90. Mitteilung). Über ein Oxydationsprodukt C₃₂H₄₆O₅ aus Acetyl‐β‐amyrin und zwei isomere Oxydationsprodukte C₃₃H₄₆O₇ aus Acetyl‐oleanolsäuremethylester und Acetyl‐glycyrrhetinsäure‐methylester

First Occurrence of a Furano‐glycyrrhetinoate and Its Cytotoxicity

“…Interestingly, while from the reaction of (18β)‐ 3 with SeO 2 in glacial acetic acid lactone 13 (Scheme ) was obtained , the reaction of (18α)‐ 6 with SeO 2 in glacial acetic acid at 145°C for 24 h also yielded 13 but as a by‐product lactone 14 was formed in 11% yield. The reaction of (18β)‐configurated 3 with SeO 2 in pyridine (microwave assisted, 6 h, 160°C) afforded furane 15 in 52% yield, whereas from the reaction of 3 with SeO 2 in glacial acetic acid (120°C, 24 h) selenophene 16 was obtained as the main product.…”

“…285–289°C (lit. : 285–286°C, 288–290°C ); [α] D = +2.99° ( c = 0.5 CHCl 3 ) (lit. : 2.4° ( c = 3.5, CHCl 3 )); R f = 0.52 (silica gel, toluene/ethyl acetate/heptane/formic acid, 80:20:30:4); IR (KBr): ν = 3449br, 3024w, 2970m, 2948m, 1778s, 1736s, 1690w, 1449m, 1382m, 1369m, 1248s, 1218m, 1197m, 1153m, 1081m, 1109m, 1081m, 1058m, 1024m, 1010m, 980m cm −1 ; UV‐vis (CHCl 3 ): λ max (log ϵ) = 232 (2.22) nm; 1 H NMR (400 MHz, CDCl 3 ): δ = 4.55 ( dd , J = 9.2, 7.4 Hz, H‐3), 3.72 ( s , 3H, H‐31), 3.08 ( s , 1H, H‐9), 2.33 ( ddd , J = 13.9, 13.9, 3.3 Hz, 1H, H‐21a), 2.07 ( ddd , J = 14.0, 7.0, 3.5 Hz, 1H, H‐1a), 2.04 ( s , 3H, H‐33), 1.87 ( ddd , J = 15.0, 14.9, 3.6 Hz, 1H, H‐16a), 1.76 ( ddd , J = 13.9, 6.6, 3.3 Hz, 1H, H‐21b), 1.76–1.65 ( m , 4H, H‐15a + H‐6a + H‐2), 1.63–1.53 ( m , 4H, H‐7 + H‐22a + H‐6b), 1.47 ( ddd , J = 13.6, 6.9, 3.4 Hz, 1H, H‐22b), 1.42 ( s , 3H, H‐29), 1.45–1.38 ( m , 1H, H‐16b), 1.32–1.18 ( m , 2H, H‐15b + H‐1b), 1.18 ( s , 3H, H‐26), 1.16 ( s , 6H, H‐25 + H‐28), 1.11 ( s , 3H, H‐27), 0.96–0.90 ( m , 1H, H‐5), 0.88 ( s , 6H, H‐23 + H‐24) ppm; 13 C NMR (100 MHz, CDCl 3 ): δ = 203.9 (C‐11), 174.7 (C‐30), 174.4 (C‐12), 170.9 (C‐32), 151.5 (C‐19), 119.2 (C‐18), 80.5 (C‐3), 67.8 (C‐13), 65.6 (C‐9), 55.3 (C‐5), 52.9 (C‐31), 48.5 (C‐14), 43.4 (C‐20), 42.4 (C‐8), 37.9 (C‐4), 36.8 (C‐1), 36.6 (C‐16), 35.8 (C‐10), 35.3 (C‐22), 34.1 (C‐7), 32.8 (C‐15), 31.4 (C‐21), 30.8 (C‐17), 28.2 (C‐23), 26.9 (C‐28), 26.8 (C‐27), 23.4 (C‐26), 23.3 (C‐2), 21.4 (C‐33), 21.3 (C‐29), 18.9 (C‐6), 17.3 (C‐25), 16.5 (C‐24) ppm; ESI‐MS (MeOH): m/z = 555.3 (22%, [M+H] + ).…”

(+)-Methyl 3β-acetoxy-13-carboxy-19-hydroxy-11-oxo-C-norolean-18-en-30-oate γ-lactone

“…In context with corresponding research (Classen-Houben et al, 2009;Beseda et al, 2010;Amer et al, 2010) we came across the title compound, (I), which was of interest because it is an unusual derivative of glycyrrhetinic acid. Obtained initially by the Nobel laureate Ruzicka and his group (Jeger et al, 1944), it was later on synthesized from methyl glycyrrhetate acetate, C 33 H 50 O 5 , in a one-step reaction by oxydation with SeO 2 under introduction of two more oxygen atoms, elimination of four hydrogen atoms, rearrangement of one ring, and generation of an additional unsaturated γlactone ring (Brownlie & Spring, 1956). The assignment of a structural formula to this compound was as yet based on combustion analysis, derivatizations, chemical tests for funtional groups and stereochemical considerations but not on present day methods like NMR spectroscopy.…”