Full text of DOI:10.1016/0040-4020(77)80033-1

854
A. BIA~?O el aL
A~, 2.',0 nm (Ig e = 4.1); IR {CHCI,): 2740 (C-H aid). 1725 (C=O
non conj.), 1665 (C=O conj.), 1635 (C=C coni.)cm
'
Enzymatic hydrolysis o/$. $ (100rag) was dissolved in H~O
(3 ml) and treated at 37" with ~-glucosidase (50 rag) (Fluka). After
12 h $ appeared completely transformed into a compound showing
the same chromatographic hehavlour of 6e. The solution was
extracted with EtOAc (5 x 30 ml) and the organic layer evaporated
in racuo, afforded a residue (~ rag) which, chromatographed on
(b
silica gel in EtOAc: MeOH = 95:5. gave pure
~ (15 rag).
NaBH, redaction o/4a: isoeucommiol 3.41= (100 rag). prepared
by ,8-gluco~idas¢ hydrolysis of 2,2 was dissolved in H:O (3 ml) and
treated with an excess of NaBH, ( -. 10 equiv). After 15 min the
reaction was interrupted bubbling CO: until ~pH 7 and the
solution adsorbed on decolorizing charcoal (I g). The suspension,
as a layer on a C~ch funnel, was washed with H:O and then
eluted with MeOH. The MeOH solution, contaimn8 3 as main
product (sdtca gel TI.C in water-sat BuOH and cellulose TI.C),
was evaporated in racuo affording
chtomatographed on cellulose powder (8 g) in water-sat BuOH.
gave pure (55 rag) as colourless viscous oil. Rt - 0.52 (green-
a residue (80rag) which,
,11
I.
~
3
grey): IR (KBr). 1655 (C=C) cm '; PMR (D:O): 8 5.80 is. H-5). 4.60
(d. H-I). 424 (s. CH~OH-4). 375 it. ~H_:OH. J 6.6 Hz). 371 (d.
.8. (hs. H-3).
"
CH2OH-3, J = 4.0 Hz. A~ part of an A.. × system),
2.3-1.7 (cm, H-2 and CHd. [a]D.~o'-_ - 1230 (MeOH. c = 07%);
(Found: C. 57.08; H, 8.74. Calc for Cd'/,,(),: C. 57.43; H. 859%).
Tetrabenzoate g. 3 (50 mg), dissolved in pyridine (0.5 ml), was
treated with a solution of pyridine: henzoyl chloride = 2:1 (0.5 ml)
for 1.5 h at room temp. After addition of H~O (I ml). the solution
was allowed to stand for 30 rain and then extracted with benzene.
The organic layer, successively washed with 2N H.,SO,, sat aq
NaHCO,. and H=O. appeared to contain only g (TLC in benzene:
Et20 = 8:2). The residue (150 rag) obtained after evaporation in
tacuo, chtomatographed on silica gel 115 g) in benzene: Et~O =
8: 2. afforded pure g (125 rag) as colourless vL~cous oil. (Found: C.
73.13; H. 5.44. Cole. for C,,H,O,: C, 73.50; H. 5.33%).
4
3
2
Fig. 2. Significant reg)ons of PMR spectra (D:O) of: "isoeucom-
miol 3, "trideuteroisoeucommiol le.
H-9 would be expected as well as C-3 racemisation, and is
not observed.
Besides periodic controls on the possible presenc~ of 3
in Eucommia ulmoides, research is in progress on the
obtaining of similar cyclopentenoid derivatives from
other iridoid aglycones.
Tetraacetate 9.3 (50 nag) was treated with pyridin¢ (0.3 ml) and
Ac20 (0.6 ml) for 2h at room temp After ~klition of M e O H (I ml)
the solution was allowed to stand for 20 rain, then evaporated to
ipve
a residue (60rag) which on TI.C (CHCh: Et=O=7:3)
appeared to be conslJtuted only by 9. This residue, chxoma-
tographcd on silica gel (6g) in CHCI,:Et~O = 8:2. gave pure 9
(50 nag) as colourless viscous oil. IR (CHCI,): 1735 (C=O}, 1655
(C=C)cm '. PMR (CDCI,): 8 5.82 fl~. H-5), 5 .~0 (bd, HAL 4.70
Silica gel (Merck, 140-230 mesh) used for column chroma-
tography was washed several times with hot water then dried and
activated at 120" for 12 h. Silica gel 60 F,~ (Merck) and cellulose F
(Merck) plates were used in TLC. Cellulo~e plates were eluted
with B u O H - M e O H - H 2 0 (7:1:3). I~ values were determined on
paper chromatograms (Schleicher and ~h011 Nr 2043 b Mgl)
eluted with B u O H - A c O H - H = O (63 : I0: 27). Visualization of spots
was achieved by spraying either with 2N H~SOo and heating for
2-3 rain at I00" (silica gel plates) or with a 0.7% soln of vanillin in
2% mcthanolic HCI and heating for 2-3 min at I00" (cellulose
plates and paper chromatograms). IR spectra were recorded on a
(bs. ('H~()Ac-4). 4.60--3.85 (o. CH:OAc-3). 4.14 It. ('H:OAc.
J = 6.6 Hz), 2.94 (bs. H-3). ' H-2),
"
, 7 - . . 3 (m, 2.1-1.7 (m, ~Hz).
Deuteroisoeucommiol 10. 4a (80 rag) was dissolved in D~O (3 ml)
and treated with an excess of NaBDo. The resulting mixture.
worked up as described for 3, gave pure le (45 mg) as colourless
viscous oil. (Found: C, 56.27; H, 10.16. Calc. for CoH,,D,f),: C,
56.53; H, 10.00%).
~
K S
'A. Bianco, C. lavarone and C. Trogolo, Tetrahedron hi, 4117
Perkin Elmer 257 and U V spectra on
a Perkin Elmer 137
{1974).
:A. Bianco,
Trogolo. Ibid. in press.
'J. Grimshaw and H. R. Juneja. ('hem. and Ind. 656 (1960).
"A. J. Birch and G. Subba Rao, In Adrances in Organic Chemi~t~"
(Edited by E C. Taylor), Vol. 8, p ~t9. Wiley-lnterscicnc¢, New
York (1972).
'A. Bianco. M. Guiso. C. [a,,arone. R. Marini-Bettolo and
Trogolo. Go::. Ckim. hal. 1(16. 7"~3 (1976).
spectrophotometers. Optical rotations were measured on a Galileo
instrument. PMR spectra were reipstered with a Perkin Elmer
R-'~2 (90 Mllz) instrument, using TMS a.s internal reference for the
spectra run in ('IX'I, while for those in D:O the HI'X) signal (,5
4.70 from TMS) was taken as internal reference and the TMS
signal as external reference. Spin decoupling experiments were
performed with the spin decoupler accessory of the Perkin Elmer
R-32 instrument using frequency sweep mode. Chemical shifts are
expressed in ,~ (ppm downfield from TMS) and J are quoted in Hz.
"(?MR spectra, determined at ~ MHz using a Varian CFT-20
Fourier-Transform Spectrometer. were referred to the dioxane
carbon signal and converted to ,5, values from TMS.
Acid hydrolysis o/5: dialdchyde (hl. $ (I00 nag) dissolved at 25*
in 2N HCI (3 ml) appeared after 40 rain completely transformed
into a less polar compound (TI.C in C H C h : M e O H = 95:5). The
solution was extracted with E t O A c (3 x 3Oral) and collected
extracts, neutralized with NaHCO, and evaporated/n racuo, gave
a residue (25 rag) which, chromatographed on silica gel (3g) in
EIOAc: MeOH - 95: 5, afforded amorphous pure 64 UV (MeOH),
M Guiso. C. iavatom~, P. Passacantilli and C.
C
"A. Bianco. M. Gui~. (" la,,arone and C. Trogolo, Ibid. 106.
725 (1976}.
"G. ('. Levy and G. 1.. Nelson, C'ar~on-13 Nuclear Magnetic
Resonance for Organic Chemists, Wiley-lnterscicnc¢, New York
(1972).
"G. Wolczunowicz. F G. Cocu and Th. Posternak. Heir. ('hun.
Acta 53. 2275 (1970): "F. (;. Cucu. G Wolczuno~icz. 1. Bors
and Th. Posternak. ibid. $3. 739 (1970).
°H. O. House, Modern Synthetic Reactions. 2nd Edn, p. 55.
Benjamin. New York (1972).