Three‐Component,One‐Pot Synthesis of Pyrazolo[3,4‐b]pyridine Derivatives in Aqueous Media

6‐Amino‐4‐aryl‐5‐cyanopyrazolo[3,4‐b]pyridines were synthesized by a three‐component reaction of aromatic aldehydes, malononitrile, and 5‐amino‐3‐methyl‐1‐phenylpyrazole using sodium 1‐dodecanesulfonic (SDS) as catalyst in aqueous media. The reaction has the advantages of good yields, less pollution, ease of separation, and environmental friendliness.     

Condensation of 2‐Pyrone with 3‐Aminopyrazolone. A Novel Synthesis of Pyrazolo[3,4‐b]pyridines

Abstract

A simple route to the preparation of new heterocyclic systems: pyrazolo[3,4‐b]pyridines from the easily available 2‐pyrone and 3‐aminopyrazolone. The structure of the compounds and the mechanism of their formation are reported.     

Synthesis of Some Novel Fluorinated Pyrazolo[3,4‐b]Pyridines

Abstract

Reaction of 5‐amino‐3‐substituted pyrazoles (1a–c) and 5‐amino‐1,3‐disubstituted pyrazoles (1d–i) with fluorinated‐β‐diketones (2) results in the formation of the single isomer of pyrazolo[3,4‐b]pyridines (4a–h). A one‐pot procedure for the synthesis of title compounds starting from α‐cyanoacetophenones along with a possible mechanistic pathway for the formation of the title compounds is described.     

Efficient and Convenient One‐Pot Synthesis of Phosphoramidates and Phosphates

A simple and efficient one‐pot method is described for the synthesis of phosphoramidates/phosphates in excellent yields from dialkylphosphites and trichloroisocyanuric acid in acetonitrile and subsequent treatment with dialkyl amines/alcohols. The procedure is operationally simple, has reduced reaction times, and uses a one‐pot procedure.     

Facile Synthesis of Pyrazolo[3,4‐d]pyrimidines and Pyrimido[4,5‐d]pyrimidin‐4‐one Derivatives

Pyrazolopyrimidine and pyrimidopyrimidine derivatives have shown a wide range of biological activities such as acting as A₁ adenosine receptors, kinase insert domain receptor (KDR), Rous sarcoma oncogene (Src), epidermal growth factor receptor (EGFR), antiproliferative, dihydrofolate reductase (DHFR), antimicrobial, antifungal, and lipid peroxidation. Because of this wide range of activities, we have synthesized pyrazolo[3,4‐d]pyrimidines and pyrimido[4,5‐d]pyrimidin‐4‐one derivatives.     

Convenient and Regioselective One‐Pot Solvent‐Free Synthesis of ß‐Hydroxyphosphonates

A simple, efficient, regioselective, and solvent‐free method has been developed for the synthesis of β‐hydroxyphosphonates from epoxides and triethyl phosphite using ZnCl₂ in high yields under mild conditions.     

A Convenient One‐Pot Preparation of Stable Equivalents of Cyclobutane‐1,2‐dione and Cyclobutanetrione

A very short, high‐yielding, one‐pot procedure has been developed for the preparation of half‐protected cyclobutane‐1,2‐dione. This compound is much more stable than cyclobutane‐1,2‐dione itself and allowed further transformation to give diprotected cyclobutanetrione equivalents.     

Convenient One‐Pot Synthesis of Sulfonamides from Thiols using Trichloroisocyanuric Acid

A convenient synthesis of sulfonamides from thiols is described. In situ preparation of sulfonyl chlorides from thiols is accomplished by oxidation with trichloroisocyanuric acid (TCCA), benzyltrimethylammonium chloride and water (2.5 equiv). The sulfonyl chlorides are then further allowed to react with excess amine in the same reaction vessel. Triethylamine can be optionally added as acid scavenger.     

Convenient One‐Pot Heterogeneous Catalytic Method for the Preparation of 3,4‐Dihydropyrimidin‐2(1H)‐ones

A new, simple, environmentally friendly synthesis of dihydropyrimidinones from aromatic and aliphatic aldehydes, ethyl acetoacetate, and urea or thiourea using a small‐pore‐size zeolite as catalyst is described. Compared with the classical Biginelli reaction conditions, this method has the advantage of high yield, shorter reaction time, and recyclable and reusable catalyst.     

Convenient One‐Pot Synthesis of Vinyl Ethers from Phenyl 2‐Hydroxyalkyl Selenides

Vinyl ethers were prepared with good yields in a one‐pot, two‐step transformation by O‐alkylation reaction of phenyl 2‐hydroxyalkyl selenides with primary or secondary organic halides followed by oxidation elimination with 30% hydrogen peroxide.     

KF‐Alumina Catalyzed One‐Pot Synthesis of Pyrido[2,3‐d]Pyrimidine Derivatives

Abstract

A series of pyrido[2,3‐d]pyrimidine derivatives was synthesized by the reaction of arylaldehyde, malononitrile, and 4‐amino‐2,6‐dihydroxylpyrimidine in ethyl alcohol at 80°C catalyzed by KF‐Al₂O₃. Compared with other synthetic methods, this new method has the advantage of easier workup, milder reaction conditions, and good yields.     

One‐Pot,High‐Yielding Synthesis of Novel Dihydrothiazolo[3,2‐a]pyrimidinones

Reaction between 6‐(un)substituted‐2‐thiouracils and E‐ethyl 4‐bromocrotonate under basic conditions at room temperature is an easy, mild, high‐yielding, and regioselective method for the preparation of 7‐(un)substituted dihydrothiazolo[3,2‐a]pyrimidinone derivatives.     

Synthesis of Fused Tetrazolo[1,5‐c] pyrrolo[3,2‐e]pyrimidines and Their Reductive Conversion to New 4‐Aminopyrrolo[2,3‐d]pyrimidines

Some new 7,9‐substituted 7H‐1,2,3,4‐tetrazolo[1,5‐c]pyrrolo[3,2‐e]pyrimidines 5 have been synthesized either by diazotization of 4‐hydrazino‐5,7‐disubstituted‐7H‐pyrrolo[2,3‐d]pyrimidines 4 obtained by hydrazinolysis of 4‐chloro‐5,7‐disubstituted 7H‐pyrrolo[2,3‐d]pyrimidines 3 or via a substitution reaction between 3 and sodium azide. 5,7‐Disubstituted‐7H‐pyrrolo[2,3‐d]pyrimidin‐4(3H)‐ones 2 were obtained by cyclocondensation of 1,4‐disubstituted 2‐amino‐3‐cyanopyrroles 1 with formic acid, which, on chlorination using phosphorus oxychloride, afforded 3. 2‐Amino‐3‐cyanopyrroles 1 were synthesized from the reaction between (2-bromo-1-(4-fluorophenyl) ethylidene) propanedinitrile and substituted aromatic amines under Gewald reaction conditions. A novel route for the synthesis of 4‐amino‐5,7‐disubstituted‐7H‐pyrrolo[2,3‐d]pyrimidines 6 by the reductive ring cleavage of 5 has been reported.     

A Convenient Approach to the Synthesis of Dialkyl 5‐Oxo‐1,2‐dihydro‐5H‐chromeno [4,3‐b]pyridine‐2,3‐dicarboxylates

Coumarin and its analogs are considered privileged scaffolds in the current synthetic and pharmacological research. The chemical behavior of enaminocarbaldehydes of the coumarin moiety under intramolecular Wittig reaction conditions in the presence of triphenylphosphine and dimethyl or diethyl acetylenedicarboxylates has been studied, resulting in the isolation of a series of dimethyl and diethyl 5‐oxo‐1,2‐dihydro‐5H‐chromeno[4,3‐b]pyridine‐2,3‐dicarboxylates in good to high yields.     

Covalent Modification of Organo‐Functionalized Graphene Oxide and its Scope as Catalyst for One‐Pot Pyrazolo‐Pyranopyrimidine Derivatives

The surface of graphene oxide (GO) was modified using [3‐(2‐aminoethylamino)propyl]trimethoxysilane (diamine), which exhibited excellent catalytic activity for one‐pot multicomponent reactions. The newly synthesized material was fully characterized by various instrumental techniques including Fourier‐transfer infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The instrumental analysis confirmed the successful grafting of organic amine functional groups onto the graphene oxide surface. The diamine‐functionalized GO proved to be an excellent catalyst for the synthesis of pyrazolo‐pyranopyrimidine derivatives with 93 % yield and high selectivity. The catalytic activity almost remained unaltered up to three cycles. The newly synthesized pyrazolo‐pyranopyrimidine derivatives have potential use as scaffolds in designing new pharmaceutical products.     

One‐Pot Synthesis of Pyrazole‐5(3)‐carboxyamides

Abstract

A convenient one‐pot synthesis of eight pyrazole‐5(3)‐carboxyamides from the reaction of the 5(3)‐trichloromethylpyrazoles with amines, in good yield, is reported. These reactions show that the trichloromethyl group is a convenient precursor to carboxyamide groups.     

One‐Pot Synthesis of 5‐Alkylfuran‐2(5H)‐ones

5‐Alkylfuran‐2(5H)‐ones can be efficiently obtained using a one‐pot approach, starting from methyl 3‐nitropropanoate and aldehydes, in ethyl acetate, with Amberlyst A‐21 as catalyst, in 60–90% overall yield.     

Simple and Convenient One‐Pot Synthesis of Benzimidazoles and Benzoxazoles using N,N‐Dimethylchlorosulfitemethaniminium Chloride as Condensing Agent

N,N‐Dimethylchlorosulfitemethaniminium chloride (SOCl₂‐DMF) has been found to be an efficient reagent for the one‐pot synthesis of benzimidazoles and benzoxazoles in excellent yield by condensation of carboxylic acids with o‐phenylenediamine/2‐amino‐phenol.     

Synthesis of Functionalized Pyrano[3,2‐c]pyridines and Their Transformations to 4‐Hydroxy‐3[(1E)‐N‐hydroxyalkanimidoyl]pyridones

Reaction of 4‐hydroxy‐6‐methyl‐2(1H)‐pyridones 1a and 4‐hydroxy‐1,6‐dimethyl‐2(1H)‐pyridones 1b with diethyl malonates 2a–e leads to the formation of pyrano[3,2‐c]pyridines 4a–j. Degradation of 4a–i affords the corresponding ketones 6a–i. Condensation of ketones 6a–i with hydroxyl amine or phenyl hydrazine hydrochloride is described.     

SbCl3‐Al2O3–Catalyzed,Solvent‐Free,One‐Pot Synthesis of Benzo[b]1,4‐diazepines

This article explores the use of antimony(III) chloride adsorbed on neutral alumina as an efficient catalyst for the one‐pot synthesis of benzo[b]1,4‐diazepines (83–94%) under solvent‐free conditions. The process is easy, efficient, ecofriendly, and economical.