- Vibrational conformational analysis of isopropyl fluoroformate
-
Infrared spectra of vapour and low temperature amorphous and crystalline phases, and Raman spectra of the vapour, liquid and low temperature crystalline phases of isopropyl fluoroformate (FCOOCH(CH3)2) and four isotopically substituted derivatives (FCOOCD(CH3)2, FCOOCH(CH3)(CD3), FCOOCH(CD3)2 and FCOOCD(CD3)2) are reported.The spectra indicate the presence of the same single conformer in each of these phases.Asymmetric top infrared contour simulation of the carbonyl streching vibration in methyl, tert-butyl and isopropyl fluoroformate shows that in the isopropylester the ester function has the s-cis conformation, while the isopropyl group shows a quasi-gauche orientation.
- Veken, B. J. van der,Liefooghe, H. H.
-
-
Read Online
- Atmospheric chemistry of isopropyl formate and tert-butyl formate
-
Formates are produced in the atmosphere as a result of the oxidation of a number of species, notably dialkyl ethers and vinyl ethers. This work describes experiments to define the oxidation mechanisms of isopropyl formate, HC(O)OCH(CH3)2, and tert-butyl formate, HC(O)OC(CH 3)3. Product distributions are reported from both Cl- and OH-initiated oxidation, and reaction mechanisms are proposed to account for the observed products. The proposed mechanisms include examples of the α-ester rearrangement reaction, novel isomerization pathways, and chemically activated intermediates. The atmospheric oxidation of isopropyl formate by OH radicals gives the following products (molar yields): acetic formic anhydride (43%), acetone (43%), and HCOOH (15-20%). The OH radical initiated oxidation of tert-butyl formate gives acetone, formaldehyde, and CO2 as major products. IR absorption cross sections were derived for two acylperoxy nitrates derived from the title compounds. Rate coefficients are derived for the kinetics of the reactions of isopropyl formate with OH (2.4 ± 0.6) × 10-12, and with Cl (1.75 ± 0.35) × 10-11, and for tert-butyl formate with Cl (1.45 ± 0.30) × 10-11 cm3 molecule-1 s-1. Simple group additivity rules fail to explain the observed distribution of sites of H-atom abstraction for simple formates.
- Pimentel, Andre Silva,Tyndall, Geoffrey S.,Orlando, John J.,Hurley, Michale D.,Wallington, Timothy J.,Andersen, Mads P. Sulbaek,Marshall, Paul,Dibble, Theodore S.
-
-
Read Online
- NOVEL VINBLASTINE DERIVATIVES, THEIR PREPARATION, USE AND PHARMACEUTICAL COMPOSITIONS COMPRISING THE SAID DERIVATIVES
-
The invention provides vinblastine derivatives represented by the following formula 1 or their physiologically acceptable salts, their preparation, use and pharmaceutical compositions comprising the said derivatives. The said vinblastine derivatives show inhibiting activities against tumor cell lines and can be used as medicaments for treating malignant tumors.
- -
-
Page/Page column 38-39
(2010/05/13)
-
- NOVEL VINBLASTINE DERIVATIVES, THEIR PREPARATION, USE AND PHARMACEUTICAL COMPOSITIONS COMPRISING THE SAID DERIVATIVES
-
The invention provides vinblastine derivatives represented by the following formula 1 or their physiologically acceptable salts, their preparation, use and pharmaceutical compositions comprising the said derivatives. The said vinblastine derivatives show inhibiting activities against tumor cell lines and can be used as medicaments for treating malignant tumors.
- -
-
Page/Page column 38-39
(2009/12/05)
-
- NOVEL DITHIOLOPYRROLONES AND THEIR THERAPEUTICAL APPLICATIONS
-
The present invention provides novel dithiolopyrrolone compounds and their salts, which promote production of white blood cells and are useful as prevention and treatments for microbial infections such as HIV infection and blood disorders such as neutropenia and other related diseases. The present invention also provides therapeutic compositions comprising particularly useful types of dithiolopyrrolones, the salts thereof, and methods and use in the manufacture of a medication for treatment of diseases.
- -
-
Page/Page column 36
(2008/06/13)
-
- Carbamate series of juvenoids: Variation of the O-alkyl substituent
-
By changing the O-alkyl substituents of the carbamate moiety of alkyl N-{2-{4-[(2-oxocyclohexyl)methyl]phenoxy}ethyl}carbamates and subsequent transformation of the oxo group in the cyclohexyl substituent, the juvenoids 1-20 were synthesized (Scheme). The methyl (1-4), propyl (9-12), isopropyl (13-16), and prop-2-ynylcarbamates (17-20) were subjected to biological screening on several non-related insect species (Tenebrio molitor, Galleria mellonella, Dysdercus cingulatus, and Pyrrhocoris apterus). Some of the juvenoids showed high biological activity and excellent selectivity with respect to target insect species (Table 2).
- Wimmer,Saman,Nemec,Francke
-
p. 561 - 568
(2007/10/02)
-
- KINETICS AND MECHANISM OF PHOSGENATION OF ALIPHATIC ALCOHOLS. IV. EFFECT OF HYDROGEN CHLORIDE ON THE REACTION RATE
-
The reaction of phosgene with alcohols is inhibited by hydrogen chloride.Here, as shown for the model methanolysis of methyl chloroformate, the halide ions have practically no effect on the reaction rate.The inhibition is due to the formation of associates, which do not possess nucleophilic characteristics between the alcohol and the hydrogen chloride.In proton-inert solvents at low temperatures the reaction only goes to the extent of a third on account of the formation of a stable unreactive 2:1 associate of the alcohol with hydrogen chloride.
- Orlov, S. I.,Chimishkyan, A. L.,Stepanov, M. B.,Sidel'kovskii, A. L.,Grabarnik, M. S.,Elinevskii, A. V.
-
p. 2278 - 2286
(2007/10/02)
-
- KINETICS AND MECHANISM OF THE PHOSGENATION OF ALIPHATIC ALCOHOLS II. EFFECT OF THE SOLVENT ON THE REACTION RATE
-
A quantitative analysis of the effect of the characteristics of the medium on the phosgenation rate of alcohols was made by means of the parameters of the Koppel-Palm equation.An equation is proposed which describes the effect of the solvent on the reaction rate and which takes account of the interdependence of the components of nonspecific and specific solvation.The applicability of the proposed equation to other solvolytic reactions was demonstrated.An equation is obtained which makes it possible to asses the phosgenation rate of alcohols in relation to the properties of the medium and the structure of the alcohol.
- Chimishkyan, A. L.,Orlov, S. I.,Elinevskii, A. V.,Grabarnik, M. S.,Shebeko, S. M.
-
-
- KINETICS AND MECHANISM OF PHOSGENATION OF ALIPHATIC ALCOHOLS
-
The kinetics of the reaction of phosgene with various aliphatic alcohols were investigated in heptane and dioxane and without a solvent.The effects of the polarity of the medium the structure of the alcohol, and the activation parameters of the process are consistent with an addition-elimination mechanism.
- Orlov, S. I.,Chimishkyan, A. L.,Grabarnik, M. S.
-
p. 1977 - 1981
(2007/10/02)
-
