Structures of ozonolysis products of methyl oleate obtained in a carboxylic acid medium

1995 ◽  
Vol 72 (6) ◽  
pp. 735-740 ◽  
Author(s):  
Naoki Nishikawa ◽  
Kaoru Yamada ◽  
Shigeaki Matsutani ◽  
Moriaki Higo ◽  
Hitoshi Kigawa ◽  
...  
Keyword(s):  
Carboxylic Acid ◽  
Methyl Oleate ◽  
Acid Medium

The small stones of Coimbra in the huge tetrapyrrolic chemistry building

2009 ◽  
Vol 13 (04n05) ◽  
pp. 429-445 ◽  
Author(s):  
António M.d'A. Rocha Gonsalves ◽  
Arménio C. Serra ◽  
Marta Pineiro
Keyword(s):  
Carboxylic Acid ◽  
Acid Medium ◽  
Synthetic Methods ◽  
Simple Manner ◽  
Biomimetic Oxidation ◽  
Oxidation Level ◽  
Wide Range ◽  
Synthetic Methodologies ◽  
Yield And Purity ◽  
The Way

Improvements over the Rothemund classical reaction methods have allowed the development of capacity to obtain a wide range of structures that were earlier unavailable. Performing the reaction in a mixed nitrobenzene/carboxylic acid medium allowed improvements of yield and purity of the porphyrin obtained, and in some cases the control of the oxidation level of the macrocycle. More recently, novel microwave synthetic methodologies were exploited to achieve important improvements in simple porphyrin chemistry. Tidy sulphonations of simple porphyrins opened the way to diverse desired, inexpensive structures in a very simple manner. The option to concentrate interests on improvements of synthetic methods to obtain simple and diversified tetrapyrrolic structures proved to be advantageous. Interesting biomimetic oxidation and photooxidation systems and PDT sensitizers were developed and significant knowledge was achieved in these specific and related areas. This review presents a view of our own results in the synthetic area, and outlines the contributions therefrom to the study of biomimetic and therapeutic processes.

One-Pot Polyimide Synthesis in Carboxylic Acid Medium

2000 ◽  
Vol 12 (3) ◽  
pp. 445-460 ◽  
Author(s):  
Alexander A Kuznetsov
Keyword(s):  
Carboxylic Acid ◽  
Acid Medium ◽  
One Pot

scholarly journals The relative importance of competing pathways for the formation of high-molecular-weight peroxides in the ozonolysis of organic aerosol particles

2006 ◽  
Vol 6 (4) ◽  
pp. 7137-7176
Author(s):  
M. Mochida ◽  
Y. Katrib ◽  
J. T. Jayne ◽  
D. R. Worsnop ◽  
S. T. Martin
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Methyl Oleate ◽  
High Molecular Weight ◽  
Myristic Acid ◽  
Aerosol Particles ◽  
Atmospheric Particles ◽  
Organic Peroxides ◽  
Relative Importance ◽  
Criegee Intermediates

Abstract. High-molecular-weight (HMW) organic compounds are an important component of atmospheric particles, although their origins, possibly including in situ formation pathways, remain incompletely understood. This study investigates the formation of HMW organic peroxides through reactions involving stabilized Criegee intermediates (SCI's). The model system is methyl oleate (MO) mixed with dioctyl adipate (DOA) and myristic acid (MA) in submicron aerosol particles. Criegee intermediates are formed by the ozonolysis of the double bond in methyl oleate. An aerosol flow tube coupled to an Aerodyne quadrupole aerosol mass spectrometer is employed for the studies. The relative importance of different HMW organic peroxides, including secondary ozonides (SOZ's), α-acyloxyalkyl hydroperoxides and α-acyloxyalkyl alkyl peroxides (αAAHP-type compounds), diperoxides, and monoperoxide oligomers, is determined for the ozonolysis of different mixing mole fractions of MO in DOA and MA. Two SOZ's are identified as the HMW products of the ozonolysis of pure methyl oleate. Changes in the mobility and vacuum aerodynamic diameters of the particles indicate that up to 67% of the product mass remains in the particles, with the balance evaporating. In mixed particles, SOZ's form within an inert matrix of DOA to as low as 0.04 mole fraction MO. In comparison, in mixed particles of MO and MA, αAAHP-type compounds form in high yields for initial MO mole fractions under 0.5, suggesting that SCI's efficiently attack the carboxylic acid group of myristic acid. The reactions of SCI's with carboxylic acid groups to form αAAHP-type compounds therefore compete with those of SCI's with aldehydes to form SOZ's, provided that both types of functionalities are present at significant concentrations. The results suggest that SCI's formed by the ozonolysis of unsaturated organic molecules in atmospheric particles could lead to the transformation of carboxylic acids and other protic groups into HMW organic peroxides.

Synthese und Kristallstruktur eines Lithium(trimethylacetoxy-di-tert-butylsilanolats) / Synthesis and Crystal Structure of a Lithium(trimethylacetoxy-di-tert-butylsilanolate)

1987 ◽  
Vol 42 (10) ◽  
pp. 1253-1255 ◽  
Author(s):  
Kerstin Dippel ◽  
Nayla K. Keweloh ◽  
Peter G. Jones ◽  
Uwe Klingebiel ◽  
Dieter Schmidt
Keyword(s):  
Crystal Structure ◽  
Carboxylic Acid ◽  
Acid Medium ◽  
Structure Determination ◽  
Acid Ester ◽  
Lithium Salt ◽  
Crystal Structure Determination ◽  
Synthesis And Crystal Structure ◽  
Acyl Chlorides

Abstract In an acid medium di-tert-butylsilanediol reacts with acyl chlorides to give the di-tert-butylchlorosilanol (2) and the carboxylic acid. A lithium salt of a silanol-carboxylic acid ester (5) is formed in the reaction of the lithiated diol with 2,2-dimethylpropionyl chloride. 5 reacts with phenylacetyl chloride to give the first mixed dicarboxyl-silane. The crystal structure determination of 5 shows a Li-O-cubane with C = 0 ···Li chelate bonds.

Thermal Cyclocondensation of Ethyl (1-Methyl-5- and 6-Benzimidazolyl/benzotriazolyl)aminomethylenepropanedioates

1994 ◽  
Vol 59 (5) ◽  
pp. 1145-1152 ◽  
Author(s):  
Viktor Milata ◽  
Dušan Ilavský ◽  
Igor Goljer ◽  
Lubomír Zalibera
Keyword(s):  
Carboxylic Acid ◽  
Acid Medium ◽  
Uv Spectroscopy ◽  
Reaction Products ◽  
Aprotic Medium ◽  
C Nmr ◽  
Ir And Uv Spectroscopy

Thermal cyclocondensation of starting ethyl (1-methyl-5- and 6-benzimidazolyl/benzotriazolyl)aminomethylenepropanedioates (Ia - Ie) in aprotic medium gives angularly condensed ethyl azolo[4,5-f]quinolonecarboxylates IIa, IIc, IIe and azolo[5,4-f]quinolonecarboxylates IIb, IId, respectively, which are hydrolyzed to the corresponding carboxylic acid III in acid medium. The structure of reaction products has been confirmed by 1H and 13C NMR, IR, and UV spectroscopy.

scholarly journals The relative importance of competing pathways for the formation of high-molecular-weight peroxides in the ozonolysis of organic aerosol particles

2006 ◽  
Vol 6 (12) ◽  
pp. 4851-4866 ◽  
Author(s):  
M. Mochida ◽  
Y. Katrib ◽  
J. T. Jayne ◽  
D. R. Worsnop ◽  
S. T. Martin
Keyword(s):  
Molecular Weight ◽  
Carboxylic Acid ◽  
Methyl Oleate ◽  
High Molecular Weight ◽  
Myristic Acid ◽  
Aerosol Particles ◽  
Atmospheric Particles ◽  
Organic Peroxides ◽  
Relative Importance ◽  
Criegee Intermediates

Abstract. High-molecular-weight (HMW) organic compounds are an important component of atmospheric particles, although their origins, possibly including in situ formation pathways, remain incompletely understood. This study investigates the formation of HMW organic peroxides through reactions involving stabilized Criegee intermediates (SCI's). The model system is methyl oleate (MO) mixed with dioctyl adipate (DOA) and myristic acid (MA) in submicron aerosol particles, and Criegee intermediates are formed by the ozonolysis of the double bond in methyl oleate. An aerosol flow tube coupled to a quadrupole aerosol mass spectrometer (AMS) is employed to determine the relative importance of different HMW organic peroxides following the ozonolysis of different mixing mole fractions of MO in DOA and MA. Possible peroxide products include secondary ozonides (SOZ's), α-acyloxyalkyl hydroperoxides and α-acyloxyalkyl alkyl peroxides (αAAHP-type compounds), diperoxides, and monoperoxide oligomers. Of these, the AMS data identify two SOZ's as major HMW products in the ozonolysis of pure methyl oleate as well as in an inert matrix of DOA to as low as 0.04 mole fraction MO. In comparison, in mixed particles of MO and MA, αAAHP-type compounds form in high yields for MO mole fractions of 0.5 or less, suggesting that SCI's efficiently attack the carboxylic acid group of myristic acid. The reactions of SCI's with carboxylic acid groups to form αAAHP-type compounds therefore compete with those of SCI's with aldehydes to form SOZ's, provided that both types of functionalities are present at significant concentrations. The results therefore suggest that SCI's in atmospheric particles contribute to the transformation of carboxylic acids and other protic groups into HMW organic peroxides.

Reactions of some 2-(6-azauracil-5-yl)phenylhydrazones

1979 ◽  
Vol 44 (8) ◽  
pp. 2438-2442 ◽  
Author(s):  
Jan Slouka
Keyword(s):  
Carboxylic Acid ◽  
Acid Medium ◽  
Alkaline Medium ◽  
Acidic Medium ◽  
Diazonium Salt ◽  
Azo Coupling

Azo coupling of the diazotized 6-(2-aminophenyl)-2,3,4,5-tetrahydro-1,2,4-triazine-3,5-dione with ethyl cyanoacetylcarbamate and diethyl malonyl-bis-carbamate has been used for preparation of the hydrazones I and II. The latter substances have been boiled in strongly acidic medium to give 2,3,4,6-tetrahydro-1,2,4-triazino[5,6-c]cinnoline-3-one (III) which has also been obtained by reduction of the mentioned diazonium salt with alkali sulphite and sebsequent cyclization of the formed hydrazine sulphonate by boiling in acid medium. In alkaline medium the hydrazones I and II have been cyclized to the nitrile IV and to 2-[2-(3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazin-6-yl)-phenyl]-3,5-dioxo-2,3,4,5-tetrahydro-1,2,4-triazine-6-carboxylic acid (V), respectively.

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