Synthesis of Benzannulated Derivatives of Podocarpic Acid

1991 ◽  
Vol 44 (10) ◽  
pp. 1383 ◽  
Author(s):  
RC Cambie ◽  
MR Metzler ◽  
PS Rutledge ◽  
PD Woodgate
Keyword(s):  
Reaction Sequence ◽  
Derivatives Of ◽  
Moderate Yield

Two cyclopentaannulated derivatives of podocarpic acid have been converted into benzannulated derivatives by a two-step reaction sequence in moderate yield.

Gas Chromatographic Analysis of Amino Acids as the jV-Heptafluorobutyryl Isobutyl Esters

1987 ◽  
Vol 70 (1) ◽  
pp. 151-160 ◽  
Author(s):  
Samuel L MacKenzie
Keyword(s):  
Amino Acids ◽  
Capillary Column ◽  
Packed Column ◽  
Complex Mixture ◽  
Amino Acid Profile ◽  
Reaction Sequence ◽  
Maximum Resolution ◽  
Acid Catalyzed ◽  
Derivatives Of ◽  
Heptafluorobutyric Anhydride

Abstract The N-heptafluoroburyryl isobutyl derivatives of proteic amino acids are well resolved by gas chromatography and form the basis of a convenient, rapid assay. The derivatives are prepared by acid-catalyzed esterification at 120°C for 20 min in 3N HCl-isobutanol followed by acylation with heptafluorobutyric anhydride at 150°C for 10 min. The reaction sequence is performed without any transfers or extractions and thus is compatible with microscale analysis. A complete proteic amino acid profile can be completed in less than 20 min by using a packed column or less than 10 min by using a capillary column in combination with an elevated oven temperature program rate. Physiological sample matrixes, which frequently contain a complex mixture of components, and thus require maximum resolution, can be assayed in less than 1 h using a program rate of 4°C/min. A capillary column is recommended for this application. Capillary column chromatography, in combination with a nitrogenspecific detector, is useful for identifying and assaying nonproteic amino acids in physiological sample matrixes. Frequently, a prior cleanup of the sample can be avoided.

The Meisenheimer Rearrangement in Heterocyclic Synthesis. IV. Derivatives of the 2H,6H-1,5,4-Benzodioxazocine and 7H-1,6,5-Benzodioxazonine Ring Systems: X-Ray Crystal Structure of 10-Methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7H-1,6,5-benzodioxazonine

1988 ◽  
Vol 41 (3) ◽  
pp. 293 ◽  
Author(s):  
JB Bremner ◽  
EJ Browne ◽  
LM Engelhardt ◽  
IWK Gunawardana ◽  
AH White
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Ring System ◽  
Heterocyclic Synthesis ◽  
Rearrangement Product ◽  
Ring Systems ◽  
X Ray ◽  
Derivatives Of ◽  
Moderate Yield

Meisenheimer rearrangement of the N-oxides (4) derived from a series of 5-aryl-4-methyl-2,3,4,5-tetrahydro-1,4-benzoxazepines (3) gave rise to eight derivatives (5) of the new 2H,6H-1,5,4-benzodioxazocine ring system. Reaction of 9-methoxy-5-methyl-6-phenyl-3,4,5,6- tetrahydro-2H-1,5-benzoxazocine (6) with 3-chloroperoxybenzoic acid gave an unstable N-oxide (7). A Meisenheimer rearrangement product from (7), 10-methoxy-5-methyl-7-phenyl-2,3,4,5-tetrahydro-7 H-1,6,5- benzodioxazonine (8), the first example of this ring system, was isolated directly in moderate yield on oxidation of (6) with cooling. The crystal and molecular structure of (8) has been determined by X-ray crystallographic methods.

scholarly journals Synthesis of alkyl derivatives of 3,7,10-trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane and evaluation of their biological activity

2021 ◽  
Vol 101 (1) ◽  
pp. 19-26
Author(s):  
А.А. Sinitsyna ◽  
◽  
S.G. Il’yasov ◽  
Keyword(s):  
Biological Activity ◽  
Influenza A ◽  
Bacillus Pumilus ◽  
Maximum Yield ◽  
Methyl Derivative ◽  
Tert Butyl ◽  
Alkyl Derivatives ◽  
Derivatives Of ◽  
And Staphylococcus Aureus ◽  
Moderate Yield

Today 3,7,10-trioxo-2,4,6,8,9,11-hexaaaza[3.3.3]propellane (THAP) has not yet received widespread re-search attention due to the complexity of the synthesis. This work is devoted to the development of a method for the THAP derivatives synthesis, as well as to the study of their biological activity in comparison with al-kyl-substituted glycolurils (subject of comparison). ТНАРwas N-alkylated to furnish novel hexaalkyl deriva-tives of ТНАРwith methyl, ethyl and propyl substituents. The conditionsfor obtaining the maximum yield of the target productwere optimizedon the base of methyl derivative. The reaction proceeded in DMSO/КОНat 75–80ºC for 13hours in a moderate yield of 56%. The ethyl and propyl derivatives of ТНАРwere synthe-sized under the same conditions. The biological activity of the obtained ТНАРalkyl derivatives and glycoluril alkyl derivatives was evaluated against Sporosarcina ureae, Bacillus pumilus, Salmonella typhimurium and Staphylococcus aureus bacteria and influenza A virus. All the samples were found to exhib-it antibacterial activity against Staphylococcus aureus.It was shown that 2,4,6,8,9,11-hexapropyl-ТНАР, di-tert-butyl-diphenyl-, di-tert-butyl-dibenzyl-, di-tert-butyl-dimethyl-and di-isopropyl-dibenzylglycoluril, have exhibited also toxicity to living cells besides antiviral activity

Synthesis of some 2,5-benzoxazocine and 2,6-benzoxazonine derivatives from ω-(Dihydroisoindol-2-yl)alkanol precursors by means of cyanogen bromide

1982 ◽  
Vol 35 (11) ◽  
pp. 2307 ◽  
Author(s):  
JB Bremner ◽  
N Thirasasana
Keyword(s):  
Cyanogen Bromide ◽  
Ring Systems ◽  
Derivatives Of ◽  
Medium Ring ◽  
Moderate Yield

Reaction of cyanogen bromide with 2-(1-phenyl-2,3-dihydro-1H-isoindol-2-yl)ethanol (5a) gave 1-phenyl-3,4,5,6-tetrahydro-1H-2,5-benzoxazocine-5-carbonitrile (6a) in a low to moderate yield. Similarly, 3-(1-phenyl-2,3-dihydro-1H-isoindol-2-yl)propan-1-ol (5c) gave 1-phenyl-1,3,4,5,6,7-hexa-hydro-2,6-benzoxazonine-6-carbonitrile (6c). The analogous 1-(4-methoxyphenyl) derivatives of both medium ring systems were also prepared, and some mechanistic aspects of the results are discussed. Conversion of (6a) into the analgesic, Nefopam,is described.

Synthesis of 12-Hydroxy and 12-Dioxane Derivatives of the closo-1-Carbadodecaborate(1-) Ion. Variations on the Plešek's Cobalt Bis(dicarbollide) Pattern

2002 ◽  
Vol 67 (7) ◽  
pp. 953-964 ◽  
Author(s):  
Bohumír Grüner ◽  
Ivana Císařová ◽  
Josef Čáslavský ◽  
Bernard Bonnetot ◽  
David Cornu
Keyword(s):  
Molecular Structure ◽  
High Field ◽  
Dimethyl Sulfate ◽  
High Yield ◽  
X Ray Diffraction ◽  
Melting Points ◽  
X Ray ◽  
Derivatives Of ◽  
Moderate Yield ◽  
Dioxane Ring

Synthesis of two new B(12) substituted derivatives of the closo-[1-CB11H12]- anion (1) is reported. The zwitterionic derivative containing dioxane ring {12-[O(CH2CH2)2O]+-1-CB11H11-}0 (2) was obtained in moderate yield using reaction of anion 1 with dioxane as solvent, induced by dimethyl sulfate. The anion [12-(HO)-1-CB11H11]- (3) was obtained in high yield upon treatment of the parent anion with 80% H2SO4 at high temperature. Both compounds containing reactive functionalities were designed to serve as useful synthons for a variety of synthetic purposes. The compounds were characterized by 11B and 1H high-field NMR, IR spectroscopy, mass spectrometry, melting points and TLC. Molecular structure of compound 2 was determined by single crystal X-ray diffraction analysis.

Derivatives of orthoacids. II. The preparation of olefins from 1,2-diols

1964 ◽  
Vol 17 (12) ◽  
pp. 1392 ◽  
Author(s):  
G Crank ◽  
FW Eastwood
Keyword(s):  
Carbon Dioxide ◽  
Allyl Alcohol ◽  
Ethyl Formate ◽  
Diethyl Maleate ◽  
Compound I ◽  
Reaction Sequence ◽  
Ethyl Orthoformate ◽  
Derivatives Of

Ethyl orthoformate reacted with pinacol to form 2-ethoxy-4,4,5,5-tetramethyl-1,3-dioxolan (I) which decomposed on heating to yield ethanol, carbon dioxide, and 2,3-dimethylbut-2-ene. When subjected to the same reaction sequence diethyl- D-tartrate, diethyl-meso-tartrate, meso-1,2-diphenylethane-1,2-diol, and cis-cyclo-hexane-1,2-dial underwent specific cis-elimination to yield diethyl fumarate, diethyl maleate, cis-stilbene, and cyclohexane respectively. Glycerol, butane-1,2,4-trial, and pentane-1,2,5-triol formed polymers which decomposed to yield allyl alcohol, but-1-en-4-ol, and pent-1-en-5-ol respectively. Pyrolysis of the monoformyl esters of cis-cyclohexane-1,2-diol, glycerol, butane-1,2,4-triol, and pentane-l,2,5-trio1 gave the respective products enumerated above whereas the monoformyl ester of pinacol yielded pinacolone. When compound (I) was heated in the presence of p-toluenesulphonic acid it gave ethyl formate, pinacolone, 2,3-dimethylbutadiene, and water.

In Search of New Approaches to Asymmetric Conjugate Addition: Screening Studies on the Use of [Zn(bpy*)X(R)] Reagents and α,β-Unsaturated Amide Michael Acceptors

2007 ◽  
Vol 72 (8) ◽  
pp. 1107-1121 ◽  
Author(s):  
Alexander J. Blake ◽  
Daniela Giunta ◽  
Jonathan Shannon ◽  
Maurizio Solinas ◽  
Francesca Walzer ◽  
...  
Keyword(s):  
Ligand Exchange ◽  
Conjugate Addition ◽  
Nmr Studies ◽  
Conjugate Additions ◽  
New Approaches ◽  
Michael Acceptors ◽  
Derivatives Of ◽  
Moderate Yield ◽  
C Nmr

Conjugate additions of [Zn(bpy*)Cl(Et)] (bpy* = 4,4'-di-tert-butyl-2,2'-bipyridine) to cyclohex-2-en-1-one are promoted by ZnMe2 in 88% ee but in moderate yield under CuI phosphoramidite catalysis. In the absence of ZnMe2 the [Zn(bpy*)Cl(Et)] is inactive indicating a Schlenk-type equilibrium. Other derivatives of [Zn(bpy*)Cl(R)] (R = Bu, 4-methylbenzyl), prepared in situ from [ZnCl(R)] and the bipyridine give low yields due to competing chloride abstraction. 13C NMR studies indicate facile organo-ligand exchange between [Zn(bpy*)(Et)2] and [Zn(bpy*)Cl2] complexes. In the presence of the bipyridine, [ZnBr(allyl)] disproportionates into [Zn(bpy*)Br2] and [Zn(bpy*)(allyl)2] species. In separate studies, simple (E)-MeCH=CHCONMeR (R = Me, OMe) α,β-unsaturated amides undergo asymmetric 1,4-addition of EtMgBr in 75-99% yield and 48-79% ee in the presence of the diphosphines JosiPhos or MeDuPhos and copper(I) sources.

The selective cleavage of permethylated glycopyranosiduronic acid linkages by oxidative decarboxylation with lead tetraacetate

1981 ◽  
Vol 59 (6) ◽  
pp. 935-940 ◽  
Author(s):  
Gerald Oliver Aspinall ◽  
Hany Kamal Fanous ◽  
Nimal Savitri Kumar ◽  
Velupillai Puvanesarajah
Keyword(s):  
Sodium Borohydride ◽  
Gum Arabic ◽  
Lead Tetraacetate ◽  
Oxidative Decarboxylation ◽  
Hydroxyl Groups ◽  
Reaction Sequence ◽  
Pectic Acid ◽  
Acid Methyl ◽  
Sterculia Urens ◽  
Derivatives Of

Reaction of permethylated glycopyranosiduronic acids with lead tetraacetate furnishes epimeric 5-acetoxypentopyranosides as products of oxidative decarboxylation. Glycoside cleavage then occurs on treatment with sodium borohydride which affords the corresponding pentitols with exposure of aglyconic hydroxyl groups. The reaction sequence has been performed with permethylated derivatives of methyl β-melibiosiduronic acid, methyl β-gentiobiosiduronic acid, gum arabic, leiocarpan A, Sterculia urens gum, and citrus pectic acid. The scope of the reaction sequence in polysaccharide studies is discussed.

The synthesis of 1,4-diketones

1976 ◽  
Vol 29 (2) ◽  
pp. 339 ◽  
Author(s):  
S Nimgirawath ◽  
E Ritchie ◽  
WC Taylor
Keyword(s):  
Michael Addition ◽  
Addition Product ◽  
Phenacyl Bromide ◽  
Unsaturated Ketone ◽  
Lower Yield ◽  
Derivatives Of ◽  
Acyl Derivatives ◽  
Moderate Yield

Recent methods for the synthesis of 1,4-diketones are briefly reviewed.Zinc and phenacyl bromide in dimethoxyethane afforded 1,4-diphenylbutane-l,4-dione in moderate yield, but other solvents or metals examined gave no or a lower yield. The route is unsatisfactoryfor aliphatic 1,4-diketones. Attempts to use 'levulinyl chloride' to acylate olefins or acetylenes were fruitless. Routes involving aldol condensations of hexane-2,5-dione or its monoacetal had very restricted success, as did those depending on the halogenolysis of acyl derivatives of phenacylmalonic ester. A fairly general route to 1,4-diketones was found in the sequence: valine to N-acylvaline to oxazol-5-one to Michael addition product with an α, β-unsaturated ketone followed by alkaline hydrolysis.The Michael addition is not regiospecific and valine derivatives may also be isolated. Yields of 1,4-diketones are only moderate but the synthesis is quick and convenient.

Synthesis of Quaternary 1-[2-(Phosphonomethoxy)ethyl] Derivatives of 2,4-Diaminopyrimidine and Related Acyclic Nucleotide Analogs

1999 ◽  
Vol 64 (2) ◽  
pp. 242-256 ◽  
Author(s):  
Antonín Holý ◽  
Miloš Buděšínský ◽  
Jaroslav Podlaha ◽  
Ivana Císařová
Keyword(s):  
Aqueous Ammonia ◽  
Reaction Sequence ◽  
Nucleotide Analogs ◽  
Halo Derivative ◽  
Dna Viruses ◽  
X Ray ◽  
X Ray Crystallography ◽  
Subsequent Hydrolysis ◽  
Amino Pyrimidine ◽  
Derivatives Of

Quaternization of 2,4-diaminopyrimidine (2) by diisopropyl 2-chloroethoxymethanephosphonate (3) followed by bromotrimethylsilane treatment and subsequent hydrolysis gave zwitterionic N1-[2-(phosphonomethoxy)ethyl] derivative, hydrogen {[2-(2,4-diaminopyrimidin-1-io)ethoxy]methyl}phosphonate (5). Its structure was confirmed by X-ray crystallography. The same product was obtained from 2-amino-4-[(dimethylaminomethylene)amino]pyrimidine (6) by an analogous reaction sequence followed by an aqueous ammonia treatment after the transsilylation reaction. Also the quaternizations of 4,6-diaminopyrimidine (7) and 2,4,6-triaminopyrimidine (8) with the halo derivative 3 afforded the zwitterionic N1-substituted compounds 9 and 10, respectively. In contrast to this regiospecific reaction, 2-aminopyrimidine (11) gave on treatment with compound 3 and following deprotection the exo-N2-isomer 13. This compound was also obtained by the reaction starting from 2-[(dimethylaminomethylene)amino]pyrimidine (12) which was prepared by treatment of compound 11 with dimethylformamide dineopentyl acetal. Also 2,3-diaminopyridine (14) gave by the above reaction a mixture of 2-amino-3-{[2-(phosphonomethoxy)ethyl]amino}pyridine (15) and quaternary N1-[2-(phosphonomethoxy)ethyl] derivative (16). None of these analogs of the antiviral PMEDAP exhibited any antiviral activity against DNA viruses or retroviruses, nor any cytostatic activity.

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