Nitroketene Dithioacetal Research Articles

Synthesis of Functionalized Bicyclic Pyridones Containing the Dithiocarbamate Group Using Thioazlactones, Diamines, and Nitroketene Dithioacetal

AbstractAn efficient method for the synthesis of highly substituted bicyclic pyridone derivatives containing the dithiocarbamate group is reported via a one-pot three-component reaction of 2-(alkylthio)thio­azlactones, diamines, and nitroketene dithioacetal in EtOH under catalyst-free conditions. The reaction proceeds via a domino amidation–­intramolecular 1,4-addition-type Friedel–Crafts alkylation reaction to afford the corresponding fused bicyclic pyridones with high yields and diastereoselectivity.

Synthesis of Spiropyrazolines via a Pseudo‐Six Component Reaction

A novel and eco‐friendly route for the synthesis of highly functionalized spiropyrazolines via a pseudo‐six component reaction of hydrazine hydrate, nitro ketene dithioacetal, isatin, and active methylene under mild condition at room temperature in ethanol media has been developed. The key steps in the synthetic strategy involve the formation of 1,1‐dihydrazino‐2‐nitroethylene from hydrazine hydrate with nitro ketene dithioacetal and its reaction with Knoevenagel adduct derived from the corresponding isatin and active methylene. The reaction is particularly attractive due to features such as high bond‐forming efficiency, optimum convergence, mild condition, atom economy, easy work‐up/purification, and reduced waste production without using any additive.

One‐pot Four‐component Synthesis of Highly Functionalized Pyridines Using Nitroketene Dithioacetal as a Source of Methyl Thiolate Under Solvent‐free Condition

A simple method for the synthesis of highly functionalized 2‐amino‐6‐(methylthio)pyridine‐3,5‐dicarbonitriles is presented. In this method, pyridine derivatives are synthesized from the reaction of malononitrile, aromatic aldehydes, nitroketene dithioacetal in the presence of ethylene diamine. The notable features of this method are the simple Experimental procedure, short reaction time, and good yields.

A Simple One‐Pot Synthesis of Fully Substituted 1H‐Pyridone[1,2‐a]‐Fused‐1,3‐Diazaheterocycles

An efficient procedure for the synthesis of 7‐(aryl)‐8‐nitro‐2,3,6,7‐tetrahydroimidazo[1,2‐a]pyridinones, 8‐(aryl)‐9‐nitro‐3,4,7,8‐tetrahydropyridone[1,2‐a]pyrimidines and 9‐(aryl)‐10‐nitro‐2,3,4,5,8,9‐hexahydropyridone[1,2‐a]diazepine via one‐pot three component reaction of diamine, nitroketene dithioacetal (1,1‐bis(methylsulfanyl)‐2‐nitroethene), and coumarine‐3‐ carboxylic acid derivatives in EtOH under reflux conditions is reported. The advantages of this procedure are simplicity, easy purification, good yields, and catalyst‐free conditions. All products were confirmed by 1H‐ and 13C‐NMR, IR, MS, and X‐ray crystal structure analyses.

An Efficient One‐Pot Four‐Component Synthesis of Some New Spirooxindole Dihydropyridine Using Alum as a Heterogeneous Green Catalyst

Abstract4‐Nitro‐2,3‐dihydrospiro[imidazo[1,2‐a]indeno[2,1‐e]pyridine‐5,3′‐indoline]‐2′,6(1H)‐dione derivatives have been synthesized in good yields in a one‐pot four‐component, and efficient process by reaction of corresponding isatins, 1,3‐indandione, diamine, and nitro ketene dithioacetal in the presence of KAl(SO4)2.12H2O (Alum) as a nontoxic and easily available heterogeneous green catalyst.

Synthesis of Novel 1H‐Imidazol[1,2‐a]Indeno[2,1‐e]Pyridine‐6(5H)‐Ones Derivatives via a One‐Pot Four‐Component Condensation Reaction

1H‐imidazol[1,2‐a]indeno[2,1‐e]pyridine‐6(5H)‐ones derivatives were synthesized in a one‐pot four‐component condensation of corresponding aldehydes, 1,3‐indandione, diamine, and nitro ketene dithioacetal using KAl(SO4)2·12H2O (alum) as nontoxic, reusable, inexpensive and easily available catalyst in good to excellent yields. This green protocol provides a powerful entry into fused polycyclic structures related to bioactive heterocycles.

ChemInform Abstract: Synthesis of 2‐Oxopyrrole‐Fused 1,n‐Diazaheterocyclic Compounds and Substituted 2‐Oxopyrroles via a Three‐Component Reaction.

An effective route to 2-oxopyrrole-fused 1,n-diazaheterocyclic compounds and substituted 2-oxopyrroles is described. This involves reaction of 1,n-diamines or monoamines 1 and nitroketene dithioacetal (1,1-di(methylthio)-2-nitroethene) in the presence of dialkyl acetylenedicarboxylate 2 in EtOH to give 2-oxopyrrole derivatives 3 in good yields (Table 1). The structures were corroborated spectroscopically (IR, 1H and 13C NMR, and EIMS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 1).

Synthesis of 2‐Oxopyrrole‐fused 1,n‐Diazaheterocyclic Compounds and Substituted 2‐Oxopyrroles via a Three‐Component Reaction

An effective route to 2‐oxopyrrole‐fused 1,n‐diazaheterocyclic compounds and substituted 2‐oxopyrroles is described. This involves reaction of 1,n‐diamines or monoamines 1 and nitroketene dithioacetal (1,1‐di(methylthio)‐2‐nitroethene) in the presence of dialkyl acetylenedicarboxylate 2 in EtOH to give 2‐oxopyrrole derivatives 3 in good yields (Table 1). The structures were corroborated spectroscopically (IR, 1H and 13C NMR, and EIMS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 1).

Catalyst- and solvent-free synthesis of highly functionalized octahydro-imidazo[1,2-a]quinolin-6-ones via a one-pot sequential four-component reaction in melt conditions

Abstract This is a report of an innovative, one-pot, catalyst-free, four-component synthesis of octahydro-imidazo[1,2- a ]quinolin-6-ones from aromatic aldehydes, cyclic 1,3-diones, diamines, and nitro ketene dithioacetal in stoichiometric melt conditions. The protocol avoids the use of expensive catalysts, toxic organic solvents and anhydrous conditions, and affords potentially bioactive compounds in excellent to high yields.

Recyclization of 2-Iminochromenes via Ketene Aminal Intermediates: One-Pot, Three-Component Reaction for Synthesis of 1,4-Dihydropyridines-fused-1,3-diazaheterocycles

An efficient, one-pot synthesis of 4-aryl-1,4-dihyropyrido[1,2-a]-fused-1,3-diazaheterocycles by three-component reaction of 1,n-diamine, nitroketene dithioacetal (1,1-di(methylthio)-2-nitroethene), and 2-iminochromenes in EtOH is reported. This new protocol has the advantages of good yields, short reaction times, and convenient operation. The structures were corroborated spectroscopically (infrared, 1H and 13C NMR, and electron impact–mass spectrometry) and by elemental analyses. A plausible mechanism for this type of recyclization is proposed. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.

A Novel and Efficient Synthesis of Pyrido[1,2‐a]‐Fused 1,3‐Diazaheterocyclic Compounds via a One‐Pot Three‐Component Reaction

AbstractAn efficient one‐pot synthesis of pyrido[1,2‐a]‐fused 1,3‐diazaheterocyclic compounds by three‐component reaction of diamine, nitroketene dithioacetal (=1,1‐bis(methylsulfanyl)‐2‐nitroethene), and electron‐poor itaconic anhydride (=2‐methylidenesuccinic anhydride=2‐methylidenebutanedioic anhydride) in aqueous EtOH is reported. This protocol has the advantages of easiness, higher yields, and shorter reaction times. The structures were corroborated spectroscopically (IR, 1H‐ and 13C‐NMR, and EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 2).

ChemInform Abstract: Nitroketene Dithioacetal Chemistry: Synthesis of 2‐Alkylthio‐3‐nitrothiophenes from Nitroketene Dithioacetate and Chloromethyl Ketones.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Synthesis of 3‐Methylthio‐4‐aryl‐3‐pyrroline‐2,5‐diones and 3‐Arylpyrrolidine‐2,5‐diones by Reaction of Nitroketene Dithioacetal with Arylacetonitriles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of 3-Methylthio-4-aryl-3-pyrroline-2,5-diones and 3-Arylpyrrolidine-2,5-diones by Reaction of Nitroketene Dithioacetal with Arylacetonitriles

The reaction of nitroketene dithioacetal (la), i.e., 2,2-bis(methylthio)-1-nitroethylene, with arylacetonitriles (2a-I) in the presence of the base like sodium hydroxide gave 4-nitrobut-2-enenitriles (3a-I) which were converted into 5-hydroxyimino-4-methylthio-3-phenyl-3-pyrrolin-2-ones (4a-i) under refluxing in methanol. Title compounds (5a-i) were readily obtained by the treatment of 4a-i with hydrochloric acid and were finally led to N-methylated products (6a-I) with methyl iodide. The reduction of maleimides (4 - 6) with zinc dust in acetic acid afforded the corresponding 3-arylpyrrolidine-2,5-diones (7a-i) that can be converted to pharmacologycally active compounds like mesembrines.

Simple Synthesis of Polyfunctional Nitropyridines

Upon treatment with nitroketene dithioacetal (2) in refluxing acetonitrile, enaminonitriles (1) afforded nitrodienamines (3). Polysubstituted nitropyridines (4 and 5) were obtained by cyclization of intermediates (3) with orthoformate and acetic anhydride respectively

Studies on cycloaddition reactions of 1,3-diphenyl-2-azaallyl lithium and ethyl (benzylideneamino) acetate anion with α-oxoketene dithioacetals

The α-oxoketene dithioacetals undergo anionic [1,3] cycloaddition with l,3-diphenyl-2-azaallyllithium to give either pyrroles or spiropyrrolines with two exceptions. Lithium bromide/triethylamine induced cycloaddition of ethyl (benzylideneamino)acetate ( 7 ) with acyclic ct-oxoketene dithioacetals afforded either pyrrolidine, pyrrole or the corresponding 3-benzylideneamino-pyran-2-one derivatives depending on the reaction conditions and the structural variations in the a- oxoketene dithioacetals. Nitroketene dithioacetal also underwent anionic [1,3]cycloaddition with either 1 or 7 under described conditions to afford pyrrolidine or pyrrole derivatives. Probable mechanisms for the formation of various products are suggested.

A Novel 1,6 Cyclization of Imidazolium N-Allylides (1) : Formation of Mesomeric Betaines, 8-Oxoimidazo[1,2-a]pyridiniumides

Treatment of imidazolium N-allylide (3) in refluxing 1,2,4-trimethylbenzene resulted in 1,6-cyclization to give the mesomeric betaine, 7-iminoimidazo [1,2-a] pyridiniumide (4). On the other hand, heating of 1-cyanoimidoylmethylimidazolium N-ylide (6) in refluxing 1,2,4-trimethyl-benzene underwent 1,6-cyclization and debenzylation to give 8-amino-imidazo [1,2-a] pyrazine (7). Furthermore, treatment of the imidazolium salt (1a) and ethyl ethoxymethylenenitroacetate (2d) with K 2 CO 3 in DMSO afforded the mesomeric betaine, imidazo [1,2-a] pyridiniumide (12), whereas the reaction of 1a and nitroketene dithioacetal (2e) with K 2 CO 3 in DMSO resulted in 1,5-dipolar cyclization to produce pyrrolo [1,2-a] imidazole (13) and pyrrolo [1,2-a] pyrazine (14)

ChemInform Abstract: Synthesis of 2‐Methylthioindolizine‐3‐carbonitriles Using Nitroketene Dithioacetal.

AbstractThe nitroketene dithioacetal (II) reacts with the N‐(cyanomethyl)pyridinium chlorides (I), generated from the corresponding pyridines and chloroacetonitrile, to form the thioindolizines (III) and (IV).

Synthesis of 2‐methylthioindolizine‐3‐carbonitriles using nitro ketene dithioacetal

AbstractThe reaction of 1‐cyanomethylpyridinium chloride or bromide,1a‐i, with 1,1‐bis(methylthio)‐2‐nitroethylene (2) in the presence of triethylamine as a base in ethanol gave the corresponding 2‐methylthioindolizine‐3‐carbonitrile3and 2‐methyl‐thio‐1‐nitroindolizine‐3‐carbonitrile4in good yields, respectively. Compounds3a,fwere key intermediates for the synthesis of cycl[3.2.2]azine derivatives.