40 research outputs found
Structure-reactivity study of O-tosyl Cinchona alkaloids in their new synthesis and in hydrolysis to 9-epibases : unexpected formation of cinchonicine enol tosylate accelerated by microwave activation
New methods for
O
-
tosylation of
the
natural
Cinchona
alkaloids
have been
discovered
as
a
biphasic
processes with Bu
3
N as a
catalyst.
The
optimized
excess of
tosy
l chloride
,
necessary for
transformation
of each
of the
four alkaloid
s
into
O
-
tosy
l derivative
, decreases
in the following
order
:
quinine, quinidine, cinchonidine and cinchonine
. The same
decreasing order has been
noticed
for
the
hy
drolysis
rate
of
the
appropriate
tosylates
to 9
-
epibases
.
D
iffic
ult conversion
of
O
-
tosy
lcinchonine
in the
hydrolytic medium
of
aq
ueous tarta
ric
acid
gives
9
-
epicinchonine
together with
parallel
formation
of
cinchonicine enol
tosylate. The latter product
is
obtained
as
the main
when
both cinchonine and cinchonidine
tosylates
react
in the presence of salicylic acid
under
controlled microwave heating
.
On the basis of X
-
ray
structure of the new alkene product,
the
stereoselective
syn
-
E2
quinuclidine
ring opening process
,
competing to
the
S
N
2 hydrolysis
is
postulated
for this transformation
Bis(2-{[2,8-bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-ium) tetrachloridodiphenylstannate(IV)
In the title salt, (C17H17F6N2O)2[Sn(C6H5)2Cl4], the complete anion is generated by crystallograaphic inversion symmetry, giving a trans-SnC2Cl4 octahedral coordination geometry for the metal atom. In the cation, the quinoline residue is almost normal to the other atoms, so that the ion has an L-shaped conformation [the C—C—C—C torsion angle linking the fused-ring systems is 100.9 (7)°]; the six-membered piperidin-1-ium ring has a chair conformation. An intramolecular N—H⋯O interaction occurs. In the crystal, N—H⋯Cl and O—H⋯Cl hydrogen bonds link the components into a supramolecular chain propagating along the a axis. C—H⋯Cl interactions are also present
2-{[2,8-Bis(trifluoromethyl)quinolin-4-yl](hydroxy)methyl}piperidin-1-ium 3-amino-5-nitrobenzoate sesquihydrate
The asymmetric unit of the title salt solvate, C17H17F6N2O+·C7H5N2O4
−·1.5H2O, comprises a piperidin-1-ium cation, a 3-amino-5-nitrobenzoate anion, and three fractionally occupied [i.e. 0.414 (3), 0.627 (6) and 0.459 (5)] disordered water molecules of solvation. The cation has an L shape with a C—C—C—C torsion angle of −102.9 (3)° for the atoms linking the quinolinyl group to the rest of the cation. In the anion, the carboxylate and nitro groups are essentially coplanar with the benzene ring [O—C—C—C torsion angle = 179.7 (2)° and O—N—C—C torsion angle = −3.9 (3)°]. In the crystal, extensive O—H⋯O, O—H⋯F and N—H⋯·O hydrogen bonding leads to the formation of a layer in the ab plane
Adaptation of wheat cells to short-term ozone stress: the impact of α-tocopherol and gallic acid on natural and model membranes
Intensity-Modulated Radiotherapy (IMRT) vs Helical Tomotherapy (HT) in Concurrent Chemoradiotherapy (CRT) for Patients with Anal Canal Carcinoma (ACC): an analysis of dose distribution and toxicities
Membrane permeability and micro- and macroelement accumulation in spring wheat cultivars during the short-term effect of salinity- and PEG-induced water stress
Avaliação da intoxicação de cultivares de cana-de-açúcar e I. grandifolia ao amicarbazone
Use of chlorophyll fluorescence for estimation of some adjuvants efficacy in a mixture with atrazine
W pracy przedstawiono szybką metodę fluorescencji chlorofilu do oceny działania wybranych adiuwantów w mieszaninie z atrazyną na rośliny owsa. Atrazyna jako herbicyd triazynowy jest inhibitorem fotosyntetycznego transportu elektronowego w fotosystemie II, co może być rejestrowane za pomocą specjalnego fluorymetrów. Do po-miarów zastosowano fluorymetr impulsowy PAM-200 firmy Walz, mierzono parametr ETR. Wyniki badań wykazały zróżnicowanie reakcji roślin na zastosowane preparaty zależnie od rodzaju zastosowanego adiuwantu. Spośród badanych mieszanin Break-Thrue S-240 i Adbros 85 SL okazały się najbardziej skuteczne, natomiast Adbios 85 SL neutralizował biologiczne działanie atrazyny w mieszaninie z Azoprimem.In the paper is presented a quick chlorophyll fluorescence method for estimation of action of some adjuvants in the mixture with atrazine on oat plants. Atrazine is - a triazine herbicide - is an inhibitor of photosynthetic electron transport in photosystem II, which can be measured by means of the special pulse PAM-200 fluorometer. Results of the ETR measurements show differences between the phytotoxicity of the applied adjuvants. Of the studied mixtures Break-Thrue S-240 and Adbros 85 SL were the most effective, whereas Adbios 85 SL neutralised the biological action of atrazine in the connection with Azoprim
The effect of Atpolan 80 EC on atrazine residues in the soil
The persistence of atrazine residues in soils may have an effect on the contamination of the ground water or surface water. Besides the active ingredients, pesticide formulations contain many other compounds called adjuvants. One of them is the Atpolan 80 EC which belongs to the group of oil mineral adjuvants used as lank-mix. The utilization of a fraction of paraffin oil 1113 is one of the examples of utilising waste as the component of Atpolan 80 EC in agriculture. When the Atpolan concentration comprised 1.25% (v/v), the atrazine degradation rate decreased in the sandy loam and muck soil. The half-life of atrazine increased over a period of 40 or 57 days, depending on the type of the soil. The least significant effect was caused by Atpolan concentration at 0.25 and 0.75%. This result points at the capability of limiting atrazine run-off and leaching down the soil profile. Each ingredient of the pesticide, besides having the overall ability to distribute between different phases, also demonstrates some single compound behaviour. This paper shows our current understanding of the factors that influence the adjuvant performance and their potentially complex interactions with the pesticide