Synthesis of 4,5-Dialkyl-2-perfluoroaryl-1H-imidazol-1-ols and 4,5-Dimethyl-2-perfluoroaryl-1H-imidazoles

Russian Journal of Organic Chemistry - Aliphatic α-hydroxyamino oximes reacted with perfluoroaromatic aldehydes to give α-perfluoroaryl nitrones which underwent cyclization in acetic acid...     

Regiospecific synthesis of trichloromethyl substituted 4,5‐dihydro‐1h‐1‐tosylpyrazoles

The regiospecific synthesis of a new series of eight 3‐alkyl(aryl)‐5‐hydroxy‐5‐trichloromethyl‐4,5‐dihydro‐1H‐1‐tosylpyrazoles is reported. The 1‐p‐tosyl‐2‐pyrazolines were obtained from the cyclocondensation reaction of 4‐alkyl(aryl)‐4‐alkoxy‐1,1,1‐trichloroalk‐3‐en‐2‐ones, [where alkyl = H, Me and aryl = ‐C₆H₅, 4‐CH₃C₆H₄, 4‐OCH₃C₆H₄, 4‐FC₆H₄, 4‐ClC₆H₄, 4‐BrC₆H₄,] with p‐tosylhydrazine in 64 to 92 % yields, employing anhydrous toluene at reflux or diethyl ether at room temperature as the reaction condition.     

v-triazolines. XI . Rearrangement of 1-aryl-4,5-diamino-4,5-dihydro-v-triazoles

The reaction of arylazides with 1,2-diaminoethylenes ( 1a-b ) or α,β-diaminostyrenes ( 1c-f ) gave N-(1,2-diaminoethylideneanilines ( 2a-e ) and N-(1,2-diamino-2-phenylethylidene)anilines ( 2g-i ), respectively. These amidine derivatives are formed through the rearrangement of unstable 1-aryl-4,5-diamino-v-triazolines. The regiospecificity of the cycloaddition reaction has been elucidated on the basis of the products obtained.     

3-(4,5-Dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-ylmethyl)oxazolidines and 3-(4,5-dihydro-1<Emphasis Type="Italic">H</Emphasis>-pyrazol-1-ylmethyl)perhydro-1,3-oxazines

3-(4,5-Dihydro-1H-pyrazol-1-ylmethyl)oxazolidines and 3-(4,5-dihydro-1H-pyrazol-1-ylmethyl)perhydro-1,3-oxazines were synthesized in 54–85% yield by reactions of α-amino alcohols and 3-aminopropan-1-ol, respectively, with formaldehyde and 4,5-dihydro-1H-pyrazoles.     

One-pot synthesis of 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives via a four-component reaction

An effective route to functionalized 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives is described. This involves reaction of N-alkyl-3-oxobutanamides, which result from the addition of an amine to the diketene, and a primary amine in the presence of dibenzoylacetylene. The 1,3-dicarbonyl compounds obtained from the addition of an amine to diketene were trapped with a primary amine to produce (Z)-3-(alkylamino)-N¹-alkyl-2-butenamide, which reacts with dibenzoylacetylene to produce 4,5-dihydro-1H-pyrrol-3-carboxamide derivatives.     

Synthesis of 4,5-dihydroisoxazoles from <Emphasis Type="Italic">N</Emphasis>-nitroso-4,5-dihydropyrazoles

N-Nitroso-4,5-dihydropyrazoles obtained from ethyl(methyl) 5-aryl-4,6-dioxo-1,3a, 4,5,6,6a-hexahydropyrrolo[3,4-c]pyrazole-3-carboxylates and ethyl(methyl) 7-aryl-6,8-dioxo-1,2,7- triazaspiro[4.4]non-2-ene-3-carboxylates eliminate nitrogen molecule on heating to afford the corresponding 4,5-dihydroisoxazole derivatives.Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 10, 2004, pp. 1561–1565.Original Russian Text Copyright © 2004 by Molchanov, Stepakov, Kostikov.     

Über ein 4,5;7,9-Bis-epoxy-hasubanan

Reaction of the enol ether1 with N-bromoacetamide in methanol gave the 7 -bromoacetal3 which rearranged in acidic media to the 7,9-epoxide5. As an oxide bridge from C-9 to C-7 in indolinocodeinone can only be formed in the -position, the isolation of5 is the chemical proof of the configuration at C-9.     

1‐Methyl‐1H‐imidazo[4,5‐f]quinolin‐6‐ium chloride monohydrate

The title compound, C₁₁H₁₀N₃⁺·Cl^?·H₂O, belongs to the N1‐methyl‐substituted imidazo­[4,5‐f]­quinoline family, in which the heterocyclic ring is protonated at the pyridine rather than at the imidazole N atom. The mol­ecule as a whole is almost exactly planar. The molecular structure has been compared with that of the 2‐amino analogue described in the literature, and it was found that the extra amino group of the latter is involved in conjugation with the adjacent double bond, i.e. the conjugation does not extend over the entire heterocyclic system. The cation of the title compound forms a strong hydrogen bond with the Cl^? anion and the anions are interconnected by the water solvent mol­ecule.     

Characterization of 4,5‐Dihydro‐1H‐Pyrazole Derivatives by 13C NMR Spectroscopy

The ¹³ C NMR resonances of 19 1‐acyl‐3‐(2‐nitro‐5‐substitutedphenyl)‐4,5‐dihydro‐1H‐pyrazoles, and 19 1‐acyl‐3‐(2‐amino‐5‐substituted)‐4,5‐dihydro‐1H‐pyrazoles, were completely assigned using the concerted application of one‐ and two‐dimensional NMR experiments (DEPT, gs‐HSQC and gs‐HMBC). Copyright © 2012 John Wiley & Sons, Ltd.     

Alkylation of 4,5-dichloropyridazin-6-one with α,ω-dibromoalkanes or 4,5-dichloro-1-(ω-bromoalkyl)pyridazin-6-ones

Alkylations of 4,5-dichloropyridazin-6-one (1) with dibromoalkanes 2 or 3 in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide were investigated under restricted condition. Reactions of 1 with 2 or 3, except for 2b and 3b , in the presence of potassium carbonate or tetrabutylammonium bromide/potassium hydroxide gave only the N-alkylation products 3 and/or 4. Alkylation of 1 with 2b or 3b in the presence of potassium carbonate yielded the N-alkylation products 3b and/or 4b and the O-alkylation product 5 as the main product, whereas treatment of 1 with 2b or 3b in the presence of tetrabutylammonium bromide/potassium hydroxide afforded selectively the N-alkylation products 3b and/or 4b.     

Synthesis of 4,5-dichloro-1-(4,5-dichloropyridazin-3-yl)pyridazin-6-one

This paper presents the synthesis of 4,5-dichloro-1-(4,5-dichloropyridazin-3-yl)pyridazin-6-one from 4,5-dichloropyridazin-6-one.