US4734533A
Expired / Lapsed
US
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Process for the preparation of (2,2)-paracyclophane and derivatives thereof
Assignee: Montedison SpA
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Filing: 1986-12-12
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Granted: 1988-03-29
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Expires: 2006-12-12
Abstract
Abstract Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p.-methylbenzyltrimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a ketone of the formula: Ch.sub.3 --CO--CH.sub.2 --R (I) wherein R is hydrogen, a halogen, or an alkyl-carboxylic group.
Inventors
- 👤 Raffaele Ungarelli
- 👤 Maurizio A. Beretta
- 👤 Alessandro Malacrida
- 👤 Loris Sogli
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 08:31
CPC Classifications
C; C07; C07C; C07C23/00; C07C23/18; C07C23/20; C07C23/38; C07C1/00; C07C1/32; C07C1/321; C07C1/323; C07C17/00; C07C17/26; C07C17/263; C07C2603/00; C07C2603/92
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
143 words
A process for preparing (2,2)-paracyclophane and derivatives thereof of the formula: ##STR5## wherein X is a halogen atom, an alkyl radical, an aralkyl radical, or a halo-aralkyl radical, and n is zero or an integer from 1 to 4, by the Hofmann elimination of p.methylbenzyltrimethylammonium hydroxide or derivatives thereof of the formula: ##STR6## wherein X and n are the same as defined hereinabove, in an aqueous solution of an alkali metal hydroxide, characterized in that said elimination is carried out at a temperature between 50° and 150° C., and in the presence of at least a catalytic amount of a ketone having the formula: CH.sub.3 --CO--CH.sub.2 --R (I) wherein R is hydrogen, halogen, or an alkyl-carboxylic group containing 1 to 4 carbon atoms in the alkyl chain, the ketone concentration being from 0.1 to 200%, based on the p.methylbenzyltrimethylammonium hydroxide or derivatives thereof.
Claim 2
Dependent Claim
143 words
A process for preparing (2,2)-paracyclophane and derivatives thereof of the formula: ##STR5## wherein X is a halogen atom, an alkyl radical, an aralkyl radical, or a halo-aralkyl radical, and n is zero or an integer from 1 to 4, by the Hofmann elimination of p.methylbenzyltrimethylammonium hydroxide or derivatives thereof of the formula: ##STR6## wherein X and n are the same as defined hereinabove, in an aqueous solution of an alkali metal hydroxide, characterized in that said elimination is carried out at a temperature between 50° and 150° C., and in the presence of at least a catalytic amount of a ketone having the formula: CH.sub.3 --CO--CH.sub.2 --R (I) wherein R is hydrogen, halogen, or an alkyl-carboxylic group containing 1 to 4 carbon atoms in the alkyl chain, the ketone concentration being from 0.1 to 200%, based on the p.methylbenzyltrimethylammonium hydroxide or derivatives thereof.
Claim 3
Dependent Claim
34 words
The process according to claim 1, wherein the p.methylbenzyltrimethylammonium hydrogen of formula (III) is prepared in situ from the corresponding halide by the action of the alkali metal hydroxide present in the reaction medium.
Claim 4
Dependent Claim
16 words
The process according to claim 1 or 2, wherein the ketone of formula (I) is acetone.
Claim 5
Dependent Claim
16 words
The process according to claim 1 or 2, wherein the ketone of formula (I) is chloroacetone.
Claim 6
Dependent Claim
16 words
The process according to claim 1 or 2, wherein the ketone of formula (I) is acetylacetone.
Claim 7
Dependent Claim
18 words
The process according to claim 1 or 2, wherein the ketone of formula (I) is prepared in situ.
Claim 8
Dependent Claim
24 words
The process according to claim 6, wherein the ketone of formula (I) is prepared in situ starting from mesityl oxide or a derivative thereof.
Claim 9
Dependent Claim
22 words
The process according to claim 6, wherein the ketone of formula (I) is prepared in situ starting from diacetone-alcohol or its derivatives.
Claim 10
Dependent Claim
38 words
The process according to claim 1 or 2, wherein the amount of ketone of formula (I), of mesityl oxide or derivatives thereof, or of diacetone alcohol or derivatives thereof, ranges from 1 to 50%, based on p.methylbenzyltrimethylammonium hydroxide.
Claim 11
Dependent Claim
34 words
The process according to claim 1 or 2, wherein the concentration of the aqueous solution of an alkali metal hydroxide is maintained, during the Hofmann elimination reaction, at from 25 to 35% by weight.
Claim 12
Dependent Claim
38 words
The process according to claim 1 or 2, wherein the Hofmann elimination is carried out at a temperature between 70° and 125° C., over the course of 1-40 hours, and in the presence of an inert organic solvent.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-29 | 1991-09-28 | 1992-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-29 | 1995-09-28 | 1996-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-29 | 1999-09-28 | 2000-03-29 | $7700.00 | Window Closed / Lapsed |