Synthesis of Vinca Alkaloids and Related Compounds. Part 84. Sulfonamide Derivatives of Some Vinca Alkaloids with Cardiovascular Activity

(+)?Vincamine ( 1 ) and (+)?vinpocetine ( 2 ) were chlorosulfonylated and the resulting sulfonyl chloride isomers ( 3–6 ) were transformed into sulfonamides ( 7–10 ). The ester group of sulfonamides was modified by selective hydrolysis and transesterification. Apovincaminol derivatives ( 14–16 ) were also prepared by reduction. In addition to the known cerebrovascular effects of the unsubstituted compounds ( 1,2 ), sulfonamides also show a significant peripheral vasodilator effect.     

Synthesis and Comparative Inotropic Effects of Several Isoquinoline Alkaloids

Pharmaceutical Chemistry Journal - Compounds 3a [1-(3′,4′-methylenedioxyphenyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline] and 3b...     

植物生物碱抗肿瘤作用机制的研究进展

对有关文献报道的植物生物碱对肿瘤细胞的几种不同作用机制，如直接杀伤作用、干扰细胞周期、诱导细胞分化、诱导细胞凋亡、逆转细胞抗凋亡作用等进行了综述，以期提供从天然产物中寻找优良的抗癌新药的信息和思路。     

Antiplatelet Effects of Some Aporphine and Phenanthrene Alkaloids in Rabbits and Man

Two aporphines (boldine and laurolitsine) and five phenanthrene alkaloids (litebamine, secoboldine, N-cyanosecoboldine, N-methylsecoglaucine and N-methylsecopredicentrine) were evaluated in-vitro for their ability to inhibit platelet aggregation. All seven alkaloids inhibited aggregation of rabbit platelets and inhibited the release of ATP induced by arachidonic acid and collagen in rabbit platelets. Those aggregations induced by platelet-activating factor (PAF), thrombin, U46619 and ADP were inhibited by the three N-substituted secoboldine derivatives only. Thromboxane B₂ formation caused by arachidonic acid was also suppressed by these compounds. They did not affect the generation of [³H]inositol monophosphate caused by collagen, PAF and thrombin in the presence of indomethacin. Platelet cyclic AMP level was unaffected by litebamine, but was increased by N-methyl-secoglaucine. Litebamine suppressed the secondary aggregation, but not the primary aggregation, induced by ADP and adrenaline in platelet-rich plasma from man, whereas N-methylsecoglaucine inhibited both primary and secondary aggregation. It is concluded that the antiplatelet effect of these seven aporphine and phenanthrene alkaloids is mainly a result of inhibition of thromboxane A₂ formation; N-methylsecoglaucine has additional antiplatelet activity as a result of increasing the levels of platelet cyclic AMP.     

Synthesis of the Preininger-Alkaloid and its Enantioselective Reduction to Macrostomine

The Preininger-alkaloid, dehydro-normacrostomine ( 2b , Scheme 1) was synthesized starting from rac. α-acetyl-3,4-dimethoxybenzylcyanide (3) (Scheme 2). The key intermediate 4-acetyl-6,7-dimethoxy-1-(3,4-methylene-dioxybenzyl)isoquinoline (11) is converted via a Mannich base to the nitrile 17 (Scheme 7) which in turn is cyclized to the Preininger-alkaloid (2b) by careful hydrogenation. - Reduction of 2b with a modified Iwakuma-reagent, followed by N-formylation and subsequent LiAlH₄-reduction produced (R)-(+)-macrostomine (enantiomer of 1 ) in 72% optical purity.     

Separation and Quantification of Some Alkaloids from Fumaria parviflora by Capillary Isotachophoresis1

The isotachophoretic separation of some isoquinoline alkaloids in acid-base partially purified extracts from Bulgarian FUMARIA PARVIFLORA was studied. The electrolyte system for model mixtures of alkaloids (-)-stylopine, (-)-canadine, coptisine, berberine, protopine, cryptopine, chelidonine, bulbocapnine, papaverine, parfumine and for the plant extracts contained the leading ion K (+) (0.01 M), counter ion CH (3)COO (-), pH (L) 5.5, and the terminating ion H (+) (acetic acid 0.01 M). In the plant extracts, protopine and parfumine were quantitatively determined during F. PARVIFLORA growth and development in the term May-June 1984.     

6-氯代苯骈吡喃类化合物的合成

钾离子通道启开剂大多为苯骈吡喃类化合物。它们具有明显的舒血管活性且很可能成为有前途的抗高血压药物。笔者对发现较早的钾离子通道启开剂cromakalim进行结构修饰的研究时，根据苯骈吡喃类化合物的构效关系，以cromakalim为先导化舍物，设计并合成了4个苯骈吡喃类衍生物，以期望获得抗高血压活性更强，副作用更小的化合物，经元素分析（IR，HNMR，MS）确证其中2个化舍物均未见文献报道。     

Synthesis of Some Metabolites of Promethazine

The synthesis of the N-methylnitrone 11 , N-monoalkylhydroxylamine 9 , N,N-dialkylhydroxylamine 10 , Oxime 8 and other potential metabolites of promethazine (1) and of its N-dealkyl derivatives 2,3 are described.     

Alkaloids of Annonaceae. XXIX. Alkaloids of Annona muricata

From leaves, root - and stem - barks of Annona muricata L., seven isoquinoline alkaloids have been isolated: reticuline (main alkaloid), coclaurine, coreximine, atherosperminine, stepharine. Anomurine and anomuricine, two minor alkaloids, are new tetrahydrobenzylisoquinolines, with 5, 6, 7 substituted ring A. The phytochemical significance of these alkaloids is discussed.     

10'-Fluorovinblastine and 10'-Fluorovincristine: Synthesis of a Key Series of Modified Vinca Alkaloids

A study on the impact of catharanthine C10 and C12 indole substituents on the biomimetic Fe(III)-mediated coupling with vindoline led to the discovery and characterization of two new and substantially more potent derivatives, 10'-fluorovinblastine and 10'-fluorovincristine. In addition to defining a pronounced and unanticipated substituent effect on the biomimetic coupling, fluorine substitution at C10', which minimally alters the natural products, was found to uniquely enhance the activity 8-fold against both sensitive (IC(50) = 800 pM, HCT116) and vinblastine-resistant tumor cell lines (IC(50) = 80 nM, HCT166/VM46). As depicted in the X-ray structure of vinblastine bound to tubulin, this site resides at one end of the upper portion of the T-shaped conformation of the tubulin-bound molecule, suggesting the 10'-fluorine substituent makes critical contacts with the protein at a hydrophobic site uniquely sensitive to steric interactions.     

Alkaloids of Annonaceae. XXIX. Alkaloids of Annona muricata.]

From leaves, root - and stem - barks of ANNONA MURICATA L., seven isoquinoline alkaloids have been isolated: reticuline (main alkaloid), coclaurine, coreximine, atherosperminine, stepharine. Anomurine and anomuricine, two minor alkaloids, are new tetrahydrobenzylisoquinolines, with 5, 6, 7 substituted ring A. The phytochemical significance of these alkaloids is discussed.     

美罗培南全合成的改进

报道了美罗培南的全合成,并对其中去硅醚和烯丙基保护的方法进行了改进。     

Enantioselective organocatalysis

Enantioselective organocatalysis has emerged as a powerful synthetic paradigm that is complementary to metal-catalysed transformations and has accelerated the development of new methods to make diverse chiral molecules. The operational simplicity, ready availability of catalysts and low toxicity associated with organocatalysis makes it an attractive method to synthesise complex structures. Here, we discuss the impact of enamine, iminium, nucleophilic and Br?nsted acid catalysts in organic synthesis, and highlight key strategic methods to assemble useful molecules with high enantiomeric purity.     

Alkaloids of papaveraceous plants

From the whole plants of CORYDALIS TASHIROI M AKINO a new quaternary protoberberinium base dehydrodiscretamine chloride was isolated along with four known quaternary alkaloids by the application of droplet countercurrent chromatography (DCCC). The structure of the new base was established by spectral and chemical evidence. Eight known tertiary alkaloids were also isolated from the same plant.     

Analysis of Ergot Alkaloids

The principles and application of established and newer methods for the quantitative and semi-quantitative determination of ergot alkaloids in food, feed, plant materials and animal tissues are reviewed. The techniques of sampling, extraction, clean-up, detection, quantification and validation are described. The major procedures for ergot alkaloid analysis comprise liquid chromatography with tandem mass spectrometry (LC-MS/MS) and liquid chromatography with fluorescence detection (LC-FLD). Other methods based on immunoassays are under development and variations of these and minor techniques are available for specific purposes.