Synthesis of substituted poly(aniline)s

Details Synthesis of substituted poly(aniline)s Synthesis of substituted poly(aniline)s

2002-07-29

2004-05-18

Hampton-Hightower, P. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Nitrogen-containing reactant

C528S394000, C528S489000, C528S490000, C525S540000, C252S500000

Reexamination Certificate

active

06737504

ABSTRACT:

FIELD OF THE INVENTION
This invention relates to methods of synthesizing substituted poly(aniline)s. More particularly, the invention relates to the use of poly(aniline boronic acid) as a precursor in these methods.
BACKGROUND OF THE INVENTION
Substituted poly(aniline)s are of great interest for a variety of applications ranging from polymer-based electronics to sensors, as well as numerous electrocatalytic applications. As a result, there has been considerable interest in developing new synthetic approaches for their production.
Typically, these substituted polymers are generated by the oxidative polymerization of the corresponding monomer. See, for example, Pringsheim, et al.,
Anal. Chim. Acta
357:247-252 (1997). However, in many cases the desired moiety is either too difficult to oxidize or is sensitive to oxidative or acidic conditions. One alternative method involves the use of a monomer containing a reactive substituent group to synthesize a precursor polymer that subsequently can be modified to form the desired structure Tsuchida, et al.,
Macromolecules
26, 7389-7390 (1993).
Boronic acid groups are reactive and provide a versatile chemical precursor for various transformations with isolated yields typically greater than 90%. Examples of such transformation reactions are illustrated in Schemes 1-9.
Aromatic boronic acid groups can be used for transformations via ipso-hydroxylation under mild conditions (Simon, et al.,
J. Org. Chem.
66:633-634 (2001)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in the following Scheme 1:
Simon also describes the regioselective oxidation of arylboronic acids to phenols and their one-pot conversions to symmetrical diaryl ethers under mild conditions (room temperature).
Aromatic boronic acid groups can be used for transformations via ipso-halogenation under mild conditions ((i) Nesmeyanov, et al.,
Chem. Ber.
93:2717 (1960); and (ii) Kuivila, et al.,
J. Org. Chem.
76:2679-2682 (1954) and Thiebes, et al.,
Synlett
141-142 (1998)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in the following Scheme 2:
Aromatic boronic acid groups can be used for copper-mediated cross-coupling with alkyl thiols (Herradura, et al.,
Org. Lett.
2(14):2019-2022 (2000)), as shown in the following Scheme 3:
Aromatic boronic acid groups can be used for a trans-metallation reaction, as shown in the following Scheme 4:
Aromatic boronic acid groups can be used for copper carboxylate-mediated, catalyzed thioalkyne cross-coupling reactions to produce substituted alkynes (Savarin, et al.,
Org. Lett.
3(1):91-93 (2001)), as shown in the following Scheme 5:
Aromatic boronic acid groups can be used for cross-coupling reactions with thiol avarin, et al.,
Org. Lett.
2(20):3229-3231 (2000)), as shown in the following Scheme 6:
Aromatic boronic acid groups can also be used in a reaction that is widely known as the Suzuki cross-coupling reaction. This coupling reaction is an extremely powerful route to produce C—C bonds under mild conditions (Suzuki,
Pure Appl. Chem.
63:419 (1991) and Badone, et al.
J. Org. Chem.
62:7170-7173 (1997)), as shown in the following Scheme 7:
Aromatic boronic acid groups can be used for the synthesis of organoborane compounds (Vogels, et al.,
Can. J Chem.
77(7):1196-1207 (1999)), as shown in the following 8:
Aromatic boronic acid groups can be used for transformations via ipso-nitration under mild conditions (Salzbrunn, et al.,
Synlett
1485-1487 (2000)). A boron activation/electrophilic displacement mechanism giving this ipso-substitution has been proposed, as shown in Scheme 9.
In spite of the advances in the art, there continues to be a need to develop synthetic strategies for the synthesis of this useful class of compounds. For example, conventional methods of producing diaryl ethers such as Ulman reactions require activated substrates (Patai,
The Chemistry of the Hydroxyl Group, Part
1, Wiley, New York, 1971) and high temperature conditions (140-160° C., Cohen, et al.,
Tetrahedron Lett.
3555-3558 (1974), and Cohen, et al.,
J. Am. Chem. Soc.
88, 4521-4522 (1966)). Accordingly, it is desirable to develop synthetic routes that avoid the need for such activated substrates and high temperatures.
Other problems associated with current methodologies relate to side reactions that occur, resulting in a variety of products that can result from a single reaction. An important example of a substituted poly(aniline) whose structure is complicated by side reactions occurring during oxidative polymerization of its monomer 1, is poly-(hydroxyaniline) 4, as shown in the scheme below:
The structure of the polymer produced by the electrochemical oxidation of 1 is complicated due to the similar oxidative reactivity of both —NH
2
and —OH groups as well as the loss of —NH
2
to form
2
. Several reports exist in the literature regarding whether a ladder
3
or linear
4
polymer is formed (Kunimura, et al.,
Macromolecules
21:894-900 (1988); Ohsaka, et al.,
Electrochim. Acta
33:639-645 (1988); Barbero, et al.,
J. Electroanal. Chem.
263:333-352 (1989); Barbero, et al.,
J. Electroanal. Chem.
291:81-101 (1990); Goncalves, et al., J. Electroanal. Chem. 487:90-99 (2000); and Zhang, et al.
J. Electroanal. Chem.
373:115-121 (1994)). Evidence has been presented that suggests both forms are possible. Accordingly, it is desirable to develop synthetic routes that provide for the exclusive generation of the desired product, for example compound
4
.
Additional problems associated with current methodologies relate to the synthesis of compounds such as halogen-substituted poly(aniline)s, which are difficult to synthesize using standard approaches (Dao, et al.,
Synth. Met.
29:E377-382 (1989) and Pringsheim, et al.,
Anal. Chim. Acta
357:247-252 (1997)). For example, during standard oxidative polymerization conditions, halogen-substituted anilines have been known to undergo elimination, resulting in the loss of a significant amount of halogen (4-48% for Cl and Br) in the resulting polymer (Snauwaert, at el.,
Synth. Met.
16:245-255 (1986)).
The present invention addresses these needs by using poly(aniline boronic acid) as the precursor in the synthesis of a wide range of substituted poly(aniline)s.
SUMMARY OF THE INVENTION
One aspect of the invention relates to a method of synthesizing a substituted poly(aniline), comprising reacting poly(aniline boronic acid) with a reagent to produce a substituted poly(aniline) of formula I:
where n is an integer within the range of about 1-10,000,000; R
a
, R
b
and R
c
are independently selected from the group consisting of —H, —B(OH)
2
, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and Z is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Another aspect of the invention pertains to a method of synthesizing a substituted poly(aniline), comprising: reacting poly(aniline 3-boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; to produce a substituted poly(aniline) of formula I, where n is an integer within the range of about 1-10,000,000; R
a
, R
b
and R
c
are independently selected from the group consisting of —H, —B(OH)
2
, alkyl, cycloalkyl, cycloheteroalkyl, aryl, heteroaryl and silyl; and Z is a substituent produced by the reaction of the reagent and the boronic acid substituent.
Yet another aspect of the invention relates to a method of synthesizing a substituted poly(aniline) comprising reacting poly(aniline boronic acid) with at least one reagent selected from the group consisting of oxidation reagents, ipso-substitution reagents, and cross-coupling reagents; stopping the reaction before all of the boronic acid substituents in the poly(aniline boronic acid) undergo oxidation, substitution or cross-coupling; to produce a substituted poly(aniline) of formula I′:
where n is an integer wit

Affiliated with

Also associated with

Rating

Synthesis of substituted poly(aniline)s does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Synthesis of substituted poly(aniline)s, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Synthesis of substituted poly(aniline)s will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3225384