Anionic cycloaromatization of 1-aryl-3-hexen-1,5-diynes initiated by methoxide addition: synthesis of phenanthridinones,benzo[c]phenanthridinones,and biaryls

Treatment of 2-((Z)-6-substituted-3-hexene-1,5-diynyl)benzonitriles with sodium methoxide in refluxing methanol in the presence of a polar aprotic solvent, such as DMSO, HMPA, THF, or 18-crown-6, gave phenanthridinones in 21-77% yields. In these cases, addition of 10% DMSO into the reaction mixture gave the highest yield. On the other hand, methanolysis of 2-(2-(2-alkynylphenyl)ethynyl)benzonitriles under the same reaction conditions gave benzo[c]phenanthridinones in 31-57% yields. Methanolysis of (Z)-1-aryl-3-hexen-1,5-diynes in the presence of 2 equiv of tetrabutylammonium iodide gave biaryls in 14-64% yields. It is found that the reactions with aryl groups bearing electron-withdrawing groups proceeded at greater rates and gave better yields.     

Synthesis of carbazoles via an intramolecular cyclization of 2-(6-substituted 3(Z)-hexen-1,5-diynyl)anilines and their related molecules

Various 2-(6-substituted 3(Z)-hexen-1,5-diynyl)anilines 1a-g were treated with potassium tert-butoxide or potassium 3-ethylpentanoxide in NMP at 60 degrees C for 2 h to give the corresponding 5-substituted carbazoles 2a-g in 36-65% yields together with indoles 9a-g in 21-40% yields, respectively. Exposing the trifluoroacetamide analogues 10h-k under the same reaction conditions gave the carbazoles 2b-e in 37-57% yields and indoles 9b-e in 15-27% yields. Subsequent cyclizations of acetamide analogues 10a-g gave carbazoles 2a-g in 53-86% yields.     

Synthesis of 1,5-Disubstituted 3-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines

Summary. A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, ¹H and ¹³C NMR, IR, and mass spectroscopic measurements.     

Synthesis of 6-substituted-4,5-dihydro-3(2H)-pyridazinones

A convenient synthetic method for the pharmaceutically important 6-substituted-4,5-dihydro-3(2H)-pyridazinones is described. The synthetic strategy is based on Δ-soxazolines chemistry which were in turn unmasked by N? O bond cleavage and cyclized to the target compounds.     

Reduction of 3-(2-hydroxyethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene

Reduction of the nitro groups in 3-(2-hydroxyethyl)-1,5-dinitro-3-azabicyclo[3.3.1]non-6-ene was studied. The structures of the reaction products were confirmed using ¹H and ¹³C NMR spectroscopy.     

Ring opening reactions of 6-oxo-substituted spiro-pyrrolidinediones: Synthesis of 4-substituted-1,5-dihydro-3-hydroxy-2-oxo-1,5-diphenyl-2H-pyrroles

Reaction of 2-oxocylalkaneglyoxylate esters with N-phenylmethyleneaniline yields spiro compounds such as 2-aza-3,4,6,-trioxo-1,2-diphenylspiro[4.4]nonane 4 and cycloalkane-2-aza-3,4,6-trioxo-1,2-diphenylspiro-[4.5]decanes 5–7 . These undergo solvolytic opening of the the oxocycloalkane ring to yield 4-substituted-1,5-dihydro-3-hydroxy-2-oxo-1,5-diphenyl-2H-pyrroles 12–17 .     

Synthesis of 1,5-Disubstituted 3-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines

A series of 1,5-disubstituted 3-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-pyrazolines were synthesized by the reaction of α,β-unsaturated ketones derived from dehydroacetic acid and hydrazine in hot acetic acid or propionic acid. The structures of all new compounds were elucidated by microanalyses, ¹H and ¹³C NMR, IR, and mass spectroscopic measurements.     

微波促进水杨醛肟一锅法制备2-二氟甲氧基苯腈

以氯二氟乙酸钠为二氟甲基化试剂,碳酸钾为碱,实现了微波促进水杨醛肟一锅脱水成腈及二氟甲基化反应,以中等收率获得了8个2-二氟甲氧基苯腈类化合物,其中7个为新化合物.利用核磁共振波谱、红外光谱和高分辨质谱等手段对目标产物进行了表征.讨论了二氟甲基化试剂、碱和溶剂的种类、微波功率、反应温度和时间对反应的影响.确定了最优反应条件:含有不同取代基的水杨醛肟、氯二氟乙酸钠、碳酸钾和N,N-二甲基甲酰胺的摩尔比为1∶1.5∶1.5∶13,微波功率300 W,反应温度85℃,反应时间20 min.结合对比实验,提出了可能的反应机理.     

Synthesis of new trans-2-benzyl-3-(furan-2-yl)-4-substituted-1,2,3,4-tetrahydroisoquinolinones

The reaction of homophthalic anhydride and N-(furan-2-yl-methylidene)- benzylamine in different solvents and varying temperatures was studied in detail. Mixtures of the expected trans- and cis-1,2,3,4-tetrahydroisoquinoline-4-carboxylic acids trans-5 and cis-5, along with by-products 6 and 7 were obtained in dichloroethane or benzene. In pyridine, used for the first time, the reaction became completely diastereoselective, giving only the trans isomer. The carboxylic acid group of trans-5 was transformed in four steps into cyclic aminomethyl groups which yielded various new tetrahydroisoquinolinones trans- 11a-g, incorporating both a known fragment of pharmacological interest and various pharmacophoric substituents.     

3-芳基-6-(6-/8-取代-4-氯喹啉-3-基)1,2,4-三唑-[3,4-b]-1,3,4-噻二唑类化合物的合成

研究了3－芳基－4－氨基－5－巯基－1，2，4－三唑与6－／8－取代－4－羟基喹啉－3－酸在三氯氧磷催化下的反应，制得16个的3-芳基－6－（6－／8－取代－4－氯喹啉－3－基）1，2－4，－三唑[3,4-b)-1,3,4-噻二唑，新化合物的结构通过元素分析，IR,^1H NMR和MS确定，讨论了其波谱性质。     

Silyl stabilization of unsymmetrical bisketenes: 3-(Trimethylsilyl) and 3-(triisopropylsilyl)-2-substituted-1,3-butadiene-1,4-diones

The bisketenes 2-phenyl and 2-methyl-3-(trimethylsilyl)-1,3-butadiene-1,4-dione ( 8 and 10 ) are calculated on the basis of additivity of substituent effects to be less stable than the 3-phenyl and 3-methyl-4-(trimethylsilyl)cyclobut-3-ene-1,2-diones ( 7 and 9 ) by 1.9 and 2.6 kcal/mol, respectively. In agreement with this prediction, 8 and 10 are formed by photolysis of 7 and 9 , respectively, and undergo thermal reversion to their precursors at similar rates. The concentration of 8 in thermal equilibrium with 7 in CDCl₃, as measured by ¹H NMR spectroscopy, varied from 2.8% (161°C) to 0.5% (100.5°C), whereas the amount of 10 present at equilibrium with 9 was distinctly less. These measurements allowed the calculation of values of Δ G° (25°C) = 4.4 kcal/mol, Δ H° = 6.9±(1.3) kcal/mol, and Δ S° = 8.5 (±3.2) cal/deg mol for the conversion of 7 to 8 , and the equilibrium concentration of 8 at 25°C was estimated to be 0.06%. The triisopropylsilyl analog 12 of 8 was prepared and at 66°C was 2.6 times more reactive in ring closure to the corresponding cyclobutenone compared to 8 . Reactions of 8 and 10 with MeOH in CDCl₃ give the isolable monoketenes 3-phenyl and 3-methyl-2-(trimethylsilyl)-3-carbomethoxy-1-ene-1-one ( 20 , 21 ). Reaction of 20 with excess MeOH or H₂O gave the diastereomeric dimethyl 2-(trimethylsilyl)-3-phenylsuccinates ( 22 ) or ester-acids 24 , respectively. Reaction of 8 with excess N-methylaniline gave the diamide 25 .     

Solvation of UCl6(2-) anionic complex by MeBu3N(+), BuMe2Im(+), and BuMeIm(+) cations

The complexes [MeBu 3N] 2[UCl 6] and [BuMe 2Im] 2[UCl 6] were characterized in the solid state and in solution of [MeBu 3N][Tf 2N], [BuMe 2Im][Tf 2N], and [BuMeIm][Tf 2N] room-temperature ionic liquids using single-crystal XRD, EXAFS, electrochemistry, UV-visible absorption spectroscopy, and NMR. In the solid state and in solution, the existence of hydrogen bonding between the UCl 6 (2-) complex and the ionic liquid cations was revealed by these techniques. The MeBu 3N (+) cation interacts with UCl 6 (2-) via the protons on the alpha-carbon atoms of nitrogen. The protons of the imidazolium ring account for the interaction between the BuMe 2Im (+) cation and the UCl 6 (2-) anion. For the BuMeIm (+) cation the major interaction was confirmed between the most acidic proton on C(2) and the chlorides of UCl 6 (2-). The experimental results also show that the intensity of the interaction between the UCl 6 (2-) anion and the cation varies with the ionic liquid cation in the following order: MeBu 3N (+) approximately BuMe 2Im (+) < BuMeIm (+).     

Hydrolysis of 6-Aryl-2-amino-4-(dicyanomethylidene)-3-azabicyclo[3.1.0]hex-2-ene-1,5-dicarbonitriles

Russian Journal of Organic Chemistry - 6-Aryl-2-(dicyanomethylidene)-4-oxo-3-azabicyclo[3.1.0]hexane-1,5-dicarbonitriles were synthesized by treatment of...