Etude en résonance magnétique nucléaire du 13C des paramètres de substitution de la fonction azide

1977 ◽  
Vol 55 (15) ◽  
pp. 2829-2834 ◽  
Author(s):  
A. Pancrazi ◽  
I. Kaboré ◽  
B. Delpech ◽  
A. Astier ◽  
Q. Khuong-Huu ◽  
...  
Keyword(s):  
Nitrogen Atom ◽  
Spatial Arrangement ◽  
The Other ◽  
Azide Group ◽  
Other Hand ◽  
Résonance Magnétique ◽  
C Nmr

The various effects (α, β, γ and δ) on the 13C nmr of azido steroids have been measured. For cyclohexane azides constrained to equatorial and axial configurations, the α-effects were determined to be 33.6 and 31.2 ppm. Both γ- and δ-effects have magnitudes near those for OH and NH2 groups. On the other hand, the β-effect of the azides is slightly smaller than those of hydroxyls or amines as its magnitude is reduced by a γ-effect of the second nitrogen atom of the azide group. This additional γ-effect is a function of the spatial arrangement of the Cβ—H bond with respect to the azide group. [Journal translation]

17O and 13C NMR spectra of some geminal diacetates

1988 ◽  
Vol 53 (3) ◽  
pp. 588-592 ◽  
Author(s):  
Antonín Lyčka ◽  
Josef Jirman ◽  
Jaroslav Holeček
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
The Other ◽  
13C Nmr Spectra ◽  
Other Hand ◽  
Carboxylic Esters ◽  
C Nmr ◽  
Oxygen Atoms

The 17O and 13C NMR spectra of eight geminal diacetates RCH(O(CO)CH3)2 derived from simple aldehydes have been measured. In contrast to the dicarboxylates R1R2E(O(CO)R3)2, where E = Si, Ge, or Sn, whose 17O NMR spectra only contain a single signal, and, on the other hand, in accordance with organic carboxylic esters, the 17O NMR spectra of the compound group studied always exhibit two well-resolved signals with the chemical shifts δ(17O) in the regions of 183-219 ppm and 369-381 ppm for the oxygen atoms in the groups C-O and C=O, respectively.

An assessment of the factors controlling the productivity of maize in England

1951 ◽  
Vol 41 (3) ◽  
pp. 271-281 ◽  
Author(s):  
E. S. Bunting ◽  
G. E. Blackman
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Plant Density ◽  
Spatial Arrangement ◽  
The Other ◽  
Mass Selection ◽  
Grain Production ◽  
Forage Production ◽  
Field Scale ◽  
Other Hand

Between 1942 and 1950, some thirty field experiments have been carried out in the southern half of England to assess the potential value, either for grain or forage production, of seventeen openpollinated flint or dent maizes together with twentynine single or double hybrids of American or Canadian origin.Early-maturing flint varieties will consistently ripen grain, but before mechanical threshing or storage, the cobs require drying. Sibthorp, a mass selection made from an unknown German variety, is the earliest and most productive flint maize so far tested, and in the experiments has yielded as much as 39 cwt. of grain per acre with an average of 24 cwt. The earliest American hybrids, i.e. those with a U.S.A. rating of 80 days from sowing to maturity, give very high yields of grain in favourable seasons. Within the group Wisconsin 240–275, a yield level equal to or exceeding 50 cwt./acre has on occasion been recorded. On the other hand, in the most unfavourable years, such hybrids just failed to produce ripe cobs.Attempts to maintain sixty-five parent inlines of the earliest hybrids have largely failed. However, many of the parent single crosses have matured, and the production on a field scale of the double-cross seed of both Wisconsin 240 and 255 has been carried out.Spacing experiments indicate that for optimum grain production a density of 6 plants/sq.yd. is required for both flint varieties and the earliest hybrids. A spatial arrangement of individual plants is to be preferred to that of groups or hills.American hybrids, in the class of ‘90 days’ to maturity, will in all but the most unfavourable seasons reach the ‘early-dent’ stage of the grain before the incidence of autumn frosts. Yields of dry matter of plants harvested in this phase have ranged from 30 to 85 cwt. of dry matter per acre. In these trials, the plant density was standardized at 4 plants/sq.yd. and higher densities may be demanded for optimal yields.The ratio of the ‘ear’ (that is, the cob, immature grain and enclosing leaf sheaths) to the total shoot weight at harvest varies greatly with the variety or hybrid. With White Horsetooth, the usual variety grown for fodder in England, no cobs are formed before the plants are killed by frost, while with the early hybrids, the ear may be half the weight of the whole shoot.The earliest variety Sibthorp from an early May sowing takes approximately 70–80 days to reach full anthesis, while ‘80-day’ American hybrids are a week later. From sowing to full maturity the period in England is from 140 to 160 days, thus compared to conditions in Minnesota the period is nearly twice as long. Because of the much slower rate of development and because of the humidity of English autumns, it is concluded that until the date of maturity can be advanced some 14 days, grain production on a field scale is not yet feasible. On the other hand, many of the American hybrids are well fitted to the production of silage. The greatest drawback to the introduction of such hybrids is the liability of the seed and seedlings to be attacked by rooks.

scholarly journals The magnetic survey of the early Scythian burial site and settlements in the Turan-Uyuk valley in Tuva

2020 ◽  
Vol 55 ◽  
pp. 343-368
Author(s):  
Łukasz Oleszczak ◽  
Marcin M. Przybyła ◽  
Igor Pieńkos ◽  
Konstantin V. Chugunov ◽  
Nina A. Zhogova
Keyword(s):  
Russian Federation ◽  
Spatial Arrangement ◽  
The Other ◽  
Magnetic Survey ◽  
Archaeological Excavation ◽  
Burial Site ◽  
Significant Information ◽  
Non Invasive ◽  
Other Hand ◽  
Rule Out

In 2019, Polish archaeologists took part in an expedition of the Hermitage Museum, led by K.V. Chugunov, in Chinge-Tey cemetery, Tuva (Russian Federation). This paper presents the results of magnetic surveys carried out within the so-called western chain of barrows and around the princely barrow of Chinge-Tey I. This method of non-invasive research is very well suited to the landscape and has produced a significant body of information. Among others, the survey of the western chain identified a stone mantle in barrow 8, which makes it different from other barrows from this group, whose mounds were built of earth. Another important result is the identification of a stone circle surrounding a cult feature (certainly associated with eschatological rituals) known as the northern complex. The presence of the circle came as a surprise for the investigators of the site, as it does not manifest itself at all on the surface of the site. On the other hand, worth noting is one negative result, which nevertheless allows for some conclusions, namely the lack of detectable anomalies connected with one of the tombs in the vicinity of Chinge-Tey I (barrow 15). Despite being clearly discernible in the landscape, and even more evident in LIDAR images, the barrow is invisible on images produced with a magnetometer. This means that one cannot rule out a possibility that other structures undetectable by magnetic surveys may be present within the investigated part of the cemetery. Nevertheless, one cannot but arrive at the conclusion that the results generated by the magnetic research provide significant information concerning the spatial arrangement of the cemetery and are helpful in planning of archaeological excavation.

Aripiprazole salts. I. Aripiprazole nitrate

2012 ◽  
Vol 68 (4) ◽  
pp. o170-o173 ◽  
Author(s):  
Eleonora Freire ◽  
Griselda Polla ◽  
Ricardo Baggio
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Intermolecular Interactions ◽  
Spatial Arrangement ◽  
The Other ◽  
Structural Elements ◽  
Torsion Angles ◽  
Π Interactions ◽  
Other Hand ◽  
Counter Ions

The crystal structure of aripiprazole nitrate (systematic name: 4-(2,3-dichlorophenyl)-1-{4-[(2-oxo-1,2,3,4-tetrahydroquinolin-7-yl)oxy]butyl}piperazin-1-ium nitrate), C23H28Cl2N3O2+·NO3−or AripH+·NO3−, is presented and the molecule compared with the aripiprazole molecules reported so far in the literature. Bond distances and angles appear very similar, except for a slight lengthening of the C—NH distances involving the protonated N atom, and the main differences are to be found in the molecular spatial arrangement (revealed by the sequence of torsion angles) and the intermolecular interactions (resulting from structural elements specific to this structure,viz. the nitrate counter-ions on one hand and the extra protons on the other hand as hydrogen-bond acceptors and donors, respectively). The result is the formation of [100] strips, laterally linked by weak π–π and C—Cl...π interactions, leading to a family of undulating sheets parallel to (010).

Alkylation by secondary alcohols. I. The reaction of xanthydrol with some N1-monosubstituted sulfanilamides and related compounds

1967 ◽  
Vol 45 (13) ◽  
pp. 1411-1424 ◽  
Author(s):  
R. E. Moskalyk ◽  
L. G. Chatten
Keyword(s):  
Nitrogen Atom ◽  
Tautomeric Form ◽  
Heterocyclic Ring ◽  
The Other ◽  
Secondary Alcohols ◽  
Amino Group ◽  
Aromatic Character ◽  
Carbonium Ion ◽  
Other Hand ◽  
Related Compounds

Sulfanilamides were found to undergo alkylation with xanthydrol, yielding either mono- or di-xanthenyl derivatives. The site of substitution, common to all sulfanilamides having a free p-amino group, was shown to be the N4-position in the sulfanilamide molecule. Three additional unique reactive sites were observed. Sulfanilamides carrying a thiazole, thiadiazole, or pyridazine substituent in the N1-position were also alkylated on the annular nitrogen atom of the heterocyclic ring, the reaction having occurred from the imido tautomeric form. Sulfisoxazole (IK), on the other hand, reacted from the amido form to give the N1,N4-dixanthenyl derivative. Sulfadimethoxine (Ih) was substituted at carbon, as well as at nitrogen, to yield N4-xanthenyl-N1-(2,6-dimethoxy-5-(9-xanthenyl)-4-pyrimidyl)sulfanilamide.Sulfanilamides possessing pKa values of about 5.5 were found to be sufficiently acidic to catalyze their own reaction with xanthydrol, and no external catalyst was necessary. The exceptional ease of formation of the xanthylium ion was postulated to be associated with the resulting stability of this carbonium ion by virtue of its acquired aromatic character.

scholarly journals Flavonoid Aglycones and Glycosides from the Leaves of some Japanese Artemisia Species

2018 ◽  
Vol 13 (5) ◽  
pp. 1934578X1801300
Author(s):  
Ayumi Uehara ◽  
Kazuhide Shimoda ◽  
Yoshinori Murai ◽  
Tsukasa Iwashina
Keyword(s):  
Acid Hydrolysis ◽  
Methyl Ether ◽  
The Other ◽  
Flavonol Glycosides ◽  
Flavonoid Aglycones ◽  
Other Hand ◽  
Artemisia Species ◽  
C Nmr

Sixteen Japanese Artemisia taxa were surveyed for flavonoid aglycones and glycosides. The leaves were rinsed with acetone and then extracted with MeOH. Isolated flavonoids were identified by UV, LC-MS, acid hydrolysis, 1H and 13C NMR, and/or HPLC comparisons with authentic samples. Thus, nine flavone aglycones, apigenin (10), luteolin (5), chrysoeriol (11), hispidulin (6), jaseosidin (7), nepetin (15), sudachitin (8), luteolin 7-methyl ether (13) and eupatilin (14), three flavonol aglycones, axillarin (9), quercetin 3-methyl ether (16) and 5,7,4′-trihydroxy-3,6-dimethoxyflavone (12), one flavanone aglycone, pinocembrin (4), three dihydroflavonol aglycones, taxifolin (1), taxifolin 3-acetate (2) and padmatin (3) were found in their Artemisia taxa with the various combination. On the other hand, four flavonol glycosides, quercetin 3- O-rutinoside (17), quercetin 3- O-glucoside (18), patuletin 3- O-glucoside (19) and patuletin 3- O-rhamnosylglucoside (20), were isolated from a few Artemisia taxa.

scholarly journals New Acylated Anthocyanins and Other Flavonoids from the Red Flowers of Clematis Cultivars

2011 ◽  
Vol 6 (11) ◽  
pp. 1934578X1100601 ◽  
Author(s):  
Masanori Hashimoto ◽  
Toshisada Suzuki ◽  
Tsukasa Iwashina
Keyword(s):  
Nmr Spectroscopy ◽  
The Other ◽  
Flavonol Glycosides ◽  
Chemical Structures ◽  
Other Hand ◽  
Acylated Anthocyanins ◽  
C Nmr

Six new acylated cyanidin glycosides, cyanidin 3- O-β-(2′′- E-caffeoylglucopyranosyl)-(1→2)- O-β-galactopyranoside (1), cyanidin 3- O-β-(2′′- E-caffeoylglucopyranosyl)-(1→2)- O-β-(6′′-malonylgalactopyranoside) (2), cyanidin 3- O-β-(2′′- E-caffeoylglucopyranosyl)- (1→2)- O-β-(6″-succinylgalactopyranoside) (3), cyanidin 3- O-β-(2′'- E-caffeoylglucopyranosyl)-(1→2)- O-β-galactopyranoside-3′- O-β-glucuronopyranoside (4), cyanidin 3- O-β-(2′′- E-caffeoylglucopyranosyl)-(1→2)- O-β-(6′'-malonylgalactopyranoside)-3′- O-β-glucuronopyranoside (5), and cyanidin 3- O-β-(2′'- E-feruloylglucopyranosyl)-(1→2)- O-β-(6′'-malonylgalactoside)-3′- O-β-glucuronopyranoside (6), were isolated from the red flowers of two Clematis cultivars, ‘Niobe'and ‘Madame Julia Correvon'. The chemical structures of the isolated anthocyanins were determined by UV, LC-MS, HPLC, TLC, characterization of hydrolysates, and 1H and 13C NMR spectroscopy, including H-H COSY, C-H COSY, HMBC, HMQC and NOESY. The last three anthocyanins were widely distributed in 37 red flower Clematis cultivars. On the other hand, the first three compounds were found only in two cultivars. Five known flavonol glycosides, kaempferol 3- O-glucoside, kaempferol 3- O-rutinoside, quercetin 3- O-galactoside, quercetin 3- O-glucoside and quercetin 3- O-rutinoside, were isolated from the flowers of ‘Madame Julia Correvon'.

Synthesis of N-Phenylsulfonyl Protected Furo[3,2-b]pyrroles

1994 ◽  
Vol 59 (2) ◽  
pp. 499-502 ◽  
Author(s):  
Vladimír Bobošík ◽  
Alžbeta Krutošíková
Keyword(s):  
Nitrogen Atom ◽  
Phase Transfer Catalysis ◽  
Phase Transfer ◽  
The Other ◽  
Lithium Salts ◽  
Benzenesulfonyl Chloride ◽  
Heterocyclic Molecules ◽  
Other Hand ◽  
Indole Series

Protection of nitrogen atom of heterocyclic molecules, such as indole and pyrrole types, enables various reactions of these systems. N-Phenylsulfonyl derivatives, which have been widely used for this purpose, were prepared in the indole series by the reaction of N-sodium and N-lithium salts with benzenesulfonyl chloride. This method requires waterfree and oxygenfree conditions. On the other hand, the phase transfer catalysis conditions used in this work obviates these disadvantages. We therefore selected the latter method for the preparation of variously substituted 4-phenylsulfonylfuro[3,2-b]pyrroles (I - VII) and 1-phenylsulfonylbenzo[b]furo[3,2-b]pyrroles (VIII - IX).

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

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