TYK2 inhibitors and uses thereof

1. A compound of formula I:

or a pharmaceutically acceptable salt thereof, wherein:

each of X and Y is independently ═C(R 6 )— or ═N—, provided that X and Y are not simultaneously ═C(R 6 )—;

Ring A is phenyl; a 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; a 3-6 membered saturated or partially unsaturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur; or a 4-6 membered saturated or partially unsaturated carbocyclic ring; wherein Ring A is substituted with m instances of R 7 ;

each of R 1 and R 1′ is independently hydrogen, —R 2 , halogen, —CN, —NO 2 , —OR, —SR, —NR 2 , —S(O) 2 R, —S(O) 2 NR 2 , —S(O)R, —C(O)R, —C(O)OR, —C(O)NR 2 , —C(O)N(R)OR, —OC(O)R, —OC(O)NR 2 , —N(R)C(O)OR, —N(R)C(O)R, —N(R)C(O)NR 2 , or —N(R)S(O) 2 R; or

R 1 and R 1′ are taken together with their intervening atoms to form an optionally substituted 3-7 membered spiro-fused ring having 0-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur;

each R 2 is independently an optionally substituted group selected from C 1-6 aliphatic, phenyl, a 4-7 membered saturated or partially unsaturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and a 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur;

R 3 is a group selected from C 1-6 alkyl, phenyl, a 3-7 membered saturated or partially unsaturated carbocyclic ring, a 3-7 membered saturated or partially unsaturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and a 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur; wherein R 3 is substituted with n instances of R 8 ;

R 4 is hydrogen or optionally substituted C 1-6 aliphatic;

R 5 is a group selected from hydrogen, —R 2 , halogen, —CN, —NO 2 , —OR, —SR, —NR 2 , —S(O) 2 R, —S(O) 2 NR 2 , —S(O)R, —C(O)R, —C(O)OR, —C(O)NR 2 , —C(O)N(R)OR, —OC(O)R, —OC(O)NR 2 , —N(R)C(O)OR, —N(R)C(O)R, —N(R)C(O)NR 2 , —N(R)S(O) 2 R, phenyl, a 3-7 membered saturated or partially unsaturated heterocyclic ring having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and a 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur;

wherein R 5 is substituted with p instances of R 9 ;

provided that when R 3 is other than phenyl, R 5 is not hydrogen or unsubstituted alkyl when L 1 is a covalent bond;

each instance of R 6 , R 7 , and R 8 is independently —R 2 , halogen, —CN, —NO 2 , —OR, —SR, —NR 2 , —S(O) 2 R, —S(O) 2 NR 2 , —S(O)R, —C(O)R, —C(O)OR, —C(O)NR 2 , —C(O)N(R)OR, —OC(O)R, —OC(O)NR 2 , —N(R)C(O)OR, —N(R)C(O)R, —N(R)C(O)NR 2 , or —N(R)S(O) 2 R;

each instance of R 9 is independently oxo, C 1-6 hydroxyaliphatic, —R 2 , halogen, —CN, —NO 2 , —OR, —SR, —NR 2 , —S(O) 2 R, —S(O) 2 NR 2 , —S(O)R, —C(O)R, —C(O)OR, —C(O)NR 2 , —C(O)N(R)OR, —OC(O)R, —OC(O)NR 2 , —N(R)C(O)OR, —N(R)C(O)R, —N(R)C(O)NR 2 , or —N(R)S(O) 2 R;

L 1 is a covalent bond or a C 1-6 bivalent saturated or unsaturated, straight or branched hydrocarbon chain wherein one or two methylene units of the chain are optionally and independently replaced by —N(R)—, —N(R)C(O)—, —C(O)N(R)—, —N(R)S(O) 2 —, —S(O) 2 N(R)—, —O—, —C(O)—, —OC(O)—, —C(O)O—, —S—, —S(O)— or —S(O) 2 —;

m is 0-4;

n is 0-4;

p is 0-6; and

each R is independently hydrogen, or an optionally substituted group selected from C 1-6 aliphatic, phenyl, a 4-7 membered saturated or partially unsaturated heterocyclic having 1-2 heteroatoms independently selected from nitrogen, oxygen, and sulfur, and a 5-6 membered heteroaryl ring having 1-4 heteroatoms independently selected from nitrogen, oxygen, and sulfur, or:

two R groups on the same nitrogen are taken together with their intervening atoms to form a 4-7 membered saturated, partially unsaturated, or heteroaryl ring having 0-3 heteroatoms, in addition to the nitrogen, independently selected from nitrogen, oxygen, and sulfur.

2. The compound of claim 1 of one of formula III-a, III-b, or III-c:

or a pharmaceutically acceptable salt thereof.

3. The compound of claim 1 wherein Ring A is phenyl, pyridin-2-yl, pyridine-3-yl, or pyrazol-4-yl.

4. The compound of claim 3 of one of formula V-a, V-b, V-c, or V-d:

or a pharmaceutically acceptable salt thereof.

5. The compound of claim 1 wherein L 1 is —CH 2 C(O)—, —C(O)—, or a covalent bond.

6. The compound of claim 5 , wherein L 1 is —CH 2 C(O)— or —C(O)—.

7. The compound of claim 5 , wherein L 1 is a covalent bond.

8. The compound of claim 5 , wherein R 5 is pyrrolidinyl or piperidinyl, and one instance of R 9 is oxo, thereby forming a compound of formula VII-a or VII-b:

or a pharmaceutically acceptable salt thereof, wherein p is 0-2.

9. The compound of claim 1 wherein R 3 is phenyl, pyrrolidinyl, or piperidinyl.

10. The compound of claim 9 of formula VIII-a:

or a pharmaceutically acceptable salt thereof.

11. The compound of claim 10 wherein n is 1-3.

12. The compound of claim 10 wherein at least one R 8 is halogen, —CN, or —CF 3 .

13. The compound of claim 1 wherein R 3 is pyrrolidinyl or piperidinyl.

14. The compound of claim 13 of formula VIII-b-i or VIII-c-i:

or a pharmaceutically acceptable salt thereof.

15. The compound of claim 14 wherein at least one R 8 is C 1-6 alkyl.

16. The compound of claim 1 wherein both R 1 and R 1′ are hydrogen.

17. The compound of claim 1 wherein said compound is selected from those depicted, or a pharmaceutically acceptable salt thereof:

Com-

pound

Structure

I-1

I-2

I-3

I-4

I-5

I-6

I-7

I-8

I-9

I-10

I-11

I-12

I-13

I-14

I-15

I-16

I-17

I-18

I-19

I-20

I-21

I-22

I-23

I-24

I-25

I-26

I-27

I-28

I-29

I-30

I-31

I-32

I-33

I-34

I-35

I-36

I-37

I-38

I-39

I-40

I-41

I-42

I-43

I-44

I-45

I-46

I-47

I-48

I-49

I-50

I-51

I-52

I-53

I-54

I-55

I-56

I-57

I-58

I-59

I-61

I-62

I-63

I-64

I-65

I-66

I-67

I-68

I-69

I-70

I-71

I-72

I-73

I-74

I-75

I-76

I-77

I-78

I-79

I-80

I-81

I-82

I-83

I-84

I-85

I-86

I-87

I-88

I-89

I-90

I-91

I-92

I-93

I-94

I-95

I-96

I-97

I-98

I-99

I-100

I-101

I-102

I-103

I-104

I-105

I-106

I-107

I-108

I-109

I-110

I-111

I-112

I-113

I-114

I-115

I-116

I-117

I-118

I-119

I-120

I-121

I-122

I-123

I-124

I-125

I-126

I-127

I-128

I-129

I-130

I-131

I-132

I-133

I-134

I-135

I-136

I-137

I-138

I-139

I-140

I-141

I-142

I-143

I-144

I-145

I-146

I-147

I-148

I-149

I-150

I-151

I-152

I-153

I-154

I-155

I-156

I-157

I-158

I-159

I-160

I-161

I-162

I-163

I-164

I-165

I-166

I-167

I-168

I-169

I-170

I-171

I-172

I-173

I-174

I-175

I-176

I-177

I-178

I-179

I-180

I-181

I-182

I-183

I-184

I-185

I-186

I-187

I-188

I-189

I-190

I-191

I-192

I-193

I-194

I-195

I-196

I-197

I-198

I-199

I-200

I-201

I-202

I-203

I-204

I-205

I-206

I-207

I-208

I-209

I-210

I-211

I-212

I-213

I-214

I-215

I-216

I-217

I-218

I-219

I-220

I-221

I-222

I-223

I-224

I-225

I-226

I-227

I-228

I-229

I-230

I-231

I-232

I-233

I-234

I-235

I-236

I-237

I-238

I-239

I-240

I-241

I-242

I-243

I-244

I-245

I-246

I-247

I-248

I-249

I-250

I-251

I-252

I-253

I-254

I-255

I-256

I-257

I-258

I-259

I-260

I-261

I-262

I-263

I-264

I-265

I-266

I-267

I-268

I-269

I-270

I-271

I-272

I-273

I-274

I-275

I-276

I-277

I-278

I-279

I-280

I-281

I-282

I-283

I-284

I-285

I-286

I-287

I-288

I-289

I-290

I-291

I-292

18. A pharmaceutical composition comprising a compound according to claim 1 , or a pharmaceutically acceptable salt thereof, and a pharmaceutically acceptable carrier, adjuvant, or vehicle.

19. A method of inhibiting TYK2 in a biological sample comprising contacting the sample with the compound of claim 1 , or a pharmaceutically acceptable salt thereof.

20. A method of treating inhibiting TYK2 in a patient comprising administering to said patient the compound of claim 1 .