Photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction. Part 7: methanol, conjugated dienes, and 1,4-dicyanobenzene

1994 ◽  
Vol 72 (11) ◽  
pp. 2291-2304 ◽  
Author(s):  
Kimberly A. McManus ◽  
Donald R. Arnold
Keyword(s):  
Potassium Cyanide ◽  
Addition Product ◽  
Conjugated Dienes ◽  
Acetonitrile Solution ◽  
Mercury Vapour ◽  
Aromatic Substitution ◽  
Cyanide Ion ◽  
Marked Contrast ◽  
Methanol Solutions ◽  
Mercury Vapour Lamp

The scope of the photochemical nucleophile–olefin combination, aromatic substitution (photo-NOCAS) reaction has been extended to include conjugated dienes: 1,3-butadiene (9), 2-methyl-1,3-butadiene (10), 2,3-dimethyl-1,3-butadiene (11), and 2,5-dimethyl-2,4-hexadiene (12). Acetonitrile–methanol solutions of the dienes 9,10, and 11, and 1,4-dicyanobenzene (1), with and without codonor (biphenyl (5)), were irradiated with a medium-pressure mercury vapour lamp through Pyrex. Both 1,2- and 1,4-addition products were formed in approximately equal amounts (combined yields of photo-NOCAS products, 50–65%). In marked contrast, when an acetonitrile–methanol solution of 2,5-dimethyl-2,4-hexadiene (12), 1, and 5 was irradiated, only the 1,4-addition product, trans-2-(4-cyanophenyl)-5-methoxy-2,5-dimethyl-3-hexene (22,82%), was obtained. This photolysate also contained a small amount of another 1,4-addition product, that which had incorporated cyanide ion instead of methanol, trans-2-(4-cyanophenyl)-2,2,5-trimethyl-3-hexenenitrile (23, 2%). Irradiation of an acetonitrile solution (no methanol) of 12,1, and 5 gave 23 in good yield (68%). An excellent yield (80%) of 23 was obtained upon irradiation of an acetonitrile solution of 1,12, 5, potassium cyanide, and 18-crown-6. Addition of 2,4,6-trimethylpyridine (collidine, 25), a mild, non-nucleophilic base, to the reaction mixture diverts the reaction involving 12 from photo-NOCAS products to 1:1 substitution products; 3-(4-cyanophe-nyl)-2,5-dimethyl-1,4-hexadiene (26), trans-5-(4-cyanophenyl)-2,5-dimethyl-1,3-hexadiene (27), (Z)-1-(4-cyanophenyl)-2,5-dimethyl-2,4-hexadiene (28), and (E)-1-(4-cyanophenyl-2,5-dimethyl-2,4-hexadiene (29) were formed. The mechanisms of these reactions are discussed and an explanation for the observed regio- and stereoselectivity is given.

Phosphonium salts. III. The action of cyanide ion and other nucleophiles on some bis-phosphonium salts

1969 ◽  
Vol 22 (7) ◽  
pp. 1405 ◽  
Author(s):  
JJ Brophy ◽  
MJ Gallagher
Keyword(s):  
Sodium Azide ◽  
Sodium Methoxide ◽  
Sodium Acetate ◽  
Potassium Cyanide ◽  
Dimethyl Sulphoxide ◽  
High Yield ◽  
Phosphonium Salts ◽  
Elimination Reaction ◽  
Cyanide Ion ◽  
Reaction Proceeds

Cyclic and acyclic bis-phosphonium salts with a two-carbon bridge are smoothly cleaved to phosphines in high yield by potassium cyanide in dimethyl sulphoxide. Evidence is presented that the reaction proceeds by an elimination-addition sequence. An elimination reaction also occurs when sodium methoxide, sodium azide, sodium acetate, and triethylamine react with ethane-1,2-bis(tri-phenylphosphonium) dibromide. ��� In a novel reaction, triphenylphosphine is converted into its oxide by a mixture of sodium azide and dimethyl sulphoxide.

scholarly journals Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

2019 ◽  
Vol 15 ◽  
pp. 474-489 ◽  
Author(s):  
Andrejs Šišuļins ◽  
Jonas Bucevičius ◽  
Yu-Ting Tseng ◽  
Irina Novosjolova ◽  
Kaspars Traskovskis ◽  
...  
Keyword(s):  
Nucleophilic Aromatic Substitution ◽  
Secondary Amines ◽  
Acetonitrile Solution ◽  
Quantum Yields ◽  
Cell Labelling ◽  
Aromatic Substitution ◽  
Fluorescent Properties ◽  
Substitution Reactions ◽  
Low Cytotoxicity ◽  
Electron Donating Groups

The synthesis of novel fluorescent N(9)-alkylated 2-amino-6-triazolylpurine and 7-deazapurine derivatives is described. A new C(2)-regioselectivity in the nucleophilic aromatic substitution reactions of 9-alkylated-2,6-diazidopurines and 7-deazapurines with secondary amines has been disclosed. The obtained intermediates, 9-alkylated-2-amino-6-azido-(7-deaza)purines, were transformed into the title compounds by CuAAC reaction. The designed compounds belong to the push–pull systems and possess promising fluorescence properties with quantum yields in the range from 28% to 60% in acetonitrile solution. Due to electron-withdrawing properties of purine and 7-deazapurine heterocycles, which were additionally extended by triazole moieties, the compounds with electron-donating groups showed intramolecular charge transfer character (ICT/TICT) of the excited states which was proved by solvatochromic dynamics and supported by DFT calculations. In the 7-deazapurine series this led to increased fluorescence quantum yield (74%) in THF solution. The compounds exhibit low cytotoxicity and as such are useful for the cell labelling studies in the future.

scholarly journals Intercalibration of different light-traps and bulbs used in moth monitoring in northern Europe

1998 ◽  
Vol 9 (1) ◽  
pp. 37-51 ◽  
Author(s):  
Reima Leinonen ◽  
Guy Söderman ◽  
Juhani Itämies ◽  
Seppo Rytkönen ◽  
Ilpo Rutanen
Keyword(s):  
The Other ◽  
Northern Europe ◽  
Mercury Vapour ◽  
Light Traps ◽  
Mercury Vapour Lamp ◽  
Species Being ◽  
Tungsten Lamp

Four different combinations of light-traps and bulbs were tested during the summer 1996 in Kainuu, northern Finland: a Jalas model with a 160-W (J/160W) blended light lamp or a 125-W (J/125W) mercury vapour lamp, a Ryrholm trap with a 125-W (R/125W) mercury vapour lamp and a Rothamsted trap with a 200-W tungsten lamp (G/200W). The traps were rotated between four sites every night, but were kept in the same position for the fifth night in order to prevent the possible influence of moonlight. The longest distance between the traps was 150m, and there was no direct visibility between any of them. Three orders were inspected, i.e. Lepidoptera, Coleoptera and Hemiptera, the total numbers of individuals and species being as follows: 20857/425, 862/101 and 1868/58. G/200W collected significantly fewer moths than the other traps. In some cases, J/125W collected significantly more moths and less species than the J/160W design. The R/125W design collected significantly more species than the J/160W design. Similar differences in the effectiveness of the lamps and traps were found in the case of Coleoptera and Hemiptera. Alpha diversities showed the same trend.

Photorearrangement of 2-cyanobicyclo[2.2.1]hept-2-ene. Observation of 1,2- and 1,3-sigmatropic shifts

1982 ◽  
Vol 60 (13) ◽  
pp. 1657-1663 ◽  
Author(s):  
Ikbal A. Akhtar ◽  
John J. McCullough ◽  
Susan Vaitekunas ◽  
Romolo Faggiani ◽  
Colin J. L. Lock
Keyword(s):  
Single Crystals ◽  
Lithium Aluminum Hydride ◽  
Aluminum Hydride ◽  
Major Product ◽  
Molecular Structures ◽  
Lithium Aluminum ◽  
Mercury Vapour ◽  
X Ray ◽  
Crystal And Molecular Structures ◽  
Mercury Vapour Lamp

Irradiation of 2-cyanobicyclo[2.2.1]hept-2-ene (2-cyanonorbornene, 4) in hexane, with the full arc of a mercury vapour lamp, gives the rearrangement products 1-cyanobicyclo[4.1.0]hept-2-ene 5 and 7-cyanotricyclo[4.1.0.03.7]heptane 6 in the ratio 20:1. These products were separated by preparative vpc. The structure of the major product 5 was determined by single crystal X-ray analysis. Reduction of 5 with lithium aluminum hydride gave the corresponding primary amine, which was converted to the p-bromobenzenesulfonamide 9, mp 150–151 °C, which gave single crystals from ethanol–water. The crystal and molecular structures are described. The minor product 6 was hydrogenated to give 7-cyanobicyclo[2.2. 1]heptane. Formation of 5 and 6 may involve concerted σ2s + π2s and σ2a + π2a processes respectively, which are photochemically allowed.

scholarly journals The photographic efficiency of heterogeneous light

1921 ◽  
Vol 100 (703) ◽  
pp. 109-113 ◽  
Keyword(s):  
Absorption Coefficient ◽  
White Light ◽  
Photographic Plate ◽  
Silver Halide ◽  
Radiant Energy ◽  
Spectral Lines ◽  
Photographic Emulsion ◽  
Mercury Vapour ◽  
Mercury Vapour Lamp

There are some sources of illumination which are much more active photographically than others, and one of the most active of all artificial sources is the mercury vapour lamp. The energy of the radiation from this lamp is concentrated in a comparatively few spectral lines, and most of these are in that region of the spectrum which is the region of greatest absorption by the silver halide grains of which the photographic emulsion is composed. This, in itself, may be the complete explanation of the intense photographic activity of this particular illuminant, but the question arises as to whether the explanation is, in part, merely the fact that the light is concentrated into a few wave-lengths, apart altogether from any consideration of the absorption coefficient. In other words, a given quantity of radiant energy absorbed in the grains may give a greater photographic effect when it is all of one frequency than when it is a complex radiation such as white light. The object of the present paper is to discuss this question in the light of recent researches on the photographic plate.

scholarly journals The distillation of vitamin D

1930 ◽  
Vol 107 (748) ◽  
pp. 76-90 ◽  
Keyword(s):  
Vitamin D ◽  
Vacuum Distillation ◽  
Complex Mixture ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Silica Tube ◽  
Ethereal Solution ◽  
Mercury Vapour Lamp

The work described below has been done in an attempt to isolate vitamin D from the complex mixture formed by the ultra-violet irradiation of ergosterol. It is evident that vacuum distillation might be of use for this purpose, but, except for a brief statement by Windaus and Holtz (1927), we are unaware of previous work on the distillation of vitamin D. We have distilled various products obtained from ergosterol, and most frequently have used resinous products prepared as follows. A solution of ergosterol in ether was exposed to the unfiltered radiation from a mercury vapour lamp while flowing through a narrow silica tube at a rate such tat about 40 per cent. of the ergosterol was destroyed. Thy unchanged ergosterol was then removed by precipitation with digitonin as described in a previous paper (Webster and Bourdillon, 1928) and the ethereal solution of the products of radiation was evaporated in vacuo to a dry resin.

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