Iron(III)-Catalyzed Prins-Type Cyclization Using Homopropargylic Alcohol: A Method for the Synthesis of 2-Alkyl-4-halo-5,6-dihydro-2<i>H</i>-pyrans

A new Prins-type cyclization between homopropargylic alcohol and aldehydes in the presence of FeX3 to obtain 2-alkyl-4-halo-5,6-dihydro-2H-pyrans in good yield is described. Osmium-catalyzed cis dihydroxylation provided direct access to trans-2-alkyl-3-hydroxy-tetrahydro-pyran-4-ones. Anhydrous ferric halides are also shown to be excellent catalysts for the standard Prins cyclization using homoallylic alcohol. Isolation of an intermediate acetal provides substantiation of a proposed mechanism

Design, Synthesis, and Biological Evaluation of Hybrid Molecules Containing α-Methylene-γ-Butyrolactones and α-Bromoacryloyl Moieties

The synthesis and biological activity of hybrids 8−18 prepared combining α-methylene-γ-butyrolactones and α-bromoacryloylamides have been described and their structure−activity relationships discussed. All these heterobifunctional compounds demonstrate good antileukemic activity, significantly superior to that of both alkylating units alone. Using the human leukemia HL-60 cell line, selected compounds 10, 11, 13, and 17 were found to induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death

Isolation, Structure Elucidation, Total Synthesis, and Evaluation of New Natural and Synthetic Ceramides on Human SK-MEL-1 Melanoma Cells

Two new long-chain ceramides, trametenamides A (1) and B (2), were isolated from the methanolic extract of the fruiting body of the fungus Trametes menziesii. The structures were elucidated by spectroscopic analyses and chemical transformations, and the absolute stereochemistry of trametenamide B (2) was determined by stereoselective total synthesis of four possible diastereomers. The acetyl derivative of the natural ceramide (1a) and synthetic ceramides (24−27) showed cytotoxicity on the human melanoma cell line SK-MEL-1, which was caused by induction of apoptosis as determined by DNA fragmentation, poly(ADP-ribose) polymerase cleavage, and procaspase-9 and -8 processing

Sesquiterpenoids from <i>Pulicaria </i><i>c</i><i>anariensis</i> and Their Cytotoxic Activities^#

Thirteen new sesquiterpenes, pulicanadiene A (1), B (2), and C (3), pulicanone (4), pulicanol (5), pulicanarals A (6), B (7), and C (8), pulicanadienals A (9) and B (10), pulicanadienol (11), and pulioplopanones A (12) and B (13), and seven known compounds, stigmasterol, ergosterol peroxide, calenduladiol, 7,4‘-di-O-methyldihydrokaempferol, 5,7-dihydroxy-3,3‘,4‘-trimethoxyflavone, dihydroquercetin 7,3‘-dimethyl ether, and 6,15α-epoxy-1β,4β-dihydroxyeudesmane, were isolated from Pulicaria canariensis. Compound 4a showed cytotoxicity on the human myeloid leukemia cell line HL-60. The cytotoxicity was caused by induction of apoptosis as determined by microscopy of nuclear changes, activation of caspases, and the cleavage of poly(ADP-ribose) polymerase-1

Sesquiterpene Lactones from <i>Gonospermum gomerae</i> and <i>G. fruticosum</i> and Their Cytotoxic Activities

Four new sesquiterpene lactones (1−4) and a new sesquiterpene (5) together with 20 known compounds were isolated from two Gonospermum species (G. gomerae Bolle and G. fruticosum Less). Their structures were determined by analysis of spectroscopic data, including 1D and 2D NMR. The cytotoxicity of several new and known natural and semisynthetic sesquiterpene lactones was also assessed against human myeloid leukemia cell lines (HL-60 and U937), human melanoma cells (SK-MEL-1), and human adenocarcinoma (A549)

Isolation from <i>Eucalyptus </i><i>o</i><i>ccidentalis</i> and Identification of a New Kaempferol Derivative that Induces Apoptosis in Human Myeloid Leukemia Cells

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2α,3β-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release

Sesquiterpenoids from <i>Pulicaria </i><i>c</i><i>anariensis</i> and Their Cytotoxic Activities^#

Thirteen new sesquiterpenes, pulicanadiene A (1), B (2), and C (3), pulicanone (4), pulicanol (5), pulicanarals A (6), B (7), and C (8), pulicanadienals A (9) and B (10), pulicanadienol (11), and pulioplopanones A (12) and B (13), and seven known compounds, stigmasterol, ergosterol peroxide, calenduladiol, 7,4‘-di-O-methyldihydrokaempferol, 5,7-dihydroxy-3,3‘,4‘-trimethoxyflavone, dihydroquercetin 7,3‘-dimethyl ether, and 6,15α-epoxy-1β,4β-dihydroxyeudesmane, were isolated from Pulicaria canariensis. Compound 4a showed cytotoxicity on the human myeloid leukemia cell line HL-60. The cytotoxicity was caused by induction of apoptosis as determined by microscopy of nuclear changes, activation of caspases, and the cleavage of poly(ADP-ribose) polymerase-1

Isolation from <i>Eucalyptus </i><i>o</i><i>ccidentalis</i> and Identification of a New Kaempferol Derivative that Induces Apoptosis in Human Myeloid Leukemia Cells

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2α,3β-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release

Enantioselective Synthesis and Biological Activity of (3<i>S</i>,4<i>R</i>)- and (3<i>S</i>,4<i>S</i>)-3-Hydroxy-4-hydroxymethyl- 4-butanolides in Relation to PGE₂

Compounds 9 and 13 were synthesized, and their structures and stereochemistry were elucidated by spectroscopic methods. In competition binding experiments, specific [3H]-PGE2 binding was significantly displaced by compound 9 and, to a lesser extent, by 13, in a dose-dependent manner. The biological properties of compound 9 were studied on HL-60 cells, and several effects were found related to those of PGE2. Compound 9 increases c-fos mRNA level as does PGE2 and antagonizes TPA-induced terminal differentiation

Isolation from <i>Eucalyptus </i><i>o</i><i>ccidentalis</i> and Identification of a New Kaempferol Derivative that Induces Apoptosis in Human Myeloid Leukemia Cells

In this paper we report the isolation and structural elucidation of a new flavonoid (1) and three known compounds, 6,8-di-C-methylkaempferol 3-methyl ether (2), oleanolic acid, and 2α,3β-dihydroxyurs-12-en-28-oic acid, from aerial parts of Eucalyptus occidentalis collected in Algeria. Flavonoids 1 and 2 were used to study their biological activities on the human promyelocytic leukemia cell line, HL-60. Our data show that these compounds induce morphological changes and internucleosomal DNA fragmentation characteristic of apoptotic cell death, which is mediated by caspase-8/caspase-3 activation and cytochrome c release