Jolantidine — A new base fromMerendera jolantae

Abstract

By the chromatographic separation on a column of alumina of the mixture of bases from the epigeal parts of Merendera jolantae Czerniak, collected in the fruit-bearing period (March, ]976), we have isolated fractions of eluates from acetone and acetone-methanol (95:5 and 90:10). The fraction contained two identical compounds differing in their physicochemical constants from known tetrahydroisoquinoline alkaloids of colchicine-containing species of plants [1-4]. The first of these bases, which has been called jolantidine (I), had the composition C18H2304N, M + 317, mp 275-277°C (acetone), [a] D +102 ° (c0.4; methanol). The second base (II), with the composition C19H2704N, had mp 201-202°C (acetone-methanol) and [a] D +i0 ° (c 0.3; methanol). The structure of (I) has been established. The UV spectrum of (I) has absorption maxima at 216 and 290 nm and the IR spectrum absorption bands of the C==C bonds of a benzene ring (1600 cm-Z), of active hydrogens (3580, 3360 cm-1), and of methylene groups (1470-1440 cm-Z). In the PMR spectrum of (I) there are the signals of one aromatic proton (6.50 ppm) and the protons of a methoxy group (3.86 ppm). Under the action of acetyl chloride, (I) formed a O,O,N-triacetyl derivative (III) the IR spectrum of which showed absorption bands at 1750, 1745, and 1645 cm-z The hydrolysis of (III) led to the N-monoacetyl derivative (IV) (IR spectrum: 1645 cm-Z). These transformations showed the presence in the molecule of (I) of two hydroxy groups and an imine group. Confirmation of this was provided by the following transformations: Under the action of methyl iodide in the presence of potassium acetate, a methiodide (V) was formed, the PMR spectrum (in CFsCOOH) of which showed the signals of the protons of two N-methyl groups (2.95; 2.55 ppm) of a methoxy group (3.54 ppm), and of an aromatic proton (6.38 ppm). In the PMR spectrum of acetylated (V)-(VI)-the signals appeared of the protons of two O-acetyl groups (6 H, s, 2.00 ppm) of 2 N-methyl groups (3.62, 3.00 ppm), of a methoxy group (3.85 ppm), of an aromatic proton (6.58 ppm), and of a tertiary proton geminal to an acetoxy group (5.10 ppm). According to the half-width of its signal (J = 6 Hz), the last-mentioned proton has the equatorial orientation. The IR spectrum of (VI) contains absorption bands at 1750 and 1740 cm-I On the basis of the facts given above, structure (I) was proposed for jolantidine, and this has been confirmed by the identity of its methiodide (V) with the methiodide of regelamine [2] and the identity of their acetyl derivatives (VI).

Enantioselective Total Syntheses of Pentacyclic Homoproaporphine Alkaloids

“…Our retrosynthetic analysis is depicted in Scheme . Several members of the pentacyclic homoproaporphines such as (+)-regeline ( 1 ), (+)-jolantidine ( 5 ), and (+)-regelinine ( 6 ) could share the same intermediate, N -benzyloxycarbonyl (+)-jolantidine ( 9 ), in which the hydroxyl-lactol moiety of the D-ring could be realized through sequential Baeyer–Villiger oxidation of the C11–C12 bond of the ketone intermediate 10 and SmI 2 -mediated aldehyde–ester pinacol-type cyclization . With the use of a Suzuki coupling reaction to introduce a 2-aminoethyl moiety at the phenyl ring, followed by a Wittig reaction and a Pictet–Spengler cyclization, the fused C and B rings would be achieved from an enone intermediate 11 , delivering the ketone intermediate 10 .…”

“…Direct removal of the N -benzyloxycarbonyl group of (−)- 9 by Pd/C-catalyzed hydrogenation provided (+)-jolantidine ( 5 ) [[α] 25 D = +90.5 ( c 0.4, MeOH) (lit . = +102 ( c 0.4, MeOH))] in 73% yield.…”