Perfluoroalkylation of benzo crown ethers with sodium perfluoroalkanesulfinates in the presence of oxidant

Using Ce(SO4)2 or Mn(OAc)3 as oxidant, dibenzo crown ethers such as dibenzo-18-crown-6 (1) and dibenzo-24-crown-8 (5) and benzo-12-crown-4 (7) reacted smoothly with sodium perfluoroalkanesulfinates (2a-2e) to give the corresponding perfluoroalkylated products (3,4,6,7) in good yields with two isomers obtained in the case of dibenzo crown ethers. This provides a facile synthesis of perfluoroalkyl-containing crown ethers.     

Amidrazones and 2‐Acetylcyclopentanone in the Synthesis of Cyclopenta[e][1,3,4]Oxadiazepines

Amidrazones reacted with 2‐acetylcyclopentanone at room temperature to give cyclopenta[e ]‐[1,3,4]oxadiazepines. The structure of the obtained products was proved by IR, mass, and NMR spectra and elemental analyses. Two‐dimensional NMR spectroscopy was used to differentiate between other possible isomers. The reaction mechanism is also discussed.     

Rearrangement of aryl- and benzylthiopyridinium imides with participation of a methyl substituent

6-Methyl substituted 2-aryl- and 2-benzylthiopyridinium N-imides reacted with an excess of isocyanates to give N,N-disubstituted exocyclic1H-imidazo[4,5-b]pyridin-2(3H)-ones. The products easily underwent spontaneous [1,5] hydrogen shift to provide the heteroaromatic imidazopyridinone isomers. The transformation implied the initial formation of [1,2,4]triazolo[2,3-a]pyridinium salt, followed by deprotonation and carbamoylation of the methylene moiety, and, finally, a rearrangement following a [1,3] sigmatropic pattern. Mechanistic considerations suggest and some experimental findings reveal the nonconcerted two-step mechanism of the ring transformation step.     

2-氯甲基苯并恶唑的Darzens反应研究

本文报道用2-氯甲基苯并恶唑作为卤代物,进行Darzens反应。义固体氧化钾作碱,在非质子极性溶剂N,N-甲基酰胺中,将其与相应的羰基化合物反应, 生成了环氧化合物。     

Synthesis of caulersin and its isomers by reaction of indole-2,3-dicarboxylic anhydrides with methyl indoleacetates

1-Benzenesulfonylindole-2,3-dicarboxylic anhydride was reacted with methyl 1-benzenesulfonylindole-2-acetate to give the corresponding 2-acylindole-3-carboxylic acid as the sole product in high yield, which could be converted to caulersin in four steps. In a similar manner, three isomers A, B, and C were synthesized by reaction of indole-2,3-dicarboxylic anhydrides with methyl indoleacetates.     

Synthesis and nuclear magnetic resonance spectra of fused pyrimidines

Ethy phenylpropiolate reacted with 2-aminobenzothiazoles, benzimidazoles, thiazoline and thiazole to give the corresponding fused 2-oxopyrimidines. 2-Mercaptobenzimidazole reacted with ethyl phenylpropiolate to give 4-phenyl-2H-1-thiapyrimido(1,2-a ]benzimidazol-2-one in very good yield. The thiones, methylthio iodides and the hydrobromides of some of the products were prepared. Analysis of the nmr spectra of the benzothiazole and benzimidazole products and their 3-deuterio analogs showed that the proton at position 6 is shielded and absorbs together with the proton at position 3 near δ 6.0 ppm. The nmr and ir spectral data of all the products are tabulated and discussed.     

Oxidative transformation of the natural lignan hydroxymatairesinol with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone

The oxidative transformation of the two isomers of the natural lignan hydroxymatairesinol from Norway Spruce (Picea abies) by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), has been studied. Significant differences in the outcome of the reactions were observed when the pure isomers of hydroxymatairesinol were reacted with DDQ under the same conditions. The different stereoelectronic effects in the two isomers as well as their conformational structures seem to determine the site of reaction, which results in different reaction products. Several products were identified by GC-MS and NMR spectroscopy. Oxomatairesinol was obtained in a yield of 25%.     

Activation of nitroso group with thiols. A new transformation of primary amines to organic sulfides or thiols

Aliphatic primary amines reacted with 2-mercaptobenzothiazole in the presence of t-butylnitrite at room temperature to give condensation products, 2-(alkylthio)benzothiazole.     

Synthesis and Isomer Composition of 2-Polyfluoroalkoxy-1,3,2-dioxaphospholanes and -phosphinanes

Polyfluoroalkanols readily reacted with 2-chloro-1,3,2-dioxaphospholanes and 2-chloro-1,3,2-dioxaphosphinanes in hexane in the presence of triethylamine (–10 to 25°C, 5 h) to give 2-polyfluoroalkoxy-1,3,2- dioxaphospholanes and 2-polyfluoroalkoxy-1,3,2-dioxaphosphinanes in 48–72% yield. The products were found to exist as mixtures of cis and trans isomers with the trans isomer predominating for the phospholanes and cis isomer predominating for the phosphinanes according to the ¹H, ¹³C, ¹⁹F, and ³¹P NMR data.     

Amination of thioxanthene-1,4,9-trione and its chloro derivatives

Thioxanthene-1,4,9-trione and its 2(3)-chloro and 2,3-dichloro derivatives reacted with amines to give the corresponding 2-amino-substituted products.     

Selective preparation of pyridines, pyridones, and iminopyridines from two different alkynes via azazirconacycles

Selective preparation of pyridine derivatives from two different alkynes and a nitrile was achieved by a novel procedure in which an alkyne and a nitrile couple first to give an azazirconacyclopentadiene followed by reaction with the second alkyne in the presence of 1 equiv of NiCl(2)(PPh(3))(2). This procedure gives only single products of pyridine derivatives from two different symmetrical alkynes and a nitrile. Our novel procedure can be used even with two similar alkyl-substituted alkynes such as 3-hexyne and 4-octyne. Two possible pyridine isomers from 3-hexyne, 4-octyne, and acetonitrile could be completely and independently prepared as single products by this method. The origin of the selectivity comes from the addition order of two different alkynes. This method was applied for the formation of pyridones and iminopyridines using isocyanate and carbodiimide derivatives instead of nitriles, respectively. Reaction of an alkyne with Cp(2)ZrEt(2) and an isocyanate or a carbodiimide gives an azazirconacycle. Treatment of the azazirconacycle with the second alkyne in the presence of 1 equiv of NiCl(2)(PPh(3))(2) gave a pyridone or an iminopyridine derivative. The use of two different unsymmetrical alkynes afforded the pyridine with five different substituents when the first alkyne has a trialkylsilyl group and the second alkyne has a phenyl group as functional groups. On the other hand, azazirconacyclopentadienes reacted with propargyl bromide in the presence of CuCl with excellent regioselectivity to give tetrasubstituted pyridine derivatives as single products. With the assistance of the trialkylsilyl groups, pyridines with all different substituents including H were also prepared.     

Condensation of isophorone and isophorone oxime with amines and aldehydes

Mannich condensations of isophorone (3,5,5-trimethylcyclohex-2-en-1-one) with paraformaldehyde and dimethylamine, benzylamine, and piperidine hydrochlorides were studied. The reactions were not selective, and they involved both activated methylene group and vinylic carbon atom, as well the exocyclic methyl group at the double bond. The corresponding isomeric amino ketones were formed in comparable amounts (42, 30, and 28%). The E and Z isomers of isophorone oxime reacted with paraformaldehyde and dimethylamine hydrochlride to give mixtures of analogous Mannich condensation products, but the fraction of the addition product at the carbon atom spatially close to the oxime hydroxy group was larger. Under analogous conditions, the reaction of isophorone with aromatic amines and aromatic aldehydes gave products of two-component condensation of isophorone with aldehydes, and the reactions involved exclusively the activated methylene group in the initial enone with formation of the corresponding trans,trans-isomeric 7-arylmethylidene derivatives.     

Direct formation of Ge-C bonds from GeO(2)

Germanium dioxide in the presence of 5% KOH reacted with dimethyl carbonate (DMC) at 250 degrees C to give (MeO)(4)Ge. The reaction of GeO(2) and DMC is similar to that reported for SiO(2); however, the rate of reaction for germanium is much higher than that of the corresponding silicon reaction. In a side-by-side experiment using SiO(2) and GeO(2) where the surface area of the silicon dioxide was 2 orders of magnitude higher than that of the GeO(2), the base-catalyzed reaction with DMC was about an order of magnitude higher for the germanium dioxide. When GeO(2) and 5% KOH were reacted with DMC at 350 degrees C, two products formed: (MeO)(4)Ge (70%) and MeGe(OMe)(3) (30%). Confirmation of the identity of MeGe(OMe)(3) was by GCMS, (1)H and (13)C NMR, and comparison to an authentic sample made by reaction of MeGeCl(3) with NaOMe. Experiments to determine the mechanism of the direct formation of Ge-C from GeO(2) ruled out participation from CO, H(2), or carbon. The KOH-catalyzed reaction of other metal oxides was explored including B(2)O(3), Ga(2)O(3), TiO(2), Sb(2)O(3), SnO(2), and SnO. Boron reacted to give unknown volatile products. Antimony reacted to give a solid which analyzed as Sb(OMe)(3). SnO reacted with DMC to give a mixture that included (MeO)(4)Sn and possibly Me(3)Sn(OMe).     

Homometathesis and cross-metathesis coupling of phosphine-borane templates with electron-rich and electron-poor olefins

Ruthenium-catalysed olefin cross-metathesis can be used to synthesise structurally diverse acyclic phosphines protected as their borane complexes. Homodimerisations have been investigated and proved successful only for the allyl-substituted borane-protected phosphines. In the presence of various olefinic partners, allyl-substituted P templates reacted in cross-couplings to give predominantly the E products but traces of the Z isomers were always detected in the crude reaction mixtures. In contrast, cross-metathesis of vinyl-substituted phosphine boranes took place with exclusive E-selectivity. Although the conversions were consistently very good to excellent, the yields of purified products were often significantly lower suggesting that some of the newly formed compounds are prone to decompose upon purification.     

四氟乙烯齐聚体的反应 III: 四氟乙烯四聚体与脂族胺以及烷氧亲核试剂的反应

3, 4-Bis (trifluoromethyl)-perfluorohexene-(3) (1) reacted with diethylamine to give the 1-N, N-diethylamino-2-pentafluoroethyl -3-trifluoromethyl-perfluoropentene-(1)(2), which was easily hydrolyzed to the corresponding N, N-diethyl-2-penta-fluoroethyl- 3-trifluoromethyl-perfluoropenteno-(2)-amide (3). When compound 1 was allowed to react with n-butyl amine at 40-50`C, the 2,3,4-tris(trifluoromethyl)-4-pentafluoroethyl-1-n-butyl-aza- cyclobutene-(2) (5) was obtained as the main product and at-30-40`C, 3,4-bis(trifluoromethyl)-4-n-butylamino-perfluorohexene-(2) (4) as the main product. The isomers 3, 4-bis(trifluoromethyl)-4-allyloxy-perfluoro-hexen-(2) (6) and 2-pentafluoroethyl-3-trifluoromethyl-3-allyloxy-perfluoropentene-(1)(7) were formed when 1 was reacted with sodium allyl alcoholate.     

Synthesis and Reactions of Some Novel Nicotinonitrile,Thiazolotriazole, and Imidazolotriazole Derivatives for Antioxidant Evaluation

The novel 2-(1H)-pyridone, the lead compound of the pyridone derivative 1, reacted with an electrophilic reagent (ethyl chloroacetate) to give the corresponding ester 2. Condensation of compound 2 with thiosemicarbazide and/or hydrazine hydrate afforded the mercaptotriazole and the corresponding acetic acid hydrazide derivatives 3 and 4, respectively. The latter compound reacted with ethyl acetoacetate, ethyl cyanoacetate, and maleic anhydride to give compounds 5, 6, and 7, respectively. Alkylation of compound 3 with methyl iodide or chloroacetic acid afforded methylsulfanyltriazole and thiazolotriazole derivatives 8 and 9, respectively. Compound 8 reacted with glycine to afford the imidazotriazole derivative 10. Both compounds 9 and 10 reacted with glucose and benzaldehyde to give compounds 11, 12, 13, and 14, respectively. Some of the prepared products were selected and subjected to screening for their antioxidant activity.     

镧系金属用于有机反应的研究(Ⅳ)——石墨附载的零价态钐与苯甲酰氯的反应

文献报道的将零价态镧系金属直接用于有机反应尚不多见,而且即使在活化试剂存在下,一些稀土金属如Ce、sm等对有机底物的活性并不象预期的那么高。为此,本文提出了用强还原剂石墨钾、萘锂还原无水稀土氯化物制得原位(in situ)生成的高分散的零价稀土金属。发现所得零价态稀土金属有较高的反应活性。本文首次报道用石墨钾(C_8K)还原无水SmCl_3得到石墨分散的零价态钐及其与苯甲酰氯的反应,产物为联苯甲酰、安息香和1,2-二苯乙烯二醇二苯甲酸酯。     

Synthesis of methyl 4-aryl-2-{[4-(carbamimidoylsulfamoyl)- phenyl]amino}-4-oxobut-2-enoates

Methyl aroylpyruvates reacted with 4-amino-N-carbamimidoylbenzene-1-sulfonamide in acetic acid–ethanol (1: 1) to give methyl 4-aryl-2-{[4-(carbamimidoylsulfamoyl)phenyl]amino}-4-oxobut-2-enoates which were found to exist in solution as mixtures of Z and E isomers.     

Condensation of ethyl phenylpropiolate with some cyanoacetyl and cyanomethylene heterocycles

N-Cyanoacetyl pyrrolidine, piperidine and morpholine reacted with ethyl phenylpropiolate to give the rearranged Michael addition products III. Some interesting results obtained from the bromination, hydrolysis and reduction of III are reported. 2-Thiophene and 2-furaneaceto-nitriles reacted with ethyl phenylpropiolate to give the Claisen addition products XVIII. Reaction of either III or XVIII with hydrazine hydrate, phenylhydrazine and hydroxylamine hydrochloride afforded 3-phenylpyrazol-5-one, 1,3-diphenylpyrazol-5-one and 3-phenylisoxazol-5-one together with the appropriate starting cyanoacetyl or cyanomethylene compounds, respectively. The mechanism for the formation of the various reaction products beside the ir and nmr spectral results are discussed.     

Reaction of N-cyanoformimidates with some heterocyclic compounds. A new synthesis of 5-azaadenine and related compounds

3-Amino-1,2,4-triazoles and 2-aminobenzimidazole were reacted with N-cyanoimidates to give 5-amino-1,2,4-triazolo[2,3-a]-1,3,5-triazines (5-azaadenines) and 4-aminobenzimidazo[1,2-a]-1,3,5-triazines, respectively. The structures of the compounds obtained were confirmed through the comparison with some of the possible isomers prepared by independant methods.