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Patent US4816608A successfully refreshed from Google Patents.
US4816608A
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Process for the preparation of (2,2)-paracyclophane and derivatives thereof
Assignee: Montedison SpA
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Filing: 1987-06-26
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Granted: 1989-03-28
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Expires: 2007-06-26
Abstract
Abstract Process for the preparation of (2,2)-paracyclophane or derivatives thereof by the Hofmann elimination of p-methylbenzyl-trimethylammonium hydroxide or derivatives thereof, in an aqueous solution of an alkali metal hydroxide, wherein said elimination is carried out in the presence of a compound of the formula (I): Y--A--(X).sub.n (I) wherein A represents an aromatic group, Y an electron donor group, X an electron acceptor group, and n is an integer from 1 to 3.
Inventors
- 👤 Giorgio Bornengo
- 👤 Alessandro Malacrida
- 👤 Stefano Campolmi
- 👤 Maurizio A. Beretta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 14:46
CPC Classifications
C; C07; C07C; C07C13/00; C07C13/28; C07C13/32; C07C13/54; C07C13/605; C07C1/00; C07C1/32; C07C1/321; C07C1/323; A; A61; A61K; A61K9/00; A61K9/10; C07C17/00; C07C17/26; C07C17/263; C07C2603/00; C07C2603/92
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
124 words
A process for preparing (2,2)-paracyclophane and derivatives thereof of the formula: ##STR4## wherein B is a halogen atom, an alkyl radical, an aralkyl radical, or a halo-aralkyl radical, having up to 20 carbon atoms, and m is zero or an integer from 1 to 4, by the Hofmann elimination of p-methylbenzyltrimethyl-ammonium hydroxide or derivatives thereof of the formula: ##STR5## wherein B and m are the same as defined hereinabove, in an alkaline aqueous solution, characterized in that said elimination is carried out in the presence of at least a catalytic amount of an aromatic compound having the formula: Y--A--(X).sub.n (I) wherein A represents an aromatic group, Y an electron donor group, X an electron acceptor, and n is an integer from 1 to 3.
Claim 2
Dependent Claim
124 words
A process for preparing (2,2)-paracyclophane and derivatives thereof of the formula: ##STR4## wherein B is a halogen atom, an alkyl radical, an aralkyl radical, or a halo-aralkyl radical, having up to 20 carbon atoms, and m is zero or an integer from 1 to 4, by the Hofmann elimination of p-methylbenzyltrimethyl-ammonium hydroxide or derivatives thereof of the formula: ##STR5## wherein B and m are the same as defined hereinabove, in an alkaline aqueous solution, characterized in that said elimination is carried out in the presence of at least a catalytic amount of an aromatic compound having the formula: Y--A--(X).sub.n (I) wherein A represents an aromatic group, Y an electron donor group, X an electron acceptor, and n is an integer from 1 to 3.
Claim 3
Dependent Claim
77 words
The process according to claim 1, characterized in that in the catalyst of formula (I), A represents a phenyl or naphthyl group, Y is an OR group wherein R represents a hydrogen atom or an alkyl group having from 1 to 4 carbon atoms, and X represents a halogen atom, a nitro group, a nitrile group, a carboxyl, carboalkoxyl, carbonyl-alkyl, sulphonylalkyl group having from 1 to 6 carbon atoms in the alkyl part, or a sulphonic group.
Claim 4
Dependent Claim
37 words
The process according to claim 1 or 2, characterized in that p-methylbenzyltrimethylammonium hydroxide 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 5
Dependent Claim
23 words
The process according to claim 1 or 2, characterized in that it is carried out in the presence of an aprotic organic solvent.
Claim 6
Dependent Claim
62 words
The process according to claim 4, characterized in that the aprotic organic solvent is dialkyl ether of mono- and poly-ethylene glycols having the formula: R.sub.1 --O--CH.sub.2 --CH.sub.2 O].sub.p R.sub.2 (IV) wherein R, and R 2 , the same or different from each other, represent alkyl groups having from 1 to 5 carbon atoms, and p is an integer from 1 to 5.
Claim 7
Dependent Claim
24 words
The process according to claim 4, characterized in that the organic aprotic solvent is selected from the group consisting of dimethyl-sulphoxide, dimethylformamide and dimethylacetamide.
Claim 8
Dependent Claim
14 words
The process according to claim 5, characterized in that the solvent is di-ethylene-glycol-dimethyl ether.
Claim 9
Dependent Claim
35 words
The process according to claim 1 or 2, characterized in that the catalyst is selected from the group consisting of p-nitrophenol, p-cyanophenyl, p-chlorophenol, 4-nitro-alphanaphthol, p-carbomethoxyphenyl, p-carboxyphenol, 2,4-dinitrophenol, p-carboethoxyphenol, p-hydroxy acetophenone, p-hydroxybenzene-sulphonic acid, and alpha-naphthol-4-sulfonic acid.
Claim 10
Dependent Claim
34 words
The process according to claim 1 or 2, characterized in that the catalyst of formula (I) is used in a molar amount ranging from 5% to 30% based on p-methylbenzyltrimethylammonium hydroxide of formula (III).
Claim 11
Dependent Claim
32 words
The process according to claim 9, characterized in that the catalyst of formula (I) is used in a molar amount ranging from 10% to 20% based on p-methylbenzyltrimethylammonium hydroxide of formula (III).
Claim 12
Dependent Claim
24 words
The process according to claim 4, characterized in that the weight ratio: organic aprotic solvent/p-methylbenzyltrimethylammonium hydroxide of formula (III) is between 2 and 50.
Claim 13
Dependent Claim
24 words
The process according to claim 11, characterized in that the weight ratio: organic aprotic solvent/p-methylbenzyltrimethylammoniun hydroxide of formula (III) is between 4 and 10.
Claim 14
Dependent Claim
36 words
The process according to claim 1 or 2, characterized in that the concentration of the aqueous solution of an alkali metal hydroxide is maintained, during the Hofmann elimination reaction, at from 15 to 35% by weight.
Claim 15
Dependent Claim
30 words
The process according to claim 1 or 2, characterized in that the molar ratio of the alkali metal hydroxide to p-methylbenzyltrimethylammonium hydroxide of formula (III) is between 1 and 10.
Claim 16
Dependent Claim
34 words
The process according to claim 1 or 2, characterized in that the Hofmann elimination is carried out at a temperature between 50° C. and 150° C. over the course of 1 to 40 hours.
Claim 17
Dependent Claim
34 words
The process according to claim 1 or 2, characterized in that the Hofmann elimination is carried out at a temperature between 70° C. and 125° C. over the course of 5 to 20 hours.
Claim 18
Dependent Claim
30 words
The process according to claim 1 or 2, characterized in that the Hofmann elimination is carried out in the presence of an inert organic solvent which is immiscible with water.
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) | 1992-03-27 | 1992-09-26 | 1993-03-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-27 | 1996-09-26 | 1997-03-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-27 | 2000-09-26 | 2001-03-28 | $7700.00 | Window Closed / Lapsed |