S. Kh. Zakirov

Alkaloids from Annona muricata leaves

We studied the alkaloid composition of Annona muricata L. (Annonaceae) leaves collected in February 2009 in Conakry Botanical Garden (Republic of Guinea). Ordinary CHCl3 extraction afforded total alkaloids (0.125%) that were separated into phenolic and nonphenolic parts. Column chromatography over silica gel of the nonphenolic fraction isolated three bases; of the phenolic fraction, one. Spectral data, physical constants of the alkaloids and their salts, chemical transformation, and comparison with authentic samples identified the pure alkaloids. Base 1, C17H15NO2, mp 120–122°C, mass spectrum (m/z): 265 [M] +, 264 [M – 1]+ (100), 250, 236, 235; identified as anonaine [1, 2]. Base 2, isolated as the hydrochloride, C19H19NO3·HCl, mp 244–246°C, identified as isolaureline [3, 4]. Base 3, C18H17NO3, mp 124–126°C (acetone), UV spectrum ( max, EtOH): 219, 282 (log 4.49, 4.25), spectrum similar to that of isolaureline. The mass spectrum of 3 had peaks for ions (m/z) 295 [M]+, 294 [M – 1]+, 280 [M – 15]+, 266 [M – 29]+, and 147.5 [M]++ that were characteristic of noraporphine alkaloids. A comparison of spectral data of 3 and 2 in addition to the difference in the molecular weights by 14 mass units suggested that 3 was norisolaureline. In fact, Hess methylation of 3 produced a base that was identical to 2. According to these results, 3 was identified as xylopine [2, 5]. Base 4, C17H19NO3, phenolic crystalline base, mp 218–220°C (acetone), identified as coclaurine [6, 7]. Thus, we studied the alkaloid composition of Annona muricata leaves and isolated for the first time and identified the aporphine alkaloids anonaine, isolaureline, and xylopine and the benzyltetrahydroisoquinoline alkaloid coclaurine, which was isolated previously from this plant [7].

Sesquiterpene lactones fromJurinea maxima

The IR spectrum of (I) (tablets with KBr) shows absorption bands at 3250 and 3565 cm -~ (OH groups), 1745 cm -I (carbonyl of a y-lactone), and 1650 cm -~ (C=C bond). In the IR spectrum of (II) there are absorption bands at 3250 and 3500 cm-* (OH groups), 1760 cm -~ (carbonyl of a y-lactone) and 1670 cm -I (C=C bond). The results obtained showed that the compounds under consideration were unsaturated dihydroxy lactones.

A new melampolide and other secondary metabolites from Artemisia baldshuanica

The composition of secondary metabolites in benzene and alcohol extracts of the epigeal part of Artemisia baldshuanica Krasch. et Zarp. (Asteraceae) collected during the vegetative phase was investigated. A new melampolide, the structure of which was established based on spectral data and an x-ray crystal structure analysis, and known compounds were isolated.

Sesquiterpene lactones of two species of Artemisia

The epigeal part of A. absinthium gathered in Tashkent province was extracted with ethanol. The concentrated extract was purified with 35% aqueous ethanol. The precipitate that deposited was separated off and the compounds to be investigated were extracted from the filtrate with ethyl acetate. When the ethyl acetate extract was chromatographed on a column of KSK silica gel, two crystalline substances were isolated. Substance (I), isolated from benzene fractions, had the composition CI~H1804, mp 230-232°C (benzene-etherS, M + 262. The IN spectrum of (I) had absorption bands at (cm -I) 1770 (~-lactone carbonyl), 1675 (~,~-unsaturated ketone), 1630 and 1620 (double bonds), and 3360 (hydroxy group).

Canin and chrysartemin B fromArtemesia aschurbajevii

We have continued a study of the sesquiterpene lactones of Artemesia aschurbajevii C. Winkl. collected in July at Chon-Kemin, KirgSSR [i]. The epigeal part of the plant was exhaustively extracted with chloroform. The extract was evaporated and the residue was dissolved in 60% aqueous ethanol. The aqueous ethanolic solution was extracted successively with petroleum ether and chloroform. The resin obtained after the evaporation of the chloroform was dissolved in a small amount of ethanol and the solution was diluted with water to form a 30% solution. The precipitate that deposited was filtered off and the resin obtained after the evaporation of the filtrate was separated on a column of silica gel with sucessive elution by benzene and by mixtures of benzene with 2 and 5% of acetone.

11,13-Dihydroarteglasin A — A new guaianolide from Artemisia argyi

Continuing the chemical study of this plant, by additional chromatography on alumina of the benzene fractions obtained in the isolation of matricarin and hanphyllin [2], with elution of the column by hexane-benzene (i:i), a colorless crystalline compound (I) has been isolated with the composition CI~H==0 s, mp 165-166°C (hexane-acetone) M + 306. Its IR spectrum showed bands of the absorption of a ~-lactone carbonyl (1775 cm -l) and of the carbonyl of an ester group (1738 and 1242 cm-1). The mass spectrum contained, in addition to the peak of the molecular ion, peaks with m/z 264 (M-42) and 246 (M-60). These facts, and also the presence in the PMR spectrum of a three-proton singlet at 1.91 ppm and of a one-proton sextet of a gem-acyl proton with its center at 4.86 ppm, showed that the lactone molecule contained a characteristic group of signals relating to the basic lactone skeleton: a threeproton doublet at 1.26 ppm (>CH-CH 3, J = 6 Hz), two three-proton singlets at 1.55 ppm (CH3C--O), and 1.65 ppm (CH3--C=C), a one-proton doublet at 2.65 ppm (J = ii Hz, proton at Cs), a one-proton singlet at 3.23 ppm (gem-epoxide proton) and a one-proton triplet with its center at 3.57 ppm (3j = i0 Hz, lactone proton).

Components of Artemisia santolinifolia.

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Molecular and crystal structure of the sesquiterpene lactone ketopelenolide A

The boat-boat conformation of the germacrane ring of ketopelenolide A has been established by x-ray structural analysis.

Structure of the new monoterpenoid liganolide

The structure of the new ester liganolide C27H38O8, isolated from the roots ofLigularia thomsonii has been established by x-ray structural analysis. Liganolide is a monoterpenoid including a six-membered ring with substitutents at C(2), C(3), and C(4), and an epoxy group at C(1) and C(6).

Artemolin — A new guaianolide fromArtemisia absinthium

The epigeal part ofArtemisia absinthium L. has yielded a new sesquiterpene lactone artemolin, C15H20O5, with mp 205°C, [α]D20 +18° (c 1.0, chloroform). The structure of artemolin has been established on the basis of chemical transformations and spectral characteristics.