A Convenient Synthesis of 2-Alkyl-mono-O-alkylated and 2-Alkyl Resorcinols

The title C, O -dialkylated resorcinols have seldom been prepared. We have developed a practical synthesis of this class of compounds starting with cyclohexane-1,3-dione. The key features of the synthesis are mono-O-alkylation of a 2-alkyl cyclohexane-1,3-dione and Pd-C catalyzed or NBS/DBU annuitization of the resultant O-alkyl-2-alkyl cyclohexane-1,3-dione. The use of cyclohexane-1,3-dione allows regioselective alkylations that would not be possible with resorcinol itself. A convenient synthesis of 2-alkyl resorcinols from cyclohexane-1,3-dione has also been achieved.     

Convenient Synthesis of Piperazine Substituted Quinolones

A series of 1‐[(4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonyl]‐4‐(substituted) piperazines 3a–c and methyl 2‐[(4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonylamino] alkanoates 5a–d has been developed by the direct condensation of ethyl [4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydro‐3‐quinoline] carboxylate 2 with N ¹‐monosubstituted piperazine hydrochlorides or amino acid ester hydrochloride in the presence of triethyl amine. The quinolone amino acid esters 5a–d were the key intermediate for the preparation of a series of 1‐[2‐((4‐hydroxy‐2‐oxo‐1‐phenyl‐1,2‐dihydroquinolin‐3‐yl)carbonylamino)alkylcarbony]‐4‐substituted piperazine derivatives 8–11 (a‐d) via azide coupling method with amino acid ester hydrochloride.     

A Convenient Synthesis of Hindered N-Aryl Substituted Cyclic Amines

An efficient and high yielding synthesis of N-substituted pyrrolidines and piperidines is described.     

A New And Convenient Synthesis Of Some Substituted Thiohydantoins

3-Substituted thiohydantoins (2a-g) were synthesized in satisfactory yields by the reaction of N-substituted thioureas (la-g) with chloroacetylchloride in the presence of triethylamine under reflux in dioxane. S-Alkylated products (7, 8) were obtained from the reaction of 3-p-tolyl -thiohydantoin (2d) with p-nitrobenzylchloride and 3-phenyl-5-chloromethyl-I,2,4-oxadiazole.     

Convenient Synthesis of Highly Substituted Imidazole Derivatives

A one-pot synthesis of the trisubstituted imidazole derivatives from α-acetoxy-α-chloro-β-keto-esters, aldehydes, and ammonium acetate has been developed.     

A Convenient Synthesis of Alkyl and Aryl Substituted Bis-1,3,4-oxadiazoles

Substituted bis-1,3,4-oxadiazoles 3a-1 have been synthesized from the cyclization of N,N'-diaroyl or N,N'-dialkanoyl diacyl hydrazides, in presence of phosphorus oxychloride. A11 new compounds have been identified by ¹H-NMR ¹³C-NMR and elemental analysis.     

A Convenient Synthesis of 5-Aryltropones

2-Methoxy-5-[[(trifluoromethyl)sulfonyl]oxy]tropone was coupled to a variety of arylzinc chlorides in the presence of a palladium catalyst to furnish 5-aryltropones in good to excellent yields.     

Convenient Synthesis of Substituted 2-Phenylbenzothiazoles Using Solid-Supported Triphenylphosphine

We report an improved procedure using solid-supported triphenylphosphine for the concise synthesis of biologically relevant 2-phenylbenzothiazoles featuring a variety of substituents on both the benzothiazole and phenyl rings. Substituted 2-phenylbenzothiazoles were synthesized by heating equimolar quantities of 2-aminothiophenol disulfides with benzaldehydes and p-toluenesulfonic acid in the presence of polymer-supported triphenylphosphine in dimethylformamide/toluene. Appealing features of this new method include simple isolation of product (removal of phosphine oxide by-product by filtration), avoidance of column chromatography, and good yields of substituted 2-phenylbenzothiazole products.

Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file.     

A Convenient Route to Substituted Thiocarbamides

A varicty of substituted thioureas result from thiuram disufides by a simple reaction with different amines.     

A Convenient Synthesis of 3-Benzoylindolizine-5-carbaldehydes

3-Benzoylindolizine-5-carbaldehydes (4a-f), which could be used as derivatization reagents for amino compounds in HPCE were synthesized based on the 1,3-dipolar cycloaddition of 1-phenacyl-2-(1,3-dioxolan-2-yl)pyridinium ylide with alkenes in the presence of TPCD.     

A Convenient Synthesis of 5-Bromo-2-Pentanone

During a series of studies aimed at the total synthesis of pentacyclic triterpenes¹ we have examined the reaction of enollactones of type 1 with a variety of Grignard reagents. ^1c,2 In one of our problems we required the organometallic reagent 2a derived from the title compound 2b. A previous literature report for the preparation of this compound involved the reaction of α-acetylbutyrolactone 3 with aqueous HBr followed by steam distillation.³ In our hands the yields of 2b via this route were non-reproducible and at best, less than 15%.     

A Convenient Synthesis of 4,6-Dichloro-5-benzylthiopyrimidine

A practical and convenient two-step synthesis of the title compound 4,6-dichloro-5-benzylthiopyrimidine (3) from 4,6-dihydroxypyrimidine (1) is described.     

Rapid and Convenient Thermal or Microwave-Assisted Synthesis of Substituted 2-Phenylbenzothiazoles

A simple one-step method for the synthesis of biologically relevant 2-phenylbenzothiazoles has been developed, using sodium metabisulfite as an oxidant following condensation between 2-aminothiophenol and substituted benzaldehydes. Attractive features of this new method include excellent yields under both microwave-assisted or thermal conditions (it is tolerant of a variety of substituents on the phenyl ring) and simple product isolation without the need for chromatographic purification.     

8-羟基喹啉制备技术进展

综述了重要有机合成中间体8-羟基喹啉的制备技术如喹啉磺化碱融、氯代喹啉水解、氨基喹啉水解以及Skraup合成法的现状和进展。同时也叙述了8-羟基喹啉的一些重要的衍生物的合成和应用。     

A New Synthesis of 3-Alkyl Isoxazoles

A two step facile synthesis of isoxazoles is described. The synthesis involves copper catalysed bromoform addition to an alkene (1) to afford tribromo derivative (2) which on treatment with sodiumnitrite in DMF gives the corresponding isoxazole (3).     

A Convenient Syntheses of some New Substituted Guanidines

The cyanamides of 2,6-dimethylaniline, N-methyl-α, β -naphthylamines, 2-methylpiperidine and indoline yielded their respective guanido derivatives on treatment with dry ammonia and their structures have been characterized through spectral studies.     

A Convenient Synthesis of the Substituted 2,3—Diarylindole the Potent Selective COX—2 Inhibitors

Phenyl sulfone-containing 2,3-diarylindole derivatives were designed and indentified to be selective COX-2 inhibitors. A convenient synthetic route was also developed for the synthesis of the novel inhibitors.