scholarly journals Synthesis of some 16,17-secoandrost-5-ene derivatives

2010 ◽  
Vol 64 (2) ◽  
pp. 81-84 ◽  
Author(s):  
Andrea Gakovic ◽  
Maja Djurendic-Brenesel ◽  
Evgenija Djurendic ◽  
Katarina Penov-Gasi ◽  
Marija Sakac
Keyword(s):  
Main Reaction ◽  
Main Reaction Product ◽  
Formyl Group ◽  
Ms Analysis ◽  
Oppenauer Oxidation ◽  
Derivatives Of

Starting from 3?-acetoxy-17-oxo-16,17-secoandrost-5-ene-16-nitrile (1), 3?-acetoxy-16,17-secoandrost-5-ene-16-nitrile (4) was synthesized by a three-stage procedure. First, the formyl group of compound 1 was reduced, to yield the alcohol 2. Compound 2 was further transformed to the mesyloxy derivative 3, whose reduction with NaBH3CN gave compound 4. Apart from compound 4 as the main reaction product, two additional products were obtained, for which the GC/MS analysis suggested that they are 8(14) and 14 derivatives of compound 4. Compound 4 was transformed into 3?-hydroxy-16,17-sesoandrost-5-ene-16-nitrile (7), the Oppenauer oxidation of which afforded 3-oxo-16,17-secoandrost-4-ene-16-nitrile (8).

The chemistry of pyrrolic compounds. XXV. The chemistry of acetal and thioacetal derivatives of pyrrolic systems

1974 ◽  
Vol 27 (2) ◽  
pp. 357 ◽  
Author(s):  
PS Clezy ◽  
CJR Fookes ◽  
DYK Lau ◽  
AW Nichol ◽  
GA Smythe
Keyword(s):  
Formyl Group ◽  
Derivatives Of

The synthesis of acetal and thioacetal derivatives of simple pyrroles is described. Methods are reported which allow the use of the thioacetal function as a means of protecting a formyl group in a pyrrolic molecule during the preparation of a dipyrrylmethane. By this procedure certain α-formyldipyrrylmethanes, not accessible by other methods, have been obtained.

Investigations on Phosphate Cements Hardening at Room Temperature

1989 ◽  
Vol 179 ◽  
Author(s):  
Alfred Zurz ◽  
I. Odler ◽  
B. Dettki
Keyword(s):  
Ultimate Strength ◽  
Room Temperature ◽  
Main Reaction ◽  
Main Reaction Product

AbstractPastes prepared from diammonium orthophosphate and calcined magnesia, MgO, exhibit a fast setting and hardening associated with NH3 liberation. Struvite, MgNH4PO4.6H2O, was found to be the main reaction product. Pastes made with NaH2PO4 or Na-polyphosphate exhibit a similar hardening reaction. The hardening reaction may be retarded and the ultimate strength moderately increased by adding appropriate retarders, such as Na2B4O7 10H2O to the system. The quality of the used MgO and its fineness has a significant effect on the rate of the hardening reaction.

GC-MS Analysis of Acylated Derivatives of Methamphetamine and Regioisomeric Phenethylamines

1995 ◽  
Vol 33 (9) ◽  
pp. 485-492 ◽  
Author(s):  
C. R. Clark ◽  
J. DeRuiter ◽  
A. K. Valaer ◽  
F. T. Noggle
Keyword(s):  
Ms Analysis ◽  
Derivatives Of

scholarly journals Oxidative Destruction of Vulcanized by Changing the Dispersion Composition of Oxidized Vulcanized

2021 ◽  
pp. 207-214
Author(s):  
Milen Dimov ◽  
Zhuldyz Smailova
Keyword(s):  
Nitric Acid ◽  
Ir Spectra ◽  
Structural Changes ◽  
Main Reaction ◽  
Chemical Heterogeneity ◽  
Main Reaction Product ◽  
Oxidative Destruction ◽  
Rubber Component ◽  
Acetone Extracts ◽  
Dispersion Composition

The aim of the present work is to study the processes of oxidative destruction of waste vulcanizates (flakes) with nitric acid. The composition of the particles of the main reaction product was determined (oxidized vulcanized). The IR spectra of hexane and acetone extracts of the oxidized vulcanizates are also presented. It was found that the rubber component of the vulcanizates undergoes deep structural changes leading to the formation of products characterized by chemical heterogeneity

scholarly journals Hundred Years of Lactitol: From Hydrogenation to Food Ingredient

2020 ◽  
Author(s):  
Sergio I. Martinez-Monteagudo ◽  
Kaavya Rathnakumar ◽  
Maryam Enteshari ◽  
Collette Nyuydze ◽  
Juan C. Osorio-Arias ◽  
...  
Keyword(s):  
Historical Development ◽  
Main Reaction ◽  
Chewing Gum ◽  
Main Reaction Product ◽  
Food Ingredient ◽  
First Report

The first report on the synthesis of lactitol dates back to the early 1920s. Nearly 100 years have passed since then, and the applications of lactitol have exceeded its original purpose. Currently, lactitol is used in bakery, confectionery, chocolate, desserts, chewing gum, cryoprotectant, delivery agent, and stabilizer in biosensors. Lactitol is the main reaction product derived from the hydrogenation of lactose. This chapter is aimed at providing a succinct overview of the historical development of lactitol, a summary of its synthesis, and an overview of its properties and applications.

scholarly journals Synthesis, Antimicrobial and Antioxidant Activities of 2-Isoxazoline Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (18) ◽  
pp. 4271
Author(s):  
Asma Alshamari ◽  
Mahmoud Al-Qudah ◽  
Fedaa Hamadeh ◽  
Lo’ay Al-Momani ◽  
Sultan Abu-Orabi
Keyword(s):  
Antioxidant Activity ◽  
Sulfonic Acid ◽  
Antioxidant Activities ◽  
Bacterial Species ◽  
Antibacterial Activities ◽  
Ms Analysis ◽  
Diammonium Salt ◽  
New Compounds ◽  
Derivatives Of

A series of derivatives of trans-3-(2,4,6-trimethoxyphenyl)4,5-dihydroisoxazolo-4,5-bis[carbonyl-(4′phenyl)thiosemicarbazide (9) and of trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydro isoxazolo-4,5-bis(aroylcarbohydrazide) (10a–c) were synthesized from trans-3-(2,4,6-trimethoxyphenyl)-4,5-dihydro-4,5-bis(hydrazenocarbonyl)isoxazole (8). The structures of the compounds were elucidated by both elemental and spectral (IR, NMR, and MS) analysis. Compound 9 shows activity against some bacterial species. No antibacterial activities were observed for compounds 10a–c. The antioxidant activity of the new compounds has been screened. Compound 9 showed higher antioxidant activity using the DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS (2’-azino–bis(3-ethylbenzoline-6-sulfonic acid) diammonium salt methods.

THE SOLVOLYSIS OF THE ALPHA- AND BETA-3,4,6-TRI-O-ACETYL-D-GLUCOPYRANOSYL CHLORIDES

1955 ◽  
Vol 33 (1) ◽  
pp. 128-133 ◽  
Author(s):  
R. U. Lemieux ◽  
G. Huber
Keyword(s):  
Acetic Acid ◽  
Double Bond ◽  
Positive Charge ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Double Bond Character ◽  
Ionic Reactions ◽  
Oxygen Bond ◽  
Bond Character ◽  
Anomeric Center

3,4,6-Tri-O-acetyl-β-D-glucopyranosyl chloride was found to undergo solvolysis in acetic acid to form 1,3,4,6-tetra-O-acetyl-α-D-glucopyranose as the main reaction product. The much less reactive anomeric α-chloride also appeared to undergo solvolysis with extensive inversion of the anomeric center. It is submitted that the tendencies for inversion obtained in these ionic reactions are due to the conformations imposed on the intermediate ions through distribution of the positive charge to the ring oxygen and the consequent introduction of double-bond character to the carbon-1 to ring-oxygen bond.

Lightweight magnesium phosphate cement composites with struvite recovered from wastewater

2020 ◽  
Author(s):  
Parisa Setayesh Gar ◽  
Sergey Lobanov ◽  
Matteo Pernechele ◽  
Cristina Zanotti
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Potassium Dihydrogen Phosphate ◽  
Magnesium Phosphate ◽  
Main Reaction ◽  
Dihydrogen Phosphate ◽  
Main Reaction Product ◽  
Lightweight Composites ◽  
Phosphate Source

A feasibility study was performed to utilize struvite, in combination with magnesium oxide (MgO), to develop magnesium phosphate cement. The struvite was a wastewater by-product from a sewage treatment plant in British Columbia, Canada. To achieve MgO-phosphate reactivity in water, two types of recycled struvite were used: heated struvite and newberyite (i.e. rehydrated struvite). A more common phosphate source, Potassium Dihydrogen Phosphate (KDP) was also adopted and replaced in different proportions by recycled struvite. Perlite was incorporated to produce lightweight composites for building applications at different strength-density ratios. Microstructural/chemical analyses were complemented with compressive strength tests at different ages. Reactivity with MgO was achieved for both heated struvite and newberyite. The main reaction product was cattite but reactivity of less soluble newberyite was lower. KDP had the fastest reaction leading to the formation of K-struvite. The lightweight composites achieved up to 90% of their strength in 7 days.

scholarly journals Allyl type monomers for hard surface coating protection

2019 ◽  
Vol 140 ◽  
pp. 02007
Author(s):  
Larisa Popova ◽  
Anzhelika Tsyrulnikova ◽  
Sergey Vershilov ◽  
Julia Bazarnova ◽  
Ekaterina Aronova ◽  
...  
Keyword(s):  
Tetrabutylammonium Bromide ◽  
Environmental Safety ◽  
Carbon Chain ◽  
High Yield ◽  
Main Reaction ◽  
Fibrous Materials ◽  
Series Of Experiments ◽  
Work Up ◽  
Derivatives Of ◽  
Improve Mass Transfer

Based on the unsaturated derivatives of polyfluoroalkanols chemical products are used to protect solid and fibrous materials surface from the effects of water, oils and other pollutants. A method for obtaining allyl ethers of polyfluoroalkanols (polyfluoroalkoxypropenes) is based on the Williamson ether reaction. This method is a heterophase process. The use of solvents to improve mass transfer requires complementary measures to ensure industrial and environmental safety. It is more preferable to obtain the target ethers in water with PTC. A series of experiments using different chain length polyfluoroalkanols was studied by GLC. Kovats retention indexes of the target ethers were determined. It was found that in the case of lower homologues (CF3CH2OH, (CF3)2CHOH, HCF2CF2CH2OH), the addition of 5-15 vol.% 1,4-dioxane as a solubilizer provides a high yield of products. The application of PTC (tetrabutylammonium bromide) is indispensable for using polyfluoroalkanols with a longer carbon chain (C≥5). PTC invariably provides the almost complete conversion of polyfluoroalkanols. The decomposition process of TBAB becomes noticeable (GLC method) upon completion of the main reaction. Polyfluoroalkoxypropenes form azeotrope with water, which can be used in the work up process.

scholarly journals Experimental Analysis and Modeling of Nitrate Removal through Zero-Valent Magnesium Particles

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1276 ◽  
Author(s):  
Siciliano ◽  
Curcio ◽  
Limonti
Keyword(s):  
Nitrate Concentration ◽  
Nitrate Removal ◽  
Experimental Results ◽  
Process Efficiency ◽  
Main Reaction ◽  
Main Reaction Product ◽  
Nitrogen Forms ◽  
Sustainable Technologies ◽  
Batch Tests ◽  
Effects Of Ph

The pollution of water by nitrates represents an important environmental and health issue. The development of sustainable technologies that are able to efficiently remove this contaminant is a key challenge in the field of wastewater treatment. Chemical denitrification by means of zero-valent metallic elements is an interesting method to reduce the oxidized forms of nitrogen. Compared to other metallic reactants, zero-valent magnesium (ZVM) has many profitable aspects, but its use for nitrate removal has scarcely been investigated. In the present work, several batch tests were conducted to examine the concurrent effects of pH, initial nitrate concentration and Mg0 quantity on process performance. The experimental results proved that at pH 3, for a given initial nitrate concentration, the dose of ZVM largely influences process efficiency. In particular, with a ratio between Mg0 and initial N-NO3− amount (Mg/NNi) of 0.33 g/mg, it is possible to obtain complete denitrification within 30 min. Beyond this ratio, no further improvement of treatment was observed. The experiments allowed us to identify the nitrogen forms produced during the treatment. Nitrogen gas was generally the main reaction product, but the trends of the different compounds (NO3−, NO2−, NH4+ and N2) notably changed in response to the modification of operating parameters. Moreover, the results demonstrated that, in a highly acidic environment, when treating solutions with a low nitrate concentration, process performances are unsatisfactory even when using a high Mg/NNi ratio. By increasing the process pH to 5 and 7, a significant denitrification decline occurred. Furthermore, at these pH levels, the enhancement of nitrate concentration caused a progressive process deterioration. Through detailed analysis of experimental results, reactions kinetics and new mathematical equations, able to describe the trends of different nitrogen forms, have been defined. Moreover, reactions pathways have been proposed. Finally, the characterization of exhausted material allowed us to identify the corrosion products formed during the treatment.

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