Molecules

174 KiB

Open AccessArticle

Microwave-Accelerated or Conventionally Heated Iodination Reactions of Some Aromatic Amines, Using ortho-Periodic Acid as the Oxidant †

by Maciej Sosnowski, Lech Skulski and Katarzyna Wolowik

Molecules 2004, 9(7), 617-621; https://doi.org/10.3390/90700617 - 30 Jun 2004

Cited by 11 | Viewed by 6922

Abstract

A fast and simple method for the oxidative iodination of some aromatic amines, either under microwave irradiation or conventional heating, is reported, using diiodine and ortho-periodic acid as the oxidant. The reactions were carried out in boiling CH2Cl2 solutions under a reflux condenser. [...] Read more.

A fast and simple method for the oxidative iodination of some aromatic amines, either under microwave irradiation or conventional heating, is reported, using diiodine and ortho-periodic acid as the oxidant. The reactions were carried out in boiling CH2Cl2 solutions under a reflux condenser. For the microwave assisted reactions, the reaction times were always notably shortened, but the yields were usually less influenced as compared with the conventional method. Full article

160 KiB

Open AccessArticle

Syntheses of Quinazoline-2,4-dione Alkaloids and Analogues from Mexican Zanthoxylum Species †

by I. A. Rivero, K. Espinoza and R. Somanathan

Molecules 2004, 9(7), 609-616; https://doi.org/10.3390/90700609 - 30 Jun 2004

Cited by 49 | Viewed by 11322

Abstract

Quinazolinone and quinazolinedione derivatives are of considerable interest due to their wide array of pharmacological properties. In this paper we report the synthesis of ten quinazolinediones. The previous isolation of two of these compounds, namely 1-methyl-3-(2'-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2'-(4'- methoxyphenyl)ethyl]-lH,3H-quinazoline-2,4-dione, from the seed husks [...] Read more.

Quinazolinone and quinazolinedione derivatives are of considerable interest due to their wide array of pharmacological properties. In this paper we report the synthesis of ten quinazolinediones. The previous isolation of two of these compounds, namely 1-methyl-3-(2'-phenylethyl)-1H,3H-quinazoline-2,4-dione and 1-methyl-3-[2'-(4'- methoxyphenyl)ethyl]-lH,3H-quinazoline-2,4-dione, from the seed husks of Mexican Zanthoxylum species has been reported Full article

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176 KiB

Open AccessArticle

Isolation and Structure Elucidation of a Flavanone, a Flavanone Glycoside and Vomifoliol from Echiochilon Fruticosum Growing in Tunisia

by S. Hammami, H. Ben Jannet, A. Bergaoui, L. Ciavatta, G. Cimino and Z. Mighri

Molecules 2004, 9(7), 602-608; https://doi.org/10.3390/90700602 - 30 Jun 2004

Cited by 70 | Viewed by 11896

Abstract

A flavanone and a flavanone glycoside, together with vomifoliol, have been isolated for the first time from the aerial parts of the plant Echiochilon fruticosum and identified. Their structures were established on the basis of spectroscopic measurements, mainly 2D NMR using COSY, HMQC [...] Read more.

A flavanone and a flavanone glycoside, together with vomifoliol, have been isolated for the first time from the aerial parts of the plant Echiochilon fruticosum and identified. Their structures were established on the basis of spectroscopic measurements, mainly 2D NMR using COSY, HMQC and HMBC experiments. Full article

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153 KiB

Open AccessArticle

Chemical Manganese Dioxide (CMD): lts Application to the Oxidative Iodination of Benzene, Halobenzenes and Some Deactivated Arenes †

by Piotr Lulinski, Barbara Krassowska-Swiebocka and Lech Skulski

Molecules 2004, 9(7), 595-601; https://doi.org/10.3390/90700595 - 30 Jun 2004

Cited by 10 | Viewed by 9372

Abstract

After comparing our previous and newer results for numerous oxidativearomatic iodination experiments using various brands of active MnO₂ as the oxidants,we recommend the use of a Chemical Manganese Dioxide (Aldrich CMD; 90 %MnO₂) as the oxidant of choice, since it [...] Read more.

After comparing our previous and newer results for numerous oxidativearomatic iodination experiments using various brands of active MnO₂ as the oxidants,we recommend the use of a Chemical Manganese Dioxide (Aldrich CMD; 90 %MnO₂) as the oxidant of choice, since it is satisfactorily pure and chemically active, andis notably less costly than other options. Full article

189 KiB

Open AccessArticle

Complexes of 3.6 kDa Maltodextrin with Some Metals

by Piotr Tomasik, James W. Anderegg and Christopher H. Schilling

Molecules 2004, 9(7), 583-594; https://doi.org/10.3390/90700583 - 30 Jun 2004

Cited by 5 | Viewed by 8010

Abstract

Preparation of magnesium, lanthanum, and bismuth(III) complexes of 3.6 kDa maltodextrin and some properties of the resulting materials are presented. The metal derivatives contain metals bound to the oxygen atoms of the hydroxyl groups of maltodextrin. Additionally, the metal atoms are coordinated to [...] Read more.

Preparation of magnesium, lanthanum, and bismuth(III) complexes of 3.6 kDa maltodextrin and some properties of the resulting materials are presented. The metal derivatives contain metals bound to the oxygen atoms of the hydroxyl groups of maltodextrin. Additionally, the metal atoms are coordinated to the hydroxyl groups of the D-glucose units of the macroligand. Such coordination stabilized the metal – oxygen bond against hydrolysis, even in boiling water. The presence of magnesium and lanthanum atoms increased the thermal stability of maltodextrin, whereas bismuth atoms decreased it. Full article

180 KiB

Open AccessArticle

A Novel Synthesis of Arylpyrrolo[1,2-a]pyrazinone Derivatives

by Fei Wang, Jiawei Wang and Shoufang Zhang

Molecules 2004, 9(7), 574-582; https://doi.org/10.3390/90700574 - 30 Jun 2004

Cited by 9 | Viewed by 9598

Abstract

Some aryl-2-methyl-1-pyrrolo[1,2-a]pyrazinones were designed and prepared to study the Structure-Activity Relationships (SAR) of pyrrolo[1,2-a]pyrazinone derivatives. With methyl pyrrole-2-carboxylate as the starting material, the title compounds were prepared through N-alkylation and two novel cyclizations. Eleven aryl-2-methyl-1- pyrrolo[1,2-a]pyrazinone derivatives not previously reported in the literature [...] Read more.

Some aryl-2-methyl-1-pyrrolo[1,2-a]pyrazinones were designed and prepared to study the Structure-Activity Relationships (SAR) of pyrrolo[1,2-a]pyrazinone derivatives. With methyl pyrrole-2-carboxylate as the starting material, the title compounds were prepared through N-alkylation and two novel cyclizations. Eleven aryl-2-methyl-1- pyrrolo[1,2-a]pyrazinone derivatives not previously reported in the literature are presented in this paper. Some of them show potent anti-inflammatory and analgesic activities. Full article

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152 KiB

Open AccessArticle

Flavone Glycosides from Calycotome Villosa Subsp. Intermedia

by Ali El Antri, Ibtissam Messouri, Rachida Chendid Tlemçani, Mohamed Bouktaib, Rachid El Alami, Brahim El Bali and Mohammed Lachkar

Molecules 2004, 9(7), 568-573; https://doi.org/10.3390/90700568 - 30 Jun 2004

Cited by 26 | Viewed by 11649

Abstract

The known flavonoid chrysin-7-O-(β-D-glycopyranoside) (chrysin glucoside,1) as a major fraction and a new glycoside flavone, chrysin-7-O-β-D-[(6”-acetyl)glycopyranoside] (2) were isolated from the flowers and leaves of CalycotomeVillosa Subsp. Intermedia, They were identified by UV-Vis, 1R, ¹H-, ¹³C-NMR and ESI-MS. Full article

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248 KiB

Open AccessArticle

Polymeric Complexes of Cornstarch and Waxy Cornstarch Phosphates with Milk Casein and Their Performance as Biodegradable Materials

by Dorota Najgebauer, Tadeusz Grega, Marek Sady and Piotr Tomasik

Molecules 2004, 9(7), 550-567; https://doi.org/10.3390/90700550 - 30 Jun 2004

Cited by 9 | Viewed by 8283

Abstract

Complexes of phosphated cornstarch and waxy cornstarch with casein were prepared and characterised. They were prepared from casein in defatted milk and corn and waxy corn starches phosphated to degree of substitution values (DS) of 0.0637 and 0.0968, respectively. The components were blended [...] Read more.

Complexes of phosphated cornstarch and waxy cornstarch with casein were prepared and characterised. They were prepared from casein in defatted milk and corn and waxy corn starches phosphated to degree of substitution values (DS) of 0.0637 and 0.0968, respectively. The components were blended in starch to casein ratios of 2:1, 1:1, and 1:2, then precipitated with hydrochloric acid. Aqueous solubility, water binding capacity, IR spectra, and thermal analysis (thermogravimetry, TG, and differential thermogravimetry, DTG) of the precipitates revealed that they were not simple physical mixtures of the components. The components interact with one another electrostatically with involvement of the starch phosphate groups and the peptide bonds of casein as documented by the IR spectra. Because of their insolubility in 7 M aqueous urea solution they might also be considered as complexes in which the components were chemically bound. Enzymatic studies showed that they are biodegradable materials. Full article

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Figure 1
(1) Differential FTIR spectra of casein/GPWCS 2:1 complex from which (a) the spectrum of GPWCS was subtracted and (b) the spectrum of casein was added for comparison; (2) Differential FTIR spectrum of the same complex from which (a) the spectrum of casein was subtracted and (b) the spectrum of GPWCS added for comparison. Full article ">Figure 2
(1) Differential FTIR spectra of casein/GPCS 1:1 complex from which (a) the spectrum of GPCS was subtracted and (b) the spectrum of casein was added for comparison; (2) Differential FTIR spectrum of the same complex from which spectrum of casein was subtracted (a) and spectrum of GPCS (b) added for comparison. Full article ">Figure 3
(1) Differential FTIR spectra of casein/PPWCS 1:2 complex from which (a) the spectrum of PPWCS was subtracted and (b) the spectrum of casein was added for comparison; (2) Differential spectrum of the same complex from which spectrum of casein was (a) subtracted and (b) the spectrum of PPWCS added for comparison. Full article ">Figure 4
Thermogram (TG, DTG, DTA) of GPWCS in the 25-500 °C range. Full article ">Figure 5
Thermogram (TG, DTG, DTA) of casein/PPCS 2:1 complex in the 25-500 °C range. Full article ">Figure 6
Thermogram (TG, DTG, DTA) of casein/GPCS 1:1 complex in the 25-500°C range. Full article ">Figure 7
Thermogram (TG, DTG, DTA) of casein/GPCS 1:2 complex in the 25-500°C range. Full article ">

186 KiB

Open AccessArticle

Isomerization Reactions of Allylic Alcohols into Ketones with the Grubbs Reagent

by Katsuyuki Nakashima, Sanae Okamoto, Masakazu Sono and Motoo Tori

Molecules 2004, 9(7), 541-549; https://doi.org/10.3390/90700541 - 30 Jun 2004

Cited by 10 | Viewed by 11479

Abstract

Allylic alcohols were isomerized into ketones by the action of the Grubbs reagent. Some model alcohols were prepared and tested under similar conditions to reveal that less substituted alkenes rearrange more easily. More hindered alcohols are stable under these conditions, however, the simple [...] Read more.

Allylic alcohols were isomerized into ketones by the action of the Grubbs reagent. Some model alcohols were prepared and tested under similar conditions to reveal that less substituted alkenes rearrange more easily. More hindered alcohols are stable under these conditions, however, the simple allylic alcohols tend to isomerize producing ethyl ketone and the corresponding degraded methyl ketone. Full article

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171 KiB

Open AccessArticle

Formation of the Imidazolinone Ring Under Mild Conditions in the Presence of Sodium Hydride

by Aleksey N. Vasiliev, Antonio F. Lopez, Julio D. Fernandez and Anibal J. Mocchi

Molecules 2004, 9(7), 535-540; https://doi.org/10.3390/90700535 - 30 Jun 2004

Cited by 7 | Viewed by 9745

Abstract

Substituted imidazolinones containing heterocyclic carboxylic acids as substituents and possessing herbicidal properties were synthesized by cyclization of 2-amino-2,3-dimethylbutyramide with heterocyclic ethyl dicarboxylates under mild conditions. The use of NaH as base leads to a significant increase in the reaction rate and allows the [...] Read more.

Substituted imidazolinones containing heterocyclic carboxylic acids as substituents and possessing herbicidal properties were synthesized by cyclization of 2-amino-2,3-dimethylbutyramide with heterocyclic ethyl dicarboxylates under mild conditions. The use of NaH as base leads to a significant increase in the reaction rate and allows the preparation of the target compounds in high yields. Full article

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183 KiB

Open AccessArticle

One Step Regioselective Synthesis of 5-Aminoisoxazoles from Nitrile Oxides and α-Cyanoenamines

by Amar Saad, Michel Vaultier and Aïcha Derdour

Molecules 2004, 9(7), 527-534; https://doi.org/10.3390/90700527 - 30 Jun 2004

Cited by 3 | Viewed by 8659

Abstract

The 1,3-dipolar cycloaddition of nitrile oxides to 1-cyanoenamines gives 5-aminoisoxazoles regioselectively. Moderate to good yields could be obtained depending on the method used to generate the nitrile oxides. The intermediate isoxazolines could not be isolated. Full article

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170 KiB

Open AccessArticle

Fluorescence Studies of Selected 2-Alkylaminopyrimidines

by Z. Abdullah, N. Mohd Tahir, M. R. Abas, Z. Aiyub and B. K. Low

Molecules 2004, 9(7), 520-526; https://doi.org/10.3390/90700520 - 30 Jun 2004

Cited by 2 | Viewed by 7647

Abstract

The reactions of 2-chloropyrimidine with methylamine, ethylamine and piperidine gave the corresponding 2-N-methylamino-, 2-N-ethylamino- and 2N- piperidinopyrimidines, respectively. The fluorescence properties of these alkylamino derivatives in chloroform, ethyl acetate, carbon tetrachloride, acetone, ether, ethanol and methanol were studied. All the alkylamino derivatives showed [...] Read more.

The reactions of 2-chloropyrimidine with methylamine, ethylamine and piperidine gave the corresponding 2-N-methylamino-, 2-N-ethylamino- and 2N- piperidinopyrimidines, respectively. The fluorescence properties of these alkylamino derivatives in chloroform, ethyl acetate, carbon tetrachloride, acetone, ether, ethanol and methanol were studied. All the alkylamino derivatives showed the highest fluorescence intensity in polar protic solvents; thus 2-N-methylaminopyrimidine (highest fluorescence intensity at 377 nm when excited at 282 nm) and 2-N-ethylaminopyrimidine (highest fluorescence intensity at 375 nm, when excited at 286 nm) showed the highest fluorescence in methanol. In ethanol, 2-N-piperidinopyrimidine showed a fluorescence peak at 403 nm when excited at 360 nm and in chloroform it fluoresced at 392 nm when excited at 356 nm. Full article

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Molecules, Volume 9, Issue 7 (July 2004) – 12 articles , Pages 520-621

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