Fusoxysporone - a new type of diterpene from fusarium oxysporum

A novel diterpene, fusoxysporone 1, was isolated from liquid cultures of the fungus Fusarium oxysporum IMB FO 18;2. The skeleton of 1 - related to the viscidane type - is described for the first time and named fusoxysporane. Additionally, fusaric acid and dehydrofusaric acid were identified in extracts of the culture medium.     

Isoagatholactone,a diterpene of a new structural type from the sponge Spongia officinalis

A new diterpene, isoagatholactone, isolated from the sponge Spongia officinalis, is the first natural compound with the carbon skeleton of isoagathic acid (2), the acid-catalyzed cyclization product of agathic acid (1). Structure 4 was assigned to isoagatholactone on spectral grounds and chemical correlation with grindelic acid (5).     

Alkaloids of a new type fromSophora alopecuroides L.

Summary The structures of aloperine and allylaloperine (fromSophora alopecuroides L.) — alkaloids of a new structural type for the genusSophora — have been established by chemical and spectral methods. A number of parameters, NMR spectra, and mass spectra characterizing this class of compounds has been obtained. The partial synthesis of allylaloperine has been performed.All-Union Scientific-Research Institute of Medicinal Plants. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 30–37, January–February, 1975.     

A phloroglucinol derivative with a new carbon skeleton from Hypericum perforatum (Guttiferae)

Examination of the aerial parts of a Chinese herbal medicine yielded a novel metabolite, perforatumone 1, which is characterized by its unique carbon skeleton. Its structure was determined by detailed spectroscopic analysis.     

Ptychanolide, a sesquiterpenoid with a new type skeleton from the liverwort ptychanthus striatus (lehm. et lindenb.) nees

The structure of ptychanolide, isolated from the liverwort Ptychanthus striatus, has been determined by spectroscopic analysis and chemical transformation.     

Cyphostemmins A-B, two new antifungal oligostilbenes from Cyphostemma crotalarioides (Vitaceae)

Two new antifungal resveratrol dimers, cyphostemmins A-B (1–2), have isolated from the roots of Cyphostemma crotalarioides planch (Vitaceae) together with resveratrol 3 and previously known reseveratrol dimers (4–7). Structures of these new compounds have been established on the basis of their MS and ¹H and ¹³C NMR spectroscopic data.     

Crystal growth and structural study of the new series Ln(OH)CrO4 (Ln = Y, Dy---Lu): Crystal structure of Er(OH)CrO4

Single crystals of the new series Ln(OH)CrO₄ (Ln = Y, Dy---Lu) have been obtained by hydrothermal procedures. The structure of Er(OH)CrO₄ has been determined by single-crystal X-ray techniques. The compound has monoclinic symmetry, space group P2₁/n, Z = 8, with a = 8.106(3), B = 11.324(2), C = 8.251(1) Å, β = 94.14(2)° and V = 755.4(3) ų. Final R values were R = 0.034, R_w = 0.049, for 2207 observed reflections. X-ray powder data show that all compounds of the title series are isomorphous. The coordination polyhedron of the lanthanide cations can be considered a square antiprism, with hydrogen bonds linking CrO₄ and LnO₈ groups. The X-ray data in this series provide evidence for the lanthanide contraction.     

Synthesis and crystal structure of Sr(2)AlH(7): a new structural type of alkaline earth aluminum hydride

The title hydride and its deuteride were successfully synthesized. The heavy atom structure and hydrogen positions were determined respectively by X-ray powder diffraction and time-of-flight neutron powder diffraction. They crystallize with a new monoclinic structure in space group I2 (No. 5); cell parameters: a = 12.575(1) A, b = 9.799(1) A, c = 7.9911(8) A, beta = 100.270(4) degrees (hydride), a = 12.552(1) A, b = 9.7826(8) A, c = 7.9816(7) A, beta = 100.286(4) degrees (deuteride), Z = 8. Sr(2)AlH(7) is the first example that consists of isolated [AlH(6)] units and infinite one-dimensional twisted chains of edge-sharing [HSr(4)] tetrahedra along the crystallographic c axis.     

Structure of anislactone A; a new skeletal type of sesquiterpene from the pericarps of Illicium anisatum

A novel sesquiterpene lactone was isolated from the pericarps of Illicium anisatum, a well known toxic plant in Japan, and its structure was established from spectral data and X-ray crystallographic analysis.     

Synthesis of chiral lithium carbamates from (S)-2-(N,N-dialkyl-aminomethyl)pyrrolidines and (S)-methoxymethylpyrrolidine

A convenient synthesis of chiral lithium N-alkyl carbamates 1a–4a from chiral pyrrolidines 1–4, LiH and CO₂ is described. The yields are good to excellent. A combined experimental (¹H, ⁶Li-HOESY, cryoscopy) and theoretical study (B3LYP/6-311++G(d,p)) succeeded in assigning the predominant solution state structure of 1a.     

Constituents of regenerated plants of Ophiorrhiza pumila; formation of a new glycocamptothecin and predominant formation of (3R)-deoxypumiloside over (3S)-congener

The regeneration of plantlets was successful from Ophiorrhiza pumila callus cultures, from which a new glucosyloxy camptothecin, 9-β-glucosyloxycamptothecin, together with 15 metabolites including six camptothecin-related alkaloids was isolated. (3S)-Deoxypumiloside, one of the plausible biogenetic precursors of camptothecin, could not be found, whereas the (3R) epimer was isolated from the regenerated plants.     

Ornstein-Zernike equation for a two-yukawa c(r)

The Ornstein-Zernike equation is solved for a direct correlation function that is the sum of two Yukawa terms outside a core region. Application is made to ionic systems.     

Stereoselective synthesis of (1R,2S)-2-amino-1,3-diols from (R)-cyanohydrins

Vinyl substituted (1R,2S)-amino alcohols 5 were obtained by addition of vinyl magnesium bromide to the corresponding cyanohydrin O-trimethylsilyl ethers (R)-2. The O- and N-protected vinyl amino alcohols 6 were ozonized at −78°C in methanol yielding (1R,2S)-2-amino-1,3-diols7 in high enantiomeric and diastereomeric excesses. For purification, compounds 7 in some cases were acetylated to give the derivatives (1R,2S)-8. Racemic 6a was converted by oxidative ozonolysis at −78°C in methanolic NaOH solution to the corresponding methyl N-acetyl-β-hydroxy propanoate 9a. The configuration of (1R,2S)-8a was confirmed by x-ray crystallographic analysis.     

Structure of turbicoryn, a new glucoside from Turbina corymbosa

From the seeds of the plant known as Ololiuqui (Turbina corymbosa),¹ a new glucoside, turbicoryn, has been isolated and the structure of its aglucone, turbicorytin, established.¹     

Structure of eucommiol, a new cyclopentenoid-tetrol from Eucommia Ulmoides

Isolation of Eucommiol a new cylopentenoid-tetrol from Eucommia Ulmoides (Eucommiaceae) is described. Its structure and absolute stereochemistry have been demonstrated.     

Syntheses of (E)- and (Z)-volkendousin

The first syntheses of the antitumor agents (E)-volkendousin (1) and acetonide 3 have been accomplished by efficient routes from readily available dehydroisoandrosterone (7) using allylic oxidation with SeO₂ to introduce the 4/gb-hydroxy group and 16-ketone. This sequence should make these compounds readily available for further biological evaluation.     

Ab Initio Study of Conformational Properties of ( Z, Z)-, ( E, Z)-, and ( E, E)-Cyclonona-1,5-dienes

Summary. Ab initio calculations at the HF/6-31G^* level of theory for geometry optimization and MP2/6-31G^*//HF/6-31G^* for a single point total energy calculation are reported for the important energy-minimum conformations and transition-state geometries of (Z,Z)-, (E,Z)-, and (E,E)-cyclonona-1,5-dienes. The C₂ symmetric chair conformation of (Z,Z)-cyclonona-1,5-diene is calculated to be the most stable form; the calculated energy barrier for ring inversion of the chair conformation via the C_s symmetric boat-chair geometry is 58.3kJmol^–1. Interconversion between chair and twist-boat-chair (C₁) conformations takes place via the twist (C₁) as intermediate. The unsymmetrical twist conformation of (E,Z)-cyclonona-1,5-diene is the most stable form. Ring inversion of this conformation takes place via the unsymmetrical chair and boat-chair geometries. The calculated strain energy for this process is 63.5kJmol^–1. The interconversion between twist and the boat-chair conformations can take place by swiveling of the trans double bond with respect to the cis double bond and requires 115.6kJmol^–1. The most stable conformation of (E,E)-cyclonona-1,5-diene is the C₂ symmetric twist-boat conformation of the crossed family, which is 5.3kJmol^–1 more stable than the C_s symmetric chair–chair geometry of the parallel family. Interconversion of the crossed and parallel families can take place by swiveling of one of the double bonds and requires 142.0kJmol^–1.