Showing papers in "Acta Chemica Scandinavica in 1985"
TL;DR: Five cheilostome bryozoans have given rise to the isolation of unique secondary natural products and the structure and chemistry of these compounds are discussed as are their origin, function and biological activity.
Abstract: Secondary metabolites from marine bryozoans are reviewed. Two ctenosome bryozoans are dealt with, one, Alcyonidium gelatinosum containing a sulfoxonium ion acting as hapten in an allergic contact dermatitis and the other, Zoobotryon verticillatum yielding bromogramines. Five cheilostome bryozoans have given rise to the isolation of unique secondary natural products. Bugula neritina is the source of the antineoplastic bryostatins and Bugula purple while Flustra foliacea have yielded an array of bromoindole alkaloids and a brominated quinoline. Chartella papyracea also have bromoindole alkaloids while Sessibugula translucens have ecological active bipyrroles. A biological active xanthine derivative has been reported from Phidolopora pacifica. The structure and chemistry of these compounds are discussed as are their origin, function and biological activity.
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TL;DR: In this article, the standard de formation de Na 3 AlF 6 liquide has been defined, in fonction of the temperature and the composition of NaF, AlF 3, NaAlF 4 and Na 3AlF 6.
Abstract: Donnees d'activite pour NaF, AlF 3 , NaAlF 4 et Na 3 AlF 6 en fonction de la temperature et de la composition. Enthalpie standard de formation de Na 3 AlF 6 liquide
56 citations
41 citations
TL;DR: The synthesis of acyclovir-phospholipid conjugate is reported through an unambiguous one-step preparation of L-alpha-dimyristoyl phosphatidic acid triethylammonium salt and the biological activity of 2 as an antiviral drug has been investigated.
Abstract: The synthesis of acyclovir-phospholipid conjugate (2) is reported through an unambiguous one-step preparation of L-alpha-dimyristoyl phosphatidic acid triethylammonium salt (5) The biological activity of 2 as an antiviral drug has also been investigated
39 citations
TL;DR: The phenylhydrazone of N-[D-fructosyl-(1)]-L-valine (1-deoxy-L -valine-D- fructose) was synthesized and was shown to exist in open form in basic solution and in closed form in acidic solution.
Abstract: The phenylhydrazone of N-[D-fructosyl-(1)]-L-valine (1-deoxy-L-valine-D-fructose) was synthesized. The hydrazone was shown to exist in open form in basic solution and in closed form in acidic solution. The findings have bearings upon the discussion of the reaction of human haemoglobin A1c with phenylhydrazine.
34 citations
TL;DR: A synthesis of a pentaribonucleotide fragment constituting the residues 59-63 of 3'-terminus of E. coli tRNAIle, 5'-ApGpUpCpC-3', has been carried out using a new, easily accessible and achiral 2'-ketal protecting group.
Abstract: A synthesis of a pentaribonucleotide fragment constituting the residues 59-63 of 3'-terminus of E. coli tRNAIle, 5'-ApGpUpCpC-3', has been carried out using a new, easily accessible and achiral 2'-ketal protecting group. The new 2'-ketal group has an additional advantage in that it is easily functionalized to the diamide with aqueous ammonia in the penultimate step of deblocking of fully protected oligoribonucleotides. Such a functionalization of the 2'-ketal group at the penultimate step of deblocking of the fully protected tRNA molecule enhances its relative rate of removal under an acidic condition with a minimum of damage of the target tRNA molecule.
31 citations
29 citations
TL;DR: In this paper, the authors expliques a l'aide des complexes decavanadates et des monomeres VO 2 + et H 2 VO 4 −, Des donnees coulometriques on a pu prouver la reaction redox VO 2+ +2H + + +e − ⇄VO 2++ +H 2 O
Abstract: Resultats expliques a l'aide des complexes decavanadates et des monomeres VO 2 + et H 2 VO 4 − . Des donnees coulometriques on a pu prouver la reaction redox VO 2 + +2H + +e − ⇄VO 2+ +H 2 O
29 citations
TL;DR: Cristallisation dans P2 1 /n avec Z=4; affinement jusqu'a R=0,033 as discussed by the authors ; Bipyramide pentagonale autour de N
Abstract: Cristallisation dans P2 1 /n avec Z=4; affinement jusqu'a R=0,033. Bipyramide pentagonale autour de N
TL;DR: The net incorporation of [2-14C]5-hydroxymethyl-2'-deoxyuridine into DNA of hematopoietic cells was low and the possibility of a repair mechanism for 5-hydoxymethyluracil bound to DNA is discussed.
Abstract: 5-Hydroxymethyl-2'-deoxyuridine is a biologically active thymidine analogue. This investigation was aimed at characterizing the cytotoxicity of 5-hydroxymethyl-2'-deoxyuridine and its incorporation into DNA. Fifty percent inhibition of cellular proliferation, assessed by incorporation of [U-14C]-L-leucine in vitro, was caused by 1.7-5.8 X 10(-5) incorporation of [U-14C]-L-leucine in vitro, was caused by 1.7-5.8 X 10(-5) M 5-hydroxymethyl-2'-deoxyuridine in seven human leukemia cell lines. Higher concentrations of 5-hydroxymethyl-2'-deoxyuridine, i.e. 6-8 X 10(-5) M, were required for a comparable inhibition in human PHA-stimulated peripheral blood lymphocytes. A new synthesis procedure for [2-14C]5-hydroxymethyl-2'-deoxyuridine was developed. The net incorporation of [2-14C]5-hydroxymethyl-2'-deoxyuridine into DNA of hematopoietic cells was low. The possibility of a repair mechanism for 5-hydroxymethyluracil bound to DNA is discussed.
TL;DR: The highly mutagenic title compound (MeIQx) was prepared in 21% overall yield from 4-fluoro-o-phenylenediamine with the 14C-label introduced in the last step through cyclization with [14C]cyanogen bromide.
Abstract: The highly mutagenic title compound (MeIQx) was prepared in 21% overall yield from 4-fluoro-o-phenylenediamine. The 3,7-dimethyl isomer may be obtained as a minor by-product. The 14C-label was introduced in the last step through cyclization with [14C]cyanogen bromide. An alternative synthesis of MeIQx from p-fluoroaniline avoided the separation of isomers but gave poorer yield.
TL;DR: In this paper, the traitement d'hydrocarbures aromatiques polycycliques par N 2 O 4 dans le dichloromethane conduit a la production des derives mononitres avec une forte selectivite positionnelle avec des rendements presque quantitatifs
Abstract: Le traitement d'hydrocarbures aromatiques polycycliques par N 2 O 4 dans le dichloromethane conduit a la production des derives mononitres avec une forte selectivite positionnelle avec des rendements presque quantitatifs
TL;DR: The highly mutagenic title compound (4,8-DiMeIQx) was synthesized in 13% overall yield from 2-fluoro-5-nitrotoluene in eight operations.
Abstract: The highly mutagenic title compound (4,8-DiMeIQx) was synthesized in 13% overall yield from 2-fluoro-5-nitrotoluene in eight operations. The average operation yield was 83%. The reaction sequence used gave, in addition to the title compound, the isomer 3,4,7-trimethyl-3H-imidazo[4,5-f]quinoxalin-2-amine (4,7-DiMeIQx).
TL;DR: Using well-established solid-phase techniques, three new analogues of arginine-vasopressin (AVP) were synthesized, one of which showed about the same antidiuretic activity as AVP but had only about half of its pressor activity.
Abstract: Using well-established solid-phase techniques, three new analogues of arginine-vasopressin (AVP) were synthesized. In these the glutamine residue in position 4 was replaced with an additional arginine. The new analogues were: [Arginine4]arginine-vasopressin ([Arg4]AVP), [2-thiopropionic acid1,arginine4]arginine-vasopressin (d[Arg4]AVP) and [1-thiocyclohexaneacetic acid1,arginine4]arginine-vasopressin (d(CH2)5[Arg4]AVP). [Arg4]AVP showed about the same antidiuretic activity as AVP but had only about 40% of its pressor activity. Unexpectedly, deamination caused a drop in the antidiuretic activity to about 50%. d(CH2)5[Arg4]AVP had practically negligible antidiuretic and low pressor effects.