Rapid purification by polymer supported quench

This application is a division of U.S. application Ser. No. 09/171,258, filed Oct. 15, 1998, now U.S. Pat. No. 6,306,959 which is the U.S. national stage of PCT/US97/07099, filed Apr. 28, 1997, which claims the benefit of application Ser. No. 60/017,422, filed May 3, 1996.

BACKGROUND OF THE INVENTION

The present invention relates to novel polymer-supported quenching reagents, to methods for their preparation, and to methods for their use in the rapid purification of synthetic intermediates and products in the practice of organic synthesis, combinatorial chemistry, and automated organic synthesis.

Combinatorial chemistry and automated organic synthesis have proven to be highly effective means for the generation of multiplicities of novel molecules known as libraries. As the size of such a library grows, so does the likelihood that it will contain individual molecules with useful biological activities which may be employed in the treatment of human, animal, and plant diseases. Research organizations that can prepare and screen a large number of diverse compounds efficiently, have an increased likelihood of discovering and optimizing new products. For recent reviews in the use of combinatorial chemistry in pharmaceutical discovery see Gallop M. A., et al.,

J. Med. Chem.,

1994;37:1233 and Gordon E. M., et al., ibid., 1994;37:1385.

In the practice of organic synthesis, the most time consuming element is typically the purification of the desired product following each synthetic transformation. Traditionally, automated organic synthesis and combinatorial chemistry have relied on a number of methods to reduce the amount of time and effort devoted to purification. Such methods include water soluble reagents, polymer-supported reagents, and polymer-supported synthesis. Water soluble reagents and byproducts derived therefrom have the advantage of being easily removed by partitioning the crude reaction mixture between water (which dissolves the reagent and associated byproducts) and an organic solvent (which dissolves the desired product). Separation of the organic layer gives a purified form of the product relative to the crude reaction mixture. An example of a water soluble reagent is N-ethyl-N′-dimethylaminopropylcarbodiimide (EDC). EDC is a reagent that is used in the coupling of carboxylic acids and amines to form amide bonds. EDC and the corresponding urea produced during the course of the reaction (N-ethyl-N′-dimethylaminopropylurea) are both soluble in water at low pH and can thus be washed away into an acidic water layer. The use of EDC greatly simplifies purification of the amide product relative to other carbodiimides such as N,N′-dicyclohexylcarbodiimide (DCC) which are not water soluble. Polymer-supported reagents and byproducts derived therefrom are likewise easily separated by filtration of the polymeric materials from a crude reaction mixture. An example of a polymer-supported reagent is poly(styrene-divinylbenzene)-supported triphenylphosphine which may be used in Wittig olefination reactions. The byproduct of this transformation, polymer-supported triphenylphosphine oxide, is easily removed by filtration which simplifies purification greatly compared to the solution phase reagent. The use of triphenylphosphine in solution phase Wittig reactions gives triphenylphosphine oxide as a byproduct which is difficult to completely remove except by time consuming chromatography or repeated crystallization. Polymer-supported synthesis minimizes time spent on purifications by attaching a starting material to a polymer. Subsequent synthetic transformations are carried out in such a manner that desired reactions are driven to completion on the polymer-supported material and excess reagents and byproducts in solution are subsequently removed by filtering the polymer and rinsing with solvent(s). At the end of the synthesis, the desired product is chemically cleaved from the polymer. The resulting product is typically obtained in greater purity than would be possible if all of the steps were carried out in solution with no chromatography or crystallization of synthetic intermediates. Purification in a multistep synthesis is thus largely reduced to a number of filtrations, although a single purification of the final product by conventional means is often necessary to remove byproducts resulting from the resin cleavage step. Thus, water soluble reagents, polymer-supported reagents, and polymer-supported synthesis each provide increased efficiency reducing purification to mechanically simple liquid-liquid and liquid-solid separation methods which are easy to automate.

The increased simplicity and efficiency which allow automation of organic synthesis using the methods described above comes at the price of increased reagent cost and/or substantial synthesis development time. Water soluble reagents and polymer-supported reagents must be customized for each type of synthetic transformation. The time necessary to optimize a particular reagent significantly increases its cost. Consequently, EDC is more expensive than DCC and polystyrene-supported triphenylphosphine is more expensive than triphenylphosphine. Polymer-supported syntheses traditionally require longer development time than solution phase due to the limitations imposed by the method. One must choose the optimum polymer, develop a linking strategy which can be reversed at the end of the synthesis and find successful conditions for each reaction without many of the conventional spectral and chromatographic analysis tools that are available to solution phase synthesis. Thus, at the current state of the art, much of the time/cost saved by increasing the efficiency of purifications via the above methods is lost to increased reagent costs and/or synthetic development time.

Polymer-supported reagents have been extensively reviewed in the literature. The following citation is representative of the current state of this art: Sherrington D. C.,

Chem. Ind.,

(London) 1991;1:1-19.

Solid-supported synthesis has been extensively reviewed in the literature. The following two citations are representative of the current state of this art: Früchtel J. S. and Jung G.,

Angew. Chem. Int. Ed. Engl.,

1996;35:17-42, Thompson L. A. and Ellman J. A.,

Chem. Rev.,

1996;96:555-600.

A purification process known as covalent chromatography has been described in the scientific literature. Using covalent chromatography a desired material is isolated from a complex mixture by selective reaction with a polymeric reagent, followed by filtration, and rinsing. The desired material is then liberated from the polymer by a chemical cleavage. Typically this process is applied to proteins and other macromolecules as a way of isolating them from complex mixtures of cellular components. This technique has also been applied in the separation of low molecular weight allergens from plant oils as described by Cheminat A., et al., in

Tetr. Lett.,

1990;617-619. Covalent chromatography differs from the instant invention in that the polymeric materials used must be both capable of covalently reacting with a desired material in a solution containing impurities and capable of subsequent cleavage of said covalent bond during the retrieval of the desired material. Polymer-supported quench methods of the present invention rely on chemically robust and ideally irreversible attachment of undesired materials that are found in the crude product of an organic reaction to a polymeric support, leaving the desired product in solution.

Polymeric reagents have been employed during the course of a reaction to enhance yield of the desired product by minimizing side reactions as described by Rubenstein M. and Patchornik A.,

Tetr. Lett.,

1975;1445-8, but this use of a polymeric reagent does not eliminate the need for conventional purification of the desired product.

Polymeric reagents which selectively remove metal ions from solutions by chelation have been described but this use of a polymeric reagent in purification does not involve formation of covalent bonds. For a review of the current state of this art see Alexandratos S. D. and Crick D. W.,

Ind. Eng. Chem. Res.,

1996;35:635-44.

The synthesis of dendritic polyamides on polymeric supports has been described by Ulrich K. E., et al.,

Polymer Bul.,

1991;25:551-8. As synthetic intermediates of the synthesis, polymer-supported dendritic polyamines are described which, by virtue of the fact that they contain an easily cleaved linker, are structurally distinct from those of the present invention which contain chemically robust linkers.

The aforementioned references do not describe or suggest the polymer-supported quench reagents disclosed herein, nor do they teach methods of preparation of polymer-supported quench reagents disclosed herein, nor do they teach the rapid purification utility of polymer-supported quench in the practice of automated organic synthesis and combinatorial chemistry as described in the present invention.

Thus, we have surprisingly and unexpectedly found that one or more polymer-supported reagents can be added at the conclusion of an organic reaction to covalently react with excess reagents and/or unwanted byproducts. The polymer bound impurities are then easily removed by conventional solid-liquid phase separation techniques leaving a solution of the desired synthetic intermediate or product which is enhanced in purity relative to the crude reaction mixture. Purification by polymer-supported quench is mechanically simple and rapid compared to conventional means of purification such as column chromatography, distillation or crystallization. This means of purification is readily applied to large variety of organic reactions and is amenable to both manual and automated organic synthesis environments. Hence, it is of tremendous value in the preparation of large libraries of organic molecules by automated parallel synthesis and by automated or manual combinatorial synthesis.

SUMMARY OF THE INVENTION

Accordingly a first aspect of the present invention is a compound of Formula I,

P—L—Q  I

wherein

P is a polymer of low chemical reactivity which is soluble or insoluble;

Q is one or more quenching reagents, or an acid or base addition salt thereof, that are capable of selective covalent reaction with unwanted byproducts, or excess reagents; and

L is one or more chemically robust linkers that join P and Q;

with the proviso that a compound of Formula I is not Merrifield resin (also known as chloromethyl-poly(styrene-divinylbenzene); benzylamine resin (also known as aminomethyl-poly(styrene-divinylbenzene)); benzyhdrylamine resin (also known as BHA resin); 4-methyl-benzhydrylamine resin (also known as MBHA resin); benzylalcohol resin (also known as hydroxymethyl-poly(styrene-divinylbenzene)); Wang resin (also known as p-benzyloxy-benzylalcohol resin); aldehyde resin (also known as formyl-poly(styrene-divinylbenzene); TentaGel® hydroxy; amino and thiol resins, benzylthiol resin (also known as thiomethyl-poly(styrene-divinylbenzene); polymer diazomethylene (also known as polymer-supported diphenyl-diazomethane); nor poly(ethyleneglycol).

A second aspect of the present invention is a method for enhancing the purity of a desired compound which comprises:

Step (a) treating a crude reaction product which contains at least one desired compound, unreacted starting materials and/or byproducts with at least one polymer-supported quenching reagent of Formula I,

P—L—Q  I

 wherein

is a polymer of low chemical reactivity which is soluble or insoluble;

Q is one or more quenching reagents, or an acid or base addition salt thereof, that are capable of selective covalent reaction with unwanted byproducts, or excess reagents; and

L is one or more chemically robust linkers that join P and Q.

Step (b) allowing the polymer-supported quenching reagent to covalently react with unreacted starting materials and/or byproducts to afford a derivatized reagent of Formula II,

P—L—Q—X  II

 wherein

X is unreacted starting material and/or byproduct and P, L, and Q are as defined above; and

Step (c) separation of the reagents of Formula I and Formula II from the solution and removal of solvent to afford a compound of enhanced purity.

A third aspect of the present invention is a process of preparing a compound of Formula I,

P—L—Q  I

wherein

P is a polymer of low chemical reactivity which is soluble or insoluble;

Q is one or more quenching reagents, or an acid or base addition salt thereof, that are capable of selective covalent reaction with unwanted byproducts, or excess reagents; and

L is one or more chemically robust linkers that join P and Q;

with the proviso that a compound of Formula I is not Merrifield resin (also known as chloromethyl-poly(styrene-divinylbenzene); benzylamine resin (also known as aminomethyl-poly(styrene-divinylbenzene)); benzyhdrylamine resin (also known as BHA resin); 4-methylbenzhydrylamine resin (also known as MBHA resin); benzylalcohol resin (also known as hydroxymethyl-poly(styrene-divinylbenzene)); Wang resin (also known as p-benzyloxybenzylalcohol resin); aldehyde resin (also known as formyl-poly(styrene-divinylbenzene); TentaGel® hydroxy; amino and thiol resins; benzylthiol resin (also known as thiomethyl-poly(styrene-divinylbenzene); polymer diazomethylene (also known as polymer-supported diphenyl-diazomethane); nor poly(ethyleneglycol), which comprises conversion of a polymeric starting material to a compound of Formula I in one to four synthetic steps, rinsing thoroughly with one or more solvents after each synthetic step.

DETAILED DESCRIPTION OF THE INVENTION

The following Table 1 provides a list of definitions and abbreviations used in the present invention.

TABLE 1

DEFINITIONS AND ABBREVIATIONS

Term

Definition

Acid addition

A salt derived from inorganic acids

salt

such as, for example, hydrochloric,

nitric, phosphoric, sulfuric,

hydrobromic, hydriodic, phosphorous,

and the like, as well as from water

soluble organic acids such as, for

example, aliphatic mono- and

dicarboxylic acids, phenyl-

substituted alkanoic acids, hydroxy

alkanoic acids, aromatic acids,

aliphatic, and aromatic sulfonic

acids and the like.

Base addition

A salt derived from inorganic metals

salt

such as, for example, sodium,

potassium, magnesium, calcium, and

the like as well as from water

soluble organic amines such as, for

example, N-methylmorpholine,

diethanolamine, ethylenediamine,

procaine, and the like.

Byproduct

An undesirable product of a reaction

which comprises at least five mole

percent of the crude product.

Isomers, enantiomers and

diastereomers of the desired product

are not considered to be byproducts

within the scope of this invention.

Chemically

Not cleaved by a wide variety of

robust

reagents used in the art of organic

synthesis.

Crude reaction

The result of a chemical reaction

product

before any purification. Synonymous

with crude product and crude reaction

mixture.

Dendritic

A subset of polyfunctional molecules

molecule

which have two or more equivalent

arm-like structures with functional

groups at the ends emanating from a

central core structure. For example,

tris(2-aminoethyl)-amine,

ethylenediaminetetraacetic acid,

tris(hydroxymethyl)aminomethane, and

1,3,5-benzenetricarboxylic acid are

dendritic molecules.

Enhancing

A) Eor a single desired compound,

purity

enhancing purity means the

process of removing excess or

unreacted starting reagents to

the limit of detection by TLC or

by NMR spectroscopy and/or

reducing the content of any

single byproduct to less than ten

molar percent, exclusive of

solvents.

B) For a combinatorial mixture of

desired compounds: The process

of removing excess or unreacted

starting reagents and or reducing

the content of a byproduct using

a procedure that has been

validated on crude reaction

products of analogous single

compounds.

Insoluble

A polymeric compound which by virtue

polymer

of its structure and high molecular

weight is incapable of dissolving in

organic and aqueous solvents and

mixtures thereof.

Polyfunctional

A compound which contains two or more

molecule

functional groups attached to a

carbon framework or interspersed with

more than one carbon framework. For

example 2,6-diamino-hexanoic acid,

1,8-diamino-3,6-diazaoctane, and 2,6-

diisocyanatohexane are polyfunctional

molecules.

Quenching

A molecule that covalently combines

reagent

with a reactant to make it less

reactive or a molecule that

covalently combines with a byproduct.

Resin

A synonym for an insoluble polymer.

Resin swelling

A solvent which penetrates pores of

solvent

an insoluble polymer and causes it to

increase in volume.

Soluble

A polymeric compound which by virtue

polymer

of its structure and low molecular

weight is able to dissolve in

selected solvents.

Abbreviation

Structural Group

Boc

tertiary Butyloxycarbonyl

Fmoc

9-Fluorenylmethyloxycarbonyl

Ph

Phenyl

Solvents and Reagents

AcOH (HOAC)

Acetic acid

Ac

2

O

Acetic acid anhydride

BuLi (nBuLi)

n-Butyllithium

Ca

2

CO

3

Cesium carbonate

CDI

N,N′-Carbonyldiimidazole

CF

3

SO

2

H

Trifluoromethanesulfonic acid

DBU

1,8-Diazabicyclo [5.4.0] undec-7-ene

DCM

Dichloromethane

DCC

N,N′-Dicyclohexylcarbodiimide

DCU

N,N′-Dicyclohexylurea

DIC

N,N′-Diisopropylcarbodiimide

DIEA (iPr

2

NEt)

N,N-Diisopropylethylamine

DMA

N,N-Dimethylacetamide

DMAP

4-Dimethylaminopyridine

DMF

N,N-Dimethylformamide

DTT

Dithiothreitol

EDC (EDAC)

N-Ethyl-N′-Dimethylamino

propylcarbodiimide

EtOAc

Ethyl acetate

Et

2

O

Diethyl ether

EtOH

Ethanol

HCl

Hydrochloric acid

HF

Hydrofluoric acid

HOBT

1-Hydroxybenzotriazole

iBuOCOCl

Isobutyl chloroformate

iPrOH

iso-Propanol

(iPrO)

3

B

Triisopropyl borate

KOtBu

Potassium tert butoxide

KOAc

Potassium acetate

K

2

CO

3

Potassium carbonate

MCPBA

Meta chloroperbenzoic acid

MeCN

Acetonitrile

MeI

Iodomethane

MeOH

Methanol

MgSO

4

Magnesium sulfate

NaAl(OtBu)

3

H

Sodium tri tert

butoxyaluminum hydride

NaBH

4

Sodium borohydride

NaCNBH

3

Sodium cyanoborohydride

NaIO

4

Sodium metaperiodate

NaI

Sodium iodide

NaOEt

Sodium ethoxide

NaOH

Sodium hydroxide

Na

2

CO

3

Sodium carbonate

NH

2

NH

2

(N

2

R

4

)

Hydrazine

NH

2

OH

Hydroxylamine

NMP

N-Methylpyrrolidone

PhN (SO

2

CF

3

)

2

N-Phenyltrifluoromethane

sulfonamide

P(Ph)

3

I

2

Diiodotriphenylphosphorane

(Ph

3

P)

4

Pd

Tetrakis (tripheny1phosphine)-

Palladium (O)

TEA (Et

3

N)

Triethylamine

TFA

Trifluoroacetic acid

THF

Tetrahydrofuran

TMEDA

N,N,N′,N′Tetramethylethylene

diamine

TMG

N,N,N′N′-Tetramethylguanidine

Analytical Method

HPLC

High performance liquid

chromatography

IR

Infrared spectroscopy

MS(CI)

Mass spectroscopy with

chemical ionization

NMR

Nuclear magnetic resonance

spectroscopy

TLC

Thin layer chromatography

GC

Gas chromatography

The first aspect of the instant invention is a compound of Formula I,

 P—L—Q  I

wherein

P is a polymer of low chemical reactivity including insoluble polymers such as, for example, poly(styrene-divinylbenzene), methacrylic acid/dimethylacrylamide copolymer, poly(styrene-divinylbenzene/poly(ethyleneglycol) copolymer (also known as TentaGel® hydroxy resin) and soluble polymers such as, for example, polystyrene or poly(ethyleneglycol), and the like;

Q is one or more quenching reagents which contain at least one functional group, or an acid or base addition salts thereof, that is capable of selective covalent reaction with unwanted byproducts, or excess reagents such as, for example, primary amine, secondary amine, tertiary amine, isocyanate, isothiocyanate, carboxylic acid, acid chloride, ketone, aldehyde, cyclic imide, cyclic anhydride, hydroxyl, diol, aminoalcohol, thiol, dithiol, aminothiol, thioether, thiourea, chlorosilane, diene, dienophile, dipole, dipolarophile, enolate, enol ether, alkylsulfonate, alkyl halide, aryl halide, arylsulfonate, arylboronic acid, hydrazine, semicarbazide, acyl hydrazide, hydroxylamine, guanidine, and the like; and

L is linker that joins P and Q such as, for example, CH

2

—CH

2

, CH═CH, CH—N, CH

2

—N, CH—O, CH

2

—O, CH—S, CH

2

—S, C(═O)N, NC(═O), NC(═O)N, N(C═O)O, OC(═O)N, combinations thereof, and the like. L is chosen so as to be chemically robust to conditions of rapid purification. In other words, it is necessary that the linker functionality is not cleavable during the course of reaction with excess reagents and unwanted byproducts and subsequent removal.

Generic descriptions of preferred polymer-supported quenching reagents are shown in Schemes 1-18. The most preferred reagents and are listed in Table 2.

The second aspect of the present invention is a method for the preparation of novel polymer-supported quenching reagents from known polymers. Polymer-supported quenching reagents are made in one to four synthetic steps from readily available starting materials, such as for example, insoluble polymers and soluble polymers or derivatives thereof which contain convenient linker functionality, and one or more polyfunctional quenching reagents which bear a compatible connecting functionality and one or more functionalities used in the quenching process.

Preferred polymeric starting materials are insoluble resins with less than five percent crosslinking such as, for example, polystyrene resin (also known as poly(styrene-divinylbenzene)), Merrifield resin (also known as chloromethyl-poly(styrene-divinylbenzene)), benzylalcohol resin (also known as hydroxymethyl resin), poly(styrene-divinylbenzene)/poly(ethyleneglycol) grafted copolymer (also known as TentaGel® hydroxy resin or TG hydroxy resin), benzylamine resin (also known as aminomethyl-poly(styrene-divinylbenzene)), benzhydrylamine resin (also known as BHA resin), 4-methylbenzhydrylamine resin (also known as MBHA resin), TentaGel® amino resin (also known as TG amino resin), aldehyde resin (also known as formyl-poly(styrene-divinyl-benzene), acetyl-poly(styrene-divinylbenzene), benzoyl-poly(styrene-divinylbenzene), carboxy-poly(styrene-divinylbenzene) (also known as carboxylic acid resin), benzylthiol resin (also known as thiomethyl-poly(styrene-divinylbenzene), TentaGel® thiol resin (also known as TG thiol resin), bromo-poly(styrene-divinylbenzene) (also known as brominated polystyrene resin), and the like. The preferred polymeric starting materials are well-known to those skilled in the art of solid-phase peptide synthesis or to those skilled in the art of solid-phase organic synthesis. They are commercially available or are known in the scientific literature.

Contrary to polymer-supported synthesis, where one usually limits the substrate loading to less than or equal to 1 mmol substrate/gram polymer, it is desirable that polymer-supported quenching reagents have a high loading of reactive groups which perform the quench. Preferred polymer-supported quenching reagents have greater than or equal to 1 mmol reactive group per gram of polymer. Most preferred quenching reagents have greater than 2 mmol reactive group per gram of polymer. It is still possible to use polymer-supported quenching reagents with less than 1 mmol reactive group per gram of polymer provided that larger quantities of the quenching polymer are used. In this regard, many solid-phase synthesis polymers which are well known to those skilled in the art of solid-phase peptide chemistry or in the art of solid-phase organic synthesis are viable polymer-supported quenching reagents, including but not limited to, Merrifield resin, benzylamine resin, benzhydrylamine resin, 4-methylbenzhydrylamine resin, benzylalcohol resin, Wang resin, aldehyde resin, TentaGel® hydroxy, amino and thiol resins, benzylthiol resin, polymer diazomethylene, poly(ethyleneglycol), and the like.

Preferred solvents used in the chemical transformations of preferred starting polymers which lead to novel polymer-supported quenching reagents include, for example, DMF, DMA, NMP, DCM, dioxane, THF, benzene, and the like. After each chemical transformation, the polymer is washed with successive cycles of solvents which may include but are not limited to DCM, chloroform, DMF, DMA, dioxane, diethyl ether, THF, benzene, toluene, hexanes, cyclohexane, methanol, ethanol, isopropanol, ethylacetate, water, triethylamine, N-methylmorpholine, acetic acid, trifluoroacetic acid, combinations thereof, and the like.

Preferred methods which afford preferred polymer-supported quenching reagents are described in Schemes 1-18. In general, there are two synthetic strategies by which the preferred high loading of quenching functionality on polymeric supports is achieved. In the first strategy, a polymer with existing functionality of greater than 1 mmol per gram of polymer is chemically modified to give a novel polymer-supported quenching reagent which has greater than 1 mmol of quenching functionality per gram of polymer. In the second strategy, polyfunctional or dendritic molecules bearing connecting functional groups and two or more quenching functional groups are attached to polymers with less than 2 mmol of attachment sites per gram of polymer. In this manner, the number of quenching sites is amplified compared to the number of attachment sites. Specific methods which afford selected examples of most preferred polymer-supported quenching reagents are illustrated in Examples 1-18.

The following legend applies to structures in Schemes 1-18, Equations 1.0-5.0, Table 2, and the Examples.

Legend

{circle around (PS)}

=

insoluble, polystyrene-divinylbenzene

{circle around (TG)}

=

insoluble, TentaGel ®

{circle around (P)}

=

any soluble or insoluble polymer

R

=

H or CH

3

R

1

=

H, Ph, or 4-MePh

R

2

=

Me, Et, iPr, tBu, Ph

R

3

=

any secondary amine, especially cyclic

aliphatic amines

R

4

=

any primary or secondary amine

R

5

=

Me, CF

3

, C

2

F

5

, Ph, 4-MePh, 4-NO

2

Ph, 4-BrPh,

4-ClPh, 4-FPh, 4-CF

3

Ph

R

6

=

CH

2

Ph, Me, Et, nPr, nBu, CH

2

CH═CH

2

(L)

=

linker

X

=

O or S

Y

=

Cl, imidazol-1-yl, 1,2,3-triazol-1-yl or

2-pyridyloxy

n

=

2 to 8

m

=

3 to 9

p

=

0 to 10

(EWG)

=

electron withdrawing group such as NO

2

,

CO

2

Me, CN, CF

3

, etc.

M

+

=

Li

+

, Na

+

, K

+

, MgBr

+

, Cs

+

The third aspect of the present invention is the use of polymer-supported quenching reagents, including novel polymer-supported quenching reagents of the present invention and known solid-phase synthesis polymers, for the rapid purification of crude product mixtures of organic reactions. Of particular importance is the use of polymer-supported quench purification as an enabling technology for the preparation of libraries of organic molecules with potential biological activity. Polymer-supported quench has utility in reducing purification time associated with automated parallel organic synthesis, manual combinatorial synthesis and automated combinatorial synthesis. Specific types of chemical transformations that benefit from a polymer-supported quench purification procedure include, but are not limited to, O- and N-acylation, O- and N-sulfonylation, O- and N-phosponylation, O- and N-phoshorylation, C-, O-, N- and S-alkylation, condensation reactions, coupling reactions, cyclization reactions involving two or more components, and the like. The scope of applications of polymer-supported quench is exemplified in Items I-IX below. Representative illustrations of specific cases wherein rapid purification of crude reaction mixtures is achieved with most preferred polymer-supported quenching reagents are described in Examples 19-29. Utility of the polymer-supported quenching reagents and methods described herein is not limited to the reactions described in these examples. On the contrary, the polymer-supported quenching reagents and methods described herein are broadly useful in these and many other organic reactions.

I. Direct Quench (Equations 1.0, 1.1, and 1.2)

Reactant A combines with reactant B to form AB. In order to drive the reaction to completion, B is used in excess (Equation 1.0). The excess reactant is quenched by adding a polymer-supported quenching reagent with A-like properties. Once the excess B is attached to the polymer, it is easily and quickly removed by a simple filtration in those cases where an insoluble polymer is used. In those cases where a soluble polymer is employed, the reaction mixture is first diluted with a solvent that precipitates the polymeric reagent, but not the desired product, and then the precipitated polymer is removed by filtration. The solution fraction contains AB which is enhanced in purity relative to the crude product.

Using this method, the chemist has a choice of whether to use A or B in excess and subsequently to quench with a polymer-supported quenching reagent with B-like or A-like properties, respectively. Additionally, the chemist may choose to add both A-like and B-like polymer-supported quenching reagents to ensure that all starting materials have been removed from the desired product in the event that the reaction did not go to completion, despite using an excess of one starting material.

Alternatively, a reaction between equimolar quantities of A and B may yield a major desired product, AB, and a minor undesired product, AB′ (Equation 1.1). AB′ may be removed with a polymer-supported quenching reagent that selectively reacts with this undesired product.

One may run analogous combinatorial reactions wherein a diversity of reactants A

1−X

are reacted with excess of a diversity of reactants B

1−Y

to form all of the possible AB combinations (Equation 1.2). The combinatorial product mixture is separated from the remaining B

1−Y

using a single polymer-supported quenching reagent with A-like properties as in the one product case above.

II. Derivative Quench (Equations 2.0 and 2.1)

C reacts with D to form CD (Equation 2.0). In order to drive the reaction to completion, D is used in excess. The excess reagent is derivatized by adding an excess of a third reactant, E. DE and excess E, are quenched by adding a larger excess of a polymer-supported quenching reagent which reacts with both DE and E. The polymeric fraction is then removed by filtration. The solution fraction contains CD which is enhanced in purity relative to the crude product.

This process may be likewise applied in cases where one of the reactants decomposes in a competing side reaction to give a byproduct (Equation 2.1). Thus when C reacts with excess D to form CD and the byproduct X

D

, the desired product is purified by adding a polymer-supported quenching reagent that selectively derivatives X

D

and removing the polymeric fraction by filtration.

Derivative quench by a polymer-supported quenching reagent may be similarly applied in a combinatorial synthesis mode.

III. Use of Polymer-Supported Quenching Reagents in Conjunction with Polymer-Supported Reactants (Equation 3.0)

A reaction which employs two soluble reactants F and G and one polymer-supported reactant, J, is run in such a fashion that G and polymer-supported-J are used in excess. The desired product, FG, is rapidly purified by adding a larger excess of a polymer-supported quenching reagent with F-like properties which consumes the remaining G. Filtration to remove the polymer-supported reactant before adding the polymer-supported quenching reagent is not necessary when insoluble polymers are used but may be required when soluble polymers are employed if a chemical incompatibility exists between the reactant and quench reagent. Filtration of the polymeric fraction gives a solution of FG which is enhanced in purity relative to the crude product.

The use of polymer-supported quenching reagents in conjunction with polymer-supported reactants may be similarly applied in a combinatorial synthesis mode.

IV. Mixed Polymer-Supported Quench (Equation 4.0)

A reaction which employs multiple reactants (K, L, M, etc.) is run in such a fashion that one of the reactants is limiting. The desired product is rapidly purified from unconsumed reagents by adding polymer-supported quenching reagents; one for each excess reactant. Insoluble polymer-supported quenching reagents may be added sequentially or concurrently. Soluble polymer-supported quenching reagents must be added and removed sequentially unless they are chemically compatible. For this reason, insoluble polymer-supported quenching reagents are preferred for combined use.

Insoluble polymer-supported quenching reagents may also be combined with insoluble ion-exchange resins, chelating resins, silica gel, reversed-phase adsorbents, alumina, activated charcoal, and the like which make noncovalent interactions with impurities as desired in order to increase the efficiency of the purification step. Upon filtration, a purified solution of N is isolated.

Such use of a mixture of solid quenching reagents is equally effective in a combinatorial synthesis mode.

V. Combined Polymer-Supported Reactant and Quench Reagent (Equation 5.0)

A polymer-supported quenching reagent may perform a dual role in purifying the product of one reaction and causing a subsequent synthetic transformation as a polymer-supported reagent. Thus A reacts with excess B to form C. Polymer-supported-D quenches the excess B and also converts product C to product E. This dual role is equally applicable in a combinatorial synthesis mode.

VI. Multistep Syntheses With Polymer-Supported Quench Purifications

Using methodologies described in Equations 1-5 above and variations thereof, individual synthetic transformations may be sequentially combined to give linear or convergent, multistep syntheses. Similar reactions may be run individually in parallel arrays, manually or with the aid of a liquid handling robot, to give single products or alternatively, they may be run in a combinatorial mode to give product mixtures. Polymer-supported quench purification may be applied at each intermediate step or at the conclusion of two or more synthetic steps as is appropriate. An individual who is skilled in the art of organic synthesis will be able to determine whether it is most expedient to purify at each step or to combine polymer-supported quench reagents for the removal of accumulated byproducts and excess reagents from two or more steps in one purification step.

VII. Polymer-Supported Quench Via Columns

As an alternative to adding the polymer-supported quenching reagent(s) to the reaction mixture, insoluble quenching reagent(s) may be packed into solid-phase extraction columns such as, for example, glass or inert plastic chromatography columns, and the like known to those skilled in the art or attached to the interior surface of a capillary column. The crude reaction mixture is eluted through the column. The column volume, the elution rate, and the number of passes through the column are optimized so that a solution of purified product(s) elutes from the column.

VIII. Polymer-Supported Quenching Filters

As an alternative to adding the polymer-supported quenching reagent(s) to the reaction mixture, insoluble quenching reagent(s) may be prepared in the form of porous filter discs or porous membranes. The reaction mixture is allowed to pass through the polymer-supported quenching filter at a rate that results in complete removal of impurities. A single filter may be used or several filters may be combined in series. The crude reaction mixture may be recycled through the filter as necessary to complete the removal of impurities.

IX. Polymer-Supported Quench in a Diversomer® Apparatus

Rapid purification by polymer-supported quench may be carried out using a Diversomer® apparatus as described in U.S. Pat. No. 5,324,483 (which is hereby incorporated by reference) provided that insoluble polymers are employed. The polymer-supported quench reagent is loaded into the pins which are assembled into the pin holder. Reactions are run in individual vials. When the reactions are complete as judged by GC, TLC or HPLC the pins are lowered into the reaction solution and clamped into place. Shaking or other agitation is applied until all excess reagents are consumed. The pins are raised slightly, rinsed into their respective vials and removed. The vials then contain purified product solutions which can be concentrated and/or divided for subsequent transformations.

The polymer-supported quench reagents and rapid purification methods of the instant invention have, for example, the following advantages over existing methods for automated organic synthesis and combinatorial chemistry:

1. A single polymer-supported quench reagent can remove many different types of reactants and byproducts hence customized reagent development time is minimized and quench reagents may be produced in bulk at decreased cost.

2. No resin attachment site needed in target molecule.

3. Solution phase synthesis results in minimal synthetic development time since more solution phase reactions are known than solid phase reactions.

4. One can choose the limiting reagent in any particular reaction based on the value of the reagent and/or nature of the reaction.

5. Convergent syntheses are possible.

6. Solutions of synthetic intermediates are easily divided into aliquots for automated parallel and combinatorial syntheses by liquid handling robots.

7. The use of resin swelling solvents is not required.

8. Reaction progress and product may be analyzed by traditional chromatographic and spectrographic methods.

9. Lack of resin cleavage reaction avoids resin-derived impurities in final product.

10. Greater product amounts may be synthesized in a given reactor volume as compared to polymer-supported synthesis.

11. A smaller excess of reagent can be used to drive reactions to completion compared to the excess required by solid-supported synthesis.

12. Reactive, volatile, toxic wastes are neutralized to nonhazardous solids by the resin and thereby waste disposal is facilitated.

TABLE 2

Purification Using Polymer-Supported

Quenching Reagents

Quenching Reagent

Removes

Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, Alkyl Halides, Alkylsulfonates, Meerwein Reagent, Epoxides, Enones, &agr;, &bgr;-unsaturated Esters, Pseudothioureas, Aldehydes, Ketones, and the like

Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, Alkyl Halides, Alkylsulfonates, Meerwein Reagent, Epoxides, Enones, &agr;, &bgr;-Unsaturated Esters, Pseudothioureas, Aldehydes, Ketones, and the like

1° and 2° Amines, Alcohols, Carboxylic Acids, Guanidines, Amidines, Hydrazines, Acid Hydrazides, Hydroxylamines, Alkoxyamines, Thiols, and the like

Alkyl Halides, Alkylsulfonates, Diazoalkanes, &agr;-Haloketones, Silyl Chlorides, Silyl Triflates, and the like

Boronic Acids, Alkyl Halides, Alkylsulfonates, Diazoalkanes, &agr;-Haloketones, Meerwein Reagent, Silyl Chlorides, Silyl Triflates, Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, and the like

Alkyl Halides, Alkylsulfonates, Meerwein Reagent, &agr;-Haloketones, Silyl Chlorides, Silyl Triflates, Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, and the like

Alcohols, Carboxylic Acids, Thiols, Silanols, Phenols, Carbanions, 1° and 2° Amines, and the like

Alcohols, Carboxylic Acids, Thiols, Silanols, Phenols, Carbanions, 1° and 2° Amines, and the like

Alkyl Halides, Alkylsulfonates, &agr;-Haloketones, Meerwein Reagent, Silyl Chlorides, Silyl Triflates, Epoxides, Oxidants, Thiols, Dissulfides, and the like

Oxidants and the like

Aryl Iodides, Aryl Bromides, Aryl Triflates, Vinyl Iodides, Vinyl Bromides, Vinyl Triflates, and the like

Alkyl Halides, Alkylsulfonates, &agr;-Haloketones, Meerwein Reagent, and the like

Aldehydes, Ketones, Imines, Alkyl Halides, Alkylsulfonates, Isocyanates, Isothiocyanates, Chloroformates, Phosgene, Thiophosgene, and the like

Dienes, Dipoles, Sulfides, 1° and 2° Amines, and the like

Dienophiles, Dipolarophiles, Cl

2

, Br

2

, I

2

, Oxidants, and the like

Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, Alkyl Halides, Alkylsulfonates, Meerwein Reagent, Epoxides, Enones, &agr;, &bgr;-Unsaturated Esters, &agr;-Diketones, &bgr;-Diketones, &bgr;-Keto Esters, and the like

Aldehydes, Ketones, Enones, &agr;, &bgr;-Unsaturated Esters, &agr;-Diketones, &bgr;-Diketones, &bgr;-Keto Esters, Acid Chlorides, Acid Anhydrides, Activated Esters, Imidazolides, Isocyanates, Isothiocyanates, Sulfonyl Chlorides, Phosphonyl Chlorides, Phosphoryl Chlorides, Alkyl Halides, Alkylsulfonates, Meerwein Reagent, Epoxides, and the like

Carbanions, primary amines, Hydroxylamine, Alkoxyamines, Hydrazines, Glycols, 1,3-Diols, 1,2-Dithiols, 1,3-Dithiols, 1,2-Aminoalcohols, 1,3-Aminoalcohols, 1,2-Aminothiols, 1,3-Aminothiols, Hydride Reducing Agents, and the like

34A

Carbanions, primary amines, Hydroxylamine,

Alkoxyamines, Hydrazines, Glycols, 1,3-Diols,

1,2-Dithiols, 1,3-Dithiols, 1,2-Aminoalcohols,

1,3-Aminoalcohols, 1,2-Aminothiols,

1,3-Aminothiols, Hydride Reducing Agents, and the

like

Carbanions, Hydroxides, Alkoxides, 1° and 2° Amines, Hydride Reducing Agents, and the like Alkyl Halides, Alkylsulfonates, &agr;-Haloketones, Meerwein Reagent, Silyl Chlorides, Silyl Triflates, Epoxides, Oxidants, Thiols, Dissulfides, Ketones, Aldehydes, and the like

Halogens, Carbocations, Electrophilic reagents, and the like

&bgr;-diketones, &bgr;-ketoesters, &bgr;-ketoamides, Vinylogous esters, Vinylogous amides, &agr;-ketoesters, &agr;-ketoamides, &agr;-diketones, &agr;-haloketones