ChemInform Abstract: Microwave-Assisted Cyclizations Promoted by Polyphosphoric Acid Esters: A General Method for 1-Aryl-2-iminoazacycloalkanes.

ChemInform ◽  
2016 ◽  
Vol 47 (48) ◽  
Author(s):  
Jimena E. Diaz ◽  
Maria C. Mollo ◽  
Liliana R. Orelli
Keyword(s):  
Polyphosphoric Acid ◽  
Microwave Assisted ◽  
Acid Esters ◽  
General Method

scholarly journals Microwave-assisted cyclizations promoted by polyphosphoric acid esters: a general method for 1-aryl-2-iminoazacycloalkanes

2016 ◽  
Vol 12 ◽  
pp. 2026-2031 ◽  
Author(s):  
Jimena E Díaz ◽  
María C Mollo ◽  
Liliana R Orelli
Keyword(s):  
Polyphosphoric Acid ◽  
General Procedure ◽  
Reaction Times ◽  
Ring Closure ◽  
Heterocyclic Synthesis ◽  
Microwave Assisted ◽  
Solvent Free Conditions ◽  
High Yields ◽  
Acid Esters ◽  
General Method

The first general procedure for the synthesis of 5 to 7-membered 1-aryl-2-iminoazacycloalkanes is presented, by microwave-assisted ring closure of ω-arylaminonitriles promoted by polyphosphoric acid (PPA) esters. 1-Aryl-2-iminopyrrolidines were easily prepared from the acyclic precursors employing a chloroformic solution of ethyl polyphosphate (PPE). The use of trimethylsilyl polyphosphate (PPSE) in solvent-free conditions allowed for the synthesis of 1-aryl-2-iminopiperidines and hitherto unreported 1-aryl-2-iminoazepanes. The cyclization reaction involves good to high yields and short reaction times, and represents a novel application of PPA esters in heterocyclic synthesis.

Synthesis of acetylenedicarboxylic acid esters and asymmetric Diels–Alder reactions of the bis(methyl (S)-lactyl) ester

1995 ◽  
Vol 73 (9) ◽  
pp. 1454-1462 ◽  
Author(s):  
James L. Charlton ◽  
Gaiklean Chee ◽  
Heather McColeman
Keyword(s):  
Diels Alder ◽  
Asymmetric Induction ◽  
Hydroxyl Group ◽  
Acetylenedicarboxylic Acid ◽  
Chiral Esters ◽  
Acid Esters ◽  
General Method

A general method has been developed for the preparation of acetylenedicarboxylic acid esters and applied to the synthesis of both achiral and chiral esters. Diels–Alder reactions of one of the chiral esters, the bis(methyl (S)-lactyl) ester, with various types of dienes, such as phenylbutadiene, orthoquinodimethanes, and isobenzofuran, have been investigated. Moderate asymmetric induction was observed in reactions with dienes bearing an α-hydroxyl group. In one case, an unusual solvent-induced reversal of asymmetric induction was observed. Keywords: acetylenedicarboxylic acid esters, phenylbutadiene, orthoquinodimethanes, isobenzofurans, Diels–Alder, asymmetric.

scholarly journals Microwave-assisted preparation of naphthenic acid esters

2006 ◽  
Vol 71 (12) ◽  
pp. 1263-1268 ◽  
Author(s):  
Vera Cirin-Novta ◽  
Ksenija Kuhajda ◽  
Slavko Kevresan ◽  
Julijan Kandrac ◽  
Ljubica Grbovic ◽  
...  
Keyword(s):  
Acid Catalysis ◽  
Naphthenic Acid ◽  
Butyl Alcohol ◽  
Naphthenic Acids ◽  
Dielectric Heating ◽  
Microwave Assisted ◽  
Microwave Dielectric ◽  
Tert Butyl Alcohol ◽  
Microwave Dielectric Heating ◽  
Acid Esters

The synthesis of esters of natural petroleum acids of the naphthenic type assisted with microwave irradiation under the conditions of acid catalysis was carried out with various alcohols: methanol, ethanol, n-butanol and tert-butyl alcohol. Microwave dielectric heating of the reaction mixture in an unmodified microwave oven with activation of the naphthenic acids with sulfuric and p-toluenesulfonic acid afforded the esters of the naphthenic acids. Depending on the catalyst and the steric and nucleophilic properties of the alcohols, the yield of naphthenic esters ranged from 31.25% to 88.90%. As a consequence of microwave dielectric heating, the esterification time was reduced from 6-10 h to 5 min. .

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