Catalytic Amount Of Potassium Carbonate Research Articles

Synthesis of Novel Oxo Pyrimido Pyrimidine and Their Derivatives

Abstract: Pyrimidine derivatives are synthesized to possess various pharmacological and biological activities. In the present work, we have synthesized 3-(4-methoxyphenyl)-1-phenyl prop-2-en-1-one (1) (chalcone) by using 4-methoxybenzaldehyde and acetophenone in the presence of alcoholic KOH by Claisen-Schmidt condensation reaction. After purification and characterization by physical and spectral methods, The synthesized chalcone have been converted into 6-(4-methoxyphenyl)-4- phenyl-1,6-dihydropyrimidin-2-amine (2) by treating with guanidine nitrate in the presence of alcoholic KOH. The structure (2) has been characterized by spectral analysis. The synthesized compound (2) is further reacted with ethyl 2-cyano-3, 3-bis (methylthio)acrylate in the presence of catalytic amount of potassium carbonate in DMF under reflux condition to givenovel 2- (4-methoxyphenyl)-8-(methylthio)-6-oxo-4-phenyl-1,6,9,9a-tetrahydro-2H-pyrimido[1,2-a] pyrimidine-7-carbonitrile(3) in good yields. The compound (3) possesses replaceable methylthio (-SCH3) group at 8 position. The compound (3) is further reacted with various nucleophiles like substituted aromatic amines, aromatic phenols, hetryl amines and active methylene compounds to give 2-(4-methoxyphenyl)-8-substituted-6-oxo-4-phenyl-1,6,9,9a-tetrahydro-2H-pyrimido[1,2-a]pyrimidine-7-carbonitrile in good yields.

Synthesis of a novel iminopyrimidooxazine and their derivatives

We have synthesized 2-(4-chlorophenyl)-8-(methylthio)-6-imino-4-phenyl-2,6,9,9a-tetrahydropyrimido[2,1-b][1,3]oxazine-7-carbonitrile (3) by the reaction of 6-(4-chlorophenyl)-4-phenyl-6H[1,3]oxazin-2-amine (2) with 2-(bis (methylthio)methylene)malononitrile in the presence of catalytic amount of potassium carbonate in DMF under reflux condition. The aminooxazine was prepared by the reaction of chalcone (1) with urea in the presence of ethanol and sodium hydroxide under reflux condition. The synthesized compounds were characterized by spectral methods. The compound (3) possesses replaceable methylthio (-SCH3) group at 8 position. The compound (3) react with various nucleophiles like substituted aromatic amines, aromatic phenols, hetarylamines and active methylene compounds to give 2-(4-chlorophenyl)-8-(substituted)-6-imino-4-phenyl-2,6,9,9a-tetrahydropyrimido[2,1-b][1,3]oxazine-7-carbonitriles in good yields.

An Efficient, Potassium Carbonate-Catalysed, Three-Component Reaction of Aldehydes, Malononitrile and Amidines Leading to Highly Functionalized Pyrimidines in Aqueous Media

Various 4-amino-5-cyanopyrimidines were readily prepared in a few minutes with good yields through a one-pot, three-component reaction of aldehydes, malononitrile and amidines in aqueous media in the presence of catalytic amounts of potassium carbonate. Short reaction times, high efficiency, generality of the method, synthesis of new derivatives, inexpensiveness, and non-toxicity of the catalyst/solvent are the interesting features of this method, which make it eco-friendly and highly attractive.

Synthesis of Novel Pyrimido Pyrimidine and Their Derivatives

Chalcone derivatives were synthesis by the reaction of some 4-nitrobenzaldehyde derivatives with acotophenone then the product obtained E-3-(4-nitrophenyl)-1-phenylprop-2-en-1-one. This product is chalcone is another react with guanidine nitrate. The hetrocyclic derivatives of guanidine nitrate respectively the final product have been characterized by elemental analysis. the product obtained is 1,6 dihydro 6(4-nitrophenyl) 4-phenylpyridine 2-amine. In present report novel pyrimidines were prepared from starting materials chalcone and guanidine nitrate. The resulting compound 1,6-dihydro-6-(4-nitrophenyl)-4 phenylpyrimidin 2 amine (2) was further reacted with 2 bis(methylthio)methylene malononitrile in the presence of catalytic amount of potassium carbonate in DMF under reflux condition that offered novel 4,6,9,9a-tetrahydro-4-imino-2-(methylthio)-8-(4-nitrophenyl) 6 phenyl 1H pyrimido[1,2 a]pyrimidine 3 carbonitrile (3). The synthesized compounds were characterized by spectral methods. The compound (3) possesses replaceable methylthio (-SCH3) group at 2 position. The compound (3) react with various nucleophiles like substituted aromatic amines, aromatic phenols, hetryl amines and active methylene compounds to give 4,6,9,9a-tetrahydro-4-imino-2-(methylthio)-8-(4-nitrophenyl)-6-phenyl-1H-pyrimido[1,2-a]pyrimidine-3-carbonitrile –carbonitrile in good yields.

Synthesis of Novel Pyrimido Thiazine and Their Derivatives

In present report novel thiazines were prepared from starting materials chalcone and thiourea. The resulting compound 6-(4-methoxyphenyl) 4-phenyl-6H-1, 3-thiazin-2-amine (2) was further reacted with ethyl 2-cyano-3, 3-bis (methylthio) acrylate in the presence of catalytic amount of potassium carbonate in DMF under reflux condition that offered novel 2-(4-methoxyphenyl) 8-(methylthio)-6-0xo-4-phenyl-4, 6, 9, 9a-tetrahydropyrimido [2, 1-b] [1, 3]-thiazine-7-carbonitrile (3). The synthesized compounds were characterized by spectral methods. The compound (3) possesses replaceable methylthio (-SCH₃) group at 8 position. The compound (3) react with various nucleophiles like substituted aromatic amines, aromatic phenols, hetryl amines and active methylene compounds to give 2-(4-methoxyphenyl)-8-substituted-6-oxo-4-phenyl-4, 6, 9, 9a-tetrahydropyrimido [2, 1-b] [1, 3] thiazine-7-carbonitrile in good yields.

Synthesis and antioxidant activity of some new substituted pyrazolo [4, 5-e]4H-pyrimido[2, 3-b] benzimidazoles

2-Amino benzimidazole condensed with ethyl-2-cyano-3, 3-bis(methylthio)acrylate using catalytic amount of potassium carbonate and DMF as solvent to form 3-cyano-2-metylthio-4-oxo-4H-pyrimido [1, 2-a] benzimidazole (3). The formed compound (3) reacted with differently substituted aryl/heteryl hydrazino compounds then it gives series of substituted pyrazolo [4, 5-e]-4H-pyrimido [2, 3-b] [1, 3] benzimidazoles (5a-h). Structure of compounds were confirmed by spectroscopic techniques IR, mass, 1H & 13C NMR and analytical properties. all synthesized compounds were screened for their antioxidant activity.

ChemInform Abstract: Synthesis of 1,2,4,5‐Tetrasubstituted Imidazoles by a Sequential Aza‐Wittig/Michael/Isomerization Reaction.

Carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aryl isocyanates, reacted with secondary amines in the presence of a catalytic amount of sodium alkoxide to give 1,2,4,5-tetrasubstituted imidazoles 7 in good yields. However, 4-acylimidazoles 11 were obtained, as phenols were used in the presence of a catalytic amount of potassium carbonate due to further air oxidation of the expected products 10.

Iminophosphorane-Mediated Efficient Synthesis of New Fluorine-Containing Triazolo[4,5-d]Pyrimidin-7-Ones

The carbodiimides 3, obtained from aza-Wittig reactions of the corresponding iminophosphorane 2 with 1 equiv. of aromatic isocyanates, were allowed to react in the presence of a catalytic amount of potassium carbonate or EtO−Na+ with p-fluorothiophenol to give 5,6-disubstituted 1,2,3-triazolo[4,5-d]- pyrimidine-7-ones 5 in satisfactory yields. Further reaction of compounds 5 with H2O2 or Na2WO4/H2O2 generated the corresponding compounds 6 and 7 in good yields, respectively.

Synthesis of 1,2,4,5-Tetrasubstituted Imidazoles by a Sequential Aza-Wittig/Michael/Isomerization Reaction

Carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aryl isocyanates, reacted with secondary amines in the presence of a catalytic amount of sodium alkoxide to give 1,2,4,5-tetrasubstituted imidazoles 7 in good yields. However, 4-acylimidazoles 11 were obtained, as phenols were used in the presence of a catalytic amount of potassium carbonate due to further air oxidation of the expected products 10.

An efficient synthesis of 4-chromanones

A two step efficient and practical synthesis of a variety of 4-chromanones is described. Phenols undergo a Michael addition to acrylonitriles in the presence of catalytic amounts of potassium carbonate and tert-butanol to generate the corresponding 3-aryloxypropanenitriles in 50–93% yields. Treatment of the resulting aryloxypropionitriles with 1.5 equiv of TfOH and 5 equiv of TFA, followed by an aqueous work up afforded 4-chromanones in moderate to excellent yields.

Reactions of aldoketeniminophosphonates with CH-acids

Aiming to obtain new polyfunctional organophosphorus compounds, we studied the reactions of aldoketeniminophosphonates with different CH-acids. The reactions were shown to proceed efficiently in anhydrous acetonitrile medium in the presence of the catalytic amounts of potassium carbonate to form the products of the addition of CH-acids to a multiple carbon-carbon bond followed by the prototropic isomerization to the corresponding γ-substituted β-functional alkylaminoethenephosphonates. The reaction of aldoketeniminophosphonates with CH-acids is found to depend significantly on the strength and nature of the acid. The formation of the carbon-carbon bond is possible mainly in the case of the CH-acids whose pKa values lie within 10–14.

Solvent-Free, anti-Michael Addition of Active Methylene Derivatives to β-Nitroacrylates: Eco-Friendly, Chemoselective Synthesis of Polyfunctionalized Nitroalkanes

The chemoselective, anti-Michael addition of active ­methylene derivatives to β-nitroacrylates can be easily performed at room temperature, under solvent-free conditions, using a catalytic amount of potassium carbonate as heterogeneous catalyst.

Functionalization of the unsaturated organophosphorus compounds. Study of reaction of dialkylaminoethynephosphonates with malonic acid derivatives and benzenesulfonylacetonitrile

Reactions of some CH-acids with dimethyl dialkylaminoethynephosphonates were studied aiming to develop methods of syntheses of the functionalized organophosphorus compounds. Reactions with malonodinitrile, ethyl cyanoacetate, and benzenesulfonylacetonitrile were shown to proceed effectively in anhydrous acetonitrile in the presence of catalytic amounts of potassium carbonate to form products of CHacids addition at the triple bond followed by prototropic isomerization to give the corresponding β-dialkylamino-β-phosphonomethyl-α-substituted acrylonitriles. In reaction with malonic acid aminoethynephosphonates are hydrolyzed to form phosphonoacetic acid dialkylamides as main products.

New iminophosphorane-mediated synthesis of thieno[3′,2′:4,5]thieno[3,2- d]pyrimidin-4(3 H)-ones and 5 H-2,3-dithia-5,7-diaza-cyclopenta[ c, d]indenes

Mono(iminophosphorane) 4 was selectively prepared from the reaction of 3,4-diaminothieno[2,3- b]thiophene 3 with excess triphenylphosphine, C 2Cl 6, and Et 3N due to intramolecular double hydrogen bond formation. Mono(iminophosphorane) 4 reacted with aromatic isocyanates to give stable carbodiimides 8, which were further treated with aliphatic secondary or primary amines to give 2-amino substituted thieno[3′,2′:4,5]thieno[3,2- d]pyrimidin-4(3 H)-ones 10 or 12 in the presence of a catalytic amounts of EtO −Na +. However, in the presence of a catalytic amounts of potassium carbonate, the carbodiimides 8 were transformed into previously unreported 5 H-2,3-dithia-5,7-diaza-cyclopenta[ c, d]indenes 13 via direct cyclization in high yields. The reaction of carbodiimides 8 with phenols in the presence of a catalytic amounts of potassium carbonate gave a mixture of 2-aryloxy substituted thieno[3′,2′:4,5]thieno[3,2- d]pyrimidin-4(3 H)-ones 14 and 13. X-ray structure analysis of 10m supported the structure and the proposed reactivity of amino group.

A Facile Synthetic Route to 2 H‐Chromenes: Reconsideration of the Mechanism of the DBU‐Catalyzed Reaction between Salicylic Aldehydes and Ethyl 2‐Methylbuta‐2,3‐dienoate

Reactions of salicylaldehydes with ethyl buta-2,3-dienoate or penta-3,4-dien-2-one catalyzed by a catalytic amount of potassium carbonate produce the corresponding 2 H-chromene products in moderate to good yields under mild conditions. A plausible reaction mechanism is discussed in the light of the results of an 18O-labeling experiment. In addition, in view of these findings, the catalytic function of DBU in reactions of this kind is reconsidered.

New Efficient Synthesis of 2‐Substituted Benzothieno[3,2‐d]pyrimidin‐4(3H)‐ones via a Tandem Aza‐Wittig Reaction.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

A Practical One‐Pot Procedure for the Synthesis of Pyrazino[2′,3′:4,5]thieno[3,2‐d]pyrimidinones by a Tandem aza‐Wittig/Heterocumulene‐Mediated Annulation Strategy.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

New Efficient Synthesis of 2-Substituted Benzothieno[3,2-d]pyrimidin-4(3H)-ones via a Tandem Aza-Wittig Reaction

1-Aryl-3-[2-(ethoxycarbonyl)benzothien-3-yl]carbodiimides 4, obtained from aza-Wittig reactions of iminophosphorane 3 with aryl isocyanates, reacted with secondary amines, phenols, or alkanols in the presence of a catalytic amount of potassium carbonate or sodium alkoxide to give 2-substituted benzothieno[3,2-d]pyrimidin-4(3H)-ones 6 in good yields. The reaction of carbodiimides 4 with primary amines RNH2 (R ≠ H, Me) in the presence of sodium ethoxide selectively produced one regioisomer 8 via a base-catalyzed cyclization mechanism. However, a different regioisomer 9 was obtained when primary amines RNH2 (R = H, Me) were used in the absence of sodium ethoxide via a direct cyclization mechanism.

A practical one-pot procedure for the synthesis of pyrazino[2′,3′:4,5]thieno[3,2- d]pyrimidinones by a tandem aza-Wittig/heterocumulene-mediated annulation strategy

A simple one-pot and efficient method is described for the synthesis of pyrazino[2′,3′:4,5]thieno[3,2- d]pyrimidinone derivatives 6 via a tandem aza-Wittig/heterocumulene-mediated annulation process. The iminophosphorane 3 reacted with aryl isocyanates, followed by heterocyclization on addition of secondary amines to give the corresponding guanidine intermediates 5, which were cyclized in the presence of a catalytic amount of potassium carbonate to tricyclic compounds 6. Similarly, iminophosphorane 3 reacts with phenols, thiophenol, or ROH to give 2-aryl(alkyl)oxy(thio)pyrazino[2′,3′:4,5]thieno[3,2- d]pyrimidinone derivatives 7 in good yields. The corresponding carbodiimide 4c and guanidine-type intermediate compounds 5 could be isolated and characterized, thus confirming the suggested reaction pathway. However, two isomeric pyrazinothienopyrimidinones 8 and 9 may be produced in the reaction of iminophosphorane 3 with aromatic isocyanates and subsequent reaction with primary amines in the presence of a catalytic amount of potassium carbonate. The effects of the nucleophiles and isocyanates on the regioselectivity of the cyclization have been investigated.

An efficient microwave-assisted synthesis of thieno[2,3- b ]quinolines under solvent-free conditions

A novel and efficient method for the synthesis of substituted thieno[2,3-b]quinolines has been developed. A simple one-pot reaction of 3-formyl-2-mercaptoquinolines 2a–l with 1-chloroacetone, 2-chloroacetamide, ethyl chloroacetate and 2-chloro-1-phenylethanone in presence of catalytic amount of potassium carbonate under microwave irradiation and solvent-free conditions gave thieno[2,3-b]quinolin-2-ylethanone derivatives 3a–e, thieno[2,3-b]quinoline-2-carboxamide derivatives 4a–e, ethyl thieno[2,3-b]quinoline-2-carboxylate 5a–e and phenyl(thieno[2,3-b]quinolin-2-yl)methanone derivatives 6a–e compounds respectively. The structures of all the newly synthesised compounds were elucidated on the basis of elemental analysis, IR, 1H NMR and mass spectral data.