Process for preparing...

Details Process for preparing... Process for preparing...

2001-11-26

2002-12-03

Shippen, Michael L. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

Reexamination Certificate

active

06489517

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to a process for preparing 3,3′,6,6′-tetraalkyl-2,2′-biphenols and 3,3′,6,6′-tetraalkyl-5,5′-dihalo-2,2′-biphenols.
BACKGROUND OF THE INVENTION
Substituted biphenols such as 3,3′,6,6′-tetraalkyl-2,2′-biphenol; 3,3′,4,4′,5,5′,6,6′-octaalkyl-2,2′-biphenols; 3,3′,5,5′,6,6′-hexaalkyl-2,2′-biphenols; 3,3′,5,5′-tetraalkyl-2,2′-biphenol; 3-alkyl-5,5′,6,6′,7,7′8,8′-octahydro-2,2′-binaphthol; 3,3′-dialkyl-5,5′,6,6′,7,7′8,8′-octahydro-2,2′-binaphthol and 3,3′6,6′-tetralkyl-5,5′-dihalo-2,2′-biphenol are compounds that can be used to make phosphorus-based catalyst ligands. Such ligands include phosphines, phosphinites, phosphonites, and phosphites. Mono(phosphorous) ligands are compounds that contain a single phosphorus atom which serves as a donor to a transition metal, while bis(phosphorus) ligands, in general, contain two phosphorus donor atoms and typically form cyclic chelate structures with transition metals.
In general, biphenols can be made by the oxidative coupling of (mono)phenols, but often other types of products, such as ketones, are obtained, and/or overall yields are poor for other reasons.
Phenols can be oxidatively coupled to make the corresponding biphenols by the use of a variety of oxidizing agents, such as nitric acid, ferric chloride, potassium ferricyanide, chromic acid, 2,3-dichloro-5,6-dicyanobenzoquinone and di-t-butyl peroxide. 2,2′-Dihydroxy-3,3′-di-isopropyl-6,6′-dimethylbiphenyl can be prepared from 2-isopropyl-5-methyl-phenol with 2,3-dichloro-5,6-dicyanobenzoquinone or di-t-butyl peroxide. See Tetrahedron, 1875, 1971 and J. Chem. Soc., Perkin Trans. II, 587, 1983. Some of the oxidants and/or co-catalysts involve the use of relatively expensive and/or explosive (peroxides) compounds, which pose disadvantages for large scale commercial use.
Phenols can also be oxidatively coupled using a combination of a transition metal catalyst and an oxidizing agent such as persulfate anion or oxygen. See U.S. Pat. Nos. 6,077,979; 4,139,544; 4,132,722; 4,354,048; and 4,108,908. See also J. Org. Chem. 1984, 49, 4456 and J. Org. Chem. 1983, 48, 4948. The cited patents disclose the use of oxygen as an oxidizing agent with various copper complexes as catalysts (copper chromite; copper acetate with sodium mercaptoacetate; copper acetate with pentasodium/diethylenetriaminepentacetate; copper acetate with 1,3-diamino-2-hydroxypropane-tetracetic acid). The examples in the patents disclose the use of 2,6-disubstituted phenol or 2,4-di-tert-butylphenol.
The use of copper amine catalysts, with oxygen as an oxidizing agent, has been described in connection with the oxidative coupling of 2,4-di-tert-butylphenol, 2-methyl-4-tert-butylphenol, 2-chlor-4-tert-butylphenol and 4-tert-butylphenol. See J. Org. Chem. 1984, 49, 4456 and J. Org. Chem. 1983, 48, 4948.
There is a continuing need in the art for methods for making with decent yields substituted biphenols suitable for making phosphorous-based catalyst ligands.
SUMMARY OF THE INVENTION
In its first aspect, the present invention is a process for making a compound of the formula I
wherein
R
1
is C
1
to C
10
primary or secondary alkyl or cycloalkyl,
R
2
is C
1
to C
10
primary or secondary alkyl or cycloalkyl, and
X is H, Cl, Br, or I, comprising:
(1) when X is Cl
(a) chlorinating a compound of the formula II
 at the 4-position thereof to produce a compound of the formula III
 wherein X is Cl,
(b) oxidatively coupling the compound of the formula III wherein X is Cl to produce a compound of the formula I wherein X is Cl;
(2) when X is H
(a) chlorinating a compound of the formula II at the 4-position thereof to produce a compound of the formula III wherein X is Cl,
(b) oxidatively coupling the compound of the formula III wherein X is Cl to produce a compound of the formula I wherein X is Cl, and
(c) dechlorinating the compound of the formula I wherein X is Cl to produce a compound of the formula I wherein X is H; or
(3) when X is Br or I
(a) chlorinating a compound of the formula II at the 4-position thereof to produce a compound of the formula III wherein X is Cl,
(b) oxidatively coupling the compound of the formula III wherein X is Cl to produce a compound of the formula I wherein X is Cl,
(c) dechlorinating the compound of the formula I wherein X is Cl to produce a compound of the formula I wherein X is H, and
(d) substituting Br or I, respectively, for H at the 5 and 5′ positions of the compound of the formula I wherein X is H.
In its second aspect, the present invention is a process for making a compound of the formula IV
wherein
R
1
is C
1
to C
10
primary or secondary alkyl or cycloalkyl,
R
4
is C
1
to C
10
primary or secondary alkyl or cycloalkyl, and
X is H, Cl, Br, or I
comprising:
(1) when X is H
(a) alkylating a compound of the formula V
 at the 4-position thereof to produce a compound of the formula VI
wherein R
3
is C
4
to C
20
tertiary alkyl,
(b) oxidatively coupling the compound of the formula VI to produce a compound of the formula VII
(c) dealkylating a compound of the formula VII to produce a compound of the formula IV wherein X is H; or
(2) when X is Cl, Br, or I
(a) alkylating a compound of the formula V at the 4-position thereof to produce a compound of the formula VI,
(b) oxidatively coupling the compound of the formula VI to produce a compound of the formula VII,
(c) dealkylating a compound of the formula VII to produce a compound of the formula IV wherein X is H, and
(d) substituting Cl, Br, or I, respectively, for H at the 5 and 5′ positions of the compound of the formula IV wherein X is H.
In its third aspect, the present invention is a process for making a compound of the formula I
wherein
R
1
is C
1
to C
10
primary or secondary alkyl or cycloalkyl,
R
2
is C
1
to C
10
primary or secondary alkyl or cycloalkyl, and
X is H,
comprising:
(a) oxidatively coupling a compound of the formula III
 wherein X is Cl, to produce a compound of the formula I wherein X is Cl, and
(b) dechlorinating the compound of the formula I wherein X is Cl to produce a compound of the formula I wherein X is H.
In another aspect the present invention is a compound selected from the group consisting of 3,3′,6,6′-tetramethyl-2,2′-biphenol, and 3,3′-di-isopropyl-6,6′-dimentyl-2,2′-biphenol.
DETAILED DESCRIPTION OF THE INVENTION
The first aspect of the present invention provides a process for preparing 3,3′,6,6′-tetraalkyl-2,2′-biphenol, comprising (1) substituting chlorine for hydrogen at the 4-position of 2,5-dialkylphenol, (2) oxidatively coupling the resulting 2,5-dialkyl-4-chloro-phenol, and (3) removing chlorine from the resulting compound. The second step is carried out by analogy with the methods of Sartori, et al (Tetrahedron, 1992, 48, 9483), but using the free phenol rather than its dichloroaluminate derivative. The three steps of the process are shown below.
wherein R
1
is C
1
to C
10
primary or secondary alkyl or cycloalkyl; and R
2
is C
1
to C
10
primary or secondary alkyl or cycloalkyl.
Preferred R
1
are methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, cyclohexyl, and cyclopentyl. Preferred R
2
are methyl and ethyl. The alkyl groups at the 2- and 5-postions may be the same or different.
In the first step of the process, a 2,5-dialkylphenol can be reacted with a chlorinating agent, such as chlorine or sulfuryl chloride, preferably in the presence of 1 to 10 mol % of a catalyst such as aluminum chloride or a diaryl sulfide such as diphenyl sulfide or a mixture thereof. See Watson,
J. Org. Chem.,
1985, 50, 2145. The reaction may be conducted neat (without a solvent) or in a medium such as dichloromethane, chlorobenzene, or other inert solvent at a temperature between −30 and 60° C., preferably at about 25° C. The react

Affiliated with

Also associated with

Rating

Process for preparing... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for preparing..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparing... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2970739