Crystal structures of 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-nitro-cyclohexa-2,4-dienone hydrate and 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-bromo-cyclohexa-2,4-dienone

Crystal structures of 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-nitro-cyclohexa-2,4-dienone hydrate (I) and 6-[(2-hydroxy-1,1-bis-hydroxymethyl-ethylamino)-methylene]-4-bromo-cyclohexa-2,4-dienone (II) have been determined. The crystals of I are monoclinic, a = 16.957(1) Å, b = 10.729(2) Å, c = 7.240(3) Å; β = 99.56(3)°, space group P2₁/c, Z = 4, R = 0.0492. The crystals of II are triclinic, a = 10.282(2) Å, b = 7.189(3) Å, c = 16.831(3) Å; α = 90.67(3)°, β = 100.10(3)°, γ = 95.87(3)°; space group P-1, Z = 4, R = 0.0591. The independent part of the unit cell of I contains one unique molecule and water of crystallization, while in II — two unique molecules A and B. C(CH₂OH)₃ fragment of the molecule B manifests the disordering of alcohol oxygen atoms. Both in I and II, the salicylidene fragment of the molecules exists in the quinoid tautomeric form.     

Synthesis of 5-(1H-benzimidazol-2-yl)-1H-pyrazolo-[3,4-<Emphasis Type="Italic">b</Emphasis>]pyridines by the <Emphasis Type="Italic">p</Emphasis>-(dimethylamino)benzaldehyde modification of Hantzsch reaction

The reactions of p-(dimethylamino)benzaldehyde with 5-amino-3-methyl-1-phenylpyrazole and 2-RCOCH₂-1H-benzimidazoles have produced 5-(1H-benzimidazol-2-yl)-1H-pyrazolo[3,4-b]pyridines. The transformation includes the formation of compounds in accordance with a Hantzsch reaction containing a 1,4-dihydropyridine ring, and is completed by the aromatization either by the splitting off of N,N-dimethylanyline or oxidation. The splitting is produced by acetic acid and the oxidation by a nitrocompound. __________ Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 578–584, April 2007.     

Condensation of 1-Substituted 1,2,3,9a-Tetrahydro-9H-imidazo[1,2-a]indol-2-one Derivatives with Aromatic Aldehydes

Condensation of 1-alkyl-, 1-allyl-, and 1-benzyl-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones with benzaldehydes in acetic acid and subsequent treatment of the reaction mixture with potassium hydroxide afforded 1-substituted 9a-(2-phenylethenyl)-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-one derivatives. 1-Methyl- and 1-ethyl-9a-[2-(4-dimethylaminophenyl)ethenyl]-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-ones were synthesized by alkylation of 9a-[2-(4-dimethylaminophenyl)ethenyl]-1,2,3,9a-tetrahydro-9H-imidazo[1,2-a]indol-2-one with methyl- and ethyl iodides in DMF in the presence of a strong base.     

An Efficient and Environment Friendly Procedure for the Synthesis of Arylmethylenemalononitrile Catalyzed by Strong Base Anion‐Exchange Resin in Water

Abstract

Knoevenagel condensation of malononitrile with aromatic aldehydes catalyzed by strong base anion‐exchange resin in water results arylmethylenemalononitrile in 74–98% yield at room temperature.     

Old Reagent,New Results: Aromatization of Hantzsch 1,4-Dihydropyridines with Supported Bismuth Nitrate under Microwave Irradiation in Solventless System

Hantzsch 1,4-dihydropyriines were rapidly and efficiently oxidized using bismuth nitrate supported onto silica gel under microwave irradiation.     

Reductive Ring Opening of Ephedrine and Pseudo-Ephedrine-Derived Oxazolidinium Methiodides by Sodium Borohydride. A Direct Access to New Chiral Amine-Borane Adducts

Sodiun borohydride reacts with oxazolidinium methiodides derived from ephedrine and pseudoephedrine, in ethereal solvents, cleaving regioselectively the C-N bond of the ring and leading, in good yields, to chiral amine-borane adducts of know absolute configuration. The ¹HNMR data allow to predict the most stable conformation.     

Synthesis of Novel N‐Morpholinoacetyl‐2,6‐diarylpiperidin‐4‐ones

A series of N‐chloroacetyl‐2,6‐diarylpiperidin‐4‐ones (10–18) obtained from the corresponding 2,6‐diarylpiperidin‐4‐ones upon base‐catalyzed condensation with morpholine afforded N‐morpholinoacetyl‐2,6‐diarylpiperidin‐4‐ones (19–27). The synthesized compounds have been characterized by their elemental, analytical, and spectral data.     

ZnO-beta zeolite: as an effective and reusable heterogeneous catalyst for the one-pot synthesis of polyhydroquinolines

Abstract

ZnO-beta zeolite, an inexpensive and mild catalyst, has been used for the synthesis of polyhydroquinolines in excellent yields from the one-pot four-component condensation of aldehydes, dimedone, ethyl acetoacetate, and ammonium acetate in ethanol at room temperature. The remarkable advantages offered by this method are a green catalyst, mild reaction conditions, simple work-up procedures, much faster reactions, and excellent yield of products. Furthermore, the catalyst could be reused several times keeping its initial activity in recycled reactions.     

La(O-i-Pr)3 CATALYZED THREE-COMPONENT CONDENSATION REACTION: A CONVENIENT SYNTHESIS OF N,N-DIALKYL-α-CYANOAMINES

ABSTRACT

In the presence of 10 mol% of La(O-i-Pr)₃, a three-component condensation reaction of aldehyde, secondary amine and trimethylsilylcyanide proceeded smoothly to afford N,N-dialkyl-α-cyanoamine in good yield.     

Three‐arm star block copolymers of aromatic polyether and polystyrene from chain‐growth condensation polymerization,atom transfer radical polymerization,and click reaction

Well‐defined (AB)₃ type star block copolymer consisting of aromatic polyether arms as the A segment and polystyrene (PSt) arms as the B segment was prepared using atom transfer radical polymerization (ATRP), chain‐growth condensation polymerization (CGCP), and click reaction. ATRP of styrene was carried out in the presence of 2,4,6‐tris(bromomethyl)mesitylene as a trifunctional initiator, and then the terminal bromines of the polymer were transformed to azide groups with NaN₃. The azide groups were converted to 4‐fluorobenzophenone moieties as CGCP initiator units by click reaction. However, when CGCP was attempted, a small amount of unreacted initiator units remained. Therefore, the azide‐terminated PSt was then used for click reaction with alkyne‐terminated aromatic polyether, obtained by CGCP with an initiator bearing an acetylene unit. Excess alkyne‐terminated aromatic polyether was removed from the crude product by means of preparative high performance liquid chromatography (HPLC) to yield the (AB)₃ type star block copolymer (M_n = 9910, M_w/M_n = 1.10). This star block copolymer, which contains aromatic polyether segments with low solubility in the shell unit, exhibited lower solubility than A₂B or AB₂ type miktoarm star copolymers. In addition, the obtained star block copolymer self‐assembled to form spherical aggregates in solution and plate‐like structures in film. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012