# Patent

## Title
Syntheses of quinazolinones

## Abstract

The present invention is directed to methods for the preparation of enantiomerically pure quinazolinones, intermediates in such methods, and compositions comprising such quinazolinones.

## Background
CROSS-REFERENCE TO RELATED APPLICATONS
This application claims the benefit of co-pending provisional U.S. Applications Ser. No. 60/357,244, filed Feb. 15, 2002 and Ser. No. 60/380,746, filed May 14, 2002, each incorporated herein by reference.


FIELD OF THE INVENTION
This invention relates to the synthesis of certain quinazolinone derivatives that are inhibitors of the mitotic kinesin KSP and are useful in the treatment of cellular proliferative diseases, for example cancer, hyperplasias, restenosis, cardiac hypertrophy, immune disorders and inflammation.
BACKGROUND OF THE INVENTION
Interest in the medicinal chemistry of quinazoline derivatives was stimulated in the early 1950's with the elucidation of the structure of a quinazoline alkaloid, 3-[β-keto-gamma-(3-hydroxy-2-piperidyl)-propyl]-4-quinazolone, from an Asian plant known for its antimalarial properties. In a quest to find additional antimalarial agents, various substituted quinazolines have been synthesized. Of particular import was the synthesis of the derivative 2-methyl-3-o-tolyl-4-(3H)-quinazolinone. This compound, though ineffective against protozoa was found to be a potent hypnotic and is known by the name methaqualone.
The pharmacologic activity of quinazolinones and related compounds has been more thoroughly investigated since the introduction of methaqualone. Quinazolinones and derivatives thereof are now known to have a wide variety of biological properties including hypnotic, sedative, analgesic, anticonvulsant, antitussive and anti-inflammatory activities.
Quinazolinone derivatives for which specific biological uses have been described include 2-(substituted phenyl)-4-oxo-quinazolines with bronchodilator activity (U.S. Pat. No. 5,147,875). U.S. Pat. Nos. 3,723,432, 3,740,442, and 3,925,548 describe a class of 1-substituted-4-aryl-2(1H)-quinazolinone derivatives useful as anti-inflammatory agents. European patent publication EP 0 056 637 B1 describes a class of 4(3H)-quinazolinone derivatives for the treatment of hypertension. European patent publication EP 0 884 319 A1 describes pharmaceutical compositions of quinazolin-4-one derivatives used to treat neurodegenerative, psychotropic, and drug and alcohol induced central and peripheral nervous system disorders.
Quinazolinones are among a growing number of therapeutic agents used to treat cell proliferative disorders, including cancer. For example, PCT WO 96/06616 describes a pharmaceutical composition containing a quinazolinone derivative to inhibit vascular smooth muscle cell proliferation. PCT WO 96/19224 uses this same quinazolinone derivative to inhibit mesengial cell proliferation. U.S. Pat. Nos. 4,981,856, 5,081,124 and 5,280,027 describe the use of quinazolinone derivatives to inhibit thymidylate synthase, the enzyme that catalyzes the methylation of deoxyuridine monophosphate to produce thymidine monophosphate, which is required for DNA synthesis. U.S. Pat. Nos. 5,747,498 and 5,773,476 describe quinazolinone derivatives used to treat cancers characterized by over-activity or inappropriate activity of tyrosine receptor kinases. U.S. Pat. No. 5,037,829 describes (1H-azol-1-ylmethyl) substituted quinazoline compositions to treat carcinomas that occur in epithelial cells. PCT WO 98/34613 describes a composition containing a quinazolinone derivative useful for attenuating neovascularization and for treating malignancies. U.S. Pat. No. 5,187,167 describes pharmaceutical compositions comprising quinazolin-4-one derivatives, which possess anti-tumor activity.
The synthesis of quinazolinones has been described, for example, by Ager et al., J. Med. Chem., 20:379–386 (1977). Quinazolinones have been obtained by acid-catalyzed condensation of N-acylanthranilic acids with aromatic primary amines. Other processes for preparing quinazolinones are described in U.S. Pat. Nos. 5,783,577, 5,922,866 and 5,187,167.
Syntheses of the class of quinazolinones presently of interest have been reported in WO 01/30768 (incorporated herein by reference) and are shown in Reaction Schemes A and B (below). 



It has become particularly desirable to produce increased quantities of certain enantiomerically pure quinazolinones. It had previously been taught that such optically active (R)- and (S)-isomers can be prepared using chiral synthons or chiral reagents, or resolved using conventional techniques, for example: via formation of diastereoisomeric salts or complexes which can be separated, e.g., by crystallisation; via formation of diastereoisomeric derivatives which can be separated, e.g., by crystallisation, gas-liquid or liquid chromatography; via selective reaction of one enantiomer with an enantiomer-specific reagent, e.g., enzymatic oxidation or reduction, followed by separation of the modified and unmodified enantiomers; or via gas-liquid or liquid chromatography in a chiral environment, e.g., on a chiral support, such as silica with a bound chiral ligand or in the presence of a chiral solvent. Where the desired enantiomer is converted into another chemical entity by one of the separation procedures described above, a further step is described as potentially required to liberate the desired enantiomeric form. Alternatively, the asymmetric synthesis of specific enantiomers has been described using optically active reagents, substrates, catalysts or solvents, or by converting one enantiomer to the other by asymmetric transformation. An example of a prior synthesis from optically active starting materials is shown in Reaction Scheme B. 



Notwithstanding such existing synthetic approaches, development of quinazolinones for new therapeutic indications has increased the need for producing these enantiomerically pure active agents. While effective for producing research quantities, the prior synthetic approaches are in many aspects too lengthy and uneconomical for production of larger scale batches of compound. Intermediate chemical resolutions require considerable time and result in relatively low yields. Moreover, certain reagents that are acceptable in small-scale syntheses (e.g., the use of bromine, sodium azide and triphenyl phosphine) are generally undesirable for large-scale production. Thus, there remains a need for improved quinzolinone syntheses, particularly for the larger scale production of enantiomerically pure quinazolinones
SUMMARY OF THE INVENTION
In accordance with the objects outlined above, the present invention provides intermediates, synthetic methods and novel quinazolinone compositions of matter, which can be used to treat diseases of proliferating cells.
In one aspect, the invention provides methods for the synthesis of enantiomerically pure quinazolinones employing the corresponding enantiomer of a naturally occurring or substituted, optionally N-protected amino acid as the starting material, especially a D-amino acid or N-protected-D-amino acid. In a preferred aspect, the amino acid is selected from: alanine, valine, leucine, isoleucine, phenylalanine, serine, threonine, cysteine, methionine, tryptophan, tyrosine, asparagine, glutamine, asparaginate, glutamate, lysine, arginine, histidine, phenylglycine and 2-aminobutyric acid, especially the D-forms, and can be substituted and/or N-protected. Particularly preferred are alanine, valine, leucine, isoleucine and 2-aminobutyric acid. More particularly preferred are D-alanine, D-valine, D-leucine, D-isoleucine, and D-2-aminobutyric acid and with these amino acids having an amine protecting group being even more preferred. Most preferred is N-Boc-D-valine or N-CBZ-D-valine.
In a related aspect, the invention provides a method for the synthesis of an enantiomerically pure quinazolinone via the use, as a starting material, of an enantiomerically pure compound of Formula 101: 



where:

    
    
        R2 is selected from: alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, and substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl; and
        X is hydrogen or a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc).

In a further related aspect, the method includes the steps of:

    
    
    A) contacting a compound of Formula 101 with isobutyl chloroformate, and
    B) contacting the product of step A with a compound of Formula 103: 


    
        where R5, R6, R7 and R8 are independently chosen from hydrogen, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl.
    
    


Still another aspect of the invention provides a method for the synthesis, from the corresponding enantiomer of a naturally occurring or substituted, optionally N-protected amino acid (especially valine) as the starting material, of a compound represented by Formula I: 



where:

    
    
        R1 is chosen from hydrogen, alkyl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R2 is chosen from alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R3 is chosen from hydrogen, alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, substituted alkylheteroaryl, oxaalkyl, oxaalkylaryl, substituted oxaalkylaryl, R9O— and R9—NH—;
        R4 is chosen from hydrogen, alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R5, R6, R7 and R8 are independently chosen from hydrogen, hydroxy, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, amino, alkylamino, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl; and
        R9 is chosen from alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl.
    
    


In one of its preferred aspects, the methods, compositions and formulations of the present invention pertain to the (R)-enantiomer of a compound represented by Formula I where:

    
    
        R1 is alkylaryl or substituted alkylaryl (preferably benzyl or substituted benzyl; most preferably benzyl);
        R2 is lower alkyl (preferably ethyl, i-propyl, c-propyl, t-butyl or c-pentyl) or substituted lower alkyl (such as methylthiomethyl);
        R3 is alkyl (preferably, methyl), substituted alkyl (preferably alkoxyalkyl such as methoxymethyl, or heterocycloalkyl such as N-morpholinomethyl), aryl (preferably phenyl), substituted aryl (preferably lower alkyl-, lower alkoxy-, and/or halo-substituted phenyl), alkylaryl (preferably benzyl and phenylvinyl), alkylheteroaryl, oxaalkylaryl (preferably phenoxy lower alkyl), oxaalkylheteroaryl, substituted alkylaryl (preferably substituted benzyl and substituted phenylvinyl), substituted alkylheteroaryl, substituted oxaalkylaryl (preferably substituted phenoxy lower alkyl), or substituted oxaalkylheteroaryl;
        R4 is substituted alkyl (preferably a primary-, secondary- or tertiary-amino-substituted lower alkyl); and
        R5, R6, R7 and R8 are chosen from hydrogen, halo (preferably chloro and fluoro), lower alkyl (preferably methyl), substituted lower alkyl, lower alkoxy (preferably methoxy), alkylthio (preferably methylthio) and cyano.
    
    


In yet another of its aspects, the present invention provides a method for the synthesis of an enantiomerically pure compound of Formula 107/203: 



where:

    
    
        R1 is chosen from hydrogen, alkyl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R2 is chosen from alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, and substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R5, R6, R7 and R8 are independently chosen from hydrogen, hydroxy, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, amino, alkylamino, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl; and
        X is hydrogen or a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc),

including the steps:

    
    
    A) contacting isobutyl chioroformate with a compound of Formula 101: 



    B) contacting the product of step A with a compound of Formula 103: 



and

    C) converting the product of step B to the compound of Formula 107/203.

In a preferred embodiment of this aspect of the invention R2 is selected from ethyl, i-propyl, c-propyl, t-butyl or c-pentyl.



In another of its aspects, the present invention pertains to a composition of matter or pharmaceutical formulation including compound or pharmaceutically acceptable salt of Formula I and a detectable amount of one or more of the following:

    A) a compound of Formula 101: 


    
        where X is hydrogen or a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc);
    
    
    B) a compound of Formula 103: 



and/or

    C) a cyclo-dehydration reagent employed in the synthesis thereof.

In a preferred embodiment of this aspect, the novel quinazolinone composition or pharmaceutical formulation contains a detectable quantity of naturally occurring or substituted, optionally N-protected amino acid, preferably a chiral amino acid (especially valine, preferably D-valine or an N-protected D-valine) and/or a detectable quantity of HMDS, lithium (or a lithium reagent) employed in synthesis of the quinazolinone.



DETAILED DESCRIPTION OF THE INVENTION
Definitions
As used in the present specification, the following words and phrases are generally intended to have the meanings as set forth below, except to the extent that the context in which they are used indicates otherwise.
The term “optional” or “optionally” means that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances in which it does not. For example, “optionally substituted alkyl” means either “alkyl” or “substituted alkyl,” as defined below. It will be understood by those skilled in the art with respect to any group containing one or more substituents that such groups are not intended to introduce any substitution or substitution patterns that are sterically impractical and/or synthetically non-feasible.
Certain compound, reactant, or reaction parameter abbreviations are defined as follows:

    Ac=acetyl
    alloc=allyloxycarbonyl
    Boc=t-butyloxy carbonyl
    Bu=butyl
    c-=cyclo
    CBZ=carbobenzoxy=benzyloxycarbonyl
    DCM=dichloromethane=methylene chloride=CH2Cl2 
    DMF=N,N-dimethylformamide
    Et=ethyl
    HMDS=hexamethyldisilazine
    HOAc=acetic acid
    IPA=isopropyl alcohol
    Me=methyl
    mesyl=methanesulfonyl
    MTBE=methyl t-butyl ether
    OAc=acetate
    Ph=phenyl
    PhOH=phenol
    PTSA=para-toluenesulfonic acid
    PyBroP=bromo-tris-pyrrolidino-phosphonium hexafluorophosphate
    rt=room temperature
    s-=secondary
    t-=tertiary
    teoc=2,2,2-trichloroethoxycarbonyl
    TFA=trifluoroacetic acid
    THF=tetrahydrofuran.


Alkyl is intended to include linear, branched, or cyclic hydrocarbon structures and combinations thereof. Lower alkyl refers to alkyl groups of from 1 to 5 carbon atoms. Examples of lower alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, s-and t-butyl and the like. Preferred alkyl groups are those of C20 or below. More preferred alkyl groups are those of C13 or below. Cycloalkyl is a subset of alkyl and includes cyclic hydrocarbon groups of from 3 to 13 carbon atoms. Examples of cycloalkyl groups include c-propyl, c-butyl, c-pentyl, norbornyl, adamantyl and the like. In this application, alkyl refers to alkanyl, alkenyl and alkynyl residues; it is intended to include cyclohexylmethyl, vinyl, allyl, isoprenyl and the like. Alkylene refers to the same residues as alkyl, but having two points of attachment. Examples of alkylene include ethylene (—CH2CH2—), propylene (—CH2CH2CH2—), dimethylpropylene (—CH2C(CH3)2CH2—) and cyclohexylpropylene (—CH2CH2CH(C6H13)—). When an alkyl residue having a specific number of carbons is named, all geometric isomers having that number of carbons are intended to be encompassed; thus, for example, “butyl” is meant to include n-butyl, sec-butyl, isobutyl and t-butyl; “propyl” includes n-propyl and isopropyl.
Alkoxy or alkoxyl refers to groups of from 1 to 8 carbon atoms of a straight, branched, cyclic configuration and combinations thereof attached to the parent structure through an oxygen. Examples include methoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, cyclohexyloxy and the like. Lower-alkoxy refers to groups containing one to four carbons.
Acyl refers to groups of from 1 to 8 carbon atoms of a straight, branched or cyclic configuration, or a combination of any such configurations, attached to the parent structure through a carbonyl functionality. Such acyl groups can be saturated or unsaturated, and aromatic or non-aromatic. One or more carbons in the acyl residue can be replaced by nitrogen, oxygen or sulfur as long as the point of attachment to the parent remains at the carbonyl. Examples include acetyl, benzoyl, propionyl, isobutyryl, t-butoxycarbonyl, benzyloxycarbonyl and the like. Lower-acyl refers to groups containing one to four carbons.
Aryl and heteroaryl mean a 5- or 6-membered aromatic or heteroaromatic ring containing 0–3 heteroatoms selected from O, N, or S; a bicyclic 9- or 10-membered aromatic or heteroaromatic ring system containing 0–3 heteroatoms selected from O, N, or S; or a tricyclic 13- or 14-membered aromatic or heteroaromatic ring system containing 0–3 heteroatoms selected from O, N, or S. The aromatic 6- to 14-membered carbocyclic rings include, e.g., benzene, naphthalene, indane, tetralin, and fluorene and the 5- to 10-membered aromatic heterocyclic rings include, e.g., imidazole, pyridine, indole, thiophene, benzopyranone, thiazole, furan, benzimidazole, quinoline, isoquinoline, quinoxaline, pyrimidine, pyrazine, tetrazole and pyrazole.
Alkylaryl refers to a residue in which an aryl moiety is attached to the parent structure via an alkyl residue. Examples are benzyl, phenethyl, phenylvinyl, phenylallyl and the like. Oxaalkyl and oxaalkylaryl refer to alkyl and alkylaryl residues in which one or more methylenes have been replaced by oxygen. Examples of oxaalkyl and oxaalkylaryl residues are ethoxyethoxyethyl (3,6-dioxaoctyl), benzyloxymethyl and phenoxymethyl; in general, glycol ethers, such as polyethyleneglycol, are intended to be encompassed by this group. Alkylheteroaryl refers to a residue in which a heteroaryl moiety is attached to the parent structure via an alkyl residue. Examples include furanylmethyl, pyridinylmethyl, pyrimidinylethyl and the like.
Oxaalkyl and oxaalkylaryl refer to alkyl and alkylaryl residues in which one or more methylenes have been replaced by oxygen. Examples of oxaalkyl and oxaalkylaryl residues are ethoxyethoxyethyl (3,6-dioxaoctyl), benzyloxymethyl and phenoxymethyl; in general, glycol ethers, such as polyethyleneglycol, are intended to be encompassed by this group.
Alkylheteroaryl refers to a residue in which a heteroaryl moiety is attached to the parent structure via an alkyl residue. Examples include furanylmethyl, pyridinylmethyl, pyrimidinylethyl and the like.
Heterocycle means a cycloalkyl or aryl residue in which one to four of the carbons is replaced by a heteroatom such as oxygen, nitrogen or sulfur. Examples of heterocycles that fall within the scope of the invention include imidazoline, pyrrolidine, pyrazole, pyrrole, indole, quinoline, isoquinoline, tetrahydroisoquinoline, benzofuran, benzodioxan, benzodioxole (commonly referred to as methylenedioxyphenyl, when occurring as a substituent), tetrazole, morpholine, thiazole, pyridine, pyridazine, pyrimidine, thiophene, furan, oxazole, oxazoline, isoxazole, dioxane, tetrahydrofuran and the like. “N-heterocyclyl” refers to a nitrogen-containing heterocycle as a substituent residue. The term heterocyclyl encompasses heteroaryl, which is a subset of heterocyclyl. Examples of N-heterocyclyl residues include 4-morpholinyl, 4-thiomorpholinyl, 1-piperidinyl, 1-pyrrolidinyl, 3-thiazolidinyl, piperazinyl and 4-(3,4-dihydrobenzoxazinyl). Examples of substituted heterocyclyl include 4-methyl-1-piperazinyl and 4-benzyl-1-piperidinyl.
Substituted alkyl, aryl and heteroaryl refer to alkyl, aryl or heteroaryl wherein one or more hydrogen atom(s) is replaced with alkyl, halogen, hydroxy, alkoxy, alkylenedioxy (e.g. methylenedioxy) fluoroalkyl, carboxy (—COOH), carboalkoxy (i.e. acyloxy RCOO—), carboxyalkyl (—COOR), carboxamido, sulfonamidoalkyl, sulfonamidoaryl, aminocarbonyl, benzyloxycarbonylamino (CBZ-amino), cyano, carbonyl, nitro, dialkylamino, alkylamino, amino, alkylthio, alkylsulfinyl, alkylsulfonyl, alkylsulfonamido, arylthio, arylsulfinyl, arylsulfonyl, amidino, phenyl, benzyl, heteroaryl, heterocyclyl, substituted heterocyclyl, phenoxy, benzyloxy, or heteroaryloxy. For the purposes of the present invention, substituted alkyl also includes oxaalkyl residues, i.e. alkyl residues in which one or more carbons has been replaced by oxygen.
Halogen refers to fluorine, chlorine, bromine or iodine. Fluorine, chlorine and bromine are preferred. Dihaloaryl, dihaloalkyl, trihaloaryl etc. refer to aryl and alkyl substituted with a plurality of halogens, but not necessarily a plurality of the same halogen; thus 4-chloro-3-fluorophenyl is within the scope of dihaloaryl.
“Pharmaceutically acceptable acid addition salt” refers to those salts that retain the biological effectiveness of the free bases and that are not biologically or otherwise undesirable, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, and organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like.
“Pharmaceutically acceptable base addition salts” include those derived from inorganic bases such as sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminum salts and the like. Particularly preferred are the ammonium, potassium, sodium, calcium, and magnesium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, and ethanolamine.
The compounds described herein contain one or more asymmetric centers (e.g., the carbon to which R2 is attached) and thus give rise to enantiomers, diastereomers, and other stereoisomeric forms that may be defined, in terms of absolute stereochemistry, as (R)- or (S)-. Most of the processes are described with regard to the presently preferred (R)-enantiomer, but are otherwise capable of producing all such possible isomers, e.g., the (S)-enantiomer. When the compounds described herein contain olefinic double bonds or other centers of geometric asymmetry, and unless specified otherwise, it is intended that the compounds include both E and Z geometric isomers. Likewise, except as otherwise specified, all tautomeric forms are also intended to be included. The term “enantiomerically pure” means having at least about 95% of the described enantiomer and preferably, at least about 97.5% enantiomeric excess.
Synthetic Processes of the Invention
The present invention provides intermediates, new and improved synthetic methods and novel quinazolinone compositions of matter, which can be used to treat diseases of proliferating cells. In one aspect, the invention provides methods for the synthesis of enantiomerically pure quinazolinones employing the corresponding enantiomer of amino acid precursors (particularly valine) as the starting material.
Initially, the present invention provides improvements upon previously disclosed methods for the synthesis of quinazolinones. For example, combining the first two steps illustrated in Reaction Scheme A via use of the same solvent (e.g., THF) for both steps and eliminating isolation of the intermediate product from Step 1 can afford a significant improvement in oxazolinone yield and overall efficiency. The ring opening, amination and re-cyclization of the third and fourth steps illustrated in Reaction Scheme A can also be combined (at the same time eliminating the use of chloroform), for example by employing toluene as the solvent and performing the re-cyclization at reflux. The bromination illustrated in Step 5 of Reaction Scheme A was observed to yield a sticky product requiring extended filtration times; this can be circumvented following the described water quenching by extracting the 2-(1′-bromoalkyl)-quinazolinone intermediate (e.g., in ethyl acetate).
The above-referenced 2-(1′-bromoalkyl)-quinazolinone is described as being converted to the corresponding 1′-amine via an azide intermediate, and then resolved (by recrystallization with tartaric acid) into S- and R-enantiomers, which are respectively used in lieu of the product produced by the first five steps shown in Reaction Scheme B. Yields in the second reaction illustrated in Reaction Scheme B can be improved by addition of a fourth substep, dehydration, for example employing LiOH (or another OH counter-ion such as K, Na, Cs, Bu4N or the like), ethylene glycol, and dioxane. The azide intermediate can also beneficially be extracted (e.g., with dichloromethane) instead of being isolated by filtration. The racemic 2-(1′-aminoalkyl)-quinazolinone can be beneficially isolated by crystallization (e.g., from ethyl acetate and MTBE) rather than chromatography, as can the resolved intermediate (from methanol). Coupling of the resolved amine with Boc-protected 3-aminopropanal can be effected by generating the aldehyde reactant and using it without isolation (in the solution in which it is produced) directly in the reductive amination. Isolation of the secondary amine (next to last step of Reaction Scheme B) can be performed by extractive work up (using aqueous NaOH). Finally, with regard to such prior processes, reducing the amounts of carbonyl chloride and the Hunnig's base (DIPEA) can eliminate the formation of undesired by-products (such as p-toluic acid) in the last step of Reaction Scheme B.
Also provided is a short and practical approach to a chiral quinazolinone amine intermediate (see Formula 107 in the Reaction Schemes). This can replace the seven steps leading to this intermediate in the route illustrated in Reaction Scheme A with basically one step, introducing the chiral center early via an aminoacid starting material, i.e., D-valine. This route offers additional advantages as it eliminates the need to carry out the operations or steps with the shortcomings described earlier (i.e. azide formation and reduction, classical resolution, etc.).
Synthetic Reaction Parameters
The terms “solvent”, “inert organic solvent” or “inert solvent” mean a solvent inert under the conditions of the reaction being described in conjunction therewith. Solvents employed in synthesis of the compounds of the invention include, for example, methanol, acetone, water, acetonitrile, 1,4-dioxane, dimethylformamide, benzene, toluene, tetrahydrofuran, chloroform, methylene chloride (or dichloromethane), diethyl ether, pyridine and the like, as well as mixtures thereof. Unless specified to the contrary, the solvents used in the reactions of the present invention are inert organic solvents.
The term “q.s.” means adding a quantity sufficient to achieve a stated function, e.g., to bring a solution to the desired volume (i.e., 100%).
Unless specified to the contrary, the reactions described herein take place at atmospheric pressure, generally within a temperature range from −10° C. to 110° C. Further, unless otherwise specified, the reaction times and conditions are intended to be approximate, e.g., taking place at about atmospheric pressure within a temperature range of about −10° C. to about 110° C. over a period of about 1 to about 24 hours.
The isolation and purification procedures described herein can be effected, if desired, by any suitable separation or purification procedure such as, for example, filtration, extraction, crystallization, column chromatography, thin-layer chromatography or preparative chromatography, or a combination of these procedures. Specific illustrations of suitable separation and isolation procedures can be had by reference to the examples hereinbelow. However, other equivalent separation or isolation procedures can, of course, also be used.
Starting Materials and Reactants
The compound NHBoc-protected D-valine, is commercially available, e.g., from Aldrich Chemical Company, Milwaukee, Wis. Other reactants are likewise commercially available or can be readily prepared by those skilled in the art using commonly employed methodology.


BRIEF DESCRIPTION OF THE REACTION SCHEMES
Reaction Scheme 1 illustrates the synthesis of a chiral [(quinazolin-2-yl)-2-substituted methylene]-carbamic acid tert-butyl ester from a corresponding NHBoc-protected D-amino acid.
Reaction Scheme 2 illustrates an alternative approach to substitution of the nitrogen at position 3 of a chiral [(quinazolin-2-yl)-2-substituted methylene]-carbamic acid tert-butyl ester.
Reaction Scheme 3 illustrates the de-protection, derivatization and amidation of the amino-methyl substituent of a [(quinazolin-2-yl)-2-substituted methylene]-carbamic acid tert-butyl ester.
Reaction Scheme 4 illustrates an alternative approach to derivatization of the nitrogen in an enantiomerically pure valine.
Reaction Scheme 5 illustrates an alternative approach to the synthesis of an N-protected [1-(4-oxo-3,4-dihydro-quinazolin-2-yl)-2-substitutedmethyl]-amine of Formula 107 from a 4-oxo-4H-benz [d][1,3]oxazin-2-yl compound of Formula 105.
While the structures in Reaction Schemes 1 to 5 are shown illustrating synthesis of an (R)-enantiomer, it should be understood that the underlying synthetic methodology is stereospecific and will produce the enantiomer corresponding to the configuration of the starting material. 



Referring to Reaction Scheme 1, Step 1, a compound of Formula 101 (e.g., an N-protected, chiral, naturally occuring or substituted amino acid such as valine; preferably N-Boc-D-valine) is converted to the corresponding 2-protected-carbonylamino-3-substituted methylamino optionally-substituted benzoic acid of Formula 104. Other naturally occurring and substituted α-amino acids can be employed as the compound of Formula 101, such as alanine, valine, leucine, isoleucine, phenylglycine, phenylalanine, serine, threonine, cysteine, methionine, tryptophan, tyrosine, asparagine, glutamine, asparaginate, glutamate, lysine, arginine, histidine and 2-aminobutyric acid; preferably alanine, valine, leucine, isoleucine, phenylglycine or 2-aminobutyric acid. Art-recognized N-protecting groups can be employed in the compound of Formula 101, including Boc, CBZ, phthalide, alloc, and teoc. The compound of Formula 101 is dissolved in an organic solvent (such as THF) in the presence of 1 to 2 molar equivalents of a base (such as N-methylmorpholine) and cooled to 0° C. Approximately 1 to 2 molar equivalents of isobutyl chloroformate (Formula 102) is slowly added (over a period of 5 to 30 minutes, preferably 15 minutes), preferably with stirring. The mixture is maintained at 0° C. and stirred for 1 to 2 hours (preferably 1.5 hours) to give the corresponding mixed anhydride (not shown). The mixed anhydride is carried forward without isolation or purification by the addition in one portion of an equimolar amount of an optionally substituted anthranilic acid [Formula 103, where R5, R6, R7 and R8 are independently chosen from hydrogen, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl; preferably hydrogen, halo (preferably chloro and fluoro), lower alkyl (preferably methyl), substituted lower alkyl, lower alkoxy (preferably methoxy), and cyano; most preferably hydrogen and one non-hydrogen substituent] followed by the addition of a second equimolar amount of the base (such as N-methylmorpholine). The reaction takes place at 0° C. over a period of 1 to 5 hours, preferably 3 hours, to give the corresponding compound of Formula 104 (which can also be carried forward without isolation or purification).
Referring to Reaction Scheme 1, Step 2, a 2-protected-carbonylamino-3-substituted methylamino optionally-substituted benzoic acid of Formula 104 is converted to the corresponding 4-oxo-4H-benz [d][1,3]oxazin-2-yl compound of Formula 105. An additional 1 to 2 molar equivalents of isobutyl chloroformate is added to the stirring benzoic acid of Formula 104 over a period of 5 to 60 minutes, preferably 30 minutes), along with the addition of 1 to 2 molar equivalents of a base (such as N-methylmorpholine). The reaction takes place at 0° C. over a period of 1 to 3 hours, preferably 2 hours, to give the corresponding compound of Formula 105 (which can also be carried forward without isolation or purification).
Referring to Reaction Scheme 1, Step 3, a 4-oxo-4H-benzo[d][1,3]oxazin-2-yl compound of Formula 105 is converted to the corresponding optionally substituted carbamoyl phenylamino compound of Formula 106. One to 3 molar equivalents of an amine (optionally substituted with a group selected from alkyl, aiyf-alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl; preferably alkylaryl such as benzyl or substituted alkylaryl such as substituted benzyl; most preferably benzylamine) are added with continued stirring to a compound of Formula 105 in one or more portions over a period of 5 to 15 minutes (preferably 10 minutes) up to 10 hours (preferably in 2 or 3 portions each at 2 hour intervals). The reaction takes place at 0° C. to the corresponding compound of Formula 106 with a small amount of the corresponding compound of Formula 107. The two compounds are separated by conventional procedures (e.g., chromatography, extraction, washing, filtration, evaporation). An alternative approach overcoming racemization in the synthesis of the quinazolinone of Formula 107 is illustrated in Reaction Scheme 5 and its accompanylng description. Notwithstanding such alternative approaches, the route illustrated in Reaction Scheme 1, Step 3 remains presently preferred both from the standpoints of safety and yield.
Referring to Reaction Scheme 1, Step 4, an optionally substituted carbamoyl phenylamino compound of Formula 106 is converted to the corresponding quinazolinone of Formula 107. The compound of Formula 106 is dissolved in an organic solvent (e.g., 1,4-dioxane/ethylene glycol 2:1 or dimethoxyethane), contacted with a slight to twice molar excess of a cyclo-dehydration reagent (stronger than NaOH pellets, e.g., lithium hydroxide monohydrate, HMDS, phosphorous oxychloride, oxalyl chloride, thionyl chloride, Brugess' reagent, Ph3P/I2, or a Vilsmeier reagent (DMF with phosphorous oxychloride, or DMF with thionyl chloride), preferably HMDS) and heated to reflux. The reaction takes place at reflux over a period of 3 to 36 hours (preferably 24 hours) followed by cooling and optionally acidification of the mixture to give a suspension of the corresponding quinazolinone of Formula 107, which is then isolated and purified by conventional procedures. Reaction time and work-up will depend on the cyclo-dehydration reagent that is employed. 



Referring to Reaction Scheme 2, Step 1, a 4-oxo-4H-benz [d][1,3]oxazin-2-yl compound of Formula 105 is converted to the corresponding carbamide of Formula 201. Gaseous ammonia is bubbled through a solution of the compound of Formula 105 (e.g., the stirring mixture obtained in Reaction Scheme 1, Step 2). The reaction takes place with stirring at 0° C. over a period of 1 to 3 hours (preferably 2 hours) followed by isolation and purification via conventional procedures.
Referring to Reaction Scheme 2, Step 2, a carbamide of Formula 201 is converted to the corresponding N-unsubstituted quinazolinone of Formula 202. The compound of Formula 201 is dissolved in an organic solvent (preferably THF) and contacted with a slight molar excess of a strong base (preferably lithium hydroxide monohydrate) to give the corresponding compound of Formula 202. The reaction takes place at reflux over a period of about 30 minutes to 2 hours, followed by cooling and acidification of the mixture to give a suspension, which is then isolated and purified via conventional procedures.
Referring to Reaction Scheme 2, Step 3, a quinazolinone of Formula 202 is converted to the corresponding 3-N-substituted quinazolinone of Formula 203. The compound of Formula 202 is dissolved in an organic solvent (e.g., DMF) and N-substituted via contact with halide of the desired substituent group (e.g., benzyl bromide) in the presence of an alkaline metal carbonate. The reaction takes place at room temperature over a period of 10 to 20 hours (preferably 16 hours) to give the corresponding compound of Formula 203, which is isolated and purified via conventional procedures (such as chromatography). 



Referring to Reaction Scheme 3, Step 1, an N-protected [1-(4-oxo-3,4-dihydro-quinazolin-2-yl)-2-substitutedmethyl]-amine of Formula 107 (where Boc is illustrated as the protecting group) is converted to the corresponding 2-(1-amino-2-substituted methyl)-3H-quinazolin-4-one compound of Formula 301. The compound of Formula 107 (or 203 or 503) is dissolved in an organic solvent (e.g., ethanol or toluene) and de-protected via addition of a strong, preferably anhydrous acid having a pKa≧1 (e.g., PTSA or methanesulfonic acid). The reaction takes place (preferably avoiding the presence of water) at reflux over a period of 30 minutes to 2 hours (preferably 1 hour) followed by cooling, removal of the solvent and neutralization (e.g., by the addition of potassium bicarbonate or NaOH) and water to give the corresponding compound of Formula 301.
Referring to Reaction Scheme 3, Step 2, a 2-(1-amino-2-substituted methyl)-3H-quinazolin-4-one compound of Formula 301 is then converted to the corresponding 2-(1-substituted-amino-2-substituted methyl)-3H-quinazolin-4-one compound of Formula 302. The compound of Formula 301 is dissolved in an organic solvent (e.g., DCM) and contacted with a slight molar excess of a reducing reagent (such as sodium triacetoxyborohydride) followed by the portionwise addition of 1.4 molar equivalents of an R4′-aldehyde (where R4′ is selected from alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl; preferably substituted alkyl), most preferably a primary-, secondary- or tertiary-amino-substituted lower alkyl aldehyde having a protected amino group (NHBoc-aminopropanal, prepared via Swern oxidation and added directly in solution into the reductive amination step, being especially preferred). The reaction takes place at 10° C., over a period of 1 to 16 hours and is then quenched (e.g., by addition of a lower alkanol such as methanol) followed by stirring for an additional 25 minutes to 1 hour). The resulting mixture is washed under acidic and basic conditions and then isolated via conventional procedures.
Referring to Reaction Scheme 3, Step 3, a 2-(1-substituted-amino-2-substituted methyl)-3H-quinazolin-4-one of Formula 302 is then acylated to give the corresponding 2-(1-acyl-1-substituted-amino-2-substituted methyl)-3H-quinazolin-4-one of Formula 304. [It should be noted, for example in cases where R4′ is a group of R4 (e.g., not a R4 precursor such as a protected amine) that the resulting compound of Formula 304 will also be a compound of Formula I.] The compound of Formula 302 is dissolved in an organic solvent (e.g., DCM) and contacted with 2 to 3.5 molar equivalents (preferably 2.2 molar equivalents) of DIPEA and stirred until dissolved. A slight molar excess of a carbonyl halide [such as Formula 303, where R3 is alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, substituted alkylheteroaryl, oxaalkyl, oxaalkylaryl, substituted oxaalkylaryl, R15O— and R15—NH—; R15 being chosen from alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl; and R16 being chosen from alkoxy, amino, alkylamino, dialkylamino, N-heterocyclyl and substituted N-heterocyclyl; R3 preferably being alkyl, substituted alkyl (preferably alkoxyalkyl such as methoxymethyl), aryl (preferably phenyl), substituted aryl (preferably lower alkyl-, lower alkoxy-, and/or halo-substituted phenyl), alkylaryl (preferably benzyl and phenylviny), alkylheteroaryl, oxaalkylaryl (preferably phenoxy lower alkyl), oxaalkylheteroaryl, substituted alkylaryl (preferably substituted benzyl and substituted phenylvinyl), substituted alkylheteroaryl, substituted oxaalkylaryl (preferably substituted phenoxy lower alkyl), or substituted oxaalkylheteroaryl], most preferably p-toluoyl chloride (5.5 g, 4.7 mL, 1.1 eq) is added to the stirring solution and stirring continues for 4 to 10 hours (preferably 6 hours) after which the reaction is quenched (e.g., by addition of a lower alkanol such as methanol) and stirred for an additional 15 minutes to 1 hour (preferably 30 minutes). The resulting mixture is washed under acidic conditions and then isolated via conventional procedures (e.g., using a silica gel column).
Referring to Reaction Scheme 3, Step 4, a compound of Formula 304 (where R4′ is a precursor to R4) is then converted to the corresponding compound of Formula I. In a preferred synthesis, a compound of Formula 304 where R4′ is N-Boc-aminopropyl is mixed with a large excess of TFA (premixed in an organic solvent, such as DCM). The reaction takes place, with stirring, at room temperature over 4 to 10 hours (preferably 6 hours), followed by cooling and addition of a strong base (e.g., 4N sodium hydroxide) until basic, isolation and purification via conventional procedures. 






The route illustrated in Reaction Scheme 4 incorporates the functionality on the primary amine even before the quinazolinone nucleus is constructed. This approach incorporates lower yield operations in early steps of the synthesis.
Referring to Reaction Scheme 4, Step 1, a solution of a 2-halo-3-substituted ethyl ester of Formula 401 in a lower alkanol (e.g., EtOH) is treated with a slight excess of a primary amine (R4′—NH2 where R4′ is as described previously) and the mixture stirred at room temperature for 16 hours. Alternatively, an amino acid alkyl ester (such as valine ethyl ester) can be substituted for the compound of Formula 401. Reductive alkylation with an aldehyde (as shown above) results in the corresponding 2-amino-3-substituted ethyl ester of Formula 402 is isolated by conventional procedures.
Referring to Reaction Scheme 4, Step 2, a crude 2-amino-3-substituted ethyl ester of Formula 402 is dissolved in an organic solvent (e.g., dichloromethane) and treated with a slight excess of an R3-acid chloride and a slight excess of triethylamine. The mixture is stirred at room temperature for 16 hours to afford the corresponding carboxamide of Formula 403, which is isolated and purified by conventional procedures.
Referring to Reaction Scheme 4, Step 3, a carboxamide of Formula 403 is dissolved in an organic solvent (e.g., THF) and then treated with a large excess (e.g., 6 eq) of aqueous LiOH. The mixture is stirred at room temperature for 16 hours overnight and then evaporated to dryness. The residue is triturated with dichloromethane, dried, filtered and evaporated to give the corresponding crude lithium salt. The lithium salt is dissolved in an organic solvent (e.g., DMF) and treated with an excess of PyBroP and a slight excess of an optionally substituted methyl anthranilate. The mixture is stirred at room temperature for 16 hours overnight to afford the corresponding carbonylamino-3-substituted methylamino optionally substituted benzoic acid methyl ester of Formula 404, which is isolated and purified by conventional procedures.
Referring to Reaction Scheme 4, Step 4, a methyl ester of Formula 404 is dissolved in an organic solvent (e.g., THF) and then treated with a large excess of aqueous LiOH. The mixture is stirred at room temperature for 16 hours overnight and then evaporated to dryness. The residue is triturated with dichloromethane, dried and isolated by conventional procedures to give the crude, lithium salt of the corresponding acid of Formula 405.
Referring to Reaction Scheme 4, Step 5, a lithium salt of Formula 405 is dissolved in an organic solvent (e.g., DMF) and treated with an excess of PyBroP and a slight excess of a primary amine (R1—NH2) in the presence of triethylamine. The mixture is stirred at room temperature for 16 hours to afford the corresponding bis-carboxamide of Formula 406, which is isolated and purified by conventional procedures.
Referring to Reaction Scheme 4, Step 6, a bis-carboxamide of Formula 406 is mixed with ethylene glycol to this is added a twice excess of a strong base (e.g., KOH). The mixture is stirred at 110C for 16 hours. After cooling to room temperature, the mixture is diluted with EtOAc and washed with NaHCO3. The corresponding quinazolinone of Formula 407 is isolated and purified by conventional procedures
Referring to Reaction Scheme 4, Step 7, quinazolinone of Formula 407 is converted to the corresponding compound of Formula I by procedures analogous to those described with reference to Reaction Scheme 3, Step 4. 



Referring to Reaction Scheme 5, Step 1, a benzoxazinone of Formula 105 is opened with methanol and converted to the corresponding ester of Formula 501. A4-oxo-4H-benz [d][1,3]oxazin-2-yl compound of Formula 105 (prepared, for example, as described with reference to Reaction Scheme 1, Steps 1–2) is dissolved in methanol.
Referring to Reaction Scheme 5, Step 2, an ester of Formula 501 is converted to the corresponding amidine of Formula 502.
Referring to Reaction Scheme 5, Step 3, an amidine of Formula 502 is cyclized to afford the corresponding 4-oxo-4H-benz [d][1,3]oxazin-2-yl compound of Formula 503.
Novel Compositions of Matter
Compounds prepared by the above-described process of the invention and the products incorporating them (e.g., pharmaceutical formulations) can be identified by the presence of a detectable amount of certain novel starting materials and/or reactants, such as the starting amino acid (e.g., valine) or a reactant (e.g., a cyclo-dehydration agent such as LiOH or HMDS). While it is well known that pharmaceuticals must meet pharmacopoeia standards before approval and/or marketing, and that synthetic reagents (such as LiOH) or side products should not exceed the limits prescribed by pharmacopoeia standards, final compounds prepared by a process of the present invention may have minor, but detectable, amounts of such materials present, for example at levels in the range of 95% purity with no single impurity greater than 1%. These levels can be detected, e.g., by emission spectroscopy. It is important to monitor the purity of pharmaceutical compounds for the presence of such materials, which presence is additionally disclosed as a method of detecting use of a process of the invention.
The present invention provides a novel composition of matter or pharmaceutical formulation including a compound or pharmaceutically acceptable salt of Formula I and a detectable amount of one or more of the following:

    A) a compound of Formula 101: 


    
        where X is a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc);
    
    
    B) a compound of Formula 103: 



and/or

    C) a cyclo-dehydration reagent (preferably HMDS, lithium (or a lithium reagent) employed in the synthesis thereof.

Preferred Processes and Last Steps



An enantiomerically pure quinazolinone is prepared via the use, as a starting material, of a compound of Formula 101: 



where:

    
    
        R2 is selected from: alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, and substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl; and
        X is a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc).

In a further preferred aspect, the process includes the steps of:

    
    
    A) contacting a compound of Formula 101 with isobutyl chloroformate, and
    B) contacting the product of step A with a compound of Formula 103: 





where R5, R6, R7 and R8 are independently chosen from hydrogen, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl.
An enantiomerically pure compound of Formula 107/203: 



where:

    
    
        R1 is chosen from hydrogen, alkyl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R2 is chosen from alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, and substituted alkylaryl, substituted heteroaryl, and substituted alkylheteroaryl;
        R5, R6, R7 and R8 are independently chosen from hydrogen, hydroxy, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, amino, alkylamino, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl and heretoaryl; and
        X is a protecting group (preferably selected from Boc, CBZ, phthalide, alloc, and teoc), is prepared by a process including the steps:
    
    
    A) contacting isobutyl chloroformate with a compound of Formula 101: 



    B) contacting the product of step A with a compound of Formula 103: 



and

    C) converting the product of step B to the compound of Formula 107/203.

In a preferred embodiment of this aspect of the invention R is selected from ethyl, i-propyl, c-propyl, t-butyl or c-pentyl.



A compound of Formula I is contacted with a pharmaceutically acceptable acid, preferably methane sulfonic acid, to form the corresponding acid addition salt.
A pharmaceutically acceptable acid addition salt of Formula I is contacted with a base to form the corresponding free base of Formula I.
Utility and Administration
The compositions made by the invention find use in a variety of applications, for example, as described in WO 01/30768 (previously incorporated by reference). As will be appreciated by those in the art, mitosis can be altered in a variety of ways; that is, one can affect mitosis either by increasing or decreasing the activity of a component in the mitotic pathway. Stated differently, mitosis can be affected (e.g., disrupted) by disturbing equilibrium, either by inhibiting or activating certain components. Similar approaches can be used to alter meiosis.
In a preferred use, the compositions made in the present invention are used to modulate mitotic spindle formation, thus causing prolonged cell cycle arrest in mitosis. By “modulate” herein is meant altering mitotic spindle formation, including increasing and decreasing spindle formation. By “mitotic spindle formation” herein is meant organization of microtubules into bipolar structures by mitotic kinesins. By “mitotic spindle dysfunction” herein is meant mitotic arrest and monopolar spindle formation.
The compositions made according to the invention are useful to bind to and/or modulate the activity of a mitotic kinesin, KSP. In a preferred embodiment, the KSP is human KSP, although KSP kinesins from other organisms can also be used. In this context, modulate means either increasing or decreasing spindle pole separation, causing malformation, i.e., splaying, of mitotic spindle poles, or otherwise causing morphological perturbation of the mitotic spindle. Also included within the definition of KSP for these purposes are variants and/or fragments of KSP. See WO 01/31335 “Methods of Screening for Modulators of Cell Proliferation and Methods of Diagnosing Cell Proliferation States”, hereby incorporated by reference in its entirety. In addition, other mitotic kinesins can be used as binding targets for the compositions made in the present invention.
Anti-mitotic agents prepared according to the invention can be administered in a physiologically acceptable carrier to a patient, as described herein. Depending upon the manner of introduction, the compounds can be formulated in a variety of ways as discussed below. The concentration of therapeutically active compound in the formulation may vary from about 0.1–100 wt. %. The agents can be administered alone or in combination with other treatments, i.e., radiation, or other chemotherapeutic agents.
Pharmaceutical formulations employ the compositions made according to the invention typically in a water soluble form, such as pharmaceutically acceptable salts, which is meant to include both acid and base addition salts.
“Pharmaceutically acceptable acid addition salt” refers to those salts that retain the biological effectiveness of the free bases and that are not biologically or otherwise undesirable, formed with inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid and the like, and organic acids such as acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, maleic acid, malonic acid, succinic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid and the like.
“Pharmaceutically acceptable base addition salts” include those derived from inorganic bases such as sodium, potassium, lithium, ammonium, calcium, magnesium, iron, zinc, copper, manganese, aluminum salts and the like. Particularly preferred are the ammonium, potassium, sodium, calcium, and magnesium salts. Salts derived from pharmaceutically acceptable organic non-toxic bases include salts of primary, secondary, and tertiary amines, substituted amines including naturally occurring substituted amines, cyclic amines and basic ion exchange resins, such as isopropylamine, trimethylamine, diethylamine, triethylamine, tripropylamine, and ethanolamine.
The pharmaceutical compositions can be prepared in various forms, such as granules, tablets, pills, suppositories, capsules, suspensions, salves, lotions and the like. Pharmaceutical grade organic or inorganic carriers and/or diluents suitable for oral and topical use can be used to make up compositions containing the therapeutically active compounds. Diluents known to the art include aqueous media, vegetable and animal oils and fats. Stabilizing agents, wetting and emulsifying agents, salts for varying the osmotic pressure or buffers for securing an adequate pH value, and skin penetration enhancers can be used as auxiliary agents. The pharmaceutical compositions can also include one or more of the following: carrier proteins such as serum albumin; buffers; fillers such as microcrystalline cellulose, lactose, corn and other starches; binding agents; sweeteners and other flavoring agents; coloring agents; and polyethylene glycol. Additives are well known in the art, and are used in a variety of formulations.
The administration of the mitotic agents prepared according to the present invention can be done in a variety of ways as discussed above, including, but not limited to, orally, subcutaneously, intravenously, intranasally, transdermally, intraperitoneally, intramuscularly, intrapulmonary, vaginally, rectally, or intraocularly. In some instances, for example, in the treatment of wounds and inflammation, the anti-mitotic agents can be directly applied as a solution or spray.
EXAMPLES
The following examples are given to enable those skilled in the art to more clearly understand and to practice the present invention. They should not be considered as limiting the scope of the invention, but merely as being illustrative and representative thereof. The syntheses reported in Examples 1 through 4.1 were performed in the laboratories of IRIX Pharmaceuticals, Inc. (Florence, S.C.).
Example 1
Synthesis of (R)-N-(3-Amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinalolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide
1.1 7-Chloro-2-isobutyl-benzo[d][1,3]oxazin-4-one
A dry 3-necked, round bottomed flask, equipped with an overhead stirrer, thermometer, dropping funnel, cooling bath and condenser was charged with 406.41 g of 2-amino-4-chlorobenzoic acid (1 eq.), 270 g (1.35 eq.) of sodium bicarbonate, Na2SO4 (as a dehydrating agent) and 1,000 mL of THF. After commencing agitation, 354.7 g (1.2 eq.) of isovaleryl chloride was added dropwise. The reaction was exothermic and generated a gas (CO2). Temperature was maintained around 20–30° C. and completion of the reaction monitored by TLC (EtOAc/hexanes 1:1). The reaction mixture was then filtered and washed with THF (1,000 mL) the majority of which was then stripped off under vacuum. Acetic anhydride (1,450 mL) was then added to the reaction vessel and the temperature raised to 90–100° C. Completion of the reaction monitored by TLC (EtOAc/hexanes 1:1). The acetic anhydride was removed under vacuum at 80–100° C., followed by cooling to 60° C. The reaction vessel was then charged with heptane (1,000 mL) and cooled to 0° C. with stirring. The resulting precipitate was isolated by filtration and then washed with heptane (300 mL) and dried in a vacuum oven at 30° C. overnight to afford the title product (507 g, 90% yield).
1.2 3-Benzyl-7-chloro-2-isobutyl-3H-quinazolin-4-one
A flask, equipped with an overhead stirrer, heating mantle, condenser and Dean-Stark apparatus was charged with 1,500 mL of toluene, 412.7 g (1 eq.) of 7-chloro-2-isobutyl-benzo[d][1,3]oxazin-4-one and 281.0 g (1.5 eq.) of benzylamine and brought to reflux for 3 hours. After removal of the water, ethylene glycol (150 mL) and 14.2 g (0.2 eq.) of NaOH were added and the mixture was heated to 115° C. for 5 hours. Completion of the reaction was monitored by TLC, after which the temperature was cooled to 60° C. and the pH adjusted to about 7 with 1N HCl, followed by the addition of 1 L of brine. The top organic layer was separated and the aqueous layer extracted with methylene chloride (2×300 mL). The organic phases were combined and dried over sodium sulfate. Solvents were stripped off leaving a viscous oil to which warm hexane (500 mL) was added. The mixture was cooled in an ice bath to give white crystals, which were separated by filtration. The filter cake was washed with cold hexane (800 mL) and air dried to give the title product as a white solid (470 g). An additional 42.4 g of title product was obtained from the mother liquor (512.4 g, 90.3%).
1.3 3-Benzyl-2-(1-bromo-2-methyl)propyl-7-chloro-3H-quinazolin-4-one
A dry 3-necked, round bottomed flask, equipped with an overhead stirrer, thermometer, heating mantle, condenser and addition funnel was charged with 445 g (1 eq.) of 3-benzyl-7-chloro-2-isobutyl-3H-quinazolin-4-one, 158 g of sodium acetate and 1,300 mL of acetic acid. Temperature was raised to 30° C. followed by the addition of 230 g (1.1 eq.) bromine/AcOH over a period of about 2.5 hours. Completion of the reaction was monitored by TLC (temperature being increased to 50° C. until all unreacted starting material is consumed). After cooling to room temperature, the reaction mixture is poured into 8 L of cold water and agitated for 1 hour followed by extraction with ethyl acetate. The combined organic layers are washed with saturated, aqueous sodium bicarbonate, dried with Na2SO4 and the solvents removed under reduced pressure at 30° C. Drying overnight in a vacuum oven at 30° C. afforded the title product (536 g, 97%) as a white solid.
1.4 2-(1-Azido-2-methyl)propyl-3-benzyl-7-chloro-3H-quinazolin-4-one
A round bottomed flask, equipped with an overhead stirrer, thermometer, heating mantle and condenser was charged with 98 g (1.5 eq.) of sodium azide and 1,500 ML of DMF followed by the portionwise addition of 407 g (1 eq.) of 3-benzyl-2-(1-bromo-2-methyl)propyl-7-chloro-3H-quinazolin-4-one over 30 minutes. Temperature is increased to 40° C. and agitation continued for 4–5 hours. Upon completion of the reaction (monitored by TLC) the mixture is cooled to room temperature, poured into 6 L of water, 2 L of methylene chloride and 2L of brine, and agitated. The bottom, organic phase is separated and the aqueous layer extracted with methylene chloride (1.2 L), dried over sodium sulfate, and the solvent stripped off leaving a warm viscous oil to which is added 0.5 L of warm hexane. Cooling on an ice bath gave a solid that was filtered and washed with 0.5 L of cold hexane. The filter cake was dried in a vacuum desiccator overnight to afford the title compound (319 g, 86.9%) as a white solid. (The filtrates can be stripped and triturated in MTBE for a second crop.)
1.5 2-(1-Amino-2-methyl)propyl-3-benzyl-7-chloro-3H-quinazolin4-one
A dry 3-necked, round bottomed flask, equipped with an overhead stirrer, thermometer, condenser and nitrogen line was charged with 708 g of triphenylphosphine and 5,000 mL of THF resulting in a slight exotherm; followed by the portionwise addition of 945 g of 2-(1-azido-2-methyl)propyl-3-benzyl-7-chloro-3H-quinazolin-4-one over a period of about 15 minutes, followed by agitation for an additional 5 minutes. Temperature was maintained at about 20° C., using an ice cooling bath to maintain temperature during the exothermic addition of 1,400 mL of 2N aqueous HCl over a period of about 30 minutes. The solvent was stripped off under reduced pressure leaving a mixture of heavy yellow oil and water, which was dissolved in 4 L of ethyl acetate and dried with Na2SO4. After filtration, 5 L of MTBE was slowly added resulting in a precipitate that was filtered and dried at 40° C. under vacuum to give the hydrochloride salt of the title product (684 g, 78%) as a white solid. (The filtrates from re-crystallization can be reworked to obtain additional product.)
A portion (50 g) of the hydrochloride salt thus obtained was treated with 500 mL of saturated sodium bicarbonate and 100 mL of brine. After extraction with methylene chloride (2×250 mL) the bottom solution was separated, dried over Na2SO4 and the solvent was removed to afford the free amine (36 g) as a thick off-white oil.
1.6 R-2-(1-Amino-2-methyl)propyl-3-benzyl-7-chloro-3H-quinazolin-4-one
A round bottomed flask, equipped with an overhead stirrer, thermometer, and heating mantle, 2-(1-Amino-2-methyl)propyl-3-benzyl-7-chloro-3H-quinazolin-4-one (1,250 g) was dissolved in 8.7 L of IPA and warmed to 60° C. In a separate flask, 1,300 g of dibenzoyl-D-tartaric acid is dissolved in 8.3 L of warm isopropyl alcohol, and then quickly added to the warm amine solution under agitation. Crystallization began after about 1 minute, and the mixture was left overnight to cool under agitation to room temperature, yielding a white solid that was isolated by filtration. (Filtrates from this first recrystallization contained mostly the S-isomer.)
A 60 L reactor was charged with the crude wet material from the above-described crystallization and 22 L of methanol. Temperature was increased to 64° C. (reflux) dissolving the filtrate, followed by the addition of 30 L of hot isopropyl alcohol (quickly and under agitation). The heat was turned off and the solution allowed to cool overnight under agitation; crystallization began at 61.5° C., leaving a fine white suspension that was isolated by filtration (removing the mother liquor to the extent possible). The filter cake was washed with 3 L of isopropyl alcohol and then dried in a vacuum oven at about 35° C. overnight to afford the title compound (804 g, 31%) as a white fluffy solid. (Filtrates from this second crystallization can be stripped and recyrstallized using the same method to obtain a second crop of the desired R-isomer.)
1.7 (R)-{3-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propylamino[-propyl}-carbamic acid tert-butyl ester.
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet and cold bath was charged with 10.0 g of 2-(1-amino-2-methyl-propyl)-3-benzyl-7-chloro-3H-quinazolin-4-one (a compound of Formula 301 prepared, e.g., as described in Example 1.6 or 3.1), 50 mL of DCM and 6.20 g (1.2 eq) of sodium triacetoxyborohydride and cooled to 10° C., followed by the portionwise addition of N-Boc-3-aminopropanal 7.1 g (1.4 eq). Upon indication of completion by TLC, the reaction was quenched with 2.0 mL of methanol and stirred for an additional 30 minutes, during which a slight exotherm was observed. The mixture was washed with 1 N hydrochloric acid (until the aqueous layer was clear and acidic)(also exothermic) and then washed with 2N sodium hydroxide (until basic), followed by drying over sodium sulfate, and filtration. The resulting off-white foam solid was filtered and solvents partially stripped under vacuum to give 16.0 g (110% yield) of the title compound of Formula 302, {3-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propylamino]-propyl}-carbamic acid tert-butyl ester.
1.8 (R)-{3-[[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-(4-methyl-benzoyl)-amino]-propyl}-carbamic acid tert-butyl ester
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet and cold bath was charged with 16.0 g of {3-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propylamino]-propyl}-carbamic acid tert-butyl ester (the compound of Formula 302 prepared, e.g., as described in Example 1.7 or 3.2), 80 mL of DCM and 9.1 g (12 mL)(2.2 eq) of DIPEA and stirred until dissolved. To the stirring solution, p-toluoyl chloride 5.5 g (4.7 mL)(1.1 eq) was added and stirring continued for approximately 6 hours until the reaction was determined to be completed by TLC (hexanes/ethyl acetate 1:1). The reaction was quenched with methanol (5 mL) and stirred for an additional 30 minutes, then cooled followed by addition of 1N hydrochloric acid (exothermic) to wash until acidic. The resulting solution was dried over sodium sulfate, the solvents stripped under vacuum at 30–40° C. The crude product thus obtained was purified on a silica gel column (eluted with 15% ethyl acetate in hexanes) and concentrated to give the title compound of Formula 304 {3-[[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-(4-methyl-benzoyl)-amino]-propyl}-carbamic acid tert-butyl ester as an off-white foam solid, 10.8 g (60% yield).
1.9 (R)-N-(3-amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet and cold bath was charged with 400.0 g of {3-[[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-(4-methyl-benzoyl)-amino]-propyl}-carbamic acid tert-butyl ester (the compound of Formula 304 prepared, e.g., as described in Example 1.8 or 3.3) and 1500 g of TFA (20 eq) premixed in DCM (6000 g). The mixture was stirred at room temperature for about 6 hours at which time the reaction was determined to be complete by TLC. The reaction vessel was cooled and slowly charged with 4N sodium hydroxide until basic. The resulting solution was washed with brine, dried over sodium sulfate and concentrated under reduced pressure at 35° C. to give the title compound of Formula I, (R)-N-(3-amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinalolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide, 325 g (97% yield) as a white foam solid.
1.10 (R)-N-(3-amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinalolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide, mesylate salt
A dry round bottomed flask, equipped with a magnetic stirrer, dropping funnel, cooling bath and nitrogen bubbler was charged with 10 g (1 eq.) of (R)-N-(3-amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide and 50 mL of MTBE, and stirred until the benzamide was dissolved. The solution was cooled to 10° C. and slowly charged with 1.86 g (1 eq.) of methane sulfonic acid via the dropping funnel. When the addition was complete, the solution was warmed to room temperature and quickly charged with 50 mL of hexanes. The resulting solid was isolated by filtration under Nitrogen, washed with 100 mL of hexanes, and dried under vacuum at 60° C. to constant weight affording the title salt of Formula I, (R)-N-(3-amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide, mesylate salt (10.2 g, 86% yield).
Example 2
Synthesis of (S)-[1-(3-Benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester
2.1 Formula 104 where R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet and an ice-bath, was charged with 250 mL of anhydrous THF, 22.82 g (0.105 mol) of dry N-Boc-L-valine (Formula 101), and 12.2 mL (0.11 mol) of anhydrous N-methylmorpholine, (99%), and was cooled to 0° C. To the stirring solution was added 14.5 mL (0.11 mol) of isobutyl chloroformate (98%) (Formula 102), over 15 min (internal temperature 5° C.) and the mixture was stirred for additional 1.5 h at 0° C. TLC analysis (hexanes/ethyl acetate 7:3) indicated complete reaction.
To the above stirring mixture at 0° C., 17.51 g (0.1 mol) of 4-chloro-anthranilic acid (98%) (Formula 103) was added in one portion and the mixture continued to stir for 2 h at 0° C. To the stirring mixture 11.1 mL (0.1 mol) of anhydrous N-methylmorpholine, (99%), was added over 15 min at 0° C. to give the title compound of Formula 104, 2-(2-tert-butoxycarbonylamino-L-3-methyl-butyrylamino)-4-chloro-benzoic acid, which was carried forward without isolation or purification. TLC analysis (hexanes/ethyl acetate 7:3) indicated complete reaction.
2.2 Formula 105 where R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
To the stirring mixture obtained in Example 2.1 was added 13.2 mL (0.1 mol) of isobutyl chloroformate, (98%), over 15 min (internal temperature 5° C.) followed by the addition of 11.1 mL (0.1 mol) of anhydrous N-methylmorpholine, (99%), over 15 min at 0° C. The mixture was stirred for an additional hour at 0° C. to give the title compound of Formula 105, (S)-[1-(7-chloro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl-2-methyl-propyl]-carbamic acid tert-butyl ester, which was carried forward without isolation or purification. TLC analysis (hexanes/ethyl acetate 7:3) indicated complete reaction. 1HNMR (300 MHz, DMSO-d6) δ (ppm) 8.10 (d, 1H), 7.70 (m, 2H), 7.45 (d, 1H), 4.20 (t, 1H), 3.85 (d, 1H), 2.1 0 (m, 1H), 1.85 (m, 1H), 1.40–1.15 (m, 9H), 1.0–0.8 (m, 6H)
2.3 Formula 106 where R1 is Benzyl; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H and Formula 107 where R1 is Benzyl; R2 is i-Propyl; R4′ is Boc; R8 is Chloro; and R5, R6 and R9 are H
To the stirring mixture obtained in Example 2.2 was added 11.0 mL (0.1 mol) of benzylamine, (99%), over 10 minutes at 0° C. The mixture was stirred for 2 h at 0° C. at which time TLC analysis (hexanes/ethyl acetate 7:3) indicated that the reaction was less than half way complete. The mixture was then allowed to warm to room temperature and stirring continued for another 2 h. TLC analysis indicated unchanged reaction. The reaction mixture was cooled to 0° C. and additional 11.0 mL (0.1 mol) of benzylamine, (99%), was added in one portion. The mixture was allowed to stir at room temperature for an additional 2 h. TLC analysis again indicated that the reaction was approximately 80% done. Then additional 11.0 mL (0.1 mol) of benzylamine, (99%), was added in one portion at room temperature. The mixture was allowed to stir at room temperature for an additional 2 h. TLC analysis again indicated that the reaction had proceeded almost to completion, giving a mixture of Formulae 106 and 107.
The reaction mixture was then diluted with 250 mL methyl-t-butyl ether (MTBE), transferred into a separatory funnel and washed successively with 3×200 mL of water, with 2×200 mL of 1N hydrochloric acid, with 100 mL of saturated sodium bicarbonate, and with 200 mL of brine. The organic layer was passed through a 25 g cake of sodium sulfate into a round-bottomed flask. The solvent was removed by rotary evaporation and the residue was dissolved in 50 mL of MTBE. The mixture was slowly added to a Erlenmeyer flask containing 250 mL of hexanes while stirred at room temperature. Initially it became cloudy and then solid started forming. The mixture was stirred at 0° C. for 4 h. A white solid was collected and dried to afford 23.9 g (52% yield) of the title compound of Formula 106, (S)-{1-[(2-benzylcarbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester. 1HNMR (300 MHz, DMSO-d6) δ (ppm) 11.90 (s, 1H), 9.39 (S, 1H), 8.60 (S, 1H), 7.80 (S, 1H), 7.30 (m, 8H), 4.50 (m, 2H), 3.80 (m, 1H), 2.15 (m, 1H), 1.40–1.20 (m, 9H), 0.85 (m, 6H). The filtrate was concentrated to dryness and applied to a 100 g silica-gel plug pre-packed with hexanes/ethyl acetate (5:1) and eluted with 10 fractions×100 mL of hexanes/ethyl acetate (5:1). 9.2 Grams (21% yield) of the title compound of Formula 107, (S)-[1−(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester was isolated as a white solid along with 5.1 g (11% yield) of Formula 106 as a white solid.
2.4A Formula 107 where R1 is Benzyl; R2 is i-Propyl; R4′ is Boc; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle and a water condenser, was charged with 60 mL of 1,4-dioxane/ethylene glycol (2:1), 4.60 g (10 mmol) of (S)-{1-[(2-benzylcarbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester (a compound of Formula 106, obtained as described in Example 2.3), and 0.46 g (11 mmol) of lithium hydroxide monohydrate. The mixture was heated to reflux and the reaction was monitored by TLC (hexanes/ethyl acetate 7:3). After 4 h of refluxing the reaction appeared to be complete. The mixture was allowed to cool to room temperature and slowly was acidified to pH=5 by adding 1N hydrochloric acid. The mixture was stirred for 1 h and the white suspension was separated by filtration and dried in high vacuum to afford 3.5 g (83% yield) of the title compound of Formula 107, (S)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester[mostly the (S) enantiomer]. 1HNMR (300 MHz, DMSO-d6) δ (ppm)8.15 (d, 1H), 7.65 (S, 1H), 7.60 (d, 1H), 7.40–7.20 (m, 5H), 5.75 (d, 1H), 4.40 (t, 1H), 2.25 (m, 1H), 1.40–1.15 (m, 10H), 0.08 (d, 3H), 0.35 (d, 3H).
2.4B Formula 107 where R1 is Benzyl; R2 is i-Propyl; R4′ is Boc; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, gas bubbler, heating mantle and a water condenser, was charged with 545.73 g (1.19 mol) of (R)-{1-[(2-benzylcarbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester (a compound of Formula 106, obtained, for example, as described in Example 2.3), 520 mL of dimethoxymethane and 520 mL (2.492 mol) of HMDS. The mixture was heated to reflux for 24 hours and then allowed to cool. The volatiles were removed by rotary evaporation, leaving an oily residue that was then triturated with ethanol (3×125 mL) to remove residual HMDS or ammonia. To the resulting oil was added 400 mL of ethanol, and the mixture was heated until a homogeneous solution had been obtained. At refulx temperature, 60 mL of water was added and the solution was allowed to cool slowly with light stirring, overnight. The resulting white suspension was allowed to settle; an aliquot of the supernatant was removed and treated dropwise with water to confirm completion (no more solid was formed). The solid was filtered, washed (3×200 mL H2O/EtOH (1:4)), and dried in an oven at 50° C. for 48 hours to afford 260.23 g (51% yield) of the enantiomerically pure title compound of Formula 107, (R)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester.
Example 3
Synthesis of [1-(3-Benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester
3.1 Formula 201 where R1 is H; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
(S)-[1-(7-Chloro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl-2-methyl-propyl]-carbamic acid tert-butyl ester (a compound of Formula 105) was prepared (e.g., as described in Example 2.2) in a 3-necked, round bottom flask equipped with a magnetic stirrer, nitrogen inlet and an ice bath. A dry-ice condenser was fitted to the reaction flask and to the stirring mixture (at 0° C.) gaseous ammonia was slowly introduced until the resulting exotherm was no longer observed. The mixture was then allowed to stir for 2 h at room temperature and TLC analysis (hexanes/ethyl acetate 7:3) indicated complete reaction. The compound of Formula 105 was consumed and the title compound of Formula 201 was formed. The reaction mixture was then diluted with 250 mL of water, and was transferred into a round bottom 1-necked flask. The organic solvent was removed by rotary evaporation. The aqueous residue was carefully acidified to pH=5 with 1N hydrochloric acid. A white solid was collected and dried to afford 35 g (76% yield) of the title compound of Formula 201, (S)-{1-[(2-carbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester. 1HNMR (300 MHz, DMSO-d6) 67 (ppm)12.15 (S, 1H), 8.65 (S, 1H), 8.30 (S, 1H), 7.85 (d, 1H), 7.70 (S, 1H), 7.35 (d, 1H), 7.20 (d, 1H), 3.75 (m, 1H), 2.10 (m, 1H), 1.40–1.20 (m, 9H), 0.90 (m, 6H).
3.2 Formula 202 where R1 is H; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle, and a water condenser, was charged with 60 mL of THF, 3.70 g (10 mmol) of (S)-{1-[(2-carbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester (the compound of Formula 201 prepared, e.g., as described in Example 3.1), and 0.46 g (11 mmol) of lithium hydroxide monohydrate. The mixture was heated to reflux and the reaction was monitored by TLC (hexanes/ethyl acetate 7:3) by which, after 1 h of refluxing, the reaction was shown to be complete. The mixture was allowed to cool to room temperature and transferred to a round bottom 1-necked flask followed by dilution with 60 mL of water. The stirring mixture was then slowly was acidified to pH=5 by adding 1N hydrochloric acid and the THF was removed by rotary evaporation. The white suspension was separated by filtration and dried in high vacuum to afford 3.5 g (100% yield) of the title compound of Formula 202, (S)-[1-(7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester. 1HNMR (300 MHz, DMSO-d6) δ (ppm)8.15 (d, 1H), 7.65 (S, 1H), 7.50 (d, 1H), 7.00 (d, 1H), 4.20 (m, 1H), 2.05 (m, 1H), 1.40–1.15 (m, 9H), 0.95–0.75 (m, 7H).
3.3 Formula 203 where R1 is Benzyl; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer and nitrogen inlet, was charged with 50 mL of DMF, 3.50 g (10 mmol) of (S)-[1-(7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (the compound of Formula 202 prepared, e.g., as described in Example 3.2), 1.34 mL of benzyl bromide (98%), and 3.04 g of potassium carbonate. The mixture was stirred at room temperature overnight. TLC (hexanes/ethyl acetate 7:3) indicated complete reaction. The mixture was transferred into a Erlenmeyer flask and mixed with 100 mL of water. To the stirring mixture was then added hexanes, 50 mL. The formed white solid was collected by filtration to afford the title compound of Formula 203 (S)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (also corresponding to Formula 107). The layers were separated and the organic was concentrated to dryness. The residue was chromatographed to afford an additional yield of the title compound.
1HNMR (300 MHz, DMSO-d6) δ (ppm)8.15 (d, 1H), 7.65 (S, 1H), 7.60 (d, 1H), 7.40–7.20 (m, 5H), 5.75 (d, 1H), 5.15 (d, 1H), 4.40 (t, 1H), 2.25 (m, 1H), 1.40–1.15 (m, 10H), 0.08 (d, 3H), 0.35 (d, 3H)
Example 4
Synthesis of N-(3-Amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinalolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide
4.1 Formula 301 where R1 is Benzyl; R2 is i-Propyl; R4′ is H; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle and water condenser, was charged with 60 mL of toluene, 4.42 g (10 mmol) of (S)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (the compound of Formula 107 or 203 prepared, e.g., as described in Example 2.4 or 3.3), and 4.20 g of PTSA. The mixture was heated to reflux for 1 h, during which the evolution of gas was observed. Upon cessation of gas evolution, TLC analysis (hexanes/ethyl acetate 7:3) indicated complete reaction. The mixture was cooled to room temperature, initially formed an oil that separated at the bottom of the flask and quickly solidified into a brown solid. Toluene was decanted and 50 mL of saturated potassium bicarbonate (room temperature) was added to the solid with stirring followed by the addition of 25 mL of water. The resulting white solid was collected by filtration to afford 3.3 g (96% yield) of the title compound of Formula 301, (S)-2-(1-amino-2-methyl-propyl)-3-benzyl-7-chloro-3H-quinazolin-4-one.
4.2 Formula I where R1 is Benzyl; R2 is i-Propyl; R3 is p-Methyl-phenyl; R4 is n-Propylamine; R7 is Chloro; and R5, R6 and R8 are H
The (S)-2-(1-amino-2-methyl-propyl)-3-benzyl-7-chloro-3H-quinazolin-4-one obtained in Example 4.1 is carried forward as described in Examples 1.7 through 1.9 to yield the S-isomer of the title compound.
Example 5
Synthesis of (R)-[1-(3-Benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester
5.1 Formula 104 where R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet and an ice-bath, is charged with 250 mL of anhydrous THF, 22.82 g (0.105 mol) of dry N-Boc-D-valine (Formula 101), and 12.2 mL (0.11 mol) of anhydrous N-methylmorpholine, (99%), and cooled to 0° C. To the stirring solution is added 14.5 mL (0.11 mol) of isobutyl chloroformate (98%) (Formula 102), over 15 min (internal temperature 5° C.) and the mixture is stirred for additional 1.5 h at 0° C. TLC analysis (hexanes/ethyl acetate 7:3) indicates complete reaction.
To the above stirring mixture at 0° C., 17.51 g (0.1 mol) of 4-chloro-anthranilic acid (98%) (Formula 103) is added in one portion and the mixture continued to stir for 2 h at 0° C. To the stirring mixture 1 1.1 mL (0.1 mol) of anhydrous N-methylmorpholine, (99%), is added over 15 min at 0° C. to give the title compound of Formula 104, 2-(2-tert-butoxycarbonylamino-D-3-methyl-butyrylamino)-4-chloro-benzoic acid, which is carried forward without isolation or purification. TLC analysis (hexanes/ethyl acetate 7:3) indicates complete reaction.
5.2 Formula 105 where R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
To the stirring mixture obtained in Example 5.1 is added 13.2 mL (0.1 mol) of isobutyl chloroformate, (98%), over 15 min (internal temperature 5° C.) followed by the addition of 11.1 mL (0.1 mol) of anhydrous N-methylmorpholine, (99%), over 15 min at 0° C. The mixture is stirred for an additional hour at 0° C. to give the title compound of Formula 105, (R)-[1-(7-chloro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl-2-methyl-propyl]-carbamic acid tert-butyl ester, which is carried forward without isolation or purification. TLC analysis (hexanes/ethyl acetate 7:3) indicates complete reaction.
5.3 Formula 106 where R1 is Benzyl; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H and Formula 107 where R1 is Benzyl; R2 is i-Propyl; R4′ is Boc; R7 is Chloro; and R5, R6 and R8 are H
To the stirring mixture obtained in Example 5.2 is added 11.0 mL (0.1 mol) of benzylamine, (99%), over 10 minutes at 0° C. The mixture is stirred for 2 h at 0° C., then allowed to warm to room temperature and stirring continues for another 2 h, then cooled to 0° C. and additional 11.0 mL (0.1 mol) of benzylamine, (99%), is added in one portion. The mixture is allowed to stir at room temperature for an additional 2 h, then an additional 11.0 mL (0.1 mol) of benzylamine, (99%), is added in one portion at room temperature. The mixture is allowed to stir at room temperature for an additional 2 h. TLC analysis indicates that the reaction will have proceeded almost to completion, giving a mixture of Formulae 106 and 107.
The reaction mixture is then diluted with 250 mL methyl-t-butyl ether (MTBE), transferred into a separatory funnel and washed successively with 3×200 mL of water, with 2×200 mL of 1N hydrochloric acid, with 100 mL of saturated sodium bicarbonate, and with 200 mL of brine. The organic layer is passed through a 25 g cake of sodium sulfate into a round-bottomed flask. The solvent is removed by rotary evaporation and the residue dissolved in 50 mL of MTBE. The mixture is slowly added to an Erlenmeyer flask containing 250 mL of hexanes while stirred at room temperature. Initially it becomes cloudy and then solid starts forming. The mixture is stirred at 0° C. for 4 h. A white solid is collected and dried to afford the title compound of Formula 106, (R)-{1-[(2-benzylcarbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester. The filtrate is concentrated to dryness and applied to a 100 g silica-gel plug pre-packed with hexanes/ethyl acetate (5:1) and eluted with 10 fractions×100 mL of hexanes/ethyl acetate (5:1). The title compound of Formula 107, (R)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester is isolated as a white solid along with Formula 106 as a white solid.
5.4 Formula 107 where R1 is Benzyl; R2 is i-Propyl; R4′ is Boc; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle and a water condenser, is charged with 60 mL of 1,4-dioxane/ethylene glycol (2:1), 4.60 g (10 mmol) of (R)-{1-[(2-benzylcarbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester (a compound of Formula 106, obtained as described in Example 5.3), and 0.46 g (11 mmol) of lithium hydroxide monohydrate. The mixture is heated to reflux and the reaction is monitored by TLC (hexanes/ethyl acetate 7:3). After 4 h of refluxing the reaction appears to be complete. The mixture is allowed to cool to room temperature and is slowly acidified to pH=5 by adding 1N hydrochloric acid. The mixture is stirred for 1 h and the white suspension is separated by filtration and dried in high vacuum to afford the title compound of Formula 107, (R)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester.
Example 6
Synthesis of (R)-[1-(3-Benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester
6.1 Formula 201 where R1 is H; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
(R)-[1-(7-Chloro-4-oxo-4H-benzo[d][1,3]oxazin-2-yl-2-methyl-propyl]-carbamic acid tert-butyl ester (a compound of Formula 105) is prepared (e.g., as described in Example 5.2) in a 3-necked, round bottom flask equipped with a magnetic stirrer, nitrogen inlet and an ice bath. A dry-ice condenser is fitted to the reaction flask and to the stirring mixture (at 0° C.) gaseous ammonia is slowly introduced until the resulting exotherm is no longer observed. The mixture is then allowed to stir for 2 h at room temperature and TLC analysis (hexanes/ethyl acetate 7:3) indicates complete reaction. The compound of Formula 105 is consumed and the title compound of Formula 201 is formed. The reaction mixture is then diluted with 250 mL of water, and transferred into around bottom 1-necked flask. The organic solvent is removed by rotary evaporation. The aqueous residue is carefully acidified to pH=5 with 1N hydrochloric acid. A white solid is collected and dried to afford the title compound of Formula 201, (R)-{1−[(2-carbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester.
6.2 Formula 202 where R1 is H; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle, and a water condenser, is charged with 60 mL of THF, 3.70 g (10 mmol) of (R)-{1-[(2-carbamoyl-5-chloro-phenylimino)-methyl]-2-methyl-propyl}-carbamic acid tert-butyl ester (the compound of Formula 201 prepared, e.g., as described in Example 6.1), and 0.46 g (11 mmol) of lithium hydroxide monohydrate. The mixture is heated to reflux and the reaction monitored by TLC (hexanes/ethyl acetate 7:3) by which, after 1 h of refluxing, the reaction is shown to be complete. The mixture is allowed to cool to room temperature and transferred to a round bottom 1-necked flask followed by dilution with 60 mL of water. The stirring mixture is then slowly acidified to pH=5 by adding 1N hydrochloric acid and the THF is removed by rotary evaporation. The white suspension is separated by filtration and dried in high vacuum to afford the title compound of Formula 202, (R)-[1-(7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester.
6.3 Formula 203 where R1 is Benzyl; R2 is i-Propyl; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer and nitrogen inlet, is charged with 50 mL of DMF, 3.50 g (10 mmol) of (R)-[1-(7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (the compound of Formula 202 prepared, e.g., as described in Example 6.2), 1.34 mL of benzyl bromide (98%), and 3.04 g of potassium carbonate. The mixture is stirred at room temperature overnight. TLC (hexanes/ethyl acetate 7:3) indicates complete reaction. The mixture is transferred into a Erlenmeyer flask and mixed with 100 mL of water. To the stirring mixture is then added hexanes, 50 mL. The formed white solid is collected by filtration to afford the title compound of Formula 203 (R)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (also corresponding to Formula 107). The layers are separated and the organic is concentrated to dryness. The residue is chromatographed to afford an additional yield of the title compound.
Example 7
Synthesis of (R)-N-(3-Amino-propyl)-N-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinalolin-2-yl)-2-methyl-propyl]-4-methyl-benzamide
7.1 Formula 301 where R1 is Benzyl; R2 is i-Propyl; R4′ is H; R7 is Chloro; and R5, R6 and R8 are H
A dry 3-necked, round bottomed flask, equipped with a magnetic stirrer, nitrogen inlet, heating mantle and water condenser, is charged with 60 mL of toluene, 4.42 g (10 mmol) of (R)-[1-(3-benzyl-7-chloro-4-oxo-3,4-dihydro-quinazolin-2-yl)-2-methylpropyl]-carbamic acid tert-butyl ester (the compound of Formula 107 or 203 prepared, e.g., as described in Example 6.4 or 6.3), and 4.20 g of PTSA. The mixture is heated to reflux for 1 h, during which the evolution of gas is observed. Upon cessation of gas evolution, TLC analysis (hexanes/ethyl acetate 7:3) indicates complete reaction. The mixture is cooled to room temperature, initially forms an oil that separates at the bottom of the flask and quickly solidifies into a brown solid. Toluene is decanted and 50 mL of saturated potassium bicarbonate (room temperature) is added to the solid with stirring followed by the addition of 25 mL of water. The resulting white solid is collected by filtration to afford the title compound of Formula 301, (R)-2-(1-amino-2-methyl-propyl)-3-benzyl-7-chloro-3H-quinazolin-4-one.
7.2 Formula I where R1 is Benzyl; R2 is i-Propyl; R3 is p-Methyl-phenyl; R4 is n-Propylamine; R7 is Chloro; and R5, R6 and R8 are H
The (R)-2-(1-amino-2-methyl-propyl)-3-benzyl-7-chloro-3H-quinazolin-4-one obtained in Example 7.1 is carried forward as described in Examples 1.7 through 1.9 to yield the (R)-isomer of the title compound.
Example 8
8.1 Formula 402 where R2 is i-Propyl; and R4′ is n-Propyl-NHBoc
A solution of 2-bromo-3-methyl-butyric acid ethyl ester in EtOH (0.3 M) is treated with 1.1 eq of n-propyl-HNBoc-amine and the mixture stirred overnight. The solvents are evaporated and the residue re-dissolved in dichloromethane and washed with 3% NaOH. The organics are dried over sodium sulfate, filtered and evaporated to dryness to give the corresponding crude title compound of Formula 402.
8.2 Formula 403 where R2 is i-Propyl; R3 is p-Methyl-phenyl; and R4′ is n-Propyl-NHBoc
The crude compound of Formula 402, prepared, e.g., as in Example 8.1, is dissolved in dichloromethane to a concentration of 0.25 M and treated with 1.1 eq of p-toluoyl chloride and 1.1 eq of triethylamine. The mixture is stirred overnight and washed with 3% NaOH. The mixture is dried over sodium sulfate, filtered and evaporated. The title compound of Formula 403 is purified over silica gel using EtOAc/hexanes as eluent.
8.3 Formula 404 where R2 is i-Propyl; R3 is p-Methyl-phenyl; R4′ is n-Propyl-NHBoc; R7 is Chloro; and R5, R6 and R8 are H
The compound of Formula 403, prepared, e.g., as in Example 8.2, is dissolved in THF to a concentration of 0.5 M and then treated with 6 eq of LiOH dissolved in water to a concentration of 1 M. The mixture is stirred overnight and then evaporated to dryness. The residue is triturated with dichloromethane, dried over sodium sulfate, filtered and evaporated to give crude lithium salt. The lithium salt is dissolved in DMF to a concentration of 0.3 M and treated with 1.5 eq of PyBroP and 1.1 eq of 2-amino-4-chloro benzoic acid methyl ester. The mixture is stirred overnight and washed with 3% NaOH. The mixture is dried over sodium sulfate, filtered and evaporated. The crude title compound of Formula 404 is purified over silica gel using EtOAc/hexanes as eluent.
8.4 Formula 405 where R2 is i-Propyl; R3 is p-Methyl-phenyl; R4′ is n-Propyl-NHBoc; R7 is Chloro; and R5, R6 and R8 are H
The compound of Formula 404, prepared, e.g., as in Example 8.3, is dissolved in THF to a concentration of 0.5 M and then treated with 6 eq of LiOH dissolved in water to a concentration of 1 M. The mixture is stirred overnight and then evaporated to dryness. The residue is triturated with dichloromethane, dried over sodium sulfate, filtered and evaporated to give the crude title compound of Formula 405 as a lithium salt.
8.5 Formula 406 where R2 is i-Propyl; R3 is p-Methyl-phenyl; R4′ is n-Propyl-NHBoc; R1 is Chloro; and R5, R6 and R8 are H
The lithium salt of Formula 405, prepared, e.g., as in Example 8.4, is dissolved in DMF to a concentration of 0.3 M and treated with 1.4 eq of PyBroP, 0.2 eq of triethylamine and 1.2 eq of benzylamine. The mixture is stirred overnight and washed with 3% NaOH. The mixture is dried over sodium sulfate, filtered and evaporated. The crude title compound of Formula 406 is purified over silica gel using EtOAc/hexanes as eluent.
8.6 Formula 407 where R1 is Benzyl; R2 is i-Propyl; R3 is p-Methyl-phenyl; R4′ is n-Propyl-NHBoc; R7 is Chloro; and R5, R6 and R8 are H
The compound of Formula 406, prepared, e.g., as in Example 8.5, is mixed with ethylene glycol to a concentration of 0.1 M and to this is added 2 eq of KOH. The mixture is stirred at 110 C overnight. After cooling to room temperature, the mixture is diluted with EtOAc and washed with NaHCO3. The solvent is dried over sodium sulfate, filtered and evaporated to dryness. The residue is purified over silica gel with EtOAc/hexanes as eluent.
8.7 Formula I where R1 is Benzyl; R2 is i-Propyl; R3 is p-Methyl-phenyl; R4 is n-Propylamine; R7 is Chloro; and R5, R6 and R8 are H
The compound of Formula 407, prepared, e.g., as in Example 8.6, is dissolved in a 95/5 mixture of TFA/water to a concentration of 0.2 M. After stirring 30 min, the mixture is evaporated to dryness. The residue is partitioned between EtOAc and NaHCO3 solution, dried over sodium sulfate, filtered and evaporated to give pure title compound of Formula I.
While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes can be made and equivalents can be substituted without departing from the true spirit and scope of the invention. In addition, many modifications can be made to adapt a particular situation, material, composition of matter, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto. All patents and publications cited above are hereby incorporated by reference.

## Claims

1. A method for the synthesis of an enantiomerically pure compound of Formula 107/203: 



where:
R1 is hydrogen, alkyl, aryl, alkylaryl, heteroaryl, alkylheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl or substituted alkylheteroaryl;
R2 is alkyl, oxaalkyl, aryl, alkylaryl, heteroaryl, alkytheteroaryl, substituted alkyl, substituted aryl, substituted alkylaryl, substituted heteroaryl or substituted alkylheteroaryl,
R5, R6, R7 and R8 are independently hydrogen, hydroxy, alkyl, alkoxy, halogen, fluoroalkyl, nitro, cyano, substituted alkyl, amino, alkylamino, dialkylamino, alkylsulfonyl, alkylsulfonamido, sulfonamidoalkyl, sulfonamidoaryl, alkylthio, carboxyalkyl, carboxamido, aminocarbonyl, aryl or heretoaryl; and
X is hydrogen or a protecting group,

said method comprising the steps of:
A) contacting isobutyl chloroformate with an enantiomerically pure compound of Formula 101: 



B) contacting the product of step A with a compound of Formula 103: 




to yield a compound of Formula 104: 


C) converting the compound of Formula 104 to a compound of Formula 105; 



D) contacting the compound of Formula 105 with an amine of the formula R1NH2 to yield a compound of Formula 106




and
E) contacting the compound of Formula 106 with a cyclo-dehydration reagent chosen from lithium hydroxide monohydrate, HMDS, phosphorous oxychloride, oxalyl chloride, thionyl chloride, Brugess' reagent, Ph3P/l2, and Vilsmeier reagent to yield the compound of Formula 107/203.

2. The method of claim 1 where R2 is ethyl, i-propyl, c-propyl, t-butyl or c-pentyl.

3. The method of claim 1, wherein:
for R2, lower alkyl is ethyl, i-propyl, c-propyl, t-butyl or c-pentyl, and substituted lower alkyl is methylthiomethyl;
R5, R6, R7 and R8 are independently hydrogen, chloro, fluoro, methyl, substituted lower alkyl, methoxy, methylthio or cyano; and
X is is Boc, CBZi phthalide, alloc, or teoc.

4. The method of claim 1 wherein said enantiomerically pure compound of Formula 107/203 is represented by the formula:

5. The method of claim 1 wherein the cyolo-dehydration reagent is HMDS.

6. The method of claim 1 wherein the compound of Formula 107/203 has an enantiomeric excess of at least about 90%.

7. The method of claim 6 wherein the compound of Formula 107/203 has an enantiomeric excess of at least about 97.5%.

8. The method of claim 1 where X is Boc, CBZ, phthalide, alloc, or teoc.

9. The method of claim 1 wherein the compound of Formula 101 is the enantiomer of a naturally occurring or substituted, optionally N-protected amino acid corresponding to the enantiomer of said quinazolinone.

10. The method of claim 9 wherein the compound of Formula 101 is valine.

11. The method of claim 1 wherein X is a protecting group and the method further comprises the step of de-protecting the compound of Formula 107/203 to yield a compound of Formula 107/203 wherein X is H.