WO2020229427A1 - Antimalarial hexahydropyrimidine analogues - Google Patents

Abstract

A series of 2-imino-6-methylhexahydropyrimidin-4-one derivatives of formula (I), substituted in the 6-position by a fused bicyclic heteroaryl moiety (including benzimidazolyl), being potent inhibitors of the growth and propagation of th ePIasmodium falciparum parasite in human blood, are beneficial as pharmaceutical agents, especially in the treatment of malaria. (Formula I)

Description

ANTIMALARIAL HEXAHYDROPYRIMIDINE ANALOGUES The present invention relates to a class of heterocyclic compounds, and to their use in therapy. More particularly, this invention is concerned with pharmacologically active substituted hexahydropyrimidine derivatives, and analogues thereof. These compounds are potent inhibitors of the growth and propagation of the Plasmodium falciparum parasite in human blood, and are accordingly of benefit as pharmaceutical agents, especially in the treatment of malaria.

Malaria is a mosquito-borne infectious disease, caused by a parasite of the genus Plasmodium, which has devastating consequences. In 2010, an estimated 225 million cases were reported, with 610,000 to 971,000 deaths, approximately 80% of which occurred in sub-Saharan Africa, mostly in young children (aged 5 years or less).

The compounds in accordance with the present invention, being potent inhibitors of the growth and propagation of the P. falciparum parasite in human blood, are therefore beneficial in the treatment of malaria.

In addition, the compounds in accordance with the present invention may be beneficial as pharmacological standards for use in the development of new biological tests and in the search for new pharmacological agents. Thus, the compounds of this invention may be useful as radioligands in assays for detecting pharmacologically active

compounds.

Co-pending international patent application no. PCT/EP2019/058249 (published on 10 October 2019 as WO 2019/192992) describes a class of heterocyclic compounds which are stated to be potent inhibitors of the growth and propagation of the P. falciparum parasite in human blood, and therefore to be beneficial in the treatment of malaria.

WO 2017/142825 describes a family of heterocyclic compounds which are stated to be potent inhibitors of P. falciparum growth in vitro that may be useful for the treatment of malaria.

WO 2017/089453 and WO 2017/144517 describe heterocyclic compounds which are stated to be potent and selective inhibitors of plasmepsin V activity that are beneficial in the treatment of malaria.

WO 2016/172255, WO 2016/118404 and WO 2011/044181 describe certain classes of heterocyclic compounds which are stated to be BACE inhibitors that may be useful for treating Ab-related pathologies including Alzheimer’s disease. WO 2008/103351, WO 2006/065277 and WO 2005/058311 describe a family of heterocyclic compounds that are stated to be aspartyl protease inhibitors. The compounds described in those publications are also stated to be effective in a method of inhibiting inter alia plasmepsins (specifically plasmepsins I and II) for treatment of malaria.

The present invention provides a compound of formula (I) or a pharmaceutically acceptable salt thereof:

wherein

W represents C(O) or S(O)2;

X represents C-R² or N;

A represents C-R³ or N;

B represents C-R⁴ or N;

D represents C-R⁵ or N;

Z represents C_1-6 alkyl, C_3-7 cycloalkyl, aryl, C_3-7 heterocycloalkyl or heteroaryl, any of which groups may be optionally substituted by one or more substituents;

R¹ represents C2-6 alkyl, optionally substituted by hydroxy; or R¹ represents C3-7 cycloalkyl, C_3-7 cycloalkyl(C_1-6)alkyl, aryl(C_1-6)alkyl, C_3-7 heterocycloalkyl, C_3-7 heterocycloalkyl(C1-6)alkyl, C4-9 heterobicycloalkyl, C4-9 spiroheterocycloalkyl or heteroaryl(C1-6)alkyl, any of which groups may be optionally substituted by one or more substituents;

R² represents hydrogen, halogen, cyano or C_1-4 alkyl; and

R³, R⁴ and R⁵ independently represent hydrogen, halogen, cyano or trifluoro- methyl.

The compounds in accordance with the present invention are encompassed within the broadest generic scope of WO 2016/172255, WO 2011/044181, WO 2008/103351, WO 2006/065277 and WO 2005/058311. There is, however, no specific disclosure in any of those publications of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof.

The present invention also provides a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, for use in therapy.

The present invention also provides a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, for use in the treatment and/or prevention of malaria.

The present invention also provides a method for the treatment and/or prevention of malaria which comprises administering to a patient in need of such treatment an effective amount of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof.

The present invention also provides the use of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for the treatment and/or prevention of malaria.

Where any of the groups in the compounds of formula (I) above is stated to be optionally substituted, this group may be unsubstituted, or substituted by one or more substituents. Typically, such groups will be unsubstituted, or substituted by one, two or three substituents, generally by one or two substituents.

For use in medicine, the salts of the compounds of formula (I) will be

pharmaceutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds of use in the invention or of their pharmaceutically acceptable salts. Standard principles underlying the selection and preparation of pharmaceutically acceptable salts are described, for example, in Handbook of Pharmaceutical Salts:

Properties, Selection and Use, ed. P.H. Stahl & C.G. Wermuth, Wiley-VCH, 2002.

Suitable alkyl groups which may be present on the compounds of use in the invention include straight-chained and branched C1-6 alkyl groups, for example C1-4 alkyl groups. Typical examples include methyl and ethyl groups, and straight-chained or branched propyl, butyl and pentyl groups. Particular alkyl groups include methyl, ethyl, n- propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2,2-dimethylpropyl and 3- methylbutyl. Derived expressions such as“C1-6 alkoxy”,“C1-6 alkylthio”,“C1-6 alkylsulfonyl” and“C_1-6 alkylamino” are to be construed accordingly. The term“C3-7 cycloalkyl” as used herein refers to monovalent groups of 3 to 7 carbon atoms derived from a saturated monocyclic hydrocarbon, and may comprise benzo- fused analogues thereof. Suitable C3-7 cycloalkyl groups include cyclopropyl, cyclobutyl, benzocyclobutenyl, cyclopentyl, indanyl, cyclohexyl and cycloheptyl.

The term“aryl” as used herein refers to monovalent carbocyclic aromatic groups derived from a single aromatic ring or multiple condensed aromatic rings. Suitable aryl groups include phenyl and naphthyl, preferably phenyl.

Suitable aryl(C_1-6)alkyl groups include benzyl, phenylethyl, phenylpropyl and naphthylmethyl.

The term“C3-7 heterocycloalkyl” as used herein refers to saturated monocyclic rings containing 3 to 7 carbon atoms and at least one heteroatom selected from oxygen, sulphur and nitrogen, and may comprise benzo-fused analogues thereof. Suitable heterocycloalkyl groups include oxetanyl, azetidinyl, tetrahydrofuranyl, dihydrobenzo- furanyl, dihydrobenzothienyl, pyrrolidinyl, indolinyl, isoindolinyl, oxazolidinyl, thiazolidinyl, isothiazolidinyl, imidazolidinyl, tetrahydropyranyl, chromanyl, dioxanyl, tetrahydrothiopyranyl, piperidinyl, 1,2,3,4-tetrahydroquinolinyl, 1,2,3,4-tetrahydro- isoquinolinyl, piperazinyl, 1,2,3,4-tetrahydroquinoxalinyl, hexahydro-[1,2,5]thiadiazolo- [2,3-a]pyrazinyl, homopiperazinyl, morpholinyl, benzoxazinyl, thiomorpholinyl, azepanyl, oxazepanyl, diazepanyl, thiadiazepanyl and azocanyl.

The term“C4-9 heterobicycloalkyl” as used herein refers to monovalent groups of 4 to 9 carbon atoms derived from a saturated bicyclic hydrocarbon, comprising one or more heteroatoms selected from oxygen, sulphur and nitrogen. Typical heterobicycloalkyl groups include 3-azabicyclo[3.1.0]hexanyl, 2-oxa-5-azabicyclo[2.2.1]heptanyl, 7-oxa- bicyclo[2.2.1]hexanyl, 6-azabicyclo[3.2.0]heptanyl, 3-azabicyclo[3.1.1]heptanyl, 6-oxa-3- azabicyclo[3.1.1]heptanyl, 3-azabicyclo[4.1.0]heptanyl, 2-oxabicyclo[2.2.2]octanyl, quinuclidinyl, 2-oxa-5-azabicyclo[2.2.2]octanyl, 3-azabicyclo[3.2.1]octanyl, 8-oxabicyclo- [3.2.1]octanyl, 8-azabicyclo[3.2.1]octanyl, 3-oxa-8-azabicyclo[3.2.1]octanyl, 3,8-diaza- bicyclo[3.2.1]octanyl, 3,6-diazabicyclo[3.2.2]nonanyl, 3-oxa-7-azabicyclo[3.3.1]nonanyl, 3,7-dioxa-9-azabicyclo[3.3.1]nonanyl and 3,9-diazabicyclo[4.2.1]nonanyl.

The term“C4-9 spiroheterocycloalkyl” as used herein refers to saturated bicyclic ring systems containing 4 to 9 carbon atoms and at least one heteroatom selected from oxygen, sulphur and nitrogen, in which the two rings are linked by a common atom.

Suitable spiroheterocycloalkyl groups include 5-azaspiro[2.3]hexanyl, 5-azaspiro[2.4]- heptanyl, 2-oxaspiro[3.3]heptanyl, 2-azaspiro[3.3]heptanyl, 2-oxa-6-azaspiro[3.3]- heptanyl, 3-oxa-6-azaspiro[3.3]heptanyl, 6-thia-2-azaspiro[3.3]heptanyl, 2-oxa-6-azaspiro- [3.4]octanyl, 2-oxa-6-azaspiro[3.5]nonanyl, 7-oxa-2-azaspiro[3.5]nonanyl, 2-oxa-7-aza- spiro[3.5]nonanyl and 2,4,8-triazaspiro[4.5]decanyl.

The term“heteroaryl” as used herein refers to monovalent aromatic groups containing at least five atoms derived from a single ring or multiple condensed rings, wherein one or more carbon atoms have been replaced by one or more heteroatoms selected from oxygen, sulfur and nitrogen. Suitable heteroaryl groups include furyl, benzofuryl, dibenzofuryl, thienyl, benzothienyl, thieno[2,3-c]pyrazolyl, thieno[3,2-c]- pyridinyl, dibenzothienyl, pyrrolyl, indolyl, pyrrolo[2,3-b]pyridinyl, pyrrolo[3,2-c]- pyridinyl, pyrrolo[3,4-b]pyridinyl, pyrazolyl, pyrazolo[1,5-a]pyridinyl, pyrazolo[3,4-b]- pyridinyl, pyrazolo[3,4-d]pyrimidinyl, indazolyl, 4,5,6,7-tetrahydroindazolyl, oxazolyl, benzoxazolyl, isoxazolyl, thiazolyl, benzothiazolyl, isothiazolyl, imidazolyl,

benzimidazolyl, imidazo[2,1-b]thiazolyl, imidazo[1,2-a]pyridinyl, imidazo[1,5-a]- pyridinyl, imidazo[4,5-b]pyridinyl, purinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-a]- pyrazinyl, oxadiazolyl, thiadiazolyl, triazolyl, [1,2,4]triazolo[1,5-a]pyridinyl,

[1,2,4]triazolo[1,5-a]pyrimidinyl, benzotriazolyl, tetrazolyl, pyridinyl, quinolinyl, isoquinolinyl, naphthyridinyl, pyridazinyl, cinnolinyl, phthalazinyl, pyrimidinyl, quinazolinyl, pyrazinyl, quinoxalinyl, pteridinyl, triazinyl and chromenyl.

The term“halogen” as used herein is intended to include fluorine, chlorine, bromine and iodine atoms, typically fluorine, chlorine or bromine.

The absolute stereochemical configuration of the chiral carbon atom in the W- containing six-membered ring of the compounds according to the invention is as depicted in formula (I) above. Generally, the compounds in accordance with the invention are at least 51% enantiomerically pure (by which it is meant that a sample thereof comprises a mixture of enantiomers containing 51% or more of the enantiomer depicted in formula (I) and 49% or less of the opposite antipode). Typically, the compounds in accordance with the invention are at least 60% enantiomerically pure. Appositely, the compounds in accordance with the invention are at least 75% enantiomerically pure. Suitably, the compounds in accordance with the invention are at least 80% enantiomerically pure. More suitably, the compounds in accordance with the invention are at least 85%

enantiomerically pure. Still more suitably, the compounds in accordance with the invention are at least 90% enantiomerically pure. Even more suitably, the compounds in accordance with the invention are at least 95% enantiomerically pure. Preferably, the compounds in accordance with the invention are at least 99% enantiomerically pure.

Ideally, the compounds in accordance with the invention are at least 99.9%

enantiomerically pure.

Where the compounds of formula (I) have one or more additional asymmetric centres, they may accordingly exist as enantiomers. Where the compounds in accordance with the invention possess one or more additional asymmetric centres, they may also exist as diastereomers. The invention is to be understood to extend to the use of all such enantiomers and diastereomers, and to mixtures thereof in any proportion, including racemates. Formula (I) and the formulae depicted hereinafter are intended to represent all individual stereoisomers and all possible mixtures thereof, unless stated or shown otherwise. In addition, compounds of formula (I) may exist as tautomers, for example keto (CH₂C=O)«enol (CH=CHOH) tautomers or amide (NHC=O)«hydroxyimine (N=COH) tautomers or imide (NHC=NH)«aminoimine (N=CNH₂) tautomers. Formula (I) and the formulae depicted hereinafter are intended to represent all individual tautomers and all possible mixtures thereof, unless stated or shown otherwise. In addition, under certain circumstances, e.g. where R³ represents halogen, compounds of formula (I) may exist as atropisomers. Formula (I) and the formulae depicted hereinafter are intended to represent all individual atropisomers and all possible mixtures thereof, unless stated or shown otherwise.

It is to be understood that each individual atom present in formula (I), or in the formulae depicted hereinafter, may in fact be present in the form of any of its naturally occurring isotopes, with the most abundant isotope(s) being preferred. Thus, by way of example, each individual hydrogen atom present in formula (I), or in the formulae depicted hereinafter, may be present as a ¹H, ²H (deuterium; D) or ³H (tritium; T) atom, preferably ¹H. Similarly, by way of example, each individual carbon atom present in formula (I), or in the formulae depicted hereinafter, may be present as a ¹²C, ¹³C or ¹⁴C atom, preferably ¹²C.

In a first embodiment, W represents C(O). In a second embodiment, W represents S(O)₂.

In a first embodiment, the present invention provides a compound of formula (IA-1) or a pharmaceutically acceptable salt thereof:

wherein

X, A, B, D, Z and R¹ are as defined above.

In a second embodiment, the present invention provides a compound of formula (IA-2) or a pharmaceutically acceptable salt thereof:

wherein

X, A, B, D, Z and R¹ are as defined above.

In a first embodiment, X represents C-R². In a second embodiment, X represents .

In a first embodiment, the present invention provides a compound of formula (IB-1) or a pharmaceutically acceptable salt thereof:

wherein

W, A, B, D, Z, R¹ and R² are as defined above.

In a second embodiment, the present invention provides a compound of formula (IA-2) or a pharmaceutically acceptable salt thereof:

wherein

W, A, B, D, Z and R¹ are as defined above.

In a first embodiment, A represents C-R³. In a second embodiment, A represents N.

In a first embodiment, B represents C-R⁴. In a second embodiment, B represents N.

In a first embodiment, D represents C-R⁵. In a second embodiment, D represents N.

In a particular embodiment, X represents N; A represents C-R³; B represents C-R⁴; and D represents C-R⁵.

Generally, Z represents C_1-6 alkyl, C_3-7 cycloalkyl, aryl or heteroaryl, any of which groups may be optionally substituted by one or more substituents. In general, Z represents aryl or heteroaryl, either of which groups may be optionally substituted by one or more substituents.

In a first embodiment, Z represents aryl, which group may be optionally substituted by one or more substituents. In a second embodiment, Z represents heteroaryl, which group may be optionally substituted by one or more substituents. In a third embodiment, Z represents C_1-6 alkyl, which group may be optionally substituted by one or more substituents. In a fourth embodiment, Z represents C3-7 cycloalkyl, which group may be optionally substituted by one or more substituents. In a fifth embodiment, Z represents C_3-7 heterocycloalkyl, which group may be optionally substituted by one or more substituents.

Typically, Z represents phenyl, naphthyl, furyl, benzofuryl, dibenzofuryl, thienyl, benzothienyl, thieno[2,3-c]pyrazolyl, thieno[3,2-c]pyridinyl, dibenzothienyl, pyrrolyl, indolyl, pyrrolo[2,3-b]pyridinyl, pyrrolo[3,2-c]pyridinyl, pyrrolo[3,4-b]pyridinyl, pyrazolyl, pyrazolo[1,5-a]pyridinyl, pyrazolo[3,4-b]pyridinyl, pyrazolo[3,4-d]- pyrimidinyl, indazolyl, 4,5,6,7-tetrahydroindazolyl, oxazolyl, benzoxazolyl, isoxazolyl, thiazolyl, benzothiazolyl, isothiazolyl, imidazolyl, benzimidazolyl, imidazo[2,1-b]- thiazolyl, imidazo[1,2-a]pyridinyl, imidazo[1,5-a]pyridinyl, imidazo[4,5-b]pyridinyl, purinyl, imidazo[1,2-a]pyrimidinyl, imidazo[1,2-a]pyrazinyl, oxadiazolyl, thiadiazolyl, triazolyl, [1,2,4]triazolo[1,5-a]pyridinyl, [1,2,4]triazolo[1,5-a]pyrimidinyl, benzotriazolyl, tetrazolyl, pyridinyl, quinolinyl, isoquinolinyl, naphthyridinyl, pyridazinyl, cinnolinyl, phthalazinyl, pyrimidinyl, quinazolinyl, pyrazinyl, quinoxalinyl, pteridinyl, triazinyl or chromenyl, any of which groups may be optionally substituted by one or more

substituents. Additionally, Z may represent tert-butyl or cyclopropyl, either of which groups may be optionally substituted by one or more substituents.

Appositely, Z represents phenyl, pyridinyl, pyridazinyl, pyrimidinyl or pyrazinyl, any of which groups may be optionally substituted by one or more substituents.

Additionally, Z may represent tert-butyl or cyclopropyl, either of which groups may be optionally substituted by one or more substituents.

More particularly, Z represents tert-butyl, cyclopropyl, phenyl or pyridinyl, any of which groups may be optionally substituted by one or more substituents.

Suitably, Z represents phenyl, which group may be optionally substituted by one or more substituents. Typical examples of optional substituents on Z include one, two or three substituents independently selected from halogen, cyano, nitro, C_1-6 alkyl, difluoromethyl, trifluoromethyl, trifluoroethyl, hydroxy, hydroxy(C1-6)alkyl, oxo, C1-6 alkoxy, difluoro- methoxy, difluoroethoxy, trifluoromethoxy, trifluoroethoxy, phenoxy, methylenedioxy, difluoromethylenedioxy, C_1-6 alkylthio, C_1-6 alkylsulfinyl, C_1-6 alkylsulfonyl, amino, C_1-6 alkylamino, di(C_1-6)alkylamino, amino(C_1-6)alkyl, di(C_1-6)alkylamino(C_1-6)alkyl, C_2-6 alkylcarbonylamino, C2-6 alkoxycarbonylamino, C1-6 alkylsulfonylamino, formyl, C2-6 alkylcarbonyl, carboxy, C_2-6 alkoxycarbonyl, aminocarbonyl, C_1-6 alkylaminocarbonyl, di(C_1-6)alkylaminocarbonyl, aminosulfonyl, C_1-6 alkylaminosulfonyl, di(C_1-6)alkylamino- sulfonyl and di(C1-6)alkylsulfoximino.

Suitable examples of optional substituents on Z include one, two or three substituents independently selected from cyano.

Typical examples of particular substituents on Z include one, two or three substituents independently selected from fluoro, chloro, bromo, cyano, nitro, methyl, ethyl, isopropyl, tert-butyl, difluoromethyl, trifluoromethyl, trifluoroethyl, hydroxy, hydroxymethyl, hydroxyethyl, hydroxyisopropyl, oxo, methoxy, isopropoxy, difluoro- methoxy, difluoroethoxy, trifluoromethoxy, trifluoroethoxy, phenoxy, methylenedioxy, difluoromethylenedioxy, methylthio, methylsulfinyl, methylsulfonyl, amino, methyl- amino, dimethylamino, aminomethyl, dimethylaminomethyl, acetylamino, methoxy- carbonylamino, methylsulfonylamino, formyl, acetyl, carboxy, methoxycarbonyl, ethoxy- carbonyl, aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, aminosulfonyl, methylaminosulfonyl, dimethylaminosulfonyl and dimethylsulfoximino.

Suitable examples of particular substituents on Z include one, two or three substituents independently selected from cyano.

Selected values of Z include tert-butyl, cyclopropyl, phenyl, cyanophenyl and pyridinyl.

An illustrative value of Z is phenyl.

Appositely, R¹ represents C_3-7 cycloalkyl, C_3-7 cycloalkyl(C_1-6)alkyl, aryl(C_1-6)- alkyl, C_3-7 heterocycloalkyl, C_3-7 heterocycloalkyl(C_1-6)alkyl, C_4-9 heterobicycloalkyl, C_4-9 spiroheterocycloalkyl or heteroaryl(C1-6)alkyl, any of which groups may be optionally substituted by one or more substituents.

Generally, R¹ represents C_2-6 alkyl, optionally substituted by hydroxy; or R¹ represents C3-7 cycloalkyl, C3-7 cycloalkyl(C1-6)alkyl, aryl(C1-6)alkyl, C3-7 heterocycloalkyl, C3-7 heterocycloalkyl(C1-6)alkyl or heteroaryl(C1-6)alkyl, any of which groups may be optionally substituted by one or more substituents.

More particularly, R¹ represents C3-7 cycloalkyl, C3-7 cycloalkyl(C1-6)alkyl, aryl- (C1-6)alkyl, C3-7 heterocycloalkyl, C3-7 heterocycloalkyl(C1-6)alkyl or heteroaryl(C1-6)- alkyl, any of which groups may be optionally substituted by one or more substituents.

Typically, R¹ represents C_3-7 heterocycloalkyl, which group may be optionally substituted by one or more substituents.

A particular value of R¹ is tetrahydropyranyl, which group may be optionally substituted by one or more substituents.

Typical examples of optional substituents on R¹ include one, two or three substituents independently selected from halogen, cyano, nitro, C1-6 alkyl, difluoromethyl, trifluoromethyl, hydroxy, hydroxy(C_1-6)alkyl, oxo, C_1-6 alkoxy, difluoromethoxy, trifluoromethoxy, C1-6 alkylthio, C1-6 alkylsulfinyl, C1-6 alkylsulfonyl, amino, C1-6 alkylamino, di(C1-6)alkylamino, amino(C1-6)alkyl, di(C1-6)alkylamino(C1-6)alkyl, C2-6 alkylcarbonylamino, C_2-6 alkoxycarbonylamino, C_1-6 alkylsulfonylamino, formyl, C_2-6 alkylcarbonyl, carboxy, C2-6 alkoxycarbonyl, aminocarbonyl, C1-6 alkylaminocarbonyl, di(C1-6)alkylaminocarbonyl, aminosulfonyl, C1-6 alkylaminosulfonyl and di(C1-6)alkyl- aminosulfonyl.

Suitable examples of optional substituents on R¹ include one, two or three substituents independently selected from C1-6 alkyl.

Typical examples of particular substituents on R¹ include one, two or three substituents independently selected from fluoro, chloro, bromo, cyano, nitro, methyl, ethyl, isopropyl, difluoromethyl, trifluoromethyl, hydroxy, hydroxymethyl, hydroxyethyl, hydroxyisopropyl, oxo, methoxy, difluoromethoxy, trifluoromethoxy, methylthio, methylsulfinyl, methylsulfonyl, amino, methylamino, dimethylamino, aminomethyl, dimethylaminomethyl, acetylamino, methoxycarbonylamino, methylsulfonylamino, formyl, acetyl, carboxy, methoxycarbonyl, ethoxycarbonyl, aminocarbonyl, methyl- aminocarbonyl, dimethylaminocarbonyl, aminosulfonyl, methylaminosulfonyl and dimethylaminosulfonyl.

Suitable examples of particular substituents on R¹ include methyl.

Particular values of R¹ include tetrahydropyranyl, methyltetrahydropyranyl and dimethyltetrahydropyranyl. More particularly, R¹ may represent tetrahydropyranyl or methyltetrahydropyranyl. In a first embodiment, R¹ represents tetrahydropyranyl. In a second embodiment, R¹ represents methyltetrahydropyranyl. In a third embodiment, R¹ represents dimethyltetrahydropyranyl.

In a first embodiment, R² represents hydrogen. In a second embodiment, R² represents halogen, especially fluoro or chloro. In one aspect of that embodiment, R² represents fluoro. In another aspect of that embodiment, R² represents chloro. In a third embodiment, R² represents cyano. In a fourth embodiment, R² represents C_1-4 alkyl, especially methyl or ethyl. In one aspect of that embodiment, R² represents methyl. In another aspect of that embodiment, R² represents ethyl.

Generally, R³, R⁴ and R⁵ independently represent hydrogen or halogen.

Generally, R³ represents hydrogen, halogen, cyano or trifluoromethyl.

Typically, R³ represents hydrogen or halogen.

In a first embodiment, R³ represents hydrogen. In a second embodiment, R³ represents halogen, especially fluoro or chloro. In one aspect of that embodiment, R³ represents fluoro. In another aspect of that embodiment, R³ represents chloro. In a third embodiment, R³ represents cyano. In a fourth embodiment, R³ represents trifluoromethyl.

Selected values of R³ include hydrogen, fluoro and chloro.

Suitably, R³ represents chloro.

Generally, R⁴ represents hydrogen, halogen, cyano or trifluoromethyl.

Typically, R⁴ represents hydrogen or halogen.

In a first embodiment, R⁴ represents hydrogen. In a second embodiment, R⁴ represents halogen, especially fluoro or chloro. In one aspect of that embodiment, R⁴ represents fluoro. In another aspect of that embodiment, R⁴ represents chloro. In a third embodiment, R⁴ represents cyano. In a fourth embodiment, R⁴ represents trifluoromethyl.

Generally, R⁵ represents hydrogen, halogen, cyano or trifluoromethyl.

Typically, R⁵ represents hydrogen or halogen.

In a first embodiment, R⁵ represents hydrogen. In a second embodiment, R⁵ represents halogen, especially fluoro or chloro. In one aspect of that embodiment, R⁵ represents fluoro. In another aspect of that embodiment, R⁵ represents chloro. In a third embodiment, R⁵ represents cyano. In a fourth embodiment, R⁵ represents trifluoromethyl.

Selected values of R⁵ include hydrogen and fluoro.

One sub-class of compounds according to the invention is represented by the compounds of formula (IIA), and pharmaceutically acceptable salts thereof:

wherein

R¹¹ represents hydrogen or methyl;

R¹² represents hydrogen or methyl; and

Z, R³ and R⁵ are as defined above.

In a first embodiment, R¹¹ represents hydrogen. In a second embodiment, R¹¹ represents methyl.

In a first embodiment, R¹² represents hydrogen. In a second embodiment, R¹² represents methyl.

In a first embodiment, R¹¹ and R¹² both represent hydrogen. In a second embodiment, R¹¹ represents hydrogen and R¹² represents methyl. In a third embodiment, R¹¹ and R¹² both represent methyl.

Specific novel compounds in accordance with the present invention include each of the compounds whose preparation is described in the accompanying Examples, and pharmaceutically acceptable salts thereof.

The present invention also provides a pharmaceutical composition which comprises a compound in accordance with the invention as described above, or a pharmaceutically acceptable salt thereof, in association with one or more pharmaceutically acceptable carriers.

Pharmaceutical compositions according to the invention may take a form suitable for oral, buccal, parenteral, nasal, topical, ophthalmic or rectal administration, or a form suitable for administration by inhalation or insufflation.

For oral administration, the pharmaceutical compositions may take the form of, for example, tablets, lozenges or capsules prepared by conventional means with

pharmaceutically acceptable excipients such as binding agents (e.g. pregelatinised maize starch, polyvinylpyrrolidone or hydroxypropyl methyl cellulose); fillers (e.g. lactose, microcrystalline cellulose or calcium hydrogenphosphate); lubricants (e.g. magnesium stearate, talc or silica); disintegrants (e.g. potato starch or sodium glycollate); or wetting agents (e.g. sodium lauryl sulfate). The tablets may be coated by methods well known in the art. Liquid preparations for oral administration may take the form of, for example, solutions, syrups or suspensions, or they may be presented as a dry product for constitution with water or other suitable vehicle before use. Such liquid preparations may be prepared by conventional means with pharmaceutically acceptable additives such as suspending agents, emulsifying agents, non-aqueous vehicles or preservatives. The preparations may also contain buffer salts, flavouring agents, colouring agents or sweetening agents, as appropriate.

Preparations for oral administration may be suitably formulated to give controlled release of the active compound.

For buccal administration, the compositions may take the form of tablets or lozenges formulated in conventional manner.

The compounds of formula (I) may be formulated for parenteral administration by injection, e.g. by bolus injection or infusion. Formulations for injection may be presented in unit dosage form, e.g. in glass ampoules or multi-dose containers, e.g. glass vials. The compositions for injection may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulatory agents such as suspending, stabilising, preserving and/or dispersing agents. Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g. sterile pyrogen-free water, before use.

In addition to the formulations described above, the compounds of formula (I) may also be formulated as a depot preparation. Such long-acting formulations may be administered by implantation or by intramuscular injection.

For nasal administration or administration by inhalation, the compounds according to the present invention may be conveniently delivered in the form of an aerosol spray presentation for pressurised packs or a nebuliser, with the use of a suitable propellant, e.g. dichlorodifluoromethane, fluorotrichloromethane, dichlorotetrafluoroethane, carbon dioxide or other suitable gas or mixture of gases.

The compositions may, if desired, be presented in a pack or dispenser device which may contain one or more unit dosage forms containing the active ingredient. The pack or dispensing device may be accompanied by instructions for administration. For topical administration the compounds of use in the present invention may be conveniently formulated in a suitable ointment containing the active component suspended or dissolved in one or more pharmaceutically acceptable carriers. Particular carriers include, for example, mineral oil, liquid petroleum, propylene glycol, polyoxyethylene, polyoxypropylene, emulsifying wax and water. Alternatively, the compounds of use in the present invention may be formulated in a suitable lotion containing the active component suspended or dissolved in one or more pharmaceutically acceptable carriers. Particular carriers include, for example, mineral oil, sorbitan monostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol, benzyl alcohol, 2-octyldodecanol and water.

For ophthalmic administration the compounds of use in the present invention may be conveniently formulated as micronized suspensions in isotonic, pH-adjusted sterile saline, either with or without a preservative such as a bactericidal or fungicidal agent, for example phenylmercuric nitrate, benzylalkonium chloride or chlorhexidine acetate.

Alternatively, for ophthalmic administration compounds may be formulated in an ointment such as petrolatum.

For rectal administration the compounds of use in the present invention may be conveniently formulated as suppositories. These can be prepared by mixing the active component with a suitable non-irritating excipient which is solid at room temperature but liquid at rectal temperature and so will melt in the rectum to release the active component. Such materials include, for example, cocoa butter, beeswax and polyethylene glycols.

The quantity of a compound of use in the invention required for the prophylaxis or treatment of a particular condition will vary depending on the compound chosen and the condition of the patient to be treated. In general, however, daily dosages may range from around 10 ng/kg to 1000 mg/kg, typically from 100 ng/kg to 100 mg/kg, e.g. around 0.01 mg/kg to 40 mg/kg body weight, for oral or buccal administration, from around 10 ng/kg to 50 mg/kg body weight for parenteral administration, and from around 0.05 mg to around 1000 mg, e.g. from around 0.5 mg to around 1000 mg, for nasal administration or administration by inhalation or insufflation.

General methods for the preparation of the compounds of formula (I) as defined above are described in WO 2016/172255, WO 2011/044181 and WO 2008/103351.

The compounds in accordance with the invention wherein W represents C(O) may be prepared by treating a compound of formula (III):

wherein X, A, B, D, Z and R¹ are as defined above, R^p represents hydrogen or an N- protecting group, and R^w represents C1-4 alkyl, especially methyl; with a base; followed, as necessary, by removal of the N-protecting group R^p.

Suitably, the base of use in the above reaction is a C1-4 alkoxide salt, typically an alkali metal alkoxide such as potassium tert-butoxide. The reaction is conveniently accomplished in a suitable solvent, e.g. a cyclic ether such as tetrahydrofuran.

Suitably, the N-protecting group R^p is tert-butoxycarbonyl (BOC).

Where the N-protecting group R^p is BOC, subsequent removal of the BOC group may suitably be accomplished by treatment with an acid, e.g. a mineral acid such as hydrochloric acid, or an organic acid such as trifluoroacetic acid, typically at ambient temperature in a suitable solvent, e.g. a chlorinated solvent such as dichloromethane, or a cyclic ether such as 1,4-dioxane.

The intermediates of formula (III) above may be prepared by reacting a compound of formula (IV) with a compound of formula (V):

wherein X, A, B, D, Z, R¹, R^p and R^w are as defined above.

Generally, the reaction between compounds (IV) and (V) is performed in the presence of a coupling agent. A suitable coupling agent is N-(3-dimethylaminopropyl)-Nʹ- ethylcarbodiimide hydrochloride (EDCI). Suitably, the reaction is performed in the presence of a base, typically an organic base such as N,N-diisopropylethylamine.

The reaction between compounds (IV) and (V) is conveniently accomplished at ambient temperature in a suitable solvent, e.g. a dipolar aprotic solvent such as N,N- dimethylformamide.

Under certain circumstances, the reaction between compounds (IV) and (V) will proceed directly to the corresponding compound of formula (III).

In an alternative procedure, the compounds in accordance with the invention wherein X represents N may be prepared by a process which comprises cyclising a compound of formula (VI):

wherein W, A, B, D, Z, R¹ and R^p are as defined above; followed, as necessary, by removal of the N-protecting group R^p.

The cyclisation is conveniently effected by treating compound (VI) with a suitable reagent, e.g. an acid such as acetic acid, or trifluoroacetic acid.

The intermediates of formula (VI) above may be prepared by reacting a compound of formula Z-C(O)NH2 with a compound of formula (VII):

wherein W, A, B, D, R¹ and R^p are as defined above, and L¹ represents a suitable leaving group; in the presence of a transition metal catalyst.

Suitably, the leaving group L¹ is a halogen atom, e.g. chloro, bromo or iodo.

Suitably, the transition metal catalyst of use in the reaction between the compound of formula Z-C(O)NH₂ and compound (VII) is a palladium-containing catalyst. Typical palladium-containing catalysts include tris(dibenzylideneacetone)dipalladium(0);

palladium(II) acetate; [(4,5-bis(diphenylphosphino)-9,9-dimethylxanthene)-2-(2¢-amino- 1,1¢-biphenyl)]palladium(II) methanesulfonate (XantPhos Pd G3); chloro[2-(dicyclohexyl- phosphino)-3,6-dimethoxy-2¢,4¢,6¢-triisopropyl-1,1¢-biphenyl][2-(2-aminoethyl)phenyl]- palladium(II) (BrettPhos Pd G1); [(2-dicyclohexylphosphino-3,6-dimethoxy-2¢,4¢,6¢-tri- isopropyl-1,1¢-biphenyl)-2-(2¢-amino-1,1¢-biphenyl)]palladium(II) methanesulfonate (BrettPhos Pd G3); and (2-dicyclohexylphosphino-2¢,6¢-diisopropoxy-1,1¢-biphenyl)[2-(2¢- amino-1,1¢-biphenyl)]palladium(II) methanesulfonate (RuPhos Pd G3).

Suitably, the reaction is performed in the presence of an organophosphorus reagent (phosphine ligand). Typical phosphine ligands include 2-dicyclohexylphosphino-2¢,4¢,6¢- triisopropylbiphenyl (XPhos); 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene

(XantPhos); (±)-2,2¢-bis(diphenylphosphino)-1,1¢-binaphthalene (rac-BINAP); and 2- (dicyclohexylphosphino)-3,6-dimethoxy-2¢,4¢,6¢-triisopropyl-1,1¢-biphenyl (BrettPhos).

Suitably, the reaction is performed in the presence of a base. Typical bases include phosphate salts, e.g. an alkali metal phosphate such as potassium phosphate; alkoxide salts, e.g. an alkali metal alkoxide such as sodium tert-butoxide; and carbonate salts, e.g. an alkali metal carbonate such as cesium carbonate.

The reaction is conveniently accomplished at an elevated temperature in a suitable solvent, e.g. an aromatic solvent such as toluene; or a cyclic ether such as 1,4-dioxane. In another procedure, the compounds in accordance with the invention wherein X represents N may be prepared by a process which comprises cyclising a compound of formula (VIII):

wherein W, A, B, D, Z, R¹ and R^p are as defined above; under conditions analogous to those described above for the cyclisation of compound (VI); followed, as necessary, by removal of the N-protecting group R^p.

The intermediates of formula (VIII) above may be prepared by a two-step procedure which comprises:

(i) reacting a compound of formula Z-CHO with a compound of formula (IX):

wherein W, A, B, D, R¹ and R^p are as defined above, and R^q represents an N-protecting group; in the presence of a transition metal catalyst; and

(ii) removal of the N-protecting group R^q.

Suitably, the N-protecting group R^q is tert-butoxycarbonyl (BOC). Suitably, the transition metal catalyst of use in the reaction between the compound of formula Z-CHO and compound (IX) is a copper-containing catalyst. Typical copper- containing catalysts include copper(II) acetate, in which case step (i) is conveniently performed at an elevated temperature in a suitable solvent, e.g. a C1-4 alkanol such as ethanol.

Where the N-protecting group R^q is BOC, the removal thereof in step (ii) may suitably be accomplished by treatment with an acid, e.g. a mineral acid such as hydrochloric acid, or an organic acid such as trifluoroacetic acid.

The intermediates of formula (IX) above wherein R^q is tert-butoxycarbonyl may be prepared by reacting tert-butyl carbamate with a compound of formula (VII), under conditions analogous to those described above for the reaction of a compound of formula Z-C(O)NH₂ with a compound of formula (VII).

The intermediates of formula (VII) above wherein L¹ represents iodo may be prepared by iodination of a compound of formula (X):

wherein W, A, B, D, R¹ and R^p are as defined above.

Iodination may be effected by treatment of compound (X) with iodine mono- chloride, in which case the reaction may conveniently be carried out at ambient temperature in a suitable solvent, e.g. a C1-4 alkanol such as methanol.

The intermediates of formula (X) above wherein W represents C(O) may be prepared by treating a compound of formula (XI):

wherein A, B, D, R¹, R^p and R^w are as defined above, and R^s represents an N-protecting group; with a base, under conditions analogous to those described above for the treatment of a compound of formula (III) with a base; followed by removal of the N-protecting group R^s.

Suitably, the N-protecting group R^s is benzyloxycarbonyl.

Where the N-protecting group R^s is benzyloxycarbonyl, subsequent removal of the benzyloxycarbonyl group may suitably be accomplished by catalytic hydrogenation.

Typically, this will involve treatment with gaseous hydrogen in the presence of a hydrogenation catalyst such as palladium on charcoal.

The intermediates of formula (XI) above may be prepared by reacting a compound of formula (V) as defined above with a compound of formula (XII):

wherein A, B, D, R^w and R^s are as defined above; under conditions analogous to those described above for the reaction between compounds (IV) and (V).

Where they are not commercially available, the starting materials of formula (IV), (V) and (XII) may be prepared by methods analogous to those described in the

accompanying Examples, or by standard methods well known from the art. It will be understood that any compound of formula (I) initially obtained from any of the above processes may, where appropriate, subsequently be elaborated into a further compound of formula (I) by techniques known from the art.

Where a mixture of products is obtained from any of the processes described above for the preparation of compounds according to the invention, the desired product can be separated therefrom at an appropriate stage by conventional methods such as preparative HPLC; or column chromatography utilising, for example, silica and/or alumina in conjunction with an appropriate solvent system.

Where the above-described processes for the preparation of the compounds according to the invention give rise to mixtures of stereoisomers, these isomers may be separated by conventional techniques. In particular, where it is desired to obtain a particular enantiomer of a compound of formula (I) this may be produced from a corresponding mixture of enantiomers using any suitable conventional procedure for resolving enantiomers. Thus, for example, diastereomeric derivatives, e.g. salts, may be produced by reaction of a mixture of enantiomers of formula (I), e.g. a racemate, and an appropriate chiral compound, e.g. a chiral base. The diastereomers may then be separated by any convenient means, for example by crystallisation, and the desired enantiomer recovered, e.g. by treatment with an acid in the instance where the diastereomer is a salt. In another resolution process a racemate of formula (I) may be separated using chiral HPLC. Moreover, if desired, a particular enantiomer may be obtained by using an appropriate chiral intermediate in one of the processes described above. Alternatively, a particular enantiomer may be obtained by performing an enantiomer-specific enzymatic biotransformation, e.g. an ester hydrolysis using an esterase, and then purifying only the enantiomerically pure hydrolysed acid from the unreacted ester antipode.

Chromatography, recrystallisation and other conventional separation procedures may also be used with intermediates or final products where it is desired to obtain a particular geometric isomer of the invention.

During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in

Protective Groups in Organic Chemistry, ed. J.F.W. McOmie, Plenum Press, 1973; and T.W. Greene & P.G.M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 3^rd edition, 1999. The protecting groups may be removed at any convenient subsequent stage utilising methods known from the art.

The following Examples illustrate the preparation of compounds according to the invention.

The compounds of the present invention are potent inhibitors of the growth and propagation of the Plasmodium falciparum parasite in human blood. As such, they are active in a P. falciparum 3D7 asexual blood stage assay, exhibiting IC50 values of 50 mM or less, generally of 20 mM or less, usually of 5 mM or less, typically of 1 mM or less, suitably of 500 nM or less, ideally of 100 nM or less, and preferably of 20 nM or less (the skilled person will appreciate that a lower IC50 figure denotes a more active compound). Asexual Blood Stage Assay

The assay used to measure the effect of test compounds on a bloodstream stage of Plasmodium falciparum 3D7 strain employs SYBR green as the readout. This is a dye that binds to double stranded deoxyribonucleic acid (DNA) with a resulting increase in fluorescence, allowing detection of P. falciparum DNA in infected erythrocytes, and thereby providing a measure of parasite growth and propagation. P. falciparum culture maintenance

Erythrocytes (A+ blood) were prepared for both parasite culture and assay by washing 4 times with incomplete media (15.9 g RPMI 1640 (25 mM HEPES, L- glutamine), 1 g NaHCO₃, 2 g glucose, 400 µL gentacin (500 mg/mL), 2 mL hypoxanthine solution (13.6 g/L in 0.1M NaOH pH 7.3) in 1 litre of media). The cells were centrifuged at 1800g for 5 minutes, before decanting the supernatant and re-suspending in fresh incomplete media. On the final wash, the cells were re-suspended in complete media (incomplete media with 5 g/L AlbumaxII), and centrifuged at 1800g for 3 minutes. This cell sediment was treated as 100% haematocrit.

P. falciparum 3D7 was cultured in erythrocytes at 5% haematocrit in complete media at 37°C (1% O₂, 3% CO₂, balance N₂). Cultures were split on a weekly basis to achieve a 1% parasitaemia in erythrocites at 5% haematocrit in fresh media. Culture media is replaced by fresh media every other day (2 times during the week). Assay Procedure

On day 1, test compounds were added to assay plates using Echo dispensing technology (1.5 fold dilution and 20 points titration). 50 nL of each compound dilution was added to 50 µL of culture (5% haematocrit, 0.5% parasitaemia) and incubated for 72 h at 37°C (1% O₂, 3% CO₂, balance N₂). Final concentrations of test compounds ranged from 50,000 nM to 15 nM, in 0.5% DMSO.

On day 4, 10 µL SYBR green (Invitrogen S7563 supplied as 10,000 x concentrate in DMSO) pre-diluted to 3 x concentrate with Lysis buffer (20 mM Tris pH 7.9, 5% EDTA, 0.16% w/v, 1.6% TX100 v/v) was added to the cultures and incubated in the dark, overnight, at room temperature.

On day 5, fluorescent signal was measured using a BioTek plate reader (excitation 485 nm, emission 528 nm). All data were processed using IDBS ActivityBase. Raw data were converted into per cent inhibition through linear regression by setting the high inhibition control (mefloquine) as 100% and the no inhibition control (DMSO) as 0%. Quality control criteria for passing plates were as follows: Zʹ > 0.5, S:B > 3,

%CV(no inhibition control) < 15. The formula used to calculate Zʹ is:

where m denotes the mean; s denotes the standard deviation; p denotes the positive control; and n denotes the negative control.

All EC50 curve fitting was undertaken using the following bi-phasic two site dose response using XLfit model 300 (IDBS):

where A = 100 minus the top of the upper curve 1 and the bottom of lower curve; B = Hill slope; log(C) = IC50 concentration at lower site; log(D) = IC50 concentration at upper site; x = inhibitor concentration; and y = % inhibition. When tested in the P. falciparum 3D7 asexual blood stage assay as described above, the compounds of the accompanying Examples were found to exhibit the following IC₅₀ values.

EXAMPLES Abbreviations

DCM: dichloromethane EtOAc: ethyl acetate

DMSO: dimethyl sulfoxide THF: tetrahydrofuran

MeOH: methanol EtOH: ethanol

DEA: diethylamine DMF: N,N-dimethylformamide

DIPEA: N,N-diisopropylethylamine TFA: trifluoroacetic acid

TFAA: trifluoroacetic anhydride

EDCI: N-(3-dimethylaminopropyl)-Nʹ-ethylcarbodiimide hydrochloride

Pd₂(dba)₃: tris(dibenzylideneacetone)dipalladium(0)

XPhos: 2-dicyclohexylphosphino-2¢,4¢,6¢-triisopropylbiphenyl

XantPhos: 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene

XantPhos Pd G3: [(4,5-bis(diphenylphosphino)-9,9-dimethylxanthene)-2-(2¢-amino-1,1¢- biphenyl)]palladium(II) methanesulfonate

h: hour M: mass

r.t.: room temperature RT: retention time

DAD: Diode Array Detector

HPLC: High Performance Liquid Chromatography

LCMS: Liquid Chromatography Mass Spectrometry

ESI: Electrospray Ionisation Nomenclature

Compounds were named in accordance with IUPAC guidelines and with the aid of Biovia Draw version 16.1. Materials

Commercially available Zn dust was activated by stirring with dilute 1N HCl, then washing with water, methanol and acetone, followed by drying under vacuum at 100- 120°C for 15 minutes. Analytical Conditions

Method 1

Column: Waters X Bridge C18, 2.1 x 30 mm, 2.5 mm

Injection Volume: 5.0 mL

Flow Rate: 1.00 mL/minute

Detection:

MS– ESI+ m/z 150 to 800

UV– DAD 220-400 nm

Solvent A: 5 mM ammonium formate in water + 0.1% ammonia

Solvent B: acetonitrile + 5% Solvent A + 0.1% ammonia

Gradient program:

5% B to 95% B in 4.0 minutes; hold until 5.00 minutes;

at 5.10 minutes concentration of B is 5%; hold up to 6.5 minutes Method 2

Column: Waters UPLC X Bridge BEH (C18, 2.1 x 50 mm, 2.5 µm)

Temperature: 45°C

Injection volume: 1.0 mL

Flow rate: 1.00 mL/minute

Detection: Mass spectrometry– +/- detection in the same run

PDA: 210 to 400 nm

Solvent A: 10 mM ammonium formate in water + 0.1% formic acid

Solvent B: 95% acetonitrile + 5% H₂O + 0.1% formic acid Time % A % B

0 95 55

0.10 95 5

2.10 5 95

2.35 5 95

2.80 95 5 Method 3

Column: X-Select C18 (50 x 3 mm, 2.5 mm)

Flow rate: 1.2 mL/minute

Phase A: 5 mM ammonium bicarbonate in water

Phase B: HPLC grade acetonitrile

Gradient:

Time (min) % A % B

0 100 0

2 2 98

3 2 98

3.2 100 0

4 100 0 Method 4

Column: Zorbax Extend C18 (50 x 4.6 mm, 5 µm, 80A)

Mobile phase: 50:50 [10 mM ammonium acetate in water] : acetonitrile to

5:95 [10 mM ammonium acetate in water] : acetonitrile gradient over 1.5 minutes, then continue elution to 4 minutes.

Flow rate: 1.2 mL/minute INTERMEDIATE 1 1-(2-Chloro-4-fluoro-3-nitrophenyl)ethanone

To a stirred solution of 1-bromo-2-chloro-4-fluoro-3-nitrobenzene (16.0 g , 63.0 mmol) in 1,4-dioxane (160 mL), degassed for 5 minutes, were added tributyl(1-ethoxy- vinyl)stannane (23.6 mL, 69.3 mmol) and bis(triphenylphosphine)palladium(II) dichloride (3.53 g, 5.03 mmol). The reaction mixture was stirred at 85°C for 16 h, then diluted with saturated KF solution, filtered through a celite pad and washed with ethyl acetate. The filtrate was collected and washed with water. The organic layer was separated and concentrated under reduced pressure. The resulting oil was dissolved in THF (50 mL), and 4M aqueous HCl (50 mL) was added. The reaction mixture was stirred at room temperature for 16 h, then diluted with water and extracted into ethyl acetate. The organic layer was separated, dried over Na2SO4 and concentrated under reduced pressure. The crude residue was purified by column chromatography to afford the title compound (8.0 g, 58%) as an off-white solid. d_H (400 MHz, CDCl₃) 7.76-7.27 (m, 1H), 7.28 (dd, J 8.2 Hz, 1H), 2.66 (s, 3H). INTERMEDIATE 2 N-[1-(2-Chloro-4-fluoro-3-nitrophenyl)ethylidene]- -2-methylpropane-2-

sulfinamide

To a stirred solution of Intermediate 1 (24.6 g, 113.4 mmol) in toluene (200 mL) were added (R)-(+)-2-methyl-2-propanesulfinamide (41.1 g, 340.1 mmol) and

titanium(IV) ethoxide (118.6 mL, 566.8 mmol). The mixture was heated at 90°C for 16 h, then quenched with ice-cold water. Ethyl acetate was added, and the mixture was filtered through a celite plug. The organic layer was separated, washed with brine and dried over anhydrous Na2SO4. The solvent was removed under reduced pressure. The crude residue was purified by column chromatography (eluting with 30% ethyl acetate in hexane) to afford the title compound (10.0 g, 27%). dH (400 MHz, CDCl3) 7.50-7.47 (m, 1H), 7.31-7.25 (m, 1H), 2.71 (s, 3H), 1.28 (s, 9H). INTERMEDIATE 3 Methyl butylsulfinyl]amino}-3-(2-chloro-4-fluoro-3-nitrophenyl)-

butanoate

Zinc powder (66.8 g, 1078 mmol) and CuCl (20.5 g, 215.6 mmol) were suspended in dry 2-methyltetrahydrofuran (90 mL). The mixture was heated at 70°C and stirred vigorously for 40 minutes, then cooled to 50°C. Methyl bromoacetate (41.2 mL, 431 mmol) was added dropwise at such a rate that reflux was re-initiated, and a controlled reflux was maintained. Once addition was complete, the reaction mixture was stirred at 50°C for 30 minutes, then cooled to room temperature. A solution of Intermediate 2 (23.0 g, 71.9 mmol) in 2-methyltetrahydrofuran (60 mL) was added dropwise. The reaction mixture was stirred at room temperature for 16 h, then filtered through a celite pad and washed with ethyl acetate. The combined filtrate was washed with water. The organic layer was separated, dried over Na₂SO₄ and concentrated under reduced pressure. The crude residue was purified by flash column chromatography (eluting with 30-70% ethyl acetate in hexane) to afford the title compound (8.0 g, 28%). d_H (400 MHz, CDCl₃) 7.95-7.91 (m, 1H), 7.66 (m, J 8.9 Hz, 1H), 5.57 (s, 1H), 3.48 (s, 3H), 3.44 (d, J 16.2 Hz, 1H), 3.28 (d, J 16.2 Hz, 1H), 1.88 (s, 3H), 1.12 (s, 9H). INTERMEDIATE 4 Methyl -3-[4-(benzenecarboximidoylamino)-2-chloro-3-nitrophenyl]-3-(tert-butyl- sulfinylamino)butanoate

To a stirred solution of Intermediate 3 (6.3 g, 16.0 mmol) in THF (35 ml) were added K2CO3 (2.64 g, 19.2 mmol) and benzamidine (1.91 g, 16.0 mmol) at 0°C. The reaction mixture was heated at 75°C and stirred for 16 h, then quenched with aqueous NH₄Cl solution and extracted with ethyl acetate. The combined organic layers were washed with brine and dried over anhydrous sodium sulphate, then filtered. The solvent was evaporated. The resulting crude material was purified by flash column

chromatography (eluting with 80% ethyl acetate in hexane) to afford the title compound (2.5 g, 31%). dH (400 MHz, CDCl3) 7.77 (br s, 2H), 7.57 (d, J 7.5 Hz, 1H), 7.48 (d, J 6.6 Hz, 1H), 7.44-7.41 (m, 2H), 7.16 (br s, 2H), 7.00 (br s, 1H), 5.44 (s, 1H), 3.48 (s, 3H), 3.32 (m, 2H), 1.87 (s, 3H), 1.15 (s, 9H). INTERMEDIATE 5 Methyl (3S)-3-amino-3-(4-chloro-2-phenyl-3H-benzimidazol-5-yl)butanoate

hydrochloride

To a stirred solution of Intermediate 4 (1.9 g, 3.8 mmol) in acetic acid (10 mL) were added ammonium formate (1.22 g, 19.19 mmol) and 10% Pd/C (1.5 g) at room temperature. The reaction mixture was stirred at room temperature for 36 h, then filtered through a celite pad. The solvent was removed under reduced pressure at low

temperature. Water and EtOAc were added, and the reaction mixture was extracted with EtOAc. The combined organic layers were washed with brine, then dried over anhydrous sodium sulphate, filtered and concentrated. The crude residue was purified by flash column chromatography. The resulting off-white solid was dissolved in 1,4-dioxane (5 mL), and 4M HCl in 1,4-dioxane (5 mL) was added. The reaction mixture was stirred at room temperature for 12 h, then concentrated and triturated with diethyl ether followed by pentane, to afford the title compound (300 mg, 64%). d_H (400 MHz, DMSO-d₆) 8.91 (br s, 3H), 8.24 (d, J 6.8 Hz, 2H), 7.62-7.57 (m, 4H), 7.35 (d, J 8.6 Hz, 1H), 3.68 (d, J 16.6 Hz, 1H), 3.47 (s, 3H), 3.37 (d, J 16.4 Hz, 1H), 1.92 (s, 3H). INTERMEDIATE 6 tert-Butyl N-(tetrahydropyran-4-ylcarbamothioyl)carbamate

To a solution of N,Nʹ-bis-tert-butoxycarbonylthiourea (12.3 g, 44.5 mmol) in THF (100 mL) under nitrogen was added 60% NaH (5 g, 124.5 mmol) portionwise over a period of 10 minutes at 0°C. The mixture was stirred for 1 h, then TFAA (11.2 mL, 80.1 mmol) was added dropwise at 0°C. The mixture was stirred for 1 h, then a solution of tetrahydropyran-4-amine (4.5 g, 44.5 mmol) in THF (20 mL) was added. The reaction mixture was stirred at r.t. for 2 h, then quenched with ice-cold water and extracted with EtOAc (2 x 500 mL). The combined organic layers were dried over sodium sulfate, then the solvent was evaporated under reduced pressure. The crude residue was purified by column chromatography (silica gel, 100-200 mesh, 3% EtOAc/hexane) to afford the title compound (9.0 g, 77%) as a pale yellow solid. dH (400 MHz, CDCl3) 9.68 (br s, 1H), 7.81 (br s, 1H), 4.46-4.44 (m, 1H), 3.95 (d, J 11.6 Hz, 2H), 3.52 (t, J 11.6 Hz, 2H), 2.07 (d, J 11.6 Hz, 2H), 1.61-1.53 (m, 2H), 1.47 (s, 9H). INTERMEDIATE 7 tert-Butyl (NE)-N-[(4S)-4-(4-chloro-2-phenyl-3H-benzimidazol-5-yl)-4-methyl-6-oxo-1- (tetrahydropyran-4-yl)hexahydropyrimidin-2-ylidene]carbamate

To a solution of Intermediate 5 (0.11 g, 0.28 mmol) and Intermediate 6 (0.08 g, 0.31 mmol), in DMF (3 mL) at 0°C, were added EDCI (0.09 g, 0.46 mmol) and DIPEA (0.11 mL, 0.62 mmol). The reaction mixture was stirred at room temperature for 24 h, then quenched with H₂O (50 mL) and extracted with EtOAc (2 x 50 mL). The organic layer was separated, dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was dissolved in dry THF (6 mL) and cooled to 0°C, then potassium tert-butoxide in THF (1M, 0.37 mL) was added. The reaction mixture was stirred for 2 h, then quenched with water (250 mL) and extracted with EtOAc (2 x 50 mL). The combined organic layers were dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, eluting with 20% EtOAc in hexane) to afford the title compound (0.09 g, 74%) as an off-white solid. MS (ESI, Method 1) [M+H]⁺ 538, RT 2.07 minutes. INTERMEDIATE 8 rac-(2S,4S)-2-Methyltetrahydropyran-4-amine

To a stirred solution of 2-methyltetrahydropyran-4-one (10.0 g, 87.6 mmol) in MeOH (100 mL) were added benzylamine (14.3 mL, 131.4 mmol) and acetic acid (0.25 mL, 4.38 mmol) under a nitrogen atmosphere. The mixture was stirred for 4 h at room temperature, then sodium cyanoborohydride (8.27 g, 131.4 mmol) was added at r.t. The reaction mixture was stirred for 16 h, then concentrated under reduced pressure. The crude residue was purified by column chromatography (100-200 mesh silica gel, eluting with 30-100% EtOAc/hexane). The resulting pale brown liquid was dissolved in MeOH (100 mL), and 10% Pd/C (10.0 g) was added in a Parr shaker vessel. The reaction mixture was stirred at r.t. for 16 h, then passed through a celite pad and washed with 10% MeOH in DCM. The filtrate was concentrated under reduced pressure to obtain the title compound (4.0 g, 71%) as a brown liquid. d_H (400 MHz, DMSO-d₆) 3.81-3.77 (m, 1H), 3.32-3.23 (m, 2H), 2.71-2.63 (m, 1H), 2.32-1.86 (br s, 2H), 1.71-1.58 (m, 2H), 1.14-1.05 (m, 4H), 0.86 (q, J 12.3 Hz, 1H). INTERMEDIATE 9 tert-Butyl N-{[rac-(2S,4S)-2-methyltetrahydropyran-4-yl]carbamothioyl}carbamate Prepared from Intermediate 8 (3.16 g, 11.46 mmol) in accordance with the procedure described for Intermediate 6 to afford the title compound (2.1 g, 60%) as an off-white solid. dH (400 MHz, DMSO-d6) 10.61 (s, 1H), 9.69 (d, J 7.5 Hz, 1H), 4.34-4.30 (m, 1H), 3.86 (dd, J 1.9, 10.8 Hz, 1H), 3.43-3.35 (m, 2H), 2.01 (d, J 10.6 Hz, 1H), 1.93 (d, J 12.2 Hz, 1H), 1.47 (s, 9H), 1.44-1.37 (m, 2H), 1.18-1.13 (m, 1H), 1.10 (d, J 6.12 Hz, 3H). INTERMEDIATES 10 & 11 tert-Butyl (NE)-N-{(4S)-4-(4-chloro-2-phenyl-3H-benzimidazol-5-yl)-4-methyl-1- [(2R*,4R*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-ylidene}- carbamate

Prepared from Intermediate 5 (0.33 g, 0.87 mmol) and Intermediate 9 (0.30 g, 0.87 mmol) in accordance with the procedure described for Intermediate 7. The resulting diastereomers were separated by chiral preparative HPLC (Column: Diacel Chiralpak-IC, 250 mm x 4.6 mm, 5 µ; Mobile Phase A: n-hexane + 0.1% isopropylamine; Mobile Phase B: 50:50 DCM:MeOH; Flow rate: 1.0 mL/minute, isocratic: 15% B) to afford the title compounds (Peak 1: 10.8 minutes, 0.06 g, 26%; and Peak 2: 12.7 minutes, 0.05 g, 20%) as off-white solids.

Intermediate 10 (Peak 1): d_H (400 MHz, DMSO-d₆) 0.81-0.91 (m, 1H), 1.02 (d, J 5.87 Hz, 3H), 1.19-1.21 (m, 1H), 1.44 (s, 9H), 1.81 (s, 3H), 2.03-2.06 (m, 1H), 2.16-2.22 (m, 1H), 3.10-3.24 (m, 3H), 3.60-3.73 (m, 2H), 4.64 (t, J 11.74 Hz, 1H), 7.15 (d, J 8.31 Hz, 1H), 7.45-7.60 (m, 4H), 8.09-8.25 (m, 2H), 10.54 (s, 1H), 13.23 (br s, 1H). MS (ESI, Method 1) [M+H]⁺ 552, RT 2.11 minutes.

Intermediate 11 (Peak 2): dH (400 MHz, DMSO-d6) 0.91 (d, J 5.87 Hz, 3H), 0.99-1.05 (m, 1H), 1.12-1.21 (m, 1H), 1.29 (d, J 10.76 Hz, 1H), 1.44 (s, 9H), 1.81 (s, 3H), 1.93 (q, J 11.90 Hz, 1H), 2.30-2.34 (m, 1H), 3.14-3.25 (m, 2H), 3.64 (d, J 16.14 Hz, 1H), 3.80 (dd, J 11.25, 3.91 Hz, 1H), 4.65 (t, J 11.98 Hz, 1H), 7.15 (d, J 8.31 Hz, 1H), 7.43-7.60 (m, 4H), 8.15 (d, J 5.87 Hz, 1H), 8.25 (br s, 1H), 10.55 (s, 1H), 13.24 (br s, 1H). MS (ESI, Method 1) [M+H]⁺ 552, RT 2.10 minutes. INTERMEDIATE 12 tert-Butyl (NE)-N-{(4S)-4-(3-amino-2-chloro-4-iodophenyl)-4-methyl-1-[(2R*,4R*)-2- methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-ylidene}carbamate

To a solution of Intermediate 41 (0.20 g, 0.44 mmol) in dry MeOH (10 mL) was added ICl (0.03 mL, 0.53 mmol) at 0°C. The reaction mixture was stirred at room temperature for 2 h, then quenched with water (25 mL) and extracted with EtOAc (3 x 20 mL). The organic layer was separated, dried over anhydrous Na₂SO₄ and concentrated in vacuo. The crude residue was purified by combi-flash chromatography (40% EtOAc in hexanes) to afford the title compound (0.18 g, 68%) as an off-white solid. dH (400 MHz, DMSO-d6) 0.90-0.98 (m, 1H), 1.06 (d, J 5.87 Hz, 3H), 1.45 (s, 9H), 1.72 (s, 3H), 1.93- 2.05 (m, 1H), 2.29-2.38 (m, 1H), 3.14 (d, J 16.06 Hz, 1H), 3.23-3.27 (m, 3H), 3.49 (d, J 16.06 Hz, 1H), 3.80-3.88 (m, 1H), 4.67 (t, J 11.92 Hz, 1H), 5.45 (s, 2H), 6.33 (d, J 8.53 Hz, 1H), 7.62 (d, J 8.53 Hz, 1H), 10.47 (br s, 1H). LCMS (Method 3, ESI) 576.9

[M+H]⁺, RT 2.28 minutes. INTERMEDIATE 13 tert-Butyl (NE)-N-{(4S)-4-[3-amino-4-(tert-butoxycarbonylamino)-2-chlorophenyl]-4- methyl-1-[ -2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-

ylidene}carbamate

A mixture of Intermediate 12 (0.11 g, 0.91 mmol), XPhos (0.06 g, 0.12 mmol), Pd2(dba)3 (0.06 g, 0.06 mmol) and K3PO4 (0.39 g, 1.83 mmol) was purged with argon for 10 minutes, then toluene (12 mL) and tert-butyl carbamate (0.12 g, 1.0 mmol)were added. The reaction mixture was purged with argon for 10 minutes and heated in sealed tube at 90°C for 3 h, then filtered through a pad of Celite® and washed with EtOAc (30 mL). The organic layer was washed with water (30 mL), dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by combi-flash chromatography (30% EtOAc in hexanes) to afford the title compound (0.122 g, 23%) as a pale brown solid. dH (400 MHz, DMSO-d6) 0.88-0.98 (m, 2H), 1.06 (d, J 5.49 Hz, 3H), 1.44 (br s, 18H), 1.72 (s, 3H), 2.01-2.10 (m, 1H), 2.24-2.33 (m, 1H), 3.11 (d, J 16.46 Hz, 1H), 3.20- 3.28 (m, 2H), 3.50 (d, J 15.96 Hz, 1H), 3.76 (dd, J 10.97, 3.49 Hz, 1H), 4.61-4.73 (m, 1H), 5.24 (br s, 2H), 6.43-6.52 (m, 1H), 7.20 (d, J 8.48 Hz, 1H), 8.50 (br s, 1H), 10.48 (br s, 1H). LCMS (Method 3, ESI) 566.2 [M+H]⁺, RT 2.24 minutes. INTERMEDIATE 14 tert-Butyl (NE)-N-{(4S)-4-[3-amino-2-chloro-4-(pyridine-3-carbonylamino)phenyl]-4- methyl-1-[(2R*,4R*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate

A mixture of Intermediate 12 (0.06 g, 0.50 mmol), XantPhos (0.02 g, 0.03 mmol), pyridine-3-carboxamide (0.066 g, 0.55 mmol) and XantPhos Pd G3 (0.02 g, 0.02 mmol) in toluene (5 mL) was purged with argon for 5 minutes, then Cs2CO3 (0.22 g, 0.67 mmol) was added. The reaction mixture was heated in a sealed tube at 90°C for 2 h, then filtered through a pad of Celite® and washed with EtOAc (2 x 50 mL). The organic layer was washed with water (50 mL) and brine (50 mL), then dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, 30-100% EtOAc in hexanes) to afford the title compound as a brown semi-solid. dH (400 MHz, DMSO-d6) 0.98-1.02 (m, 1H), 1.08 (d, J 5.87 Hz, 3H), 1.46 (s, 9H), 1.77 (s, 3H), 1.87-1.93 (m, 1H), 2.08 (d, J 11.25 Hz, 1H), 2.18 (t, J 8.07 Hz, 1H), 2.28-2.36 (m, 1H), 3.15 (d, J 16.63 Hz, 1H), 3.55 (d, J 16.14 Hz, 1H), 3.75-3.82 (m, 1H), 4.67-4.70 (m, 1H), 6.56 (d, J 8.31 Hz, 1H), 7.18 (d, J 7.83 Hz, 1H), 7.51-7.59 (m, 1H), 8.31 (d, J 8.80 Hz, 1H), 8.75 (d, J 3.42 Hz, 1H), 9.11-9.16 (m, 1H), 9.91 (br s, 1H), 10.52 (br s, 1H) (3H merged in solvent peak). LCMS (Method 3, ESI) 571.1 [M+H]⁺, RT 1.93 minutes. INTERMEDIATE 15 tert-Butyl (NE)-N-{(4S)-4-[4-chloro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-4-methyl-1- [(2R*,4R*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-ylidene}- carbamate

A stirred solution of Intermediate 14 (0.11 g, 0.12 mmol) in acetic acid (2 mL) was heated in a sealed tube at 70°C for 1 h, then quenched with water (20 mL) and extracted with EtOAc (3 x 20 mL). The organic layer was separated, dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, 30-100% EtOAc in hexanes) to afford the title compound (0.052 g, 25%) as a brown oil. LCMS (Method 3, ESI) 553.1 [M+H]⁺, RT 1.98 minutes. INTERMEDIATE 16 N-(4-Bromo-5-chloro-2-fluorophenyl)acetamide

To a stirred solution of 4-bromo-5-chloro-2-fluoroaniline (250.0 g, 1116.07 mmol) in DCM (500 mL) was added pyridine (135.124 mL, 1674.10 mmol), followed by acetyl chloride (79.6 mL, 1116.07 mmol), at 0°C. The reaction mixture was stirred at r.t. for 16 h, then water was added and the mixture was extracted with ethyl acetate. The combined organic layer was dried over Na₂SO₄ and concentrated under reduced pressure. The crude residue was purified via column chromatography (silica gel, 100-200 mesh, 20% EtOAc/hexane) to afford the title compound (189 g, 63.5%). dH (400 MHz, DMSO- d₆) 10.00 (s, 1H), 8.30 (d, J 7.4 Hz, 1H), 7.83 (d, J 10.4 Hz, 1H), 2.10 (s, 3H). INTERMEDIATE 17 N-(4-Bromo-3-chloro-6-fluoro-2-nitrophenyl)acetamide

To a stirred solution of Intermediate 16 (50.0 g, 187.61 mmol) in sulfuric acid (200 mL) at 0°C was added nitric acid (30 mL) dropwise. After addition was complete, the mixture was allowed to warm slowly to room temperature. After 1 h, the mixture was poured into ice-water, and the resulting mixture was washed with sodium bicarbonate solution and extracted with EtOAc. The combined organic layer was dried with Na2SO4 and concentrated. The crude residue was purified via column chromatography (silica gel, 100-200 mesh, 20% EtOAc/hexane) to afford the title compound (30 g, 51.0%). dH (400 MHz, CDCl3) 7.64 (d, J 8.5 Hz, 1H), 7.09 (s, 1H), 2.17 (s, 3H). INTERMEDIATE 18 1-(4-Amino-2-chloro-5-fluoro-3-nitrophenyl)ethanone

To a stirred and degassed solution of Intermediate 17 (50.0 g, 160.77 mmol) in 1,4-dioxane (500.0 mL) was added tributyl(1-ethoxyvinyl)stannane (60.2 mL, 176.84 mmol), followed by bis(triphenylphosphine)palladium(II) dichloride (11.2 g, 16.07 mmol). The reaction mixture was stirred at 85°C for 16 h under a nitrogen atmosphere, then diluted with saturated aqueous KF solution. The resulting mixture was filtered through a Celite® pad and washed with EtOAc. The filtrate was collected and washed with water. The organic layer was separated and concentrated under reduced pressure. To a stirred solution of the crude residue in THF was added aqueous hydrochloric acid (4M, 1:1). The reaction mixture was stirred at room temperature for 16 h, then diluted with water and extracted in ethyl acetate. The combined organic layer was dried over Na₂SO₄ and concentrated under reduced pressure. The crude residue was purified by column chromatography to afford the title compound (24.0 g, 54.4%). dH (400 MHz, CDCl3) 7.52 (d, J 4.9 Hz, 1H), 5.06 (s, 2H), 2.65 (s, 3H). INTERMEDIATE 19 Methyl (3S)-3-(4-amino-2-chloro-5-fluoro-3-nitrophenyl)-3- butylsulfinylamino)-

butanoate

Prepared from Intermediate 18 in accordance with the procedure described for Intermediate 2 and Intermediate 3 to afford the title compound as a white solid. d_H (400 MHz, DMSO-d₆) 7.45 (d, J 13.6 Hz, 1H), 6.20 (s, 2H), 5.38 (s, 1H), 3.50 (s, 3H), 3.36 (br s, 1H), 3.22 (d, J 16.0 Hz, 1H), 1.79 (s, 3H), 1.11 (s, 9H). INTERMEDIATE 20 Methyl butylsulfinylamino)-3-(3,4-diamino-2-chloro-5-fluorophenyl)-

butanoate

To a stirred solution of Intermediate 19 (3.0 g, 14.0 mmol) in methanol (30 mL) was added 10% Pd/C (600 mg). The reaction mixture was stirred under hydrogen balloon pressure for 4 h, then filtered through a Celite® bed and washed with methanol. The filtrate was concentrated under reduced pressure to afford the title compound (1.4 g, 50.3%) as a beige solid. dH (400 MHz, DMSO-d6) 6.58 (d, J 13.4 Hz, 1H), 5.25 (s, 1H), 5.03 (s, 2H), 4.82 (s, 2H), 3.49 (s, 3H), 3.35-3.29 (m, 1H), 3.22 (d, J 15.8 Hz, 1H), 1.76 (s, 1H), 1.12 (s, 9H). INTERMEDIATE 21 Methyl (3S)-3-amino-3-[4-chloro-7-fluoro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]- butanoate hydrochloride

To a solution of Intermediate 20 (100 mg, 0.264 mmol) and pyridine-3- carbaldehyde (1.2 equivalents) in DMF (1.0 mL) was added 38-40% aqueous sodium hydrogen sulfite solution (3 equivalents). The mixture was heated under microwave irradiation for 60 minutes at 120°C, then cooled to room temperature and diluted with EtOAc. The organic layer was separated and washed with brine. The combined organic extracts were dried over Na2SO4 and concentrated under reduced pressure. The crude residue was purified via column chromatography (50% EtOAc/hexane), then redissolved in 1,4-dioxane (2.0 mL). HCl in 1,4-dioxane (4M, 1.0 mL) was added dropwise at 0°C The reaction mixture was stirred at room temperature for 3-4 h, then evaporated and washed with diethyl ether, to afford the title compound. dH (400 MHz, DMSO-d6) 9.46 (s, 3H), 8.99 (s, 1H), 8.78 (d, J 7.2 Hz, 1H), 8.70 (d, J 8.0 Hz, 1H), 7.71-7.68 (m, 1H), 7.34 (d, J 12.6 Hz, 1H), 3.74 (d, J 16.9 Hz, 1H), 3.49 (s, 3H), 3.36 (d, J 16.9 Hz, 1H), 1.90 (s, 3H). INTERMEDIATE 22 Methyl (3S)-3-amino-3-[4-chloro-7-fluoro-2-(pyridin-4-yl)-3H-benzimidazol-5-yl]- butanoate hydrochloride

Prepared from Intermediate 20 and pyridine-4-carbaldehyde in accordance with the procedure described for Intermediate 21. dH (400 MHz, DMSO-d6) 9.03 (s, 3H), 8.90 (d, J 5.6 Hz, 1H), 8.39 (s, 2H), 7.39 (d, J 12.6 Hz, 1H), 3.75 (d, J 16.9 Hz, 1H), 3.49 (s, 3H), 3.38 (d, J 16.9 Hz, 1H), 1.90 (s, 3H). INTERMEDIATE 23 Methyl (3S)-3-amino-3-[2-(tert-butyl)-4-chloro-7-fluoro-3H-benzimidazol-5-yl]butanoate hydrochloride

Prepared from Intermediate 20 and 2,2-dimethylpropanal in accordance with the procedure described for Intermediate 21. dH (400 MHz, DMSO-d6) 8.90 (s, 3H), 7.24- 7.17 (m, 2H), 3.49 (s, 3H), 3.31 (d, J 17.0 Hz, 1H), 3.17 (d, J 16.9 Hz, 1H), 1.86 (s, 3H), 1.42 (s.9H). INTERMEDIATE 24 Methyl -3-amino-3-[4-chloro-7-fluoro-2-(pyridin-2-yl)-3H-benzimidazol-5-yl]- butanoate hydrochloride

Prepared from Intermediate 20 and pyridine-2-carbaldehyde in accordance with the procedure described for Intermediate 21. d_H (400 MHz, DMSO-d₆) 9.00 (s, 3H), 8.79 (d, J 2.9 Hz, 1H), 8.38 (d, J 7.9 Hz, 1H), 8.06 (t, J 7.7 Hz, 1H), 7.63-7.63 (m, 1H), 7.32 (d, J 12.4 Hz, 1H), 3.74 (d, J 17.0 Hz, 1H), 3.48 (s, 3H), 3.38 (d, J 17.0 Hz, 1H), 1.90 (s, 3H). INTERMEDIATE 25 Methyl (3S)-3-amino-3-[4-chloro-2-(3-cyanophenyl)-7-fluoro-3H-benzimidazol-5-yl]- butanoate hydrochloride

To a solution of Intermediate 20 (100 mg, 0.264 mmol) and 3-formylbenzonitrile (1.2 equivalents) in DMF (1.0 mL) was added 38-40% aqueous sodium hydrogen sulfite solution (3 equivalents). The mixture was heated for 12 h at 90°C, then cooled to room temperature and diluted with EtOAc. The organic layer was separated and washed with brine. The combined organic extracts were dried over Na₂SO₄ and concentrated under reduced pressure. The crude residue was purified via column chromatography (50% EtOAc/hexane), then redissolved in 1,4-dioxane (2.0 mL). HCl in 1,4-dioxane (4M, 1.0 mL) was added dropwise at 0°C The reaction mixture was stirred at room temperature for 3-4 h, then evaporated and washed with diethyl ether, to afford the title compound. dH (400 MHz, DMSO-d6) 8.98 (s, 3H), 8.72 (s, 1H), 8.60 (d, J 8.0 Hz, 1H), 8.05 (d, J 7.7 Hz, 1H), 7.81 (t, J 7.9 Hz, 1H), 7.33 (d, J 12.6 Hz, 1H), 3.74 (d, J 17.1 Hz, 1H), 3.49 (s, 3H), 3.36 (d, J 16.9 Hz, 1H), 1.90 (s, 3H). INTERMEDIATES 26 & 27 tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[ -2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-

ylidene}carbamate (Intermediate 26)

tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[(2S*,4S*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 27)

Prepared from Intermediate 21 and Intermediate 9 (1.1 equiv) in accordance with the procedure described for Intermediate 7. Separation of the resulting diastereomers (Column: Diacel Chiralpak-IC, 250 mm x 4.6 mm, 5 m; Mobile Phase A: n-hexane + 0.1% isopropylamine; Mobile Phase B: 50:50 DCM:MeOH; Flow rate: 1.0 mL/minute, isocratic: 15% B) afforded the title compounds (Peak 1 and Peak 2) as off-white solids. Intermediate 26 (Peak 1): dH (400 MHz, DMSO-d6) 0.89 (d, J 11.5 Hz, 1H), 1.06 (d, J 6.5 Hz, 3H), 1.47 (s, 9H), 1.82 (s, 3H), 2.03-2.13 (m, 1H), 2.22-2.26 (m, 2H), 3.15-3.26 (m, 3H), 3.64-3.79 (m, 2H), 4.65-4.67 (m, 1H), 7.03-7.15 (m, 1H), 7.60-7.63 (m, 1H), 8.52- 8.64 (m, 1H), 8.74 (d, J 3.5 Hz, 1H), 9.37 (br s, 1H), 10.55 (br s, 1H), 13.57 (br s, 1H). LCMS (Method 3, ESI) 571.2 [M+H]⁺, RT 2.14 minutes.

Intermediate 27 (Peak 2): d_H (400 MHz, DMSO-d₆) 0.96 (d, J 6.5 Hz, 3H), 1.04-1.06 (m, 1H), 1.32 (d, J 9.97 Hz, 1H), 1.47 (s, 9H), 1.82 (s, 3H), 1.97-2.02 (m, 1H), 2.33-2.36 (m, 2H), 3.22-3.28 (m, 2H), 3.65-3.71 (m, 1H), 3.79-3.87 (m, 1H), 4.68 (t, J 11.7 Hz, 1H), 7.02-7.14 (m, 1H), 7.56-7.68 (m, 1H), 8.53-8.65 (m, 1H), 8.74 (d, J 4.0 Hz, 1H), 9.38, 9.43 (s, 1H) 10.56 (br s, 1H) 13.57 (br s, 1H). LCMS (Method 3, ESI) 571.2 [M+H]⁺, RT 2.04 minutes.

INTERMEDIATES 28 & 29 tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-4-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[ -2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-

ylidene}carbamate (Intermediate 28)

tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-4-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[(2S*,4S*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 29)

Prepared from Intermediate 22 and Intermediate 9 (1.1 equiv) in accordance with the procedure described for Intermediate 7. Separation of the resulting diastereomers (Column: Diacel Chiralpak-IG, 250 mm x 4.6 mm, 5m; Mobile Phase A: n-hexane;

Mobile Phase B: 50:50 DCM:MeOH; Flow rate: 1.0 mL/minute, isocratic: 20% B) afforded the title compounds (Peak 1 and Peak 2) as off-white solids.

Intermediate 28 (Peak 1): dH (400 MHz, DMSO-d6) 0.89-0.92 (m, 1H), 1.06 (d, J 5.9 Hz, 3H), 1.47 (s, 9H), 1.82 (s, 3H), 2.03-2.27 (m, 3H), 3.13-3.25 (m, 3H), 3.64-3.76 (m, 2H), 4.66 (t, J 11.5 Hz, 1H), 7.06-7.18 (m, 1H), 8.16 (s, 1H), 8.22-8.24 (m, 1H), 8.80 (d, J 3.4 Hz, 2H), 10.55 (s, 1H), 13.69 (br s, 1H). LCMS (Method 3, ESI) 571.1 [M+H]⁺, RT 2.05 minutes.

Intermediate 29 (Peak 2): d_H (400 MHz, DMSO-d₆) 0.96 (d, J 5.9 Hz, 3H), 1.06 (d, J 9.3 Hz, 1H), 1.31-1.35 (m, 1H), 1.47 (s, 9H), 1.82 (s, 3H), 1.92-2.03 (m, 1H), 2.30-2.37 (m, 1H), 3.20-3.30 (m, 3H), 3.66-3.72 (m, 1H), 3.83 (dd, J 10.7, 3.9 Hz, 1H), 4.68 (t, J 11.3 Hz, 1H), 7.05-7.18 (m, 1H), 8.16 (d, J 3.91 Hz, 1H), 8.24 (d, J 4.40 Hz, 1H), 8.77-8.85 (m, 2H), 10.55 (s, 1H), 13.71 (br s, 1H). LCMS (Method 3, ESI) 571.1 [M+H]⁺, RT 2.03 minutes.

INTERMEDIATES 30 & 31 tert-Butyl (NE)-N-{(4S)-4-[2-(tert-butyl)-4-chloro-7-fluoro-3H-benzimidazol-5-yl]-4- methyl-1-[(2R*,4R*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 30)

tert-Butyl (NE)-N-{(4S)-4-[2-(tert-butyl)-4-chloro-7-fluoro-3H-benzimidazol-5-yl]-4- methyl-1-[(2S*,4S*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 31)

Prepared from Intermediate 23 and Intermediate 9 (1.1 equiv) in accordance with the procedure described for Intermediate 7. Separation of the resulting diastereomers (Column: Diacel Chiralpak-IC, 250 mm x 4.6 mm, 5 m; Mobile Phase A: n-hexane + 0.1% isopropylamine; Mobile Phase B: 1:1 DCM:MeOH; Flow rate: 1.0 mL/minute, isocratic: 10% B) afforded the title compounds (Peak 1 and Peak 2) as off-white solids. Intermediate 30 (Peak 1): LCMS (Method 3, ESI) 550.2 [M+H]⁺, RT 2.24 minutes.

Intermediate 31 (Peak 1): LCMS (Method 3, ESI) 550.2 [M+H]⁺, RT 2.23 minutes. INTERMEDIATES 32 & 33 tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-2-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[(2R*,4R*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 32)

tert-Butyl (NE)-N-{(4S)-4-[4-chloro-7-fluoro-2-(pyridin-2-yl)-3H-benzimidazol-5-yl]-4- methyl-1-[(2S*,4S*)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2- ylidene}carbamate (Intermediate 33)

Prepared from Intermediate 24 and Intermediate 9 (1.1 equiv) in accordance with the procedure described for Intermediate 7. Separation of the resulting diastereomers (Column: Diacel Chiralpak-IG, 250 mm x 4.6 mm, 5m; Mobile Phase A: n-hexane;

Mobile Phase B: 50:50 DCM:MeOH; Flow rate: 1.0 mL/minute, isocratic: 20% B) afforded the title compounds (Peak 1 and Peak 2) as off-white solids.

Intermediate 32 (Peak 1): dH (400 MHz, DMSO-d6) 0.84-0.96 (m, 1H), 1.05 (d, J 5.98 Hz, 3H), 1.47 (s, 9H), 1.82 (s, 3H), 2.04-2.12 (m, 1H), 2.18-2.30 (m, 1H), 3.14-3.26 (m, 2H), 3.63-3.80 (m, 2H), 4.60-4.73 (m, 1H), 7.04-7.09 (m, 1H), 7.57-7.65 (m, 1H), 8.05 (t, J 7.48 Hz, 1H), 8.36 (t, J 6.98 Hz, 1H), 8.78 (s, 1H), 10.55 (br s, 1H), 13.81 (br s, 1H) (2H merged in solvent peak). LCMS (Method 3, ESI) 571.1 [M+H]⁺, RT 2.19 minutes. Intermediate 33 (Peak 2): dH (400 MHz, DMSO-d6) 0.94 (d, J 5.49 Hz, 3H), 1.03-1.06 (m, 1H), 1.45 (s, 9H), 1.81 (s, 3H), 1.93-2.07 (m, 1H), 2.29-2.39 (m, 1H), 3.22 (d, J 15.46 Hz, 2H), 3.63-3.69 (m, 1H), 3.81-3.85 (m, 1H), 4.63-4.67 (m, 1H), 7.02-7.09 (m, 1H), 7.55-7.61 (m, 1H), 8.03 (t, J 7.73 Hz, 1H), 8.30-8.39 (m, 1H), 8.77 (s, 1H), 10.54 (br s, 1H), 13.81(br s, 1H) (2H merged in solvent peak). LCMS (Method 3, ESI) 571.1

[M+H]⁺, RT 2.18 minutes. INTERMEDIATE 34 tert-Butyl (NE)-N-{(4S)-4-[4-chloro-2-(3-cyanophenyl)-7-fluoro-3H-benzimidazol-5-yl]- 4-methyl-1-[ methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-

ylidene}carbamate

Prepared from Intermediate 25 and Intermediate 9 (1.1 equiv) in accordance with the procedure described for Intermediate 7 to afford the title compound (mixture of two diastereomers) as an off-white solid, which was utilised without further purification. LCMS (Method 3, ESI) 595.4 [M+H]⁺, RT 1.54 minutes. INTERMEDIATE 35 N-[1-(2-Chloro-3-nitrophenyl)ethylidene]- -2-methylpropane-2-sulfinamide

To a solution of 1-(2-chloro-3-nitrophenyl)ethanone (10.5 g, 5.1 mmol) and (R)-2- methyl-2-propanesulfinamide (11.2 g, 5.1 mmol) in dry THF (100 mL) was added titanium(IV) ethoxide (23.2 g, 10.5 mmol). The reaction mixture was heated at 75°C for 12 h, then quenched with H2O (500 mL), stirred at room temperature for 1 h and filtered through a pad of Celite. The aqueous layer was extracted with EtOAc (2 x 150 mL). The organic layer was separated and dried over anhydrous sodium sulfate, then concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, 30% EtOAc in hexanes) to afford the title compound (10.0 g, 63%) as a red liquid. LCMS (Method 1, ESI) 303.00 [M+H]⁺, RT 3.02 minutes. INTERMEDIATE 36 N-[1-(3-Amino-2-chlorophenyl)ethylidene]-2-(R)-methylpropane-2-sulfinamide

To a solution of Intermediate 35 (10.0 g, 33.2 mmol) in MeOH (100 mL) was added Raney Ni (10.0 g) at room temperature. The reaction mixture was stirred at room temperature for 6 h under hydrogen pressure, then filtered through a pad of Celite and washed with MeOH (150 mL). The filtrate was concentrated in vacuo to afford the title compound (8.80 g, 98%) as a colourless liquid, which was utilised without further purification. LCMS (Method 1, ESI) 273.00 [M+H]⁺, RT 2.58 minutes. INTERMEDIATE 37 Benzyl N-(3-{N-[(R)-tert-butylsulfinyl]-C-methylcarbonimidoyl}-2-chlorophenyl)- carbamate

To a solution of Intermediate 36 (10.0 g, 36.7 mmol) in THF (100 mL) were added DIPEA (32.5 mL, 183.0 mmol) and benzyl chloroformate (12.5 g, 73.5 mmol) at 0°C. The reaction mixture was stirred at room temperature for 16 h, then quenched with H₂O (500 mL) and extracted with EtOAc (3 x 250 mL). The organic layer was separated and dried over anhydrous sodium sulfate, then concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, 30% EtOAc in n- hexanes) to afford the title compound (12.5 g, 84%) as a yellow liquid. LCMS (Method 1, ESI) 407.00 [M+H]⁺, RT 3.43 minutes. INTERMEDIATE 38 Methyl (3S)-3-[3-(benzyloxycarbonylamino)-2-chlorophenyl]-3-{[(R)-tert-butylsulfinyl]- amino}butanoate

A suspension of CuCl (4.37 g, 44.2 mmol) and Zn (14.4 g, 221.0 mmol) in THF (90 mL) was heated at 50°C for 30 minutes. Methyl bromoacetate (11.0 g, 66.0 mmol) was added dropwise at 80°C, then the reaction mixture was heated at 50°C for 1 h.

Intermediate 37 (9.00 g, 22.0 mmol) was added at 0°C. The reaction mixture was stirred at room temperature for 16 h, then filtered through a pad of Celite. The filtrate was washed with brine (300 mL). The organic layer was separated and dried over anhydrous sodium sulfate, then concentrated in vacuo. The crude residue was purified by column chromatography (silica, 100-200 mesh, 40% EtOAc in hexanes) to afford the title compound (7.50 g, 70%) as a yellow liquid. dH (400 MHz, DMSO-d6) 9.09 (s, 1H), 7.54 (d, J 8.0 Hz, 1H), 7.29-7.43 (m, 7H), 5.39 (s, 1H), 5.14 (s, 2H), 3.47 (s, 3H), 3.31 (s, 2H), 1.86 (s, 3H) 1.13 (s, 9H). LCMS (Method 1, ESI) 481.00 [M+H]⁺, RT 3.43 minutes. INTERMEDIATE 39 Methyl (3S)-3-amino-3-[3-(benzyloxycarbonylamino)-2-chlorophenyl]butanoate

To a solution of Intermediate 38 (7.50 g, 15.6 mmol) in MeOH (80 mL) was added 4M HCl in 1,4-dioxane (15.6 mL, 62.5 mmol) at 0°C. The reaction mixture was stirred at room temperature for 6 h, then concentrated in vacuo. The residue was basified with saturated aqueous NaHCO₃ solution (200 mL) and extracted with EtOAc (2 x 250 mL). The organic layer was separated and dried over anhydrous sodium sulfate, then concentrated in vacuo, to afford the title compound (5.18 g, 90%) as a yellow liquid, which was utilised without further purification. INTERMEDIATE 40 tert-Butyl (NE)-N-{(4S)-4-[3-(benzyloxycarbonylamino)-2-chlorophenyl]-4-methyl-1- [(2SR,4SR)-2-methyltetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-ylidene}- carbamate

Prepared from Intermediate 39 (2.0 g, 5.3 mmol) and Intermediate 9 in accordance with the procedure described for Intermediate 7 to afford the title compound as an off-white solid. dH (400 MHz, DMSO-d6) 10.51 (s, 1H), 9.25 (s, 1H), 7.58 (d, J 7.8 Hz, 1H), 7.40-7.32 (m, 6H), 7.17 (d, J 8.0 Hz, 1H), 5.13 (s, 2H), 4.68-4.62 (m, 1H), 3.82 (dd, J 2.8, 11.6, 1H), 3.74-3.71 (m, 1H), 3.58 (dd, J 2.8, 16.4 Hz, 1H), 3.29-3.17 (m, 3H), 2.35-2.21 (m, 1H), 1.75 (s, 3H), 1.44 (s, 9H), 1.07 (d, J 9.3 Hz, 2H), 1.05 (d, J 17.6 Hz, 2H). INTERMEDIATE 41 tert-Butyl (NE)-N-{(4S)-4-(3-amino-2-chlorophenyl)-4-methyl-1-[(2R*,4R*)-2-methyl- tetrahydropyran-4-yl]-6-oxohexahydropyrimidin-2-ylidene}carbamate

To Intermediate 40 (1.5 g, 2.5 mmol), dissolved in methanol (20 mL), was added 10% Pd/C (200 mg). The reaction mixture was stirred under hydrogen balloon pressure at r.t. until reaction was complete, then filtered through Celite® and washed with methanol. The filtrate was concentrated under reduced pressure. The crude residue was purified by column chromatography (silica gel, 100-200 mesh, 30% EtOAc/hexane). The resulting crude off-white solid (racemic mixture) was separated using chiral HPLC purification (Column: Chiralpak IC, 250 x 20 mm, 5µ; Mobile Phase: 80/20/0.1 (v/v/v) hexane/EtOH/ DEA; Flow rate: 18 mL/minute; uv: 242 nm; Runtime: 15 minutes) to afford the title compound (Peak 2 diastereomer: 0.523 g) as an off-white solid. dH (400 MHz, DMSO-d6) 10.47 (s, 1H), 7.00 (t, J 7.9 Hz, 1H), 6.78 (d, J 8.0 Hz, 1H), 6.46 (d, J 7.8 Hz, 1H), 5.52 (s, 2H), 4.69-4.63 (m, 1H), 3.75 (dd, J 4.5, 11.2 Hz, 1H), 3.50 (d, J 16.3 Hz, 1H), 3.23- 3.18 (m, 2H), 3.11 (d, J 16.2 Hz, 1H), 2.33-2.22 (m, 1H), 2.11-2.02 (m, 1H), 1.73 (s, 3H), 1.44 (br s, 10H), 1.06 (d, J 6.0 Hz, 3H), 0.85 (d, J 7.0 Hz, 1H). LCMS (ESI, Method 4) m/e 451 [M+H]⁺, RT 1.56 minutes. EXAMPLE 1

(6S)-6-(4-Chloro-2-phenyl-3H-benzimidazol-5-yl)-2-imino-6-methyl-3-(tetrahydropyran- 4-yl)hexahydropyrimidin-4-one hydrochloride

To a solution of Intermediate 7 (0.09 g, 0.16 mmol) in DCM (6 mL) at 0°C was added TFA (0.19 g, 1.64 mmol). The reaction mixture was stirred at room temperature for 3 h, then concentrated in vacuo. The crude residue was purified by preparative HPLC (pH 3) to afford the title compound (0.081 g, 89%) as an off-white solid. d_H (400 MHz, DMSO-d₆) 0.74 (d, J 11.74 Hz, 1H), 1.65 (d, J 10.76 Hz, 1H), 1.83 (s, 3H), 2.07-2.15 (m, 1H), 2.30-2.40 (m, 1H), 3.08 (t, J 11.25 Hz, 1H), 3.27 (t, J 11.25 Hz, 1H), 3.35 (d, J 16.63 Hz, 1H), 3.67 (dd, J 11.00, 3.18 Hz, 1H), 3.78 (d, J 16.63 Hz, 1H), 3.83 (d, J 10.27 Hz, 2H), 7.22 (d, J 8.31 Hz, 1H), 7.51-7.62 (m, 4H), 8.20 (d, J 6.36 Hz, 2H), 8.91 (br s, 2H), 10.68 (s, 1H). MS (ESI, Method 2) [M+H]⁺ 438, RT 0.64 minutes. EXAMPLE 2

(6S)-6-(4-Chloro-2-phenyl-3H-benzimidazol-5-yl)-2-imino-6-methyl-3-[(2R*,4R*)-2- methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride

To a solution of Intermediate 10 (0.06 g, 0.11 mmol) in DCM (4 mL) was added TFA (0.25 g, 2.16 mmol) at 0°C. The reaction mixture was stirred at room temperature for 3 h, then concentrated in vacuo. The residue was diluted with saturated aqueous NaHCO3 solution (40 mL) and extracted with EtOAc (2 x 30 mL). The organic layer was separated and washed with brine (50 mL), then dried over anhydrous Na₂SO₄ and concentrated in vacuo. The resulting solid was dissolved in DCM (3 mL), and 4M HCl in 1,4-dioxane (0.25 mL, 0.98 mmol) was added at 0°C. The reaction mixture was stirred at room temperature for 30 minutes, then concentrated in vacuo. The crude residue was washed with diethyl ether (2 mL) and hexane (3 mL), then lyophilised with acetonitrile/ H2O (2 mL), to afford the title compound (0.046 g, 94%) as an off-white solid. dH (400 MHz, DMSO-d6) 0.79 (d, J 10.83 Hz, 1H), 1.05 (d, J 5.91 Hz, 3H), 1.74 (d, J 11.32 Hz, 1H), 1.83 (s, 3H), 1.92-2.06 (m, 2H), 3.15 (t, J 11.32 Hz, 1H), 3.31-3.46 (m, 2H), 3.63- 3.71 (m, 1H), 3.78 (d, J 16.24 Hz, 1H), 3.93 (t, J 11.32 Hz, 1H), 7.28 (d, J 8.37 Hz, 1H), 7.54-7.67 (m, 4H), 8.26 (d, J 5.41 Hz, 2H), 9.06 (br s, 2H), 10.83 (s, 1H). MS (ESI, Method 2) [M+H]⁺ 452, RT 0.68 minutes. EXAMPLE 3

(6S)-6-(4-Chloro-2-phenyl-3H-benzimidazol-5-yl)-2-imino-6-methyl-3-[(2S*,4S*)-2- methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride

Prepared from Intermediate 11 (0.05 g, 0.10 mmol) in accordance with the procedure described for Example 2 to afford the title compound (0.046 g, 94%) as an off- white solid. dH (400 MHz, DMSO-d6) 0.79 (d, J 10.83 Hz, 1H), 1.05 (d, J 5.91 Hz, 3H), 1.74 (d, J 11.32 Hz, 1H), 1.83 (s, 3H), 1.92-2.06 (m, 2H), 3.15 (t, J 11.32 Hz, 1H), 3.31- 3.46 (m, 2H), 3.63-3.71 (m, 1H), 3.78 (d, J 16.24 Hz, 1H), 3.93 (t, J 11.32 Hz, 1H), 7.28 (d, J 8.37 Hz, 1H), 7.54-7.67 (m, 4H), 8.26 (d, J 5.41 Hz, 2H), 9.06 (br s, 2H), 10.83 (s, 1H). MS (ESI, Method 2) [M+H]⁺ 452, RT 0.68 minutes. EXAMPLE 4

(6S)-6-(4-Chloro-2-cyclopropyl-3H-benzimidazol-5-yl)-2-imino-6-methyl-3-[(2R*,4R*)- 2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride

To a solution of Intermediate 13 (0.12 g, 0.14 mmol) in EtOH (3 mL) were added copper(II) acetate (0.05 g, 0.27 mmol) and cyclopropanecarbaldehyde (0.01 g, 0.20 mmol) at room temperature. The reaction mixture was heated at 90°C for 2 h, then the solvent was evaporated under reduced pressure. The reaction mixture was quenched with water (15 mL) and extracted with EtOAc (2 x 15 mL). The organic layer was separated, dried over anhydrous Na₂SO₄ and concentrated in vacuo. The resulting pale brown solid was redissolved in DCM (10 mL) and TFA (0.15 mL, 2.08 mmol) was added at 0°C. The reaction mixture was stirred at room temperature for 2 h, then concentrated in vacuo and triturated with diethyl ether (6 mL). The residue was dissolved in EtOAc (30 mL) and washed with saturated aqueous NaHCO₃ solution (20 mL). The organic layer was separated, dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by preparative HPLC (basic conditions). To the resulting off-white solid was added HCl in 1,4-dioxane (4M, 0.09 mL, 0.36 mmol) at 0°C. The solution was stirred at room temperature for 30 minutes, then concentrated under reduced pressure. The crude residue was dissolved in DCM (0.5 mL) and reprecipitiated by the addition of n-pentane (6 mL), then filtered and dried, to afford the title compound (0.019 g, 70%) as an off-white solid. d_H (400 MHz, DMSO-d₆) 0.78 (d, J 12.23 Hz, 1H), 1.06 (d, J 5.87 Hz, 3H), 1.30-1.32 (m, 4H), 1.73 (d, J 10.76 Hz, 1H), 1.80 (s, 3H), 1.91-2.04 (m, 2H), 2.33- 2.37 (m, 1H), 3.14 (t, J 11.25 Hz, 2H), 3.87-3.97 (m, 2H), 7.30 (d, J 8.80 Hz, 1H), 7.56 (d, J 8.80 Hz, 1H), 9.07 (br s, 2H), 10.85 (s, 1H) (1 exchangeable H not seen; 2H merged in solvent peak). MS (ESI, Method 2) [M+H]⁺ 416, RT 0.45 minutes. EXAMPLE 5

(6S)-6-[4-Chloro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [ -2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride

To a solution of Intermediate 15 (0.05 g, 0.03 mmol) in DCM (5 mL) was added TFA (0.01 mL, 0.15 mmol) at 0°C. The reaction mixture was stirred at room temperature for 2 h, concentrated in vacuo. The residue was triturated with diethyl ether (4 mL), then dissolved in EtOAc (20 mL) and washed with saturated aqueous NaHCO3 solution (20 mL). The organic layer was separated, dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by preparative HPLC (basic condition). To the resulting off-white solid was added HCl in 1,4-dioxane (4M, 0.04 mL, 0.16 mmol) at 0°C. The solution was stirred at room temperature for 30 minutes, then concentrated in vacuo and triturated with diethyl ether (5 mL). The crude residue was dissolved in diethyl ether (1 mL), then reprecipitiated with n-pentane (10 mL), to afford the title compound (0.0125 g, 98%) as an off-white solid. dH (400 MHz, DMSO-d6) 0.77 (d, J 11.47 Hz, 1H), 1.06 (d, J 4.99 Hz, 3H), 1.74 (d, J 10.47 Hz, 1H), 1.84 (s, 3H), 1.94-2.06 (m, 2H), 3.12-3.16 (m, 2H), 7.28 (d, J 7.98 Hz, 1H), 7.64 (d, J 7.98 Hz, 1H), 7.77-7.80 (m, 1H), 8.71-8.84 (m, 2H), 9.08 (br s, 2H), 9.48 (s, 1H), 10.77 (br s, 1H) (4H merged in solvent peak; 1 exchangeable H not seen). MS (ESI, Method 2) [M+H]⁺ 453, RT 0.53 minutes. EXAMPLE 6

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [ -2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride

To a solution of Intermediate 26 in MeOH (2 mL) was added HCl in 1,4-dioxane (4M, 0.57 mL, 2.28 mmol) at 0°C. The reaction mixture was stirred at room temperature until LCMS indicated completion, then concentrated in vacuo. The crude residue was washed with diethyl ether (2 mL) and pentane (6 mL), then lyophilised with acetonitrile/ water (2 mL), to afford the title compound. MS (ESI, Method 2) [M+H]⁺ 471, RT 0.54 minutes. EXAMPLE 7

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-3-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2S*,4S*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 27 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 471, RT 0.53 minutes. EXAMPLE 8

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-4-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2R*,4R*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 28 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 471, RT 0.54 minutes. EXAMPLE 9

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-4-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2S*,4S*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 29 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 471, RT 0.54 minutes.

EXAMPLE 10

(6S)-6-[2-(tert-Butyl)-4-chloro-7-fluoro-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2R*,4R*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 30 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 450, RT 0.64 minutes. EXAMPLE 11

(6S)-6-[2-(tert-Butyl)-4-chloro-7-fluoro-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2S*,4S*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 31 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 450, RT 0.64 minutes.

EXAMPLE 12

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-2-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2R*,4R*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 32 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 471.4, RT 0.65 minutes. EXAMPLE 13

(6S)-6-[4-Chloro-7-fluoro-2-(pyridin-2-yl)-3H-benzimidazol-5-yl]-2-imino-6-methyl-3- [(2S*,4S*)-2-methyltetrahydropyran-4-yl]hexahydropyrimidin-4-one hydrochloride Prepared from Intermediate 33 in accordance with the procedure described for Example 6. MS (ESI, Method 2) [M+H]⁺ 471.4, RT 0.65 minutes.

EXAMPLES 14 & 15

3-(7-Chloro-4-fluoro-6-{(4S)-2-imino-4-methyl-1-[(2R*,4R*)-2-methyltetrahydropyran- 4-yl]-6-oxohexahydropyrimidin-4-yl}-1H-benzimidazol-2-yl)benzonitrile (Example 14) 3-(7-Chloro-4-fluoro-6-{(4S)-2-imino-4-methyl-1-[(2S*,4S*)-2-methyltetrahydropyran-4- yl]-6-oxohexahydropyrimidin-4-yl}-1H-benzimidazol-2-yl)benzonitrile (Example 15) To a solution of Intermediate 34 (0.05 g, 0.08 mmol) in DCM (3 mL) was added TFA (0.13 mL, 1.68 mmol) at 0°C. The reaction mixture was stirred at room temperature for 4 h, then concentrated in vacuo. The residue was diluted with saturated aqueous NaHCO₃ solution (50 mL) and extracted with EtOAc (2 x 50 mL). The organic layer was separated, washed with water (50 mL) and brine (50 mL), then dried over anhydrous Na2SO4 and concentrated in vacuo. The crude residue was purified by chiral column chromatography (YMC Chiralart Cellulose-SC, 250 mm x 4.6 mm, 5 m; Mobile Phase A: n-hexane; Mobile Phase B: 50:50 EtOH:MeOH; Flow rate: 1.5 mL/minute, isocratic: 15% B) to afford the title compounds (Peak 1: 0.010 g, 25%; and Peak 2: 0.012 g, 26%) as off- white solids.

Example 14 (Peak 1): d_H (400 MHz, DMSO-d₆) 0.82-0.90 (m, 1H), 0.92 (d, J 10.76 Hz, 1H), 1.06 (d, J 5.87 Hz, 3H), 1.63 (d, J 9.78 Hz, 1H), 1.70 (s, 3H), 2.04-2.21 (m, 3H), 3.13-3.23 (m, 2H), 3.67-3.76 (m, 1H), 4.04-4.13 (m, 1H), 7.31 (d, J 11.74 Hz, 1H), 7.80 (t, J 7.83 Hz, 1H), 8.03 (d, J 7.34 Hz, 1H), 8.57 (d, J 7.34 Hz, 1H), 8.70 (s, 1H), 13.50 (br s, 1H) (2 exchangeable H not observed). MS (ESI, Method 2) [M+H]⁺ 495.1, RT 0.72 minutes.

Example 15 (Peak 2): dH (400 MHz, DMSO-d6) 0.85-0.88 (m, 1H), 0.92 (d, J 5.87 Hz, 3H), 1.55 (d, J 8.80 Hz, 1H), 1.73 (s, 3H), 2.31-2.34 (m, 2H), 3.20-3.27 (m, 2H), 3.31- 3.34 (m, 1H), 3.74-3.81 (m, 2H), 3.99-4.10 (m, 1H), 7.21-7.31 (m, 1H), 7.80 (t, J 7.83 Hz, 1H), 8.03 (d, J 7.83 Hz, 1H), 8.58 (d, J 7.34 Hz, 1H), 8.72 (s, 1H), 13.55 (br s, 1H) (2 exchangeable H not observed). MS (ESI, Method 2) [M+H]⁺ 495.3, RT 0.72 minutes.

Claims

Claims: 1. A compound of formula (I) or a pharmaceutically acceptable salt thereof:

wherein

W represents C(O) or S(O)2;

X represents C-R² or N;

A represents C-R³ or N;

B represents C-R⁴ or N;

D represents C-R⁵ or N;

Z represents C_1-6 alkyl, C_3-7 cycloalkyl, aryl, C_3-7 heterocycloalkyl or heteroaryl, any of which groups may be optionally substituted by one or more substituents;

R¹ represents C_2-6 alkyl, optionally substituted by hydroxy; or R¹ represents C_3-7 cycloalkyl, C_3-7 cycloalkyl(C_1-6)alkyl, aryl(C_1-6)alkyl, C_3-7 heterocycloalkyl, C_3-7 heterocycloalkyl(C1-6)alkyl, C4-9 heterobicycloalkyl, C4-9 spiroheterocycloalkyl or heteroaryl(C1-6)alkyl, any of which groups may be optionally substituted by one or more substituents;

R² represents hydrogen, halogen, cyano or C1-4 alkyl; and

R³, R⁴ and R⁵ independently represent hydrogen, halogen, cyano or trifluoro- methyl.

2. A compound as claimed in claim 1 wherein W represents C(O).

3. A compound as claimed in claim 1 or claim 2 wherein X represents N.

4. A compound as claimed in any one of the preceding claims wherein R¹ represents C_3-7 heterocycloalkyl, which group may be optionally substituted by one, two or three substituents independently selected from C1-6 alkyl.

5. A compound as claimed in any one of the preceding claims wherein R⁴ represents hydrogen.

6. A compound as claimed in claim 1 represented by formula (IIA), or a pharmaceutically acceptable salt thereof:

wherein

R¹¹ represents hydrogen or methyl;

R¹² represents hydrogen or methyl; and

Z, R³ and R⁵ are as defined in claim 1.

7. A compound as claimed in any one of the preceding claims wherein Z represents tert-butyl, cyclopropyl, phenyl or pyridinyl, any of which groups may be optionally substituted by one, two or three substituents independently selected from cyano.

8. A compound as claimed in any one of the preceding claims wherein R³ represents chloro.

9. A compound as claimed in any one of the preceding claims wherein R⁵ represents hydrogen or fluoro.

10. A compound as claimed in claim 1 as herein specifically disclosed in any one of the Examples.

11. A compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt thereof for use in therapy.

12. A compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt thereof for use in the treatment and/or prevention of malaria.

13. A pharmaceutical composition comprising a compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt thereof in association with a pharmaceutically acceptable carrier.

14. The use of a compound of formula (I) as defined in claim 1 or a

pharmaceutically acceptable salt thereof for the manufacture of a medicament for the treatment and/or prevention of malaria.

15. A method for the treatment and/or prevention of malaria, which comprises administering to a patient in need of such treatment an effective amount of a compound of formula (I) as defined in claim 1 or a pharmaceutically acceptable salt thereof.