2-Acylated derivatives of ergoline

1982 ◽  
Vol 47 (6) ◽  
pp. 1757-1761 ◽  
Author(s):  
Jan Beneš ◽  
Jiří Křepelka
Keyword(s):  
Molecular Weight ◽  
Boron Trifluoride ◽  
Hypotensive Effect ◽  
Boron Trifluoride Etherate ◽  
Low Molecular Weight ◽  
Aliphatic Acids ◽  
Derivatives Of

Reactions of ergoline derivatives Ia-VIIa with anhydrides of low-molecular-weight aliphatic acids, catalysed by boron trifluoride etherate, gave 2-acylated derivatives Ib-Id, IIb-IId, IIIb-Vb, or 1,2-diacylated derivatives VIb and VIIb. The compound IIb exhibited a hypotensive effect.

General Method of Preparation of N-[(S)-(3-Hydroxy-2-phosphonomethoxypropyl)] Derivatives of Heterocyclic Bases

1993 ◽  
Vol 58 (5) ◽  
pp. 1151-1163 ◽  
Author(s):  
Petr Alexander ◽  
Antonín Holý
Keyword(s):  
Sodium Salt ◽  
Boron Trifluoride ◽  
Boron Trifluoride Etherate ◽  
Cesium Carbonate ◽  
Analogous Reaction ◽  
Sodium Salts ◽  
Heterocyclic Bases ◽  
Derivatives Of ◽  
General Method ◽  
Methanolic Ammonia

Reaction of (R)-1-O-p-toluenesulfonyl-1,2,3-propanetriol (IV) with N-trimethylacetylimidazole (II) afforded (R)-1-O-p-toluenesulfonyl-3-O-trimethyacetyl-1,2,3-propanetriol (V) which was reacted with dimethoxymethane in the presence of phosphorus pentoxide to give (R)-2-O-methoxymethyl-1-O-p-toluenesulfonyl-3-O-trimethyacetyl-1,2,3-propanetriol (VI). Compound VI was treated with acetic anhydride and boron trifluoride etherate and the obtained 2-acetoxy derivative VII reacted with bromotrimethylsilane to give the intermediary bromomethyl ether VIII. Compound VIII on reaction with tris(2-propyl) phosphite afforded (R)-2-O-bis(2-propyl)phosphonomethyl-1-O-p-toluenesulfonyl-3-O-trimethyacetyl-1,2,3-propanetriol (IX). Condensation of synthon IX with sodium salts of adenine, 2,6-diaminopurine, or with cytosine, 6-azacytosine or 2-chloroadenine in the presence of cesium carbonate, afforded fully protected diesters X and XIIIb which on methanolysis and reaction with bromotrimethylsilane gave N-[(S)-(3-hydroxy-2-phosphonomethoxypropyl)] derivatives of adenine (XIa), 2- chloroadenine (XIb), 2,6-diaminopurine (XIc), cytosine (XIVa) and 6-azacytosine (XIVb). In an analogous reaction, sodium salt of 4-methoxy-2-pyrimidone reacted with compound IX to give an intermediate XIIIa which on treatment with methanolic ammonia and subsequent deblocking under the same conditions also afforded the cytosine derivative XIVa. Sodium salt of 2-amino-6-chloropurine was in this way converted into the corresponding 2-aminopurine derivative XVIII. Deprotection of this compound gave 9-(S)-(3-hydroxy-2-phosphonomethoxypropyl)-2-aminopurine (XIX).

Copper(II) complexes of low molecular weight derivatives of thymopoietin

1994 ◽  
Vol 55 (1) ◽  
pp. 67-75 ◽  
Author(s):  
Imre Sóvágó ◽  
Csilla Bertalan ◽  
László Gobi ◽  
Imre Sóvágó ◽  
Olga Nyéki
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Derivatives Of

Anticoagulant activity of low-molecular-weight sulfated derivatives of galactomannan from Cyamopsis tetragonoloba (L.) seeds

2008 ◽  
Vol 44 (1) ◽  
pp. 98-103 ◽  
Author(s):  
N. M. Mestechkina ◽  
V. D. Shcherbukhin ◽  
G. E. Bannikova ◽  
V. P. Varlamov ◽  
N. N. Drozd ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anticoagulant Activity ◽  
Low Molecular Weight ◽  
Cyamopsis Tetragonoloba ◽  
Derivatives Of

scholarly journals 2,1-Benzisothiazoles. XI. The rearrangement of 2,1-Benzisothiazol-3-yl esters. Autocatalysis of a sulfur extrusion by low-molecular-weight sulfur

1981 ◽  
Vol 34 (4) ◽  
pp. 755 ◽  
Author(s):  
M Davis ◽  
KC Tonkin
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Sulfur Addition ◽  
Derivatives Of ◽  
Acyl Derivatives

The extrusion of sulfur from acyl derivatives of 2,1-benzisothiazol-3(1H)-one (1) is autocatalytic. The catalyst is low-molecular-weight sulfur. Addition of cyclohexasulfur (5) to solutions of theseacyl derivatives increases the rate of such reactions.

scholarly journals Structural Characterization of the Symbiotically Important Low-Molecular-Weight Succinoglycan ofSinorhizobium meliloti

1999 ◽  
Vol 181 (21) ◽  
pp. 6788-6796 ◽  
Author(s):  
Lai-Xi Wang ◽  
Ying Wang ◽  
Brett Pellock ◽  
Graham C. Walker
Keyword(s):  
Molecular Weight ◽  
Nuclear Magnetic Resonance ◽  
Sinorhizobium Meliloti ◽  
Structural Basis ◽  
Low Molecular Weight ◽  
Considerable Heterogeneity ◽  
Chromatographic Techniques ◽  
Detailed Structural Analysis ◽  
Derivatives Of

ABSTRACT The production of succinoglycan by Sinorhizobium meliloti Rm1021 is required for successful nodule invasion by the bacterium of its host plant, alfalfa. Rm1021 produces succinoglycan, an acidic exopolysaccharide composed of an octasaccharide repeating unit modified with acetyl, succinyl, and pyruvyl moieties, in both low- and high-molecular-weight forms. Low-molecular-weight (LMW) succinoglycan, previously thought to consist of monomers, trimers, and tetramers of the repeating unit, has been reported as being capable of promoting the formation of nitrogen-fixing nodules by succinoglycan-deficient derivatives of strain Rm1021. We have determined that the three size classes of LMW succinoglycan species are in fact monomers, dimers, and trimers of the repeating unit and that the trimer is the species active in promoting nodule invasion. A detailed structural analysis of the components of LMW succinoglycan by using various chromatographic techniques, along with nuclear magnetic resonance analyses, has revealed that there is considerable heterogeneity within the LMW succinoglycan oligomers in terms of noncarbohydrate substitutions, and we have determined the structural basis of this heterogeneity.

Kinin-like Activities of the Synthetic Low Molecular Weight Fragment of Fibrinogen Degradation Products

1974 ◽  
Vol 32 (02/03) ◽  
pp. 350-355
Author(s):  
Akira Takaki ◽  
Tsuyoshi Yamaguchi ◽  
Keiichi Ohsato
Keyword(s):  
Molecular Weight ◽  
Smooth Muscle ◽  
Muscle Contraction ◽  
Synthetic Peptide ◽  
Degradation Products ◽  
Hypotensive Effect ◽  
Smooth Muscle Contraction ◽  
Biological Properties ◽  
Low Molecular Weight ◽  
Fibrinogen Degradation Products

SummarySome biological properties of a synthetic peptide based on an anticoagulant peptide obtained from fibrinogen degradation products by the action of plasmin are reported. This peptide produced smooth muscle contraction without the presence of bradykinin. The contraction caused by this peptide was not modified by atropin (10-6 g/ml), hyoscine (10-6 g/ml) and tetrodotoxin (2xl0-7 g/ml). A hypotensive effect was observed following the intravenous injection of the peptide into an anesthetized rat indicating that this peptide has an action similar to that of bradykinin though less potent.

Antiplatelet Actions Of Low Molecular Weight Peptides And Their Derivatives

1981 ◽  
Author(s):  
Jawed Fareed ◽  
Harry L Messmore ◽  
Daniel A Walz
Keyword(s):  
Molecular Weight ◽  
Molecular Mechanisms ◽  
Free Acid ◽  
Acid Amide ◽  
Antiplatelet Agents ◽  
Low Molecular Weight ◽  
Clot Retraction ◽  
Induced Aggregation ◽  
Derivatives Of ◽  
Aggregation Of Platelets

We have reported on the antiserine protease actions of low molecular weight peptides with arginine and lysine at the carboxyl terminus and their derivatives. In order to investigate the action of these peptides and their analogues on other components of hemostasis we studied their effects on platelet function; aggregation and release reactions, clot retraction and serotonin uptake by platelets. D-Phe-Pro-Arg-NH-heptyl, D-Phe-Pro-Arg-O-heptyl, D-Phe-Pro-Arg-thiobenzyl, D-Phe-Pro-Arg-COOH, D-Phe-Pro-Arg-NH2, D-Phe-Pro-Arginal and similar derivatives of D-Pro-Phe-Arg, D-Phe-Phe-Arg and Val-leu-lys- were screened None of these peptides produced aggregation and release reactions in concentration >10 mM. D-Phe-Pro-Arg-thiobenzyl and D-Phe-Pro-Arginal produced a strong inhibition of thrombin induced aggregation and release reactions at sub ymolar levels. Both of these peptides also inhibited thrombin’s action in amidolytic and coagulant assays. D-Phe-Pro-Arg-thiobenzyl ester also produced a complete inhibition of arachidonic acid induced aggregation of platelets and showed varying inhibitory actions against ADP, epinephrine, collagen, and serotonin induced aggregation and release reactions. Although ristocetin induced aggregation was only slightly effected, a complete block of the release reaction was seen. ADP induced β-thrombo- globulin release was also inhibited by this peptide.Heptyl amide and esters of H-D-Phe-Pro-Arg-and free acid, amide and arginal forms of various other peptides exhibited relatively weaker antiplatelet actions. Our studies suggest that peptides with amino acid resembling serine protease sensitive sites can be molecularly manipulated to design potent antiplatelet agents. Furthermore these peptides may provide a useful probe to study the molecular mechanisms involved in the pathophysiology of thrombotic disorders and to design new antiplatelet drugs.

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