Reactions of α-Arylhydrazono-β-oxo-β-phenyl-propionitriles

ω-Cyanoacetophenone was coupled with a variety of aromatic diazonium chlorides to give the corresponding arylazo derivatives 1 a – g . Analysis of the IR and UV spectra of these compounds indicated that they exist mainly as the corresponding arylhydrazones. Compounds 1 a – d, f, g reacted with diazomethane to yield the N-methyl-arylhydrazones 2 a – f . 3-Amino-4-arylazo-5-phenylpyrazoles 5 a – g and 4-arylazo-5-imino-1,3-diphenyl-2-pyrazolines 6 a – g were obtained by the interaction of 1 a – g with hydrazine hydrate and with phenylhydrazine, respectively.     

Reactions with the arylhydrazones of some α,β-diketoesters

Treatment of the α, β-diketo-ester-α-arylhydrazones 1a–e and 2a–d with GRIGNARD reagents results in the formation of the ketocarbinols 3a–h and 4a–g , respectively. The arylhydrazones of ethyl mesoxalate 5a–e react with phenylmagnesium bromide to yield compounds 3a–e . A novel synthesis of α-arylazo-β-arylchalcones 6a–e and their reaction with hydrazines are reported. Whereas the arylhydrazones 10a, b, 2a, b, d, 13a–c and 14a–c react with piperidine and formaldehyde to yield the MANNICH bases 11a, b, 12a–c and 15a–c , compound 5a was recovered unchanged.     

Intermediates of Prostanoid Synthesis. Stereospecific conversion of (+)-5β-hydroxycyclopenten-2-yl-1β-acetic acid γ-lactone into (+)-1β-methoxycarbonylmethyl-2β,3β-(p-nitrobenzylidene)-dioxycyclopentan-5-one

Starting from (+)-5β-hydroxycyclopenten-2-yl-1β-acetic acid γ-lactone ( 1 ), (+)-1β-methoxycarbonylmethyl-2β, 3β-(p-nitrobenzylidene)-dioxycyclopentan-5-one ( 7 ) was prepared within 4 steps. Subsequent cleavage of the latter gives (−)-3β-hydroxy-1-methoxy-carbonylmethylcyclopent-1-en-5-one ( 8a ). Hydroxylation of the lactone ( 1 ) was found to give (+)-2β,3β,5β-trihydroxycyclopentyl-1β-acetic acid γ-lactone ( 2a ) with cis-oriented hydroxy groups in respect to the lactone ring. No formation of the trans-isomer, as has been reported earlier [4], was observed.     

Radiation-induced copolymerization of α,β,β-trifluoroacrylonitrile with α-olefin

Homopolymerization and copolymerization of α,β,β-trifluoroacrylonitrile (FAN) with γ-olefins were carried out in bulk by γ-ray irradiation at 25°C. FAN gives very small quantities of brown and greasy low molecular weight polymer. Cyano groups in FAN polymer were found to be readily hydrolyzed to acid amide groups in the atmosphere. FAN was found to copolymerize with ethylene, propylene, and isobutylene via a radical mechanism to form equimolar copolymers in a wide range of monomer compositions. The polymerization rate increases linearly with FAN fraction in the monomer mixture. These copolymers are also hydrolyzed in the atmosphere, and the hydrolysis proceeds with more difficulty for the copolymer with higher α-olefin. The reactivity ratios r₁ (FAN) and r₂ (α-olefin) were determined to be 0.01 and 0.12 for the FAN/ethylene copolymerization and 0.01 and 0.07 for the FAN/propylene copolymerization. These results confirm that an alternating copolymerization takes place in the FAN/α-olefin system.     

Nanostructured α- and β-cobalt hydroxide thin films

A new perspective in the use of electrochemical methods to deposit cobalt hydroxide thin films is presented. Ordered arrays of α-Co(OH)₂ (hydrotalcite-like (Co-HT)) and β-Co(OH)₂ nanoparticles were synthesized on transparent conductive oxide (TCO) substrates by localized cathodic electrogeneration of hydroxyl via the reduction of NO₂⁻ (or NO₃⁻) ion precursors in solution containing Co²⁺ in very low concentration. The thin films, analyzed by X-ray diffraction and scanning electron microscopy were found to be composed of vertically oriented platelets with the crystallographic c-axis parallel to the substrate surface. Turbostratic disorder was not observed in the films. UV/Vis spectra and thermal gravimetric analyses (TGA) indicated distinct variation between the Co-HT structures. Films deposited at 60 °C using a nitrite precursor generated uniform, vibrant-green mixed-valence Co-HT (Co²⁺/Co³⁺). Nitrate precursors yielded a “hydroxyl-deficient” Co-HT (Co²⁺ only). Films deposited at 95 °C in nitrate solution yielded β-Co(OH)₂. The films obtained in presence of nitrite were thicker than those obtained in nitrate. They were formed of β-Co(OH)₂ and contained traces of Co-HT.     

Reactions with the Arylhydrazones of some α-cyanoketones

Ethereal diazomethane reacts with the arylhydrazones of mesoxalic acid dinitrile 1a–c and of ethyl α-cyanoglyoxalate 2b, d–g to yield the methylarylhydrazones 3a–c and 4a–e respectively. Treatment of 4b–e with phenylmagnesium bromide results in the formation of the imino derivatives 5a–d . Whereas 2a–g react with phenylhydrazine to yield the aminopyrazoles 8a–g , the hydrazides 10a, b are formed on treatment of 4c, e with hydrazine hydrate. 1a–c react with hydrazine hydrate and with phenylhydrazine to yield 3-amino-4-arylhydrazono-5-imino-2-pyrazoline derivatives 11a–f 11a, b react with acrylonitrile to yield 3-amino-1(β-cyanoethyl)-4-arylhydrazono-5-imino-2-pyrazoline derivatives 12a, b which can be readily cyclised to the pyrazolo[3,2-b]pyrimidine derivatives 13a, b by the action of hot acetic acid.     

An efficient Synthesis of Acetylenic γ- and δ-Hydroxy Ketones, γ- and δ-keto acids,and γ- diketones via addition of 1-alkinyllithium compounds to γ- and δ-lactones

2-Hydroxy-6-alkyn-5-ones 3 , 1-hydroxy-5-alkyn-4-ones 4 , and 1-hydroxy-6-alkyn-5-ones 5 are conveniently obtained in excellent yields through a highly selective monoaddition of an 1-alkynyllithium compound 2 to γ-valerolactone (1a) , γ-butyrolactone (1b) or δ-valerolactone (1c) . They are oxidized by pyridinium dichromate or Jones reagent to the corresponding acetylenic 1,4-diketones 6 , 4-oxo carboxylic acids 7 , and 5-oxo carboxylic acids 8 , respectively.     

Preparation and Nucleophilic Reactions of β-Fluoro-γ-Alkyl Halides

Problems related to the preparation of β-fluoro-γ-alkyl halides and the nucleophilic reactions of these compounds are described. These compounds are found to be less reactive than the corresponding halides without the fluorine atom. Nucleophilic reactions of these halides are S_N2 reactions, and no allylic rearrangements are observed in any case.     

Three‐Component Reactions of 2‐Alkynylbenzaldoximes and α,β‐Unsaturated Carbonyl Compounds with Bromine or Iodine Monochloride

The three‐component reaction of 2‐alkynylbenzaldoximes and α,β‐unsaturated carbonyl compounds with bromine or iodine monochloride is described, which generates the unexpected 2‐(4‐haloisoquinolin‐1‐yl)ethanol derivatives in good to excellent yields.     

The Synthesis of trans‐Perhydroindolic Acids and their Application in Asymmetric Domino Reactions of Aldehyde Esters with β,γ‐Unsaturated α‐Keto Esters

(2S,3aR,7aS)‐Perhydroindolic acid, the key intermediate in the synthesis of trandolapril, and its trans‐isomers, were readily prepared. These proline‐like molecules are unique in that they contain a rigid bicyclic structure, with two hydrogen atoms trans to each other at the bridgehead carbon atoms. These molecules were used successfully as chiral organocatalysts in asymmetric domino Michael addition/cyclization reactions of aldehyde esters with β,γ‐unsaturated α‐keto esters. They proved to have excellent catalytic behavior, allowing for the synthesis of multi‐substituted, enantiomerically enriched hemiacetal esters. Under optimal conditions (using 10 mol% catalyst loading), a series of β,γ‐unsaturated α‐keto esters was examined with up to 99% de, ee and yield, respectively. Additionally, the enantiomerically enriched hemiacetal esters could be readily transformed into their corresponding bioactive pyrano[2,3‐b]pyrans (possessing a multi‐substituted bicyclic backbone).     

Organocatalytic Asymmetric Formal [3+3] Cycloaddition Reactions of α,β‐Unsaturated Aldehydes with Nazarov Reagents

An organocatalytic asymmetric formal [3+3] cycloaddition reaction of α,β‐unsaturated aldehydes with Nazarov reagents promoted by prolinol derivatives afforded, after oxidation, 3,4‐dihydropyranones in good yields with high enantioselectivities of up to 97% ee.     

Kinetic Resolution of Aliphatic β‐Amino Acid Amides by β‐Aminopeptidases

Access to enantiopure β‐amino acids : β‐Aminopeptidases are hydrolases that possess the unique ability to cleave N‐terminal β‐amino acids from peptides and amides. Hydrolysis of racemic β‐amino acid amides catalyzed by these enzymes displays enantioselectivity with strong preference for substrates with the L ‐configuration, and gives access to various aliphatic β‐amino acids of high enantiopurity.

     

Synthesis of α, α′, β-trideuterovinyl acetate

Reaction conditions for the synthesis of α, α′, β-trideuterovinyl acetate by the continuous vapour phase catalytic reaction of deuteroacetylene and acetic acid-d (CH₃COOD) are described.     

X-ray analysis of α-, β-, and γ-phase Ag–Hg alloy films produced on polymer substrates by casting polyacrylamide–AgNO3 aqueous solution in Hg atmosphere

It is reported that, by dropping Hg metal on the wet α-phase Ag–Hg alloy film formed on the cast polyacrylamide–AgNO₃ aqueous solution, the α phase of fcc structure can be converted into other phases that contain more Hg. The X-ray analysis of these phases reveals that they are the β phase of hexagonal structure and the γ phase of bcc structure. It is also shown that the lattice constant of the α phase can be controlled to some extent by pH of the aqueous solution of PAAm from which the alloy film is formed.     

Polymerization of α, α-disubstituted-β-propiolactones and lactams. 9. ABA block copolymers of α-methyl-α-butyl-β-propiolactone and pivalolactone

ABA block copolymers were prepared by the anionic polymerization of α-methyl-α-butyl-β-propiolactone, MBPL (B block), and pivalolactone, PL (A blocks). The MBPL block had a very low decree of crystallinity and a glass temperature of ? 13°C, so phase separation with extensive crystallization of the PL blocks gave thermoplastic elastomers when the MBPL block constituted the principal and continuous phase. The observed crystallinity and melting point of 40–45°C in the MBPL homopolymer have not been previously reported. Measurements were obtained by electron microscopy of the initial size distribution of the PL domains as a function of copolymer composition and degree of polymerization, and on the effect of annealing on this parameter. Tensile strengths and elongations at break were both less than those previously observed for equivalent ABA block copolymers of PL and α-methyl-α-propyl-β-propiolactone.