Design and Synthesis of Antimicrobial Active (E)‐(3‐(Substituted‐styryl)‐7H‐furo[2,3‐f]chromen‐2‐yl)(phenyl)methanone Derivatives and Their In Silico Molecular Docking Studies

Nine new (E)‐(3‐(substituted‐styryl)‐7H‐furo[2,3‐f]chromen‐2‐yl)(phenyl)methanone derivatives, 7 ( a – i ), with an efficient microwave‐assisted synthetic method was achieved by reacting with (E)‐3‐(aryl)‐1‐(5‐hydroxy‐2H‐chromen‐6‐yl)prop‐2‐en‐1‐ones and 2‐bromo‐1‐(4‐bromophenyl)ethanone. The microwave irradiation method was found to be best with high yields and with shorter reaction times compared with the conventional method. All the new products structural assignments were confirmed by spectral data like FTIR, ¹H NMR, ¹³C NMR, ESI MS, and analytical data. Moreover, these newly synthesized compounds were tested in vitro for their antimicrobial activity against various bacterial and fungal strains. Some of these new chromen derivatives like 7b , 7c , and 7d exhibits good antibacterial and antifungal activities. Furthermore, these biological evolution results were a good correlation with molecular docking studies performed based on their computational DFT minimized structures exhibited high binding energies.     

Synthesis,Pharmacological, and Biological Screening of Novel Derivatives of Benzodiazepines

A series of novel 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine have been synthesized from 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one. 3‐(Substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one was prepared by condensing 2‐acetyl thiophene with various aromatic aldehydes in the presence of 20% NaOH as base. Different 3‐(substituted phenyl)‐1‐(thiophen‐2‐yl)prop‐2‐en‐1‐one on cyclization with o‐phenylenediamine in the presence of NaOH as base resulted in 4‐(substituted phenyl)‐2‐(thiophen‐2‐yl)‐2,3‐dihydro‐1H‐benzo[b][1,4]diazepine derivatives. The structures of synthesized compounds are confirmed by IR, ¹H NMR, mass spectra, and elemental analysis. All the compounds have been screened for their antimicrobial, analgesic, and anti‐inflammatory activities.     

Regioselective Synthesis and Antibacterial Activity Studies of 1,2,3‐Triazol‐4‐YL]‐4‐methyl‐2H‐chromen‐2‐ones

Synthesis, spectral analysis, and antibacterial activity of new coumarin derivatives are described in this paper. Twelve new coumarin derivatives were synthesized in moderate to good yields by the react with 4‐methyl‐6‐(prop‐2‐ynyloxy)‐2H‐chromen‐2‐one ( 3a – c ) and ethyl azide ( 4a – l ) and done by the click reaction to obtained 6‐[(l‐ethyl‐lH‐l,2,3‐triazol‐4‐yl)methoxy]‐4‐methyl‐2H‐chromen‐2‐ones ( 5a – l ). The structures of all the newly synthesized molecules were assigned by elemental analysis and spectral data. The synthesized compounds were screened for their antibacterial activities strains using Cup plate method.     

Synthesis and Antimicrobial Screening of Some Novel 2‐(5‐(4‐(1H‐Benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols Incorporated by Triazole Moiety

A novel series of 2‐(5‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐4,5‐dihydro‐1H‐pyrazol‐3‐yl)phenols derivative has been synthesized from (E)‐3‐(4‐(1H‐benzo[d][1,2,3]triazol‐1‐yl)phenyl)‐1‐(2‐hydroxyphenyl)prop‐2‐en‐1‐ones in ethanol and hydrazine hydrate under reflux condition. The synthesized compounds were screened for antibacterial activity against Gram‐positive bacteria viz Staphylococcus aureus and Bacillus subtilis and Gram‐negative bacteria viz Escherichia coli and Salmonella typhi, respectively. Some of the tested compounds showed significant antimicrobial activity. IR, ¹H NMR, mass spectral data, and elemental analysis elucidated the structures of all the newly synthesized compounds.     

Synthesis of some new 1‐acyl‐5‐aryl‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐4,5‐dihydro‐1H‐pyrazole

Some new compounds (E)‐3‐aryl‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐prop‐2‐en‐1‐ones 5a–e were prepared by 1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐ethanone and various aromatic aldehydes. Then one pot reaction was happened by compounds 5a–e with hydrazine hydrate in acetic acid or propionic acid, respectively, to give the title compounds 1acyl‐5‐aryl‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐4,5‐dihydro‐1H‐pyrazoles 6a–i . All structures were established by MS, IR, CHN, ¹H‐NMR and ¹³C‐NMR spectral data. J. Heterocyclic Chem., (2012).     

Synthesis of novel isoindolone‐based medium‐sized macromolecules and triazole containing heterocyclic compounds

A series of novel isoindolone‐based macromolecules of medium‐sized heterocyclic rings, such as 7,8‐dihydro‐6H‐benzo[4,5][1,6,3]dioxazonino[2,3‐a]isoindol‐14(9aH)‐one derivatives ( 5a‐l ), were synthesized and its frame work incorporating with a triazole moiety on phenol, ie, 2‐(4‐((1‐(2‐methoxyphenyl)‐1H‐1,2,3‐triazol‐4‐yl)methoxy)phenyl)isoindoline‐1,3‐dione ( 9a‐f ) and also a triazole moiety on carboxylic acid, ie, (1‐(2‐methoxyphenyl)‐1H‐1,2,3‐triazol‐4‐yl)methyl 4‐(1,3‐dioxoisoindolin‐2‐yl)benzoate derivatives ( 13a‐e ) with various substitutions on aryl ring system have synthesized. All the synthesized compounds were characterized and confirmed with IR, ¹H NMR_, ¹³C NMR, and ESI mass spectral analysis.     

1H and 13C chemical shifts for acridines: Part XVII. (1,3‐Benzothiazol‐2‐yl)amino‐9(10H)‐acridinone derivatives

The ¹H and ¹³C NMR resonances for 16 acridin‐9(10H)‐ones substituted with amino or (1,3‐benzothiazol‐2‐yl)amino groups were completely and unequivocally assigned by the concerted application of gs‐COSY, gs‐HMQC and gs‐HMBC experiments. Evidence for hydrogen bond and amino–imino tautomerism is presented for 1‐ and 4‐substituted acridin‐9(10H)‐ones. Copyright © 2002 John Wiley & Sons, Ltd.     

Three New Neolignans from the Aril of Myristica fragrans

Three new neolignans, named 1‐deoxycarinatone ( 1 ), isodihydrocarinatidin ( 2 ), and isolicarin A ( 3 ), together with the known neolignan (+)‐dehydrodiisoeugenol ( 4 ), were isolated from mace (the aril of Myristica fragrans Houtt .). Their structures were elucidated as 2‐[(1S)‐2‐(4‐hydroxy‐3‐methoxyphenyl)‐1‐methylethyl]‐6‐methoxy‐4‐(prop‐2‐enyl)phenol ( 1 ), 4‐[(2R,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐(prop‐2‐enyl)benzofuran‐2‐yl]‐2‐methoxyphenol ( 2 ), and 4‐{(2S,3R)‐2,3‐dihydro‐7‐methoxy‐3‐methyl‐5‐[(1E)‐prop‐1‐enyl]benzofuran‐2‐yl}‐2‐methoxyphenol ( 3 ) on the basis of spectroscopic data.     

A Novel Norlignan and a Novel Phenylpropanoid from Peperomia tetraphylla

A novel cyclobutane‐type norlignan, peperotetraphin (=methyl rel‐(1R,2S,3S)‐2,3‐bis(7‐methoxy‐1,3‐benzodioxol‐5‐yl)cyclobutanecarboxylate; 1 ), and a novel phenylpropanoid, i.e., methyl (2E)‐3‐(7‐methoxy‐1,3‐benzodioxol‐5‐yl)prop‐2‐enoate ( 2 ), along with three known compounds, α‐asarone (=1,2,4‐trimethoxy‐5‐[(1E)‐prop‐1‐en‐1‐yl]benzene), vanillic acid (=4‐hydroxy‐3‐methoxybenzoic acid), and veratric acid (=3,4‐dimethoxybenzoic acid), were isolated from the EtOH extract of the whole plant of Peperomia tetraphylla. Their structures were determined by spectroscopic methods, especially 1D‐ and 2D‐NMR techniques. This is the first report of naturally occurring cyclobutane‐type norlignans.     

A Facile Synthesis of Some New 1‐Benzothiazolyl‐3‐aryl/Hetaryl‐5‐(3‐aryl‐1‐phenyl‐4‐pyrazolyl) Pyrazoles and Their Antimicrobial Activity

Some new derivatives of 1‐benzothiazolyl‐3‐aryl/hetaryl‐5‐(3‐aryl‐1‐phenyl‐4‐pyrazolyl) pyrazoles were synthesized by the cyclocondensation of 1‐aryl/hetaryl‐3‐(3‐aryl‐1‐phenyl‐1H‐pyrazole‐4‐yl)prop‐2‐en‐1‐ones (pyrazolyl chalcones) and 6‐substituted‐2‐hydrazinobenzothiazoles.     

An efficient synthesis of 5‐aryl‐4,5‐dihydro‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐1‐(4‐phenylthiazol‐2‐yl)pyrazoles

Some new target products 5‐aryl‐4,5‐dihydro‐3‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐1‐(4‐phenylthiazol‐2‐yl)pyrazoles 5a , 5b , 5c , 5d , 5e , 5f , 5g , 5h , 5i , 5j have been synthesized by reaction of 2‐bromo‐1‐phenylethanone and compounds 4a , 4b , 4c , 4d , 4e , 4f , 4g , 4h , 4i , 4j which were prepared from the combination of thiosemicarbazide and (E)‐3‐aryl‐1‐(5‐methyl‐1‐p‐tolyl‐1H‐1,2,3‐triazol‐4‐yl)‐prop‐2‐en‐1‐ones 3a , 3b , 3c , 3d , 3e , 3f , 3g , 3h , 3i , 3j . All the structures were established by MS, IR, CHN, and ¹H NMR spectra data. Synthesis of structure diversity is applied. J. Heterocyclic Chem., (2011).     

Synthesis of Coumarin Substituted Triazolothiadiazine Derivatives via Ring Transformation Reaction

A novel ring transformation reaction for the synthesis of 3‐(3‐aryl‐7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazin‐6‐yl)‐2H‐chromen‐2‐ones has been described. Reaction of 3‐(2‐bromoacetyl)coumarins ( 1 ) with 5‐aryl‐1,3,4‐oxadiazole‐2‐thiol ( 2 ) gave ketones ( 4a–h ). The in situ formed ketones ( 4a–h ) were reacted with hydrazine hydrate to give 3‐(3‐aryl‐7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazin‐6‐yl)‐2H‐chromen‐2‐ones ( 3a–h ) and not 5 or 6 . The compounds ( 3a–h ) can also be prepared by the reaction of 3‐(2‐bromoacetyl)coumarins ( 1 ) with 5‐aryl‐1,3,4‐oxadiazole‐2‐thiol ( 2 ) in anhydrous ethanol to give corresponding 3‐(2‐(5‐aryl‐1,3,4‐oxadiazol‐2‐ylthio)acetyl)‐2H‐chromen‐2‐ones ( 4a–h ). These on reaction with hydrazine hydrate in acetic acid gave corresponding 3‐(3‐aryl‐7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazin‐6‐yl)‐2H‐chromen‐2‐ones ( 3a–h ).     

First synthesis of 2‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[h]chromen‐2‐yl)‐1‐naphthol and 3‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[g]chromen‐2‐yl)‐2‐naphthol from 1‐ and 2‐naphthol derivatives

Two new structurally isomeric, 2‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[h]chromen‐2‐yl)‐1‐naphthol ( 1 ) and 3‐(2,4,4‐trimethyl‐3,4‐dihydro‐2H‐benzo[g]chromen‐2‐yl)‐2‐naphthol ( 3 ) have been synthesized from 2‐acetyl‐1‐naphthol and ethyl‐3‐hydroxy‐2‐naphthoate, respectively, involving Grignard reaction, dehydration of the corresponding tertiary alcohols, and hetero Diels–Alder dimerization. The two benzochromenes ( 1 and 3 ) have been fully characterized by IR, NMR, and HRESIMS data. Their structures are further supported by crystallography of their corresponding acetates ( 2 and 4 ). J. Heterocyclic Chem., (2011).     

Deciphering composition and connectivity of a natural product with the assistance of MS and 2D NMR

A complementary application of three analytical techniques, viz. multidimensional nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), and single‐crystal X‐ray diffractometry was required to identify and refine two natural products isolated from Millettia versicolor and solvent of crystallization. The two compounds, namely 3‐(2H‐1,3‐benzodioxol‐5‐yl)‐6‐methoxy‐8,8‐dimethyl‐4H ,8H‐pyrano[2,3‐h ]chromen‐4‐one, or durmillone, (I), and (2E )‐1‐(4‐{[(2E )‐3,7‐dimethylocta‐2,6‐dien‐1‐yl]oxy}‐2‐hydroxyphenyl)‐3‐(4‐hydroxyphenyl)prop‐2‐en‐1‐one, (II), could not be separated by routine column chromatography and cocrystallized in a 2:1 ratio with 0.13 molecules of ethanol solvent. Compound (II) and ethanol could not be initially identified by single‐crystal X‐ray analysis due to complex disorder in the aliphatic chain region of (II). Mass spectrometry ensured that (II) represented only one species disordered over several positions in the solid state, rather than several species cohabitating on the same crystallographic site. The atomic identification and connectivity in (II) were established by several 2D (two‐dimensional) NMR techniques, which in turn relied on a knowledge of its exact mass. The derived connectivity was then used in the single‐crystal analysis to model the disorder of the aliphatic chain in (II) over three positions and allowed identification of a partially occupied ethanol solvent molecule that was disordered over an inversion center. The disordered moieties were refined with restraints and constraints.     

An Efficient,Multicomponent Synthesis of Pyrazolyl Triazolo Thiadiazinyl Chromen ‐ 2 ‐ Ones

One‐pot synthesis of 3‐(3‐(3,5‐dimethyl‐1H‐pyrazol‐1‐yl)‐7H‐[1,2,4]triazolo[3,4‐b][1,3,4]thiadiazin‐6‐yl)‐2H‐chromen‐2‐ones was achieved via the multicomponent reaction of purpald, acetyl acetone, and different derivatives of 3‐(2‐bromo‐acetyl)‐2H‐chromen‐2‐one in absolute ethanol. All the synthesized compounds were characterized by analytical and spectral data.     

Synthesis and biological study of some new chalcones and oxopyrimidines containing imidazo[1,2‐a]pyridine nucleus

Heterosubstituted chalcones and oxopyrimidines were synthesized by the reaction of 2‐(4‐Chlorophenyl)imidazo[1,2‐a]pyridine‐3‐carbaldehyde 1 and different aryl acetophenone in the presence of catalytic amount of 40% alkali to give (2E)‐3‐(2‐(4‐chlorophenyl)imidazo[1,2‐a]pyridin‐3‐yl)‐1‐arylprop‐2‐en‐1‐ones 2a – l . Compounds 2a – l on reaction with urea in the presence of basic catalyst such as KOH to give 6‐(2‐(4‐chlorophenyl)imidazo[1,2‐a]pyridin‐3‐yl)‐4‐aryl pyrimidin‐2(1H)‐ones 3a – l . Their IR, ¹H‐NMR, MASS spectral data, and elemental analysis were in accord with assigned structure. All the newly synthesized compounds were screened for their antimicrobial activity. J. Heterocyclic Chem., (2012).     

Synthesis and Fungicidal Activity of 5‐Aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole

A series of novel 5‐aryl‐1‐(aryloxyacetyl)‐3‐(tert‐butyl or phenyl)‐4‐(1H‐1,2,4‐triazol‐1‐yl)‐4,5‐dihydropyrazole 3a – 3n were synthesized by the annulation of 2‐aryloxyacetohydrazides with 3‐aryl‐1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)prop‐2‐en‐1‐ones ( 2 ) in the presence of a catalytic amount of acetic acid. Compounds 2 were obtained by the Knoevenagel reactions of 1‐t‐butyl (or phenyl)‐2‐(1H‐1,2,4‐triazol‐1‐yl)ethanone ( 1 ) with aromatic aldehydes in the presence of piperidine. Their structures were confirmed by IR, ¹H‐NMR, ESI‐MS, and elemental analyses. The preliminary bioassay indicated that some compounds displayed moderate to excellent fungicidal activity. For example, compounds 3l , 3m , and 3n possessed 100% inhibition against Cercospora arachidicola Hori at the concentration of 50 mg/L.     

An Efficient One‐pot Three‐component Method for the Synthesis of 5‐Amino‐3‐(2‐oxo‐2H‐chromen‐3‐yl)‐7‐aryl‐7H‐thiazolo[3,2‐a]pyridine‐6,8‐dicarbonitriles

A facile, convenient, and adequate method has been developed for the synthesis of novel 5‐amino‐3‐(2‐oxo‐2H‐chromen‐3‐yl)‐7‐aryl‐7H‐thiazolo[3,2‐a]pyridine‐6,8‐dicarbonitriles ( 6 ) by employing 2‐(4‐(2‐oxo‐2H‐chromen‐3‐yl)thiazol‐2‐yl)acetonitrile ( 3 ) as an important precursor. Initially, we have synthesized the target compounds in a stepwise manner and then approached a tandem method to examine the feasibility of one‐pot method. Subsequently, one‐pot three‐component protocol has been established for the synthesis of title compounds by the reaction of 3 with benzaldehyde and malononitrile in refluxing ethanol engender a new six‐membered thiazolo[3,2‐a] pyridine as a hybrid scaffold. Reaction conditions were optimized for this reaction and a broad substrate scope with various aryl and heteroaryl aldehydes make this protocol very practical, attractive, and worthy. Mechanistic aspects for the formation of these compounds were outlined comprehensively. Characterization of these newly synthesized compounds was achieved by means of IR, ¹H NMR, ¹³C NMR, and HRMS.     

Mannich Reaction as a New Route for the Synthesis of Tetrahydro Pyrimido Benzimidazolyl Coumarins

Condensation of coumarin‐4‐acetic acids ( 1 ) with ortho‐phenylenediamine ( 2 ) in anhydrous phosphoric acid afforded 4‐((1H‐benzo[d]imidazol‐2‐yl)methyl)‐2H‐chromen‐2‐ones ( 3 ). Attempted Mannich reaction of 3 with formalin and primary amines resulted in 4‐(2‐phenyl‐1,2,3,4‐tetrahydrobenzo[4,5]imidazo[1,2‐c]pyrimidin‐4‐yl)‐2H‐chromen‐2‐ones ( 6 ). The structures of synthesized compounds were elucidated by analyses including 2D HETCOR and DEPT experiments. Synthesized compounds have been subjected for anti‐inflammatory activity. Compound 6j exhibited promising anti‐inflammatory activity.