Back to results
US 6,388,151 B1Granted
Synthesis of Tetraalkylcyclopentadienes
AssigneeBoulder Scientific Company
InventorsJeffrey M. Sullivan, Richard D. Crawford
Life of this patent
Estimating the term…
Abstract
A method for synthesizing tetramethylcyclopentadiene from 2,3-dibromobutane is described. A 2-bromo-2-butene Grignard is reacted with an ethyl formate to produce a 3,5-dimethyl-2,5-heptadiene-4-ol magnesium bromide which is then quenched with acetic acid to produce 3,5-dimethyl-2,5-hepadiene-4-ol.
Claims11
The method which comprises:
- (i) reacting 2-bromo-2-butene with magnesium in a non-interfering solvent,
- wherein a first reaction mixture containing 2-butene magnesium bromide, magnesium and said non-interfering solvent;
- (ii) adding an alkyl formate
- to said first reaction mixture,
- wherein said alkyl formate reacts with said 2-butene magnesium bromide in said first reaction mixture to produce a second reaction mixture containing a compound of formula
- and
- (iii) adding an aqueous acid of formula
- wherein R1 is a two to six carbon atom alkyl group to said second reaction mixture,
- wherein a third reaction mixture containing 3,5-dimethyl-2,5-heptadiene-4-ol in said solvent is produced.
6 more elements
A method which comprises:
- (i) reacting 2-bromo-2-butene with magnesium
- wherein said reacting occurs in the presence of from about 1% to about 10% stoichiometric excess of magnesium and in the presence of tetrahydrofuran at a temperature of from about 40° C. to about 50° C.;
- and
- wherein a first reaction mixture containing 2-butene magnesium bromide, magnesium and tetrahydrofuran is produced;
- (ii) adding ethyl formate to said first reaction mixture at a temperature of from about −10° C. to about 10° C.
- wherein said ethyl formate reacts with said 2 butene magnesium bromide in said first reaction mixture to produce a second reaction mixture containing a compound of formula:
- and
- (iii) adding aqueous acetic acid to said second reaction mixture
- wherein a third reaction mixture containing 3,5-dimethyl-2,5-heptadiene-4-ol, tetrahydrofuran and magnesium acetate is produced.
6 more elements
A method which comprises:
- (i) reacting 2-bromo-2-butene with magnesium
- wherein said reacting occurs in the presence of from about 1% to about 10% stoichiometric excess of magnesium and in the presence of tetrahydrofuran at a temperature of from about 40° C. to about 50° C.;
- and
- wherein a first reaction mixture containing 2-buteno magnesium bromide, magnesium and tetrahydrofuran is produced;
- (ii) adding ethyl formate to said first reaction mixture at a temperature of from about −10° C. to about 10° C.
- wherein said ethyl formate reacts with said 2-butene magnesium bromide in said first reaction mixture to produce a second reaction mixture containing a compound of formula:
- (iii) adding aqueous acetic acid to said second reaction mixture
- wherein a third reaction mixture containing 3,5-dimethyl-2,5-heptadiene-4-ol, tetrahydrofuran and magnesium acetate is produced;
- (iv) substantially completely removing tetrahydrofuran from said step (iii) third reaction mixture
- wherein substantially tetrahydrofuran free 3,5-dimethyl-2,5-heptadiene-4-ol is produced;
- and
- (v) combining said substantially tetrahydrofuran free 3,5-dimethyl-2,5-heptadiene-4-ol from step (iv) with aqueous hydrochloric acid and ethyl ether
- wherein a fourth reaction mixture containing chlorotetramethylcyclopentene, tetramethylcyclopentadiene and ethyl ether is produce.
10 more elements
A method which comprises:
- (i) converting 2-bromo-2-butene to 3,5-dimethyl-2,5-heptadiene-4-ol, and
- (ii) converting said step (i) 3,5-dimethyl-2,5-heptadiene-4-ol to tetramethylcyclopentadiene.
Dependencies are inferred from the claim text.