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C5−C6 Carbocyclic-Fused Iminothiadiazine Dioxides as BACE Inhibitors, Their Compositions, and Their Use Benjamin Blass* Temple University School of Pharmacy, 3307 North Broad Street, Philadelphia, Pennsylvania 19140, United States Title:
C5−C6 Carbocyclic fused iminothiadiazine dioxides as BACE inhibitors, compositions, and their use
Patent Application Number:
WO2017095759A1
Publication date:
June 8th, 2017
Priority Application:
US 62/263,046
Priority date:
December 4th, 2015
Inventors:
Scott, J. D.; Blizzard, T. A.; Walsh, S. P.; Cumming, J. N.
Assignee Company:
Merck Sharp & Dohme Corporation
Disease Area:
Alzheimer’s disease
Summary:
According to the Alzheimer’s Association (www.Alz.org), in 2017 over 5 million US citizens suffered from Alzheimer’s disease, and this number is projected to increase to over 16 million by 2050. Healthcare costs for this disease and associated dementias are expected to exceed $259 billion in 2017. Despite decades of research, there is no cure for this condition, and treatment options are limited. The production of amyloid beta protein, also referred to as Aβ1−42, has been associated with disease progression, and as a result, enzymes that enable the production of this material have been the subject of intense research. Beta site amyloid precursor protein cleaving enzyme (BACE-1) is a key enzyme in this process, and it has been demonstrated that inhibition of BACE-1 inhibits the production of Aβ1−42. The present disclosure describes a series of C5−C6 carbocyclic-fused iminothiadiazine dioxides capable of inhibiting BACE-1, as well as their use for the treatment of Alzheimer’s disease. The disclosure also describes compounds capable of inhibiting BACE-2, a homologue of BACE-1.
BACE-1
Biological Target:
Important Compound Classes:
Definitions:
Ring C is a 3-, 4-, 5-, or 6-membered fused cycloalkyl group; p is 1, 2, 3, or 4, provided that the value of p does not exceed the number of substitutable hydrogen atoms on ring C; Each RC is independently selected from the group consisting of H, F, −OH, oxo, lower alkyl, lower cycloalkyl, −O−(lower alkyl) and −O−(lower cycloalkyl), wherein each said lower alkyl and lower cycloalkyl are optionally substituted with one or more fluorine, and wherein 1 to 2 nonadjacent, nonterminal carbon atoms in each said lower alkyl are optionally independently replaced with −O−, −NH−, −N−(lower alkyl)−, −S−, −S(O)−, or −S(O)2−; R1 is selected from the group consisting of H, lower alkyl, lower cycloalkyl, and −(lower alkyl)−(lower cycloalkyl), wherein each said lower alkyl and lower cycloalkyl are optionally substituted with one or more fluorine, and wherein 1 to 2 nonadjacent, nonterminal carbon atoms in each said lower alkyl are optionally independently replaced with −O−, −NH−, −N−(lower alkyl)−, −S−, −S(O)−, or −S(O)2−; ring A is selected from the group consisting of aryl and heteroaryl; m is 0, 1, 2, or 3, provided that the value of m does not exceed the number of substitutable hydrogen atoms on ring A; each RA (when present) is independently selected from the group consisting of halogen, −CN, −OH, oxo, −NH−(lower alkyl), −NHC(O)−(lower alkyl), lower alkyl, −(lower alkyl)−(lower cycloalkyl), and −O−(lower alkyl), wherein each said lower alkyl and lower cycloalkyl are optionally substituted with one or more fluorine, and wherein 1 to 2 nonadjacent, nonterminal carbon atoms in each said lower alkyl are optionally independently replaced with −O−, −NH−, −N−(lower alkyl), −S−, −S(O)−, or −S(O)2−; q is 0 or 1; −L1−, when present, represents a bond or a divalent moiety selected from the group consisting of −C(O)NH−, −CH2C(O)NH−, −NH−, −CH(CH3)NH−, −CH2NH−, −O−, and −CH2O−; ring B, when present, is selected from the group consisting of aryl, heteroaryl, cycloalkyl, and heterocycloalkyl; n is 0, 1, 2, or 3, provided that the value of n does not exceed the number of substitutable hydrogen atoms on ring B; and each RB, when present, is independently selected from the group consisting of halogen, −CN, −OH, oxo, lower alkyl, lower cycloalkyl, −(lower alkyl)−(lower cycloalkyl), −O−(lower alkyl), −O−(lower cycloalkyl), −O−(lower alkyl)−(lower cycloalkyl), −CCH, −CCCH3, −OCH2CC−H, and −OCH2CCCH3,
Received: July 3, 2017
© XXXX American Chemical Society
A
DOI: 10.1021/acsmedchemlett.7b00268 ACS Med. Chem. Lett. XXXX, XXX, XXX−XXX
ACS Medicinal Chemistry Letters
Patent Highlight
wherein each said lower alkyl and lower cycloalkyl are optionally substituted with one or more fluorine, and wherein 1 to 2 nonadjacent, nonterminal carbon atoms in each said lower alkyl are optionally independently replaced with −O−, −NH−, −N−(lower alkyl)−, −S−, −S(O)−, or −S(O)2−. Key Structures:
Recent Review Articles:
Biological Assay:
Gu, T.; Wu, W. Y.; Dong, Z. X.; Yu, S. P.; Sun, Y.; Zhong, Y.; Lu, Y. T.; Li, N. G. Development and structural modification of BACE-1 inhibitors. Molecules 2017, 22 (1), 4/1−4/13. Wyss, D. F.; Cumming, J. N.; Strickland, C. O.; Stamford, A. W. BACE Inhibitors. Methods and Principles in Medicinal Chemistry 2016, 67, 329−353. Evin, G. Future Therapeutics in Alzheimer’s Disease: Development Status of BACE Inhibitors. BioDrugs: clinical immunotherapeutics, biopharmaceuticals and gene therapy 2016, 30 (3), 173−194. BACE-l Assay: This assay monitors the increase of 620 nm fluorescence that resulted from BACE-l cleavage of an APPswedish APPswe mutant peptide FRET substrate (QSY7-EISEVNLDAEFC-europium-amide). This substrate contains an N-terminal QSY7 moiety that serves as a quencher of the C-terminal europium fluorophore (620 nm Em). In the absence of enzyme activity, 620 nm fluorescence is low in the assay and increased linearly over 3 h in the presence of uninhibited BACE-l enzyme. Inhibition of BACE-l cleavage of the QSY7-APPswe-Eu substrate by inhibitors is manifested as a suppression of 620 nm fluorescence. Varying concentrations of inhibitors at 3× the final desired concentration in a volume of 10 μL are preincubated with purified human BACE-l catalytic domain (3 nM in 10 μL) for 30 min at 30 °C in reaction buffer containing 20 mM Na-acetate pH 5.0, 10% glycerol, 0.1% Brij-35, and 7.5% DSMO. Reactions are initiated by the addition of 10 μL of 600 nM QSY7-APPswe-Eu substrate (200 nM final) to give a final reaction volume of 30 μL in a 384-well Nunc HTRF plate. The reactions are incubated at 30 °C for 1.5 h. The 620 nm fluorescence is then read on a Rubystar HTRF plate reader (BMG Labtechnologies) using a 50 ms delay followed by a 400 ms acquisition time window. Inhibitor IC50 values are derived from nonlinear regression analysis of concentration response curves. Ki values are then calculated from IC50 values using the Cheng−Prusoff equation using a previously determined micrometer value of 8 μM for the QSY7-APPswe-Eu substrate at BACE-l. BACE-l Assay: Inhibitor IC50s at purified human autoBACE-2 were determined in a time-resolved end-point proteolysis assay that measures hydrolysis of the QSY7-EISEVNLDAEFC-Eu-amide FRET peptide substrate (BACE-HTRF assay). BACE-mediated hydrolysis of this peptide results in an increase in relative fluorescence (RFU) at 620 nm after excitation with 320 nm light. Inhibitor compounds, prepared at 3× the desired final concentration in Ix BACE assay buffer (20 mM sodium acetate pH 5.0, 10% glycerol, 0.1% Brij-35), supplemented with 7.5% DMSO are preincubated with an equal volume of autoBACE-2 enzyme diluted in Ix BACE assay buffer (final enzyme concentration 1 nM) in black 384-well NUNC plates for 30 min at 30 °C. The assay was initiated by addition of an equal volume of the QSY7-EISEVNLDAEFC-Eu-amide substrate (200 nM final concentration, Km = 8 μM in 4 μM autoBACE-2) prepared in Ix BACE assay buffer supplemented with 7.5% DMSO and incubated for 90 min at 30 °C. DMSO is present at 5% final concentration in the assay. Following laser excitation of sample wells at 320 nm, the fluorescence signal at 620 nm was collected for 400 ms following a 50 μs delay on a RUBY star HTRF plate reader (BMG Labtechnologies). Raw RFU data was normalized to maximum (1.0 nM BACE/DMSO) and minimum (no enzyme/DMSO) RFU values. IC50 values were determined by nonlinear regression analysis (sigmoidal dose response, variable slope) of percent inhibition data with minimum and maximum values set to 0 and 100%, respectively. Similar IC50s were obtained when using raw RFU data. The Ki values were calculated from the IC50 using the Cheng−Prusoff equation.
B
DOI: 10.1021/acsmedchemlett.7b00268 ACS Med. Chem. Lett. XXXX, XXX, XXX−XXX
ACS Medicinal Chemistry Letters
Patent Highlight
Biological Data:
Claims:
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17 Total claims 12 Composition of matter claims 5 Method of use claims
AUTHOR INFORMATION
Corresponding Author
*Tel: 215-707-1085. E-mail:
[email protected]. Notes
The author declares no competing financial interest.
C
DOI: 10.1021/acsmedchemlett.7b00268 ACS Med. Chem. Lett. XXXX, XXX, XXX−XXX
