Preparation of some new schiff bases from 5-nitrovanillin

2019 ◽  
Vol 14 (9) ◽  
pp. 76
Author(s):  
Duong Quoc Hoan ◽  
Nguyen Thi Hanh ◽  
Truong Minh Luong ◽  
Hoang Thi Nhu Quynh ◽  
Nguyen Hien
Keyword(s):  
Acetic Acid ◽  
Spectral Analysis ◽  
Schiff Bases ◽  
13C Nmr ◽  
Aromatic Amines ◽  
Condensation Reaction ◽  
Acid Catalyst ◽  
High Yields

A series of Schiff bases were synthesized successfully based on the condensation reaction between 5-nitrovanillin and aromatic amines in moderate and high yields. The condensation underwent better in DCM solvent, acetic acid catalyst and anhydrous MgSO4 as a drying agent and increased the yield up to 100 %.These new Schiff bases were determined with 1H, 13C NMR spectral analysis and compound 3a was studied further HSQC, HMBC, NOSY and MS spectra. The C=N bond exists in E conformation.

scholarly journals SYNTHESIS OF ESTERS OF HALOGENOACETIC ACIDS

2020 ◽  
Vol 2020 (3) ◽  
pp. 38-43
Keyword(s):  
Acetic Acid ◽  
Acid Catalyst ◽  
Primary Amines ◽  
Primary Alcohols ◽  
Sulfuric Acid Catalyst ◽  
Nucleophilic Exchange ◽  
Pmr Spectra ◽  
High Yields ◽  
Esterification Reactions ◽  
Acetic Acids

Amidoalkylating reagents containing a phthalimide group are used in the synthesis of hard-to-reach primary amines and complex heterocyclic compounds. These types of amidoalkylating compounds are suitable reagents for nucleophilic substituted reactions in acidic media due to their resistance to acids. Result of reactions of amidoalkylating reagents-N-hydroxyethylphthalimide and N-hydroxymethylphthalimide with aliphatic carbonic acids can also produce new bactericidal and fungicidal esters. In this study, halogen acids reacted with N-hydroxymethylphthalimide monochloric acetic acid, monobromic acetic acid, monoiodic acetic acid, trifluoric acetic acid and trichloroacetic acid, as well as, N-b-hydroxyethylphthaleidyl monohydric acid. As a result of the reactions, new phthalimidomethyl and phthalimidoethyl esters of haloacetic acids were synthesized. The physical properties of crystalline esters have been determined. The structure of these compounds were confirmed by the analysis of their IR and PMR spectra. The esterification reactions of halogenated acetic acids were carried out in a benzene solvent and a sulfuric acid catalyst with primary alcohols, N-hydroxymethylphthalimide and N-β- beta hydroxyethylphthalimide,. It was found that in a benzene solvent, which increases the rate of bimolecular nucleophilic exchange in primary alcohols, phthalimidoethyl esters of halogen acid are formed in high yields, and phthalimidomethyl esters are formed in low yields. It was shown that the reaction of esterification of halogen acids with N-hydroxymethylphthalimide proceeds with monomolecular nucleophilic exchange.

scholarly journals Green Synthesis and Antimicrobial Activity of Some Novel N-Arylimidazo[1,2-a]pyrazine-2-Carboxamide Derivatives

2019 ◽  
Vol 32 (1) ◽  
pp. 84-90 ◽  
Author(s):  
Boggavarapu Jyothi ◽  
Nannapaneni Madhavi
Keyword(s):  
Antimicrobial Activity ◽  
Carboxylic Acid ◽  
Microwave Irradiation ◽  
Green Synthesis ◽  
13C Nmr ◽  
Aromatic Amines ◽  
Condensation Reaction ◽  
Analytical Data ◽  
Ammonia Gas ◽  
1H And 13C Nmr

The article deals with the synthesis of some novel N-arylimidazo[1,2-a]pyrazine-2-carboxamides (7a-l) by condensation reaction of imidazo[1,2-a]pyrazine-2-carboxylic acid (5) with different aliphatic/aromatic amines (6a-l) by using 1-methylimidazole, Mukaiyama’s reagent and 2-chloro-1-methylpyridinium iodide under microwave irradiation conditions. A new series of compounds 7 have been prepared from 2-iodopyrazine (1). Compound 1 on purged with ammonia gas in the presence of Cu2O and K2CO3 furnishes pyrazin-2-amine (2), which is treated with ethyl 3-bromo-2-oxopropanoate (3) to produce ethyl imidazo[1,2-a]pyrazine-2-carboxylate (4), which on hydrolysis with NaOH yields imidazo[1,2-a]pyrazine-2-carboxylic acid (5). The structures of the newly synthesized compounds have been elucidated on the basis of spectral (IR, 1H and 13C NMR and MS) and analytical data. Compounds 7a-l have also been screened for their antimicrobial activity. Some of the compounds exhibit promising antimicrobial activity

PREPARATION OF KETENE FROM GLACIAL ACETIC ACID. METHYL ACETATE, AND ETHYL ACETATE

1952 ◽  
Vol 30 (4) ◽  
pp. 332-347 ◽  
Author(s):  
K. K. Georgieff
Keyword(s):  
Acetic Acid ◽  
Phosphoric Acid ◽  
Ethyl Acetate ◽  
Methyl Acetate ◽  
Maximum Yield ◽  
Acid Catalyst ◽  
Absolute Maximum ◽  
Triethyl Phosphate ◽  
Maximum Conversion ◽  
High Yields

Laboratory studies were carried out to determine whether methyl and ethyl acetates could be pyrolyzed to give yields and conversions to ketene comparable to those obtainable from acetic acid. Acetic acid was pyrolyzed to ketene and water in the presence of 0.33% triethyl phosphate or phosphoric acid catalyst at 680°–760 °C. and 140–160 mm. Hg absolute. Maximum yield obtained was 80.6% and maximum conversion 34.5%. Methyl acetate was cracked to ketene and methanol at 610°–685 °C. and 95–400 mm. absolute, using triethyl phosphate, phosphoric acid, sulphuric acid, dimethyl sulphate, butyl borate, and silica gelboric acid as catalysts. High yields could be obtained only with phosphates in 2–3% concentration. Maximum yield to ketene, including ketene recovered as acetic acid, was 76% (conversion 31–34%). Maximum yield to methanol was 81.3% (conversion 33–34%). Methyl acetate containing 18% methanol was also cracked but results were poorer. Ethyl acetate, in the presence of 0.33% triethyl phosphate, was pyrolyzed to ketene, ethylene, and water at 630°–685 °C. and 140–190 mm. absolute. Maximum yield of ketene, including ketene recovered as acetic acid, was 85.8%. Maximum conversion to ketene was 35.4% and to ketene plus acetic acid 85.7%. Yields to ethylene were nearly quantitative.

scholarly journals Grindstone Chemistry: An Efficient and Green Synthesis of 2-Amino-4H-benzo[b]pyrans

2017 ◽  
Vol 2 (2) ◽  
pp. 78 ◽  
Author(s):  
Arumugam Thangamani
Keyword(s):  
Spectral Analysis ◽  
13C Nmr ◽  
Room Temperature ◽  
Sodium Ethoxide ◽  
Single Step ◽  
Green Method ◽  
Time Saving ◽  
Solvent Free Conditions ◽  
Ft Ir ◽  
High Yields

A single step, mild, environmentally friendly green method has been developed for the synthesis of physiologically active 2-amino-4H-benzo[b]pyrans employing solid sodium ethoxide as catalyst under solvent free conditions at room temperature via grinding. The procedure is efficient, time saving and gives high yields. The structures and purity of these compounds were confirmed by elemental analysis and spectral analysis (FT-IR, 1H-NMR and 13C-NMR).

scholarly journals Synthesis, Characterization and Use of Schiff Bases as Fluorimetric Analytical Reagents

2007 ◽  
Vol 4 (4) ◽  
pp. 531-535 ◽  
Author(s):  
Mohamed N. Ibrahim ◽  
Salah E. A. Sharif
Keyword(s):  
Schiff Bases ◽  
Aromatic Amines ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Fluorescence Properties ◽  
Ph Changes ◽  
Analytical Reagents

Many Schiff bases were prepared by condensation reaction of certain aromatic amines with aromatic aldehydes derivatives, then the fluorescence properties of these Schiff bases were examined in acidic and basic media. It shows that, these compounds can be used for spectrofluorimetric monitoring of small pH changes.

scholarly journals Synthesis, Characterization and In Vitro Antibacterial Derivatives of Doxycycline

2020 ◽  
Vol 7 (4) ◽  
pp. 215-226
Author(s):  
Muhammad Rizwan Khan ◽  
Mohsin Abbas Khan ◽  
Khalil Ahmad ◽  
Asad Hamad ◽  
Muhammad Sajid-ur-Rehman ◽  
...  
Keyword(s):  
Schiff Bases ◽  
1H Nmr ◽  
13C Nmr ◽  
Broad Spectrum ◽  
Micrococcus Luteus ◽  
Condensation Reaction ◽  
Bacterial Strains ◽  
Zone Of Inhibition ◽  
Gram Negative

Objective: Nowadays antibacterial drugs resistance is major problem in the world. To overcome this problem, some novel derivates of doxycycline were synthesized by single step condensation reaction with ten different types of aromatic and aliphatic aldehydes and ketones in ethanol as solvent and acetic acid as catalyst. In these reactions, deprotonation of primary amine occurs that results in formation of imine.  Methods: All the derivatives physically characterized and confirmed by analytical techniques i.e. FTIR and 1H NMR and 13C NMR. The derived compounds have exhibited significantly more active against both gram positive as well as gram negative bacterial strains as compared to parent drug. Results: Derived Schiff bases RDC2, RDC4 and RDC10 showed zone of inhibition against Bacillus subtilis as compared to doxycycline and derived Schiff bases RDC1, RDC2, RDC5, RDC6, RDC7 and RDC8 showed more zone of inhibition against Micrococcus luteus as compared to doxycycline. Yield (75%), m.p. 180-185°C, Mol. Wt. 1063, Elemental Analysis: (Calculated) for C58H54N4O16: iC, 65.53; H, 5.12; N, 5.27; (Found): C, 65.49; H, 5.18; N, 5.37; FTIR (ν, cm‐1): 3066 (=C-H), 1665(C=N), 1585, 1490(C=C, phenyl), 3650(OH), 1692 (C=O); 1H NMR (DMSO−d6, δ, ppm), 6.02-6.03 d, 6.91-6.92 d, (=CH-); 6.88-6.89 t (=CH), 2.89-2.90 d, (-CH); 1.07-1.08 q, (-CH3), 3.38-3.39 d; 3.17-3.18 d, (CH), 1.47-1.48 t (CH), 1.48 s, (CH3), 6.96-6.97d, 7.577-7.588 d, (-CH=) 15.21 s (OH); 4.62 s (OH); 1.46-1.47 s (OH); 13C NMR (DMSO−d6, δ, ppm). Conclusion: Doxycycline is among broad-spectrum tetracycline. The Schiff bases derived from doxycycline show significantly highly active against gram negative bacteria as compared to doxycycline. In future further study on these derived compounds will help in market new derivative of doxycycline, which will have more broad-spectrum activity than doxycycline.

scholarly journals Synthesis, Identification and Biological Activity of New Heterocyclic Compounds from Reaction of New Schiff-Bases with Phathalic Anhydride

2020 ◽  
Vol 8 (1) ◽  
pp. 12-18
Author(s):  
Alya A. Dawood ◽  
Shireen R. Mmohammed ◽  
Mohammed Mahmoud
Keyword(s):  
Acetic Acid ◽  
Schiff Bases ◽  
Heterocyclic Compounds ◽  
Mass Spectra ◽  
Glacial Acetic Acid ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Aromatic Aldehydes ◽  
Heterocyclic Ring ◽  
Second Step

Series of new Schiff bases and their derivatives (Oxazepine) have been synthesized during two steps. The first step synthesis of imines derivatives (1-10) by the condensation reaction of 1, 7-diaminohepatane and 1,8-diaminooctane with different substituted aromatic aldehydes by using glacial acetic acid as catalyst. The second step includes reaction of the prepared Schiff bases derivatives with phathalic anhydride in dry benzene to obtain   seven-membered heterocyclic ring derivatives (11-15).  The biological activities of some prepared compounds were also studied against different kinds of bacteria. The new derivatives were confirmed by suing a range of experimental techniques including 1HNMR, 13C NMR, IR and Mass spectra.

An Atom Economical Concise Green Synthetic Protocol for the Synthesis of 4-Substituted Benzylidene β-Lactams Easy Access by P2O5/SiO2 Catalyzed Schiff Base

2020 ◽  
Vol 5 (1) ◽  
pp. 56-61
Author(s):  
Neha Mishra ◽  
Takallum Khan ◽  
Himanshu Pandey ◽  
Kaushal Kumar ◽  
Pankaj Kosti ◽  
...  
Keyword(s):  
Schiff Base ◽  
Green Synthesis ◽  
Schiff Bases ◽  
Lewis Acids ◽  
Condensation Reaction ◽  
Acid Catalyst ◽  
Easy Access ◽  
Acidic Property ◽  
Reusable Catalyst ◽  
Green Protocol

A simple and efficient protocol for the synthesis of Schiff bases via condensation reaction of electron rich heterocyclic amines with electrophilic carbon of the carbonyl compound. Recently an impressive and important area in catalysis involved organic synthesis is the best implementation of Lewis acids as a acid catalyst for Schiff base synthesis. The higher acidic property and proper loading of catalyst leads to proper participation in reaction as a catalyst. The reactions of these Lewis acids are enhanced by porous solid support as heterogeneous catalyst. We report herein an efficient concise green synthesis of a new kind of β-lactam derivatives of 2-amino-6-nitro-benzothiazole via SiO2/P2O5 Lewis acid catalyzed Schiff bases. The reaction was carried out by the preparation of Schiff base through the condensation reaction of various aromatic aldehydes with substituted aromatic amines in the presence of P2O5/SiO2 under green conditions by simple conventional methods. Further this Schiff base used for the green synthesis of β-lactams by the reaction with chloro-acetyl chloride. The advantage of this reaction is good dispersion of active reagent sites, associated selectivity and easier work up with reusable catalyst. These qualities combined together prove these processes as truly eco-friendly green protocol with high product yields and short reaction time.

Adipic Acid as a Biodegradable Solid Acid Catalyst for One-Pot, Three Component Synthesis of 1-Amidoalkyl-2-naphthols

2019 ◽  
Vol 7 (1) ◽  
pp. 34-43
Author(s):  
Hassan Darbandi ◽  
Hamzeh Kiyani
Keyword(s):  
Adipic Acid ◽  
Biological Activities ◽  
Condensation Reaction ◽  
Solid Acid Catalyst ◽  
Reaction Times ◽  
Acid Catalyst ◽  
Ultrasonic Waves ◽  
One Pot ◽  
Solvent Free Conditions ◽  
High Yields

Background: 1-Amidoalkyl-2-naphthols are an attractive group of organic compounds that can be converted to oxazine heterocycles and aminoalkyl naphthols. The derivatives of 1- amidoalkyl-2-naphthols have significant biological activities and act as drug candidates. Methods: 1-Amidoalkyl-2-naphthols were synthesized via the three-component condensation reaction of 2-naphthol, acetamide/benzamide and various aldehydes in the presence of 10 mol% of adipic acid as an organocatalyst under solvent-free conditions at 120°C. Results: A simple, efficient, and operative method for the synthesis of 1-amidoalkyl-2-naphtholes in the presence of adipic acid as the biodegradable catalyst is introduced. Easy operation, acceptable reaction times, eco-friendly, availability of starting materials, simple separation of products, and high yields of products are the significant results of this method. Conclusion: In this study, 1-amidoalkyl-2-naphthols were synthesized using commercially available reactants in excellent yields and relatively shorter times. In this process, microwave or ultrasonic waves were not used to provide energy for the reaction.

scholarly journals Synthesis of substituted (oxazepine, Diazepine, tetrazde) via Schiff Bases for 2- Aminobenzo Thaizole Derivatives

2013 ◽  
Vol 10 (3) ◽  
pp. 736-748 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Nmr Spectroscopy ◽  
Schiff Bases ◽  
13C Nmr ◽  
Sodium Azide ◽  
Aromatic Amines ◽  
13C Nmr Spectroscopy ◽  
Aldehydes And Ketones ◽  
Primary Aromatic Amines ◽  
Ft Ir ◽  
Tetrazole Derivatives

This work includs synthesis of several Schiff bases by condensation of 6- methoxy – 2- amino benzothiazole with some aldehydes and ketones (2- hydroxyl benzaldehyde, 4- hydroxyl benzaldehyde, 4- N,N –dimethy amino acetophenone, benzophenone) to abtain schiff bases (1-5). These schiff bases were found to react with phthalate anhydride to give oxazepine derivatives (6-10) that were reacted with primary aromatic amines to give Diazepine derivatives (11-15). Besides, we prepared new tetrazole derivatives (16-20) from the reaction of the prepared Schiff bases with sodium azide in the prepared compounds that were characterized by physical properties, FT-IR and some of the 1H-NMR and 13C –NMR spectroscopy.

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