Synthesis of piperazine-2,5-diones related to bicyclomycin: 1,4-dibenzyl-3-hydroxy-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione. 2. Route via cyclic intermediates

1983 ◽  
Vol 61 (7) ◽  
pp. 1397-1404 ◽  
Author(s):  
Peter Yates ◽  
John Harold Hoare
Keyword(s):  
Sulfuric Acid ◽  
Structural Features ◽  
Epoxide Ring ◽  
Reaction Sequence ◽  
Model Studies ◽  
Toluenesulfonic Acid

1,4-Dibenzyl-3-hydroxy-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione (43), which incorporates several of the structural features of the antibiotic bieyclomycin, has been synthesized via a reaction sequence involving early construction of the piperazine-2,5-dione ring. In model studies 3-isopropylidenepiperazine-2,5-dione was di-N-benzylated and epoxidized to give 4,7-dibenzyl-2,2-dimethyl-1-oxa-4,7-diazaspiro[2.5]octane-5,8-dione (10). The opening of the epoxide ring of 10 by several reagents was investigated and it was found that treatment with magnesium isopropylcyclohexylamide (MICA) gives 1,4-dibenzyl-3-hydroxy-3-(1-methylethenyl)piperazine-2,5-dione (23). Treatment of ethyl 3-(2-methoxyethyl)-3-methyl-glycidate (28) with p-toluenesulfonic acid followed by hydrogenation and oxidation gives ethyl 5-methoxy-3-methyl-2-oxopentanoate, which on reaction with chloroacetamide and sulfuric acid followed by treatment of the resulting enamide with ammonia gives (Z)- and (E)-3-(4-methoxybut-2-ylidene)piperazine-2,5-dione. Di-N-benzylation of these followed by epoxidation gives (Z)- and (E)-4,7-dibenzyl-2-(2-methoxyethyl)-2-methyl-1-oxa-4,7-diazaspiro[2.5]octane-5,8-dione (41 and 42). Treatment of 41 with MICA converts it to compound 43. Chromatography of 43 on silica converts it in part to N-benzyl-N-(2-benzylamino-2-oxoethyl)-3-(2-methoxyethyl)-2-oxo-3-butenamide, which on treatment with MICA regenerates 43.

Synthesis of piperazine-2,5-diones related to bicyclomycin: 3-acetoxy-1,4-dibenzyl-3-[1-(2-methoxyethyl)- and 1-(2-hydroxyethyl)ethenyl]piperazine-2,5-dione. 1. Route via acyclic intermediates

1983 ◽  
Vol 61 (3) ◽  
pp. 519-528 ◽  
Author(s):  
Peter Yates ◽  
John Harold Hoare
Keyword(s):  
Sulfuric Acid ◽  
Carboxylic Acid ◽  
Oxygen Atom ◽  
Acetic Anhydride ◽  
Acid Chloride ◽  
Structural Features ◽  
Reaction Sequence ◽  
Hydroxyl Oxygen Atom ◽  
Compound 21 ◽  
Tetrahydropyranyl Ether

3-Acetoxy-1,4-dibenzyl-3-[1-(2-methoxyethyl)ethenyl]piperazine-2,5-dione (32) and its 2-hydroxyethyl analogue (46), which possess several of the structural features of the antibiotic bicyclomycin, have been synthesized by a route involving construction of the piperazine-2,5-dione ring at a late stage in the reaction sequence. Treatment of ethyl 3-(2-methoxyethyl)-3-methylglycidate with acetic anhydride and sulfuric acid gives ethyl 2-acetoxy-3-(2-methoxyethyl)-3-butenoate (10), which is converted to the corresponding carboxylic acid by ethanolysis, hydrolysis, and reacetylation. This, on conversion to its acid chloride and reaction with N,N′-dibenzylglycinamide, gives 2-acetoxy-N-benzyl-N-(2-benzylamino-2-oxocthyl)-3-(2methoxyethyl)-3-butenamide (21). Compound 21, on hydrolysis and oxidation, gives the corresponding 2-oxo compound, which on treatment with magnesium isopropylcyclohexylamide followed by acetylation yields 32. Demethylation of 21 with alkylthiotrimethylsilanes gives the corresponding 2-hydroxyethyl compound, whose tetrahydropyranyl ether on subjection to the above reaction sequence gives the 2-(tetrahydropyran-2-yloxy)ethyl analogue of 32. This, on hydrolysis, gives a 3: 1 mixture of compound 46 and a spiro compound formed by displacement of the acetoxyl group by the hydroxyl oxygen atom of 46.

The Gold Sulfates MAu(S04)2 (M = Na, K, Rb)

2001 ◽  
Vol 56 (12) ◽  
pp. 1340-1343 ◽  
Author(s):  
Mathias S. Wickleder ◽  
Oliver Büchner
Keyword(s):  
Sulfuric Acid ◽  
Single Crystals ◽  
Crystal Structures ◽  
Structural Features ◽  
Monovalent Cations ◽  
Coordination Numbers ◽  
Square Planar ◽  
Oxygen Atoms

AbstractThe evaporation of a solution of Au(OH)3 and Na2So4 in conc. sulfuric acid led to yellow single crystals of NaAu(SO4)2 (monoclinic, P21/n, Z = 2, a = 469.1, b = 845.9, c = 831.2 pm, β = 95.7°). Analogous procedures with K2SO4 or Rb2SO4 instead of Na2SO4 yielded single crystals of KAu(SO4)2 (monoclinic, C2/c, Z = 4, a = 1109.8, b = 724.2, c = 941.1 pm, β = 118.4°) and RbAu(S04)2, respectively, (triclinic, P1̄, Z = 1, a = 423.6, b = 497.5, c = 889.0 pm, a = 76.4°, β = 88.4°, γ = 73.5°). Although the crystal structures of the three sulfates are not isotypic they show similar structural features: The gold atoms are coordinated by four oxygen atoms in a square planar manner. These oxygen atoms belong to four SO42- ions which link the [AUO4] units to infinite chains according to 1∞[Au(SO4)4/ 2]- . These chains are connected via the monovalent cations which show coordination numbers of 6 (Na+), 10 (K+) and 12 (Rb+), respectively.

OBTAINING MICROCRYSTALLINE CELLULOSE FROM MELON CROPS AND STUDYING ITS STRUCTURE

2020 ◽  
pp. 38-41
Keyword(s):  
Heat Treatment ◽  
Hydrogen Peroxide ◽  
Sulfuric Acid ◽  
Microcrystalline Cellulose ◽  
Moisture Sorption ◽  
Structural Features ◽  
Ash Content ◽  
Optical Parameters ◽  
Cellulose Sample ◽  
Water Swelling

The aim of the study was to obtain microcrystalline cellulose from gourds. Cellulose was isolated from the stems of watermelon and pumpkin by acid and alkaline heat treatment. Microcrystalline cellulose was obtained from cellulose by hydrolysis. Cellulose was hydrolyzed in a mixture of sulfuric acid and hydrogen peroxide. The optical parameters of the microcrystalline cellulose sample, ash content, bulk density, water swelling, and moisture sorption were determined. The structural features of the obtained microcrystalline cellulose were studied by IR spectroscopy. The functional groups present under various conditions for the production of microcrystalline cellulose were determined. The influence of the duration of cellulose treatment on the degree of ordering of microcrystalline cellulose was established.

Synopses from the poster exhibition organized by R. H. Pain 1. New very efficient antibiotics in the field of cephalosporin derivatives

1980 ◽  
Vol 289 (1036) ◽  
pp. 361-376 ◽  
Keyword(s):  
Antimicrobial Activity ◽  
Structural Features ◽  
Side Chain ◽  
Unexpected Result ◽  
Reaction Sequence ◽  
General Reaction ◽  
Gram Negative ◽  
High Level ◽  
Very High

The semi-synthetic cephalosporin derivatives containing a 2-(2-amino-4-thiazolyl)-2- syn -oxyiminoacetyl side chain are obtained according to the general reaction sequence outlined in figure 1. They are characterized by a very high level of antimicrobial activity, especially against Gram-negative species. This unexpected result is due to the conjunction of two structural features: the aminothiazolyl moiety and the syn -oxyimino substituent.

Determination of para-toluenesulfonic acid and sulfuric acid in a mixture

1967 ◽  
Vol 1 (12) ◽  
pp. 705-706
Author(s):  
M. S. Goizman ◽  
A. A. Chemerisskaya
Keyword(s):  
Sulfuric Acid ◽  
Toluenesulfonic Acid
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