Display options:
Normal
Show Abstracts
Compact
Select/unselect all
Displaying article 1-11
p. 1-33
Received: 17 August 2005; in revised form: 22 September 2005 / Accepted: 22 September 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (367 KB) Abstract: A review of results of bioactivity and reactivity examinations of marine sesquiterpene (hydro)quinones is presented. The article is focused mostly on friedo- rearranged drimane structural types, isolated from sponges of the order Dictyoceratida. Examples of structural correlations are outlined. Available results on the mechanism of redox processes and examinations of chemo- and regioselectivity in addition reactions are presented and, where possible, analyzed in relation to established bioactivities. Most of the bioactivity examinations are concerned with antitumor activities and the mechanism thereof, such as DNA damage, arylation of nucleophiles, tubulin assembly inhibition, protein kinase inhibition, inhibition of the arachidonic cascade, etc. Perspectives on marine drug development are discussed with respect to biotechnological methods and synthesis. Examples of the recognition of validated core structures and synthesis of structurally simplified compounds retaining modes of activity are analyzed.
p. 34-42
Received: 3 August 2004; in revised form: 20 December 2005 / Accepted: 20 December 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (171 KB) Abstract: The reactivity of alicyclic ketazines in criss-cross cycloadditions was investigated. They react with potassium cyanate and ammonium thiocyanate in the presence of acetic acid to form spirocyclic perhydro[1,2,4]triazolo[1,2-a][1,2,4]triazole-1,5-diones and perhydro[1,2,4]triazolo[1,2-a][1,2,4]triazole-1,5-dithiones, respectively, in relatively high yields.
p. 43-48
Received: 10 November 2004; in revised form: 6 July 2004 / Accepted: 6 July 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (53 KB) Abstract: Ten new 2-(3-aryl-1-phenyl-4-pyrazolyl)benzoxazoles have been synthesized by oxidative intramolecular cyclization of the corresponding Schiff’s bases using iodobenzene diacetate in methanol as an oxidant.
p. 49-58
Received: 9 March 2005; in revised form: 12 December 2005 / Accepted: 14 December 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (225 KB) Abstract: New cis monocyclic β-lactams were synthesized by [2+2] Staudinger cycloaddition reactions of the imine (3,4-dimethoxybenzylidene)-(4-methoxyphenyl)- amine and ketenes derived from different acyl chlorides and Et3N. These monocyclic β-lactams were then cleaved by ceric ammonium nitrate (CAN) to give NH-monocyclic β-lactams, which in turn were converted to N-sulfonyl monocyclic β-lactams by treatment with four different sulfonyl chlorides in the presence of Et3N and 4,4-dimethyl- aminopyridine (DMAP).
p. 59-63
Received: 27 April 2005; in revised form: 12 December 2005 / Accepted: 15 December 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (106 KB) Abstract: Condensation of aromatic primary bis-amines with isatin (1H-indole-2,3-dione) and 5-flouroisatin occurred cleanly and efficiently in a water suspension mediumwithout using any organic solvent or acid catalyst. The corresponding bis-Schiff baseswere obtained in good yields and were easily isolated by filtration. Their structures wereconfirmed by 1 H-NMR, 13 C-NMR, IR and mass spectra.
p. 64-71
Received: 3 January 2005; in revised form: 16 December 2005 / Accepted: 17 December 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (135 KB) Abstract: A series of mono and di-N-2,3-epoxypropyl N-phenylhydrazones have beenprepared on a large scale by reaction of the corresponding N-phenylhydrazones of9-ethyl-3-carbazolecarbaldehyde, 9-ethyl-3,6-carbazoledicarbaldehyde, 4-dimethyl-amino-, 4-diethylamino-, 4-benzylethylamino-, 4-(diphenylamino)-, 4-(4,4-4'-dimethyl-diphenylamino)-, 4-(4-formyldiphenylamino)- and 4-(4-formyl-4'-methyldiphenyl-amino)benzaldehyde with epichlorohydrin in the presence of KOH and anhydrousNa2 SO4 .
p. 72-80
Received: 17 March 2005; in revised form: 19 October 2005 / Accepted: 20 October 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (85 KB) Abstract: The reactions in benzene of 9-alkyl-3-aminocarbazoles with ethyl-3-oxobutanoateyielded ethyl-3-[(9-alkyl-9H-carbazol-3-yl)amino]but-2-enoate condensation products or N-(9-ethyl-9H-carbazol-3-yl)-3-oxobutanamide acylation products. The condensation productswere cyclized to the corresponding 4,7-dihydro-pyrido[2,3-c]-carbazol-1-ones upon heatingin mineral oil at 240-250 °C. The structures of the synthesized compounds were investigatedby IR, mass spectrometry, 1 H- and 13 C-NMR spectroscopy and MM2 molecular mechanicsand AM1 semi-empirical quantum mechanical methods.
p. 81-102
Received: 21 June 2005; in revised form: 8 September 2005 / Accepted: 8 September 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (158 KB) Abstract: Several specific synthetic protocols were developed for the preparation from cyanuric chloride of a range of symmetric and non-symmetric di- and tri-substituted 1,3,5-triazines containing alkyl, aromatic, hindered, chiral and achiral hydroxyalkyl, ester and imidazole groups via sequential nucleophilic substitution of the C-Cl bond by C-O, C-N and C-S bonds.
p. 103-114
Received: 6 January 2006; in revised form: 23 January 2006 / Accepted: 24 January 2006 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (174 KB) Abstract: The content and distribution of stilbenes and resin acids in Scots pine (Pinus sylvestris) and spruce (Picea abies), sampled in central Norway, have been examined. The contents of pinosylvin stilbenes in pine heartwood/living knots were 0.2-2/2-8 % (w/w). No stilbenes could be detected in spruce (Picea abies). The resin acid contents of pine sapwood/heartwood and knots were 1-4 and 5-10 % (w/w), respectively. Minor amounts of resin acids (< 0.2/< 0.04 %w/w) were identified in spruce wood/knots. The lignan content in knots of Norwegian spruce was 6.5 % (w/w). Diastereomerically pure hydroxymatairesinol (HMR, 84 % of total lignans) was readily isolated from this source since only minor quantities (2.6 % of total lignans) of the allo-HMR diastereomer was detected. Insignificant amounts of lignans were present in the sapwood. Lignans could not be detected in the sapwood or knots of Norwegian sallow (Salix caprea), birch (Betula pendula) or juniper (Juniperus communis).
p. 115-120
Received: 16 February 2005; in revised form: 5 December 2005 / Accepted: 5 December 2005 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (194 KB) Abstract: Polymer-supported heterogeneous catalysts in a form of complexes of 8-hydroxy- quinoline with cobalt acetate were synthesized. Conjugated polymers – polyaniline (PANI), poly-o-toluidine (POT), poly-o-anisidine (POA) – were used as supports. Oxidation reactions of aliphatic and aromatic hydrocarbons were carried out in the presence of molecular oxygen at atmospheric pressure and epoxides or ketones were obtained as the main products with high selectivity.
p. 121-129
Received: 8 January 2006 / Accepted: 23 January 2006 / Published: 31 January 2006
Show/Hide Abstract
| Download PDF Full-text (159 KB) Abstract: The reactivity of the C12-21 alkene of some erythromycin A derivatives was studied. This double bond was easily oxidized to the corresponding epoxide with excellent stereoselectivity. A single crystal X-ray structure showed that the epoxide moiety was on the same side as the acetonide. When an erythromycin derivative containing a C12-21 alkene was treated with diazomethane a [3+2] cycloaddition affording a pyrazoline occurred. In the case of 6-O-allylated erythromycin derivatives the C12-21 alkene was selectively epoxidized in the presence of the 6-O-allyl moiety. These results show that the C12-21 alkene is an active reaction site, which can be used for useful further modification of erythromycin derivatives.
Select/unselect all
Displaying article 1-11
Export citation of selected articles as:
Plain Text
BibTeX
BibTeX (without abstracts)
Endnote
Endnote (without abstracts)
Tab-delimited
PubMed XML
DOAJ XML
AGRIS XML