Subject(s)
Green Chemistry Technology/methods , Isosorbide/analogs & derivatives , Formates/chemistry , Hydrogen-Ion Concentration , Indicators and Reagents/chemistry , Isosorbide/chemical synthesis , Isosorbide/chemistry , Models, Molecular , Molecular Conformation , Solvents/chemistry , TemperatureABSTRACT
Following the preliminary studies on the reactivity of the ambident nucleophile phenylhydrazine with dimethyl carbonate, investigations involving para-substituted phenylhydrazines were carried out in order to probe differences in the reactivity within this class of nucleophile. Phenylhydrazines substituted by electron withdrawing or donating substituents showed an increase in reactivity of the phenylhydrazine toward dimethyl carbonate. Under the basic conditions used, all phenylhydrazines displayed hard nucleophilicity, signifying that para-substitution on the phenyl ring has little effect on the hard-soft behavior of this class of nucleophile. This conclusion fits well within the results previously obtained using other para-substituted nucleophiles, i.e., phenols.
ABSTRACT
To explore the ambident electrophilic reactivity of dimethyl carbonate (DMC), reactions with the ambident nucleophile phenylhydrazine were investigated. When a Brönsted base was used, selective carboxymethylation occurred at N-1, after that several other compounds were produced selectively utilizing various conditions. Formation of these compounds was explained by using the Hard-Soft Acid-Base (HSAB) theory. Catalysis by some metal salts altered the reactivity of phenylhydrazine, which effected selective carboxymethylation at N-2 of phenylhydrazine instead.
ABSTRACT
[reaction: see text] A new, green, regioselective, one-step, multicomponent reaction of an aldehyde possessing a nonenolizable carbonyl function, cyclohex-2-enone (or a derivative thereof), and primary or secondary amines afforded 2-N-substituted arylmethyl anilines or 4-N,N-disubstituted arylmethyl anilines, respectively. Yields and regioselectivities were good. Evidence for a pathway involving imine and iminium intermediates is presented along with examples demonstrating amenability of the process to combinatorial chemistry.
ABSTRACT
Liquid or low melting association products of carbon dioxide and a secondary amine, both neutral molecules that may be gaseous, are recognised as "distillable" ionic media.
Subject(s)
Ionic Liquids/chemistry , Carbon Dioxide/chemistry , Dimethylamines/chemistry , Models, Molecular , Molecular StructureABSTRACT
[reaction: see text] Aryl alpha,beta-unsaturated ketones and aldehydes were synthesized, in moderate to excellent yields, with use of dimethylammonium dimethyl carbamate (DIMCARB) as a recyclable reaction medium and as a catalyst.
