Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-10-04
2002-07-23
Barts, Samuel (Department: 1621)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S328400, C525S328200, C525S333600, C525S343000, C525S374000, C525S376000, C525S378000, C525S384000
Reexamination Certificate
active
06423786
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to novel solid phase reagents useful as solid phase supports for small molecule synthesis, and as supported nucleophiles to aid purification of solution phase reactions.
BACKGROUND OF THE INVENTION
The advent of combinatorial chemistry has sparked renewed interest in the use of functionalized polymers in the synthesis of small, organic molecules (for recent reviews, see Blackburn et al. “Functionalized Resins and Linkers for Solid-Phase Synthesis of Small Molecules”,
Drugs of the Future
1997, 22(9), 1007-1025; and Shuttleworth et al., “Functionalized Polymers: Recent Developments and New Applications in Synthetic Organic Chemistry”,
Synthesis
1997, 1217-1239). Inexpensive, readily prepared functionalized resins suitable for organic synthesis applications are increasingly needed.
U.S. Pat. No. 4,873,171 and EP-104,074-A2 disclose polymers prepared by quaternization of polyvinylbenzyl chloride with a disubstituted asymmetric hydrazine such as 1,1-dimethylhydrazine. While these references disclose quaternized polymers containing units such as
are useful as polymeric mordants in photographic receiving layers and as electrically conductive polymers in plain paper electrostatic copiers, they do not suggest any application in small molecule synthesis. As the electronic-withdrawing inductive effect of the adjacent quaternized nitrogen would be expected to greatly diminish the useful nucleophilicity of the amino group, other polymers are required to address the needs of the synthetic organic chemist.
SUMMARY OF THE INVENTION
This invention pertains to a polymer comprising alkylhydrazine-functionalized styrene units of Formula 1
wherein
m is an integer from 1 to 3;
n is an integer from 0 to 50;
p is an integer from 1 to 25; and
R
1
is C
1
-C
3
alkyl or benzyl.
Said polymer is optionally grafted onto other polymers, such as polyethylene.
This invention also relates to a bead comprising a polymer comprising units of Formula 1.
Another aspect of this invention pertains to a process for preparing a polymer comprising alkylhydrazine-functionalized styrene units of Formula 1, the process comprising the steps of:
(a) treating a polymer comprising functionalized styrene units of Formula 2
wherein
m is an integer from 1 to 3;
n is an integer from 0 to 50;
p is an integer from 1 to 25; and
X is a leaving group;
with a solvent suitable to swell said polymer; and
(b) reacting the solvent-treated polymer with an alkylhydrazine of Formula 3
R
1
NHNH
2
3
wherein R
1
is C
1
-C
3
alkyl orbenzyl.
This invention also provides a process for producing a carbonyl-containing product compound from a carbonyl-containing precursor selected from the group consisting of modifiable aldehydes and ketones which bind to an alkylhydrazine group having an NH
2
end group, at said end group. This process comprises (1) condensing the precursor with a polymer comprising alkylhydrazine-functionalized styrene units of Formula 1 to bind the carbonyl carbon to the nitrogen of the end group with a hydrazone linkage; (2) modifying the bound precursor; and (3) hydrolyzing the hydrazone linkage to provide the product compound.
This invention further provides a process for producing a cyano-containing product compound from an aldehyde precursor which binds to an alkylhydrazine group having an NH
2
end group, at said end group. This process comprises (i) condensing the precursor with a polymer comprising alkylhydrazine-functionalized styrene units of Formula 1 to bind the carbonyl carbon of said aldehyde to the nitrogen of said end group with a hydrazone linkage; and (ii) oxidizing the hydrazone linkage to cleave the end group from the polymer and to produce the product compound. The bound precursor of (i) may be modified prior to oxidation.
This invention still further provides a method of chemical synthesis including purification from impurity having electrophilic functionality (e.g., one or more compounds selected from aldehydes, ketones, acyl chlorides, sulfonyl chlorides and isocyanates). This process is characterized by scavenging said impurity with a polymer comprising alkylhydrazine-functionalized styrene units of Formula 1.
DETAILED DESCRIPTION OF THE INVENTION
The polymer resins of this invention contain styrene units which are functionalized with alkylhydrazine groups. These resins are useful for small molecule synthesis, particularly in combinatorial chemistry.
Resin is defined variously in the polymer arts (see M. S. M. Alger,
Polymer Science Dictionary,
Elsevier, N.Y., 1989, p. 415). In this disclosure, resin is synonymous with polymer. Styrene polymer, polymer comprising styrene units, polystyrene, polystyrene resin and styrene polymer resin are all synonymous. Functionalized styrene polymer, polymer comprising functionalized styrene units, functionalized polystyrene, functionalized polystyrene resin and functionalized styrene polymer resin are synonymous and refer to a composition of matter comprising polymer chains formed from units corresponding to a functionalized styrene monomer and optionally also other units corresponding to other monomers such as unfunctionalized styrene. As functionalized polystyrene is often made from unfunctionalized polystyrene and in the functionalization process not every unit is functionalized, functionalized polystyrene typically will comprise unfunctionalized as well as functionalized units. Functionalized polystyrene made from a mixture of functionalized and unfunctionalized styrene monomers will also comprise both functionalized and unfunctionalized units (for a description of copolymerization of chloromethylstyrene with a variety of other monomers, see J.-P. Montheard, M. Chatzopolous and M. Camps, “Functional Polymers via Free-Radical Polymerization of Chloromethylstyrene”, in
Desk Reference of Functional Polymers, Syntheses and Applications,
R. Arshady, Ed., American Chemical Society, Washington, D.C. 1996, Chapter 1.1). In an alkylhydrazine-functionalized polystyrene of this invention, the unit corresponding to the functionalized styrene monomer is of Formula 1 as defined in the Summary of the Invention.
Preferred for reason of ease of synthesis, cost or high functional titer are:
Preferred 1. A polymer comprising units of Formula 1 wherein
L is L
1
;
m is 1, and
n is 0.
Preferred 2. A polymer of Preferred 1 wherein
R
1
is CH
3
.
Preferred 3. A polymer comprising units of Formula 1 wherein
L is L
1
;
m is 1, and
n is an integer from 4 to 25.
Preferred 4. A polymer of Preferred 3 wherein
R
1
is CH
3
.
Preferred 5. A polymer comprising units of Formula 1 wherein
L is L
2
; and
p is an integer from 4 to 10.
Preferred 6. A polymer of Preferred 5 wherein
R
1
is CH
3
.
Particularly preferred for reason of high functional titer and low cost are:
Preferred 7. A polymer comprising units of Formula 1 or any of Preferreds 1-6 consisting essentially of a polystyrene backbone which is cross-linked with about 0.5 to 20% by weight divinylbenzene units.
Preferred 8. A polymer of Preferred 7 which is cross-linked with about 0.8-8% by weight divinylbenzene units.
Preferred 9. A polymer of Preferred 8 which is cross-linked with about 1-2% by weight divinylbenzene units.
The polymer chains in an alkylhydrazine-functionalized polystyrene of this invention preferably also comprise about 0.5 to about 20% by weight units corresponding to the divinylbenzene monomer to provide cross-linking so as to improve the physical strength and resistance to solvents of the derived resin. About 0.8 to 8% by weight divinylbenzene units is preferred. Most preferred is about 1 to 2% by weight divinylbenzene units, which provides resins with very good physical properties. The polystyrene chains optionally also comprise units derived from vinylethylbenzene and other substituted vinyl benzenes (as described for ion exchange resins by F. W. Billmeyer, Jr.,
Textbook of Polymer Science,
Second Edition, Wiley-Interscience, New York, 1971, p. 407). Furthermore the polystyrene chains are optionally grafted onto other carbonaceous polymeric b
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