Facile and Rapid Access to Poly Functionalized Pyridine Derivatives

An efficient and greener protocol for the synthesis of poly functionalized pyridines using tetra‐n‐butyl ammonium fluoride (TBAF) in water is established. Remarkable advantages of the present synthetic strategy over the others are shorter reaction times, higher isolated yields, reuse of catalytic system, simple work‐up procedure and more especially its applicability to heteryl and aliphatic aldehydes.     

InCl3-Catalyzed,Three-Component Reactions for the Synthesis of Some Novel Functionalized/Annulated Barbituric Acids

Some novel 5-aminoalkylbarbituric acids and corresponding chromene derivatives were synthesized via a one-pot, three-component Mannich reaction starting from 1,3-dimethylbarbituric acid, arylaldehydes, and amines.     

新型吡啶衍生物的合成

以2-甲基吡啶为原料,经氧化、硝化、还原反应合成了重要中间体4-氨基-2-甲基吡啶(3); 3分别经1,4-加成反应、Heck反应及取代反应合成了11个吡啶类化合物(4~14),其中5, 6和8~14为新化合物,其结构经¹H NMR, ¹³C NMR, MS和HR-MS进行表征。     

新型四硫富瓦烯硫杂冠醚衍生物的合成

在高度稀释条件下, 经4,5-二溴甲基-1,3-二硫杂环戊烯-2-硫酮(7)和多缩乙二醇的1,ω-二巯基衍生物的缩合反应, 方便地合成了4,5-位带二硫杂冠醚残基的2-硫代-1,3-二硫杂环戊烯的衍生物8a～8d, 中间体硫杂冠醚8c～8d的合成中有明显的“模板效应”. 在亚磷酸三乙酯存在下, 8a～8d经自偶联生成新型的对称双臂四硫富瓦烯(TTF)硫杂冠醚衍生物10a～10d, 而与4,5-二甲硫基-1,3-二硫杂环戊烯-2-酮(9)经交叉偶联生成新型的非对称单臂四硫富瓦烯硫杂冠醚衍生物11a～11d. 用循环伏安法研究了上述目标化合物的电化学性质和离子传感性质.     

Merging Gold and Organocatalysis: A Facile Asymmetric Synthesis of Annulated Pyrroles

The combination of cinchona‐alkaloid‐derived primary amine and Au^I–phosphine catalysts allowed the selective C?H functionalization of two adjacent carbon atoms of pyrroles under mild reaction conditions. This sequential dual activation provides seven‐membered‐ring‐annulated pyrrole derivatives in excellent yields and enantioselectivities.     

A Facile Synthesis of Two Sesquiterpenes Methyl Ether

Bisabolane sesquiterpenes are a big family of naturally occurring products with significantly biological activities most of which can be separated from Chinese traditional medicines. Parahigginone (1a) was firstly separated as a bisabolane by Shen Y. C. et al. from the Taiwan marine sponges in 1999, [1] it shows very promising antitumor activity.[1] As far as we know, there is no synthetic report on it. Curcuphenol (2a) was a cytotoxic sesquiterpene which was first discovered in Pseudopterogorgia rigida[2,3] which has been synthesized by Frank[2] and Tsutomu[4] before. In order to study the relationship between the structures and the activities, we have synthesized parahiggi none methyl ether (1) and curcuphenol methyl ether (2) in six steps successfully, and the stereoselective synthesis is carried out in progress.     

新型香豆素类荧光化合物的合成及荧光性质研究

合成了两种香豆素类荧光化合物6,8-二氯-7-羟基香豆素-3-羧酸（DClC）和6-氯-7-羟基香豆素-3-羧酸（MClC）,其中DClC未见文献报道,并通过红外光谱、核磁共振、质谱等手段对产物的结构进行了表征。同时首次研究了这两种香豆素衍生物的紫外、荧光性质,以及不同极性溶剂、pH值、表面活性剂等的影响。结果表明,pH对性质测定影响较大,当pH=10时,DClC和MClC的荧光强度明显增强。     

A Route to the Synthesis of Novel Coumarins

Summary. The 1:1:1 adduct which originates from the reaction of triphenylphosphine, dialkyl acetylenedicarboxylate, and 3-formyl-4-hydroxycoumarin undergoes an intramolecular Wittig reaction to provide a series of unique 2H,5H-pyrano[3,2-c][1]benzopyran-5-ones (pyranocoumarins).     

Synthesis of a Novel Ligand Containing Phenyl Pyridine

In this article, we provide a new, efficient route to synthesize 2-[3-(3,4-bis(2-ethylhexyloxy)phenyl]phenyl pyridine ligand from readily available starting materials. The target compound was obtained by a condensation reaction and Suzuki coupling reaction. Structures of compounds were demonstrated by ¹H NMR, ¹³C NMR, and high-resolution mass spectrometry. The advantages of this synthetic route are simple operation, mild reaction conditions, and good yields.     

Synthesis and In Vitro Antibacterial Evaluation of Some Novel Annulated Quinazolinone Derivatives

Russian Journal of General Chemistry - A series of novel substituted quinazoline derivatives are synthesized. Antibacterial tests demonstrate their high activity against Gram-positive and...     

Facile Metal-Free Synthesis of 3-Aryl-4-Substituted Coumarins from O-Hydroxy Carbonyl Compounds

The intramolecular cyclization of the esters of salicylaldehyde, O-hydroxyacetophenones, methyl salicylate, and 2′-hydroxy chalcones by potassium hydroxide in pyridine leads to a short and convenient synthesis of 3,4-disubstituted coumarins. Twenty 3-phenyl coumarins were synthesized in 80–90% yields. No other by-product, such as 2-benzylchromone or β-diketones, was observed the reactions. The mild reaction condition involves the removal of more acidic benzylic proton, which leads to a relatively cheap, nontoxic, metal-free method for the synthesis of 3-aryl-4-substituted coumarins.     

Organocatalyzed Synthesis and Antibacterial Activity of Novel Quinolino Annulated Analogues of Azepinones

Starting from dimedone, two methodologies for synthesizing novel quinolino annulated azepinones have been reported. The protocol involves azepinone synthesis by the action of a newly synthesized organocatalyst derived from the reaction of TCT and DMF on oxime derivatives ( 5 and 9 ), which were obtained by the reaction of acridine dione derivatives ( 4 and 8 ) with hydroxylamine hydrochloride. The derivatives 4 and 8 were obtained by the reaction of 1 with anthranilic acid 2 and isatoic anhydride 7 , respectively. The synthesis of all the compounds was confirmed initially by TLC followed by spectral analysis through IR, ¹H NMR, ¹³C NMR, mass spectrometry, and elemental analysis. The results that emanated on the evaluation of the antibacterial activity of azepinones against two Gram‐positive and two Gram‐negative test organisms using disc diffusion method have also been discussed. Compounds 6c , 6d , 6e , 10c , and 10e have been found to display better inhibitory activity than standard drugs streptomycin and tetracycline. The minimum inhibitory concentration and IC₅₀ values for the compounds under study as well as of standard drugs were calculated. The maximum inhibition by bacterial strains was observed at 150 μg/mL.     

N-1-Naphthyl-3-oxobutanamide in Heterocyclic Synthesis: A Facile Synthesis of Nicotinamide,Thieno[2,3-b]pyridine,and Bi- or Tricyclic Annulated Pyridine Derivatives Containing Naphthyl Moiety

N-1-Naphthyl-3-oxobutanamide (1) reacts with arylidinecyanothioacetamide 2a–c in ethanol/piperidine solution under reflux to yield the pyridine-2(1H)-thiones 6a–c. Compound 6a reacts with α-haloketones 7a–e to give the 6-thio-N-1-naphthyl-nicotinamides derivatives 8a–e, which cyclized to thieno[2,3-b]pyridine derivatives 9a–e. The reaction of compound 9a with hydrazine hydrate and formamide gives the thieno[2,3-b]pyridine carbohydrazide derivative 10 and pyridothienopyrimidine derivative 11, respectively. Reaction of 9a with benzoyl isothiocyanate gave thiourea derivative 12. Compound 12, upon treatment with alcoholic NaOH, gave pyridothienopyrimidine 13. Saponifications of 9a gave the amino acid 15, which affords 16 when refluxed in Ac₂O. Treatment of compound 16 with AcONH₄/AcOH gave 17. Diazotization and self-coupling of 9b gave the pyridothienotriazine 18. Also, diazotization of the ortho-aminohydrazide 10 give the corresponding azide 19, which was subjected to Curtius rearrangement in boiling xylene to give imidazothienopyridine 20. Reaction of 10 with either formic acid or triethylorthoformate and phenyl isothiocyanate gave the corresponding pyridothienotriazepines 22 and 23, respectively. The interaction of 10 with acetylacetone furnished the pyrazolyl derivative 24. The structures of the synthesized compounds were established from their analytical and spectral data.     

Benzotriazole-Mediated Facile Synthesis of Novel Glycosyl Tetrazole

A facile, simple, and high-yielding synthetic protocol for novel glycosyl tetrazoles has been devised from different carbohydrate-containing amides using benzotriazole methodology under mild reaction condition.     

新型熊果酸单糖苷的简便合成

以熊果酸为原料,经苄基化反应制得熊果酸苄酯(2); 2与三氯乙酰亚胺酯经糖苷化反应制得酯保护的熊果酸-3-糖苷（4a~4d）;4a~4d依次脱去苄基和苯甲酰基合成了4个熊果酸-3-糖苷(6a～6d,其中6c为新化合物),其结构经¹H NMR, ¹³C NMR和MS(ESI)表征。     

新型双环吡啶类化合物的合成及其抗血小板活性

以卤代物(1a~1d、 5a~5j)为起始原料,经硫脲盐酸盐(2a~2d)、磺酸钠(6a~6e)或磺酸(6f~6j)的氯代和氨解反应,制得相应的磺酰胺片段(4a~4d、 8a~8j)。 1-Boc-4-甲基-4-哌啶甲酸(9)脱保护基后与吡啶类化合物(11)发生亲核取代反应制得中间体1-（3-氰基-5-氧代-5,7-二氢呋喃[3,4-b]吡啶-2-基）-4-甲基哌啶-4-羧酸(12); 12与磺酰胺片段发生缩合反应合成了相应的双环吡啶类化合物(13a～13n),其结构经¹H NMR, ¹³C NMR和MS(ESI)表征。采用比浊法血小板聚集试验研究了13a～13n对人源血小板聚集的抑制作用。结果表明：13c和13g具有一定的抗血小板聚集活性,其中化合物13g的IC₅₀值为44.08 μM。      

A Facile One-Step Synthesis of New Types of 8-Thiazolyl and 8-Thiadiazinyl Coumarins

N-[4-(7-Methoxy-4-methyl-2-oxo-2H-chromen-8-yl)-thiazol-2-yl]-guanidine ( 2 ) has been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) with guanylthiourea. 4-Methyl-7-methoxy-8-[2-(N′-(1-phenyl-ethylideneisopropylidene)-hydrazino]-thiazol-4-yl]chromen-2-ones ( 3 , 4 , and 5 ) have been prepared by reaction of 4-methyl-7-methoxy-8-(2-bromoacetyl) coumarin ( 1 ) and thiosemicarbazide in presence of acetophenone or acetone without any solvent. The formation of these compounds was further confirmed by the condensation of acetophenone/acetone thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin ( 1 ) in anhydrous ethanol in a two-step process. Similarly 8-[2-[N′-(benzylidene)hydrazine]-thiazol-4-yl]-7-methoxy-4-methyl-chromen-2-ones ( 6 , 7 , and 8 ) have been prepared by the condensation of 4-methyl-7-methoxy-8-(2-bromoacetyl)chromen-2-one with thiosemicarbazide and various aromatic aldehydes in a single step without any solvent. The formation of these compounds was further confirmed by the condensation of appropriately substituted benzaldehyde thiosemicarbazones with 4-methyl-7-methoxy-8-(2-bromoacetyl)coumarin in anhydrous ethanol. 4-Methyl-7-methoxy-8-(2-bromoacetyl) chromen-2-one (1) upon condensation with 3,5-dimercapto-4-amino-s-triazole in anhydrous ethanol resulted in the formation of 8-(3-mercapto-3H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl)-7-methoxy-4-methyl chromen-2-one (9). This compound ( 9 ) on reaction with various alkyl and phenacyl halides in anhydrous ethanol gave corresponding 4-methyl-7-methoxy-8-[3-(2-oxo-substituted sulphanyl)-7H-[1,2,4]triazolo[3,4-b]thiadiazin-6-yl]chromen-2-ones ( 10 to 18 ). The structures of newly prepared compounds have been confirmed from analytical and spectral data.     

InCl3‐Driven Regioselective Synthesis of Functionalized/Annulated Quinolines: Scope and Limitations

The efficient, regioselective synthesis of functionalized/annulated quinolines was achieved by the coupling of 2‐aminoaryl ketones with alkynes/active methylenes/α‐oxoketene dithioacetals promoted by InCl₃ in refluxing acetonitrile as well as under solvent‐free conditions in excellent yields. This transformation presumably proceeded through the hydroamination–hydroarylation of alkynes, and the Friedländer annulation of active methylene compounds and α‐oxoketene dithioacetals with 2‐aminoarylketones. In addition, simple reductive and oxidative cyclization of 2‐nitrobenzaldehyde and 2‐aminobenzylalcohol, respectively, afforded substituted quinolines. Systematic optimization of the reaction parameters allowed us to identify two‐component coupling (2CC) conditions that were tolerant of a wide range of functional groups, thereby providing densely functionalized/annulated quinolines. This approach tolerates the synthesis of various bioactive quinoline frameworks from the same 2‐aminoarylketones under mild conditions, thus making this strategy highly useful in diversity‐oriented synthesis (DOS). The scope and limitations of the alkyne‐, activated methylene‐, and α‐oxoketene dithioacetal components on the reaction were also investigated.