TBAF Promoted Formation of Symmetrical Trisulfides

We have developed a new method for the synthesis of functionalized symmetrical trisulfides based on (5,5‐dimethyl‐2‐thioxo‐1,3,2‐dioxa‐phosphorin‐2‐yl)disulfanyl derivatives prepared from readily available 5,5‐dimethyl‐2‐sul‐fanyl‐2‐thioxo‐1,3,2‐dioxaphosphorinane or bis(5,5‐dimethyl‐2‐thioxo‐1,3,2‐dioxaphosphorinan‐2‐yl) disulfide. The symmetrical trisulfides can be obtained from aliphatic and aromatic thiols and l ‐cysteine derivatives under mild conditions with high yield and purity.     

Microwave—prompted Reaction of Cinnamonitrile Derivatives with 5,5—Dimethyl—1,3—cyclohexanedione

In the reactions of α-cyanocinnamonitrile or β-cyano-β-carbothoxy styrene with 5,5-dimethyl-1,3-cyclohexanedione in the presence of ammonium acetate under microwave irradiation without solvent,the 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-7,7-dimethyl-4H-benzo-[b]-pyran derivatives were obtained.However,in the reactions of arylidenecyanoacetamide with 5,5-dimethyl-1,3-cyclohexanedione under the same reaction conditions,the acridine derivatives were obtained.The structures of the products were determined by single crystal X-ray diffraction analysis.     

An efficient three‐component synthesis of hexahydroquinoline derivatives in ionic liquid

A series of hexahydroquinoline derivatives were synthesized by the three‐component reaction of 5,5‐dimethyl‐3‐aminocyclohex‐2‐enone, aromatic aldehyde, and acyl acetonitrile in ionic liquid without using any catalyst. This protocol has the advantages of easier work‐up, milder reaction conditions, high yields, and environmentally benign procedure. J. Heterocyclic Chem., (2011).     

An Efficient Synthesis of Pyrido[2,3‐d][6,5‐d]dipyrimidine and 5,5′‐Arylmethylenebis(2,6‐diaminopyrimidinone) Derivatives under Microwave Irradiation

A series of pyrido[2,3‐d][6,5‐d]dipyrimidine and 5,5′‐arylmethylenebis(2,6‐diaminopyrimidinone) derivatives have been synthesized through a rapid reaction of aromatic aldehydes with aminopyrimidines in acetic acid under microwave irradiation. This method has the advantages of simple operation, high yields, short reaction time, and easy work‐up.     

Improved Synthesis of 5,5-Diamino BINAP and Application to Asymmetric Hydrogenation

5,5-Diamino BINAP has been synthesized via three steps using BINAPO as starting material with high reaction yield. Present method needed only a stoichiometric quantity of nitric acid in the step of nitration of BINAPO, giving almost quantitative reaction yield. Based on 5,5-diamino BINAP, other three new BINAP derivatives have been synthesized. These modified BINAP ligands showed better catalytic properties as compared to BINAP itself in the asymmetric hydrogenation of 2-(6‘-methoxyl-2‘-naphthyl)acrylic acid.     

Reaction of Imines with 5,5‐Dimethyl‐1, 3‐cyclohexandione

The reaction of imines 1 with 5,5‐dimethyl‐1,3‐cyclohexandione 2 in methanol was investigated. When the reaction was carried out without a catalytic amount of molecular iodine, ring‐opening derivatives of xanthenediones 3 were obtained in high yields. On the other hand, when molecular iodine and a catalytic amount of zinc powder were employed as the catalyst, xanthenediones derivatives 4 were obtained with excellent yields.     

Uncatalyzed and Solvent‐Free Process for the Synthesis of 1,4‐Diarylquinoline Derivatives

The uncatalyzed and three‐component reaction of arylaldehyde, malonodinitrile, and 3‐arylamino‐5,5‐dimethylcyclohex‐2‐enone at 160 °C under solvent‐free conditions gave 1,4‐diarylquinoline derivatives in high yields.     

Solvent‐free One‐pot Synthesis of 2,2′‐dithioxo‐[5,5′]bithiazolidinylidene‐4,4′‐diones

Solvent‐free one‐pot synthesis of 2,2′‐dithioxo‐[5,5′]bithiazolidinylidene‐4,4′‐dione (birhodanine) derivatives from the reaction of primary amines and carbon disulfide in the presence of dimethyl acetylene dicarboxylate has been reported.     

Synthesis of new C2 symmetrical dibenzospirodiamide and dibenzospirodiamine as potential chiral auxiliaries and building blocks of ionophores

2,8‐Diazadibenzo[c,i]spiro[5,5]undecan‐1,7‐dione 3 are synthesized via reaction of malonic ester with 2‐nitrobenzyl bromide, followed by reduction‐cyclization in 86% overall yield. 2,8‐Diazadibenzo[c,i]‐spiro[5,5]undecane 4 was obtained by reduction of 3 with LiAIH₄ in 90% yield. N‐Alkylation of 3 with various alkylating reagents is studied.     

The Kinetics and Mechanism of the Reaction between Barbituric Acid and Glycidol,Part II: Glycidol Reacts with Imide and Methylene Groups

Two derivatives of barbituric acid, 5,5‐diethylbarbituric acid and 1,3‐dimethyl‐barbituric acid, were used to react with glycidol. The kinetics of reactions was studied by continuous determination of epoxide number and acidic number in the reaction mixture aliquots. Based upon the kinetic experiments, the rate equation was formulated, which was consistent with product spectral identification of the derivatives as well as with previously studied reaction of barbituric acid with glycidol. Reaction mechanisms of glycidol with methylene and imide groups of barbituric acid have been proposed.     

Efficient Green Procedure for the Synthesis of Coumarin Derivatives by a One‐Pot,Three‐Component Reaction under Solvent‐Free Conditions

A simple, efficient, and general method has been developed for the synthesis of coumarin derivatives through a one‐pot reaction of aromatic aldehydes, 2,2‐dimethyl‐1,3‐dioxane‐4,6‐dione and 5,5‐dimethyl‐1,3‐cyclohexanedione, in the presence of TEBA under solvent‐free conditions using grinding methods. The mild reaction conditions, simple protocol, high yields, and cleaner reaction make this protocol practical and economically attractive.     

Identification of 5-(3,4-Dihydroxyphenyl)-5-Phenylhydantoin: A Metabolite of 5,5-Diphenylhydantdin (Dilantin1) in Rat Urine

Abstract

Using radioisotope tracer technics and GC-mass spectrometry, a new metabolite of 5,5^?diphenylhydantoin present in rat urine has been dentified as 5-(3,k-dihydroxyphenyI)-5-phenylhydantoin. This catechol represented about 2% of the total metabolites excreted in rat urine folowing administration of diphenylhydantoin in the diet for over two weeks     

离子液体介质中FeCl3•6H2O催化下芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应

考察了在离子液体1-正丁基-3-甲基咪唑四氟硼酸盐([bmim][BF₄])介质中, 芳香醛与5,5-二甲基-1,3-环己二酮的缩合反应. 实验结果表明, 在催化量的FeCl₃•6H₂O存在下, 该反应可高产率地生成氧杂蒽二酮类化合物3; 而在TMSCl/FeCl₃•6H₂O复合催化体系的催化下, 则得到氧杂蒽二酮类化合物的开环衍生物4, 反应具有非常好的选择性. 该论文提供的方法操作简单、产率高、选择性好而且对环境友好. 在反应结束后, 所用催化剂及离子液体都很容易回收, 并能有效重复使用.     

A Clean Synthesis of 1,4‐Diarylquinoline Derivatives Catalyzed by TEBAC in Aqueous Media

A series of 1,4‐diarylquinoline derivatives were synthesized by the reaction of arylmethylidenemalononitriles or 2‐cyano‐3‐aryl‐1‐acrylate and 3‐arylamino‐5,5‐dimethylcyclohex‐2‐enone in aqueous media at 100 °C catalyzed by TEBAC. Meanwhile, the water medium was chosen as green solvent.     

Synthesis of bis(azafulvene)s by dehydration of hydroxymethylpyrrole derivatives

Bis(azafulvene) was isolated in 55% yield by the reaction of 4 equivalents of phenyllithium with 5,5'-diformyl-3,3',4,4'-tetraethyl-2,2'-bipyrrole followed by quenching with acetic anhydride. Unstable bis(azafulvene)s were obtained in much higher yields by dehydrating 5,5'-bis(hydroxymethyl) derivatives of 2,2'-bipyrrole and gem-dimethyl-2,2'-dipyrrylmethane with (Boc)2O-DMAP at room temperature. X-Ray crystallography of two bis(azafulvene)s is reported.     

An Efficient One‐Pot Synthesis of Bis Butenolides

3,3′,4,4′‐Tetramethyl‐5,5′‐dioxo‐2,2′‐bifuran‐2,2′(5H,5′H) diyl diacetate was obtained from the reaction between 2,3‐dimethyl maleic anhydride and acetic anhydride in the presence of zinc in toluene. This easy synthetic route gave bis butenolide in excellent yield.     

Bromination of 2,2′-bipyridile

A simple and convenient procedure was developed for the synthesis of 5,5′-dibromo-2,2′-bipyridyl providing the target compound in a high yield without the chromatographic separation of the reaction mixture. Polybromo derivatives of 2,2′-bipyridyl were isolated and characterized for the first time.     

Surprising secondary photochemical reactions observed on conventional photolysis of diazotetrahydrofuranones

The formation of C-H insertion products of the terminal N-atom of a diazo group into the α-СН-bond of tetrahydrofuran during direct photolysis of regioisomeric 2,2-dimethyl-5,5-diphenyl and 5,5-dimethyl-2,2-diphenyl-substituted 3-diazotetrahydrofuran-4-ones in THF is dictated by photochemical cycloelimination of the originally formed (1,1-dimethyl-2-oxa-3,3-diphenyl-propano)ketene and oxetanecarboxylic acid derivatives to yield benzophenone. The latter, under subsequent UV irradiation of the reaction mixture, initiates sensitized photolysis of the starting diazoketones resulting in the appearance of the insertion products with the solvent.     

Synthesis of Trichlorophenol Derivatives

An expedient three‐step procedure for the synthesis of trichlorophenol derivatives based on the acid‐catalyzed rearrangement of the bicyclic ketone precursors 6a–e in high overall yield is described. The bicyclic ketone precursors 6a–e were obtained from Diels–Alder cycloadducts of β‐substituted vinyl acetates with tetrachloro‐5,5‐dimethoxycyclopentadiene in two steps.     

Practical modifications and applications of the sharpless asymmetric aminohydroxylation in the one-pot preparation of chiral oxazolidin-2-ones

[reaction: see text] Chiral oxazolidin-2-ones are synthetically valuable as chiral auxiliaries, and many have pharmaceutically interesting biological activity. This communication focuses on a convenient, practical one-pot preparation of chiral 4,5-disubstituted oxazolidan-2-ones in good yield with high enantioselectivities, using a modified Sharpless asymmetric aminohydroxylation of beta-substituted styrene derivatives followed by base-mediated ring closure. This procedure has been demonstrated on both small and large scale, utilizing 1, 3-dichloro-5,5-dimethyl hydantoin as an easily handled, commercially available substitute for tert-butyl hypochlorite.