Janus Kinase (JAK) Family Inhibitor, Preparation of Same, and Applications Thereof

A compound of formula (I) and a stereoisomer thereof or a pharmaceutically acceptable salt thereof:

• wherein the ring A is selected from optionally substituted 4-12-membered heterocyclyl or 5-10-membered heteroaryl;
• R1 is selected from H, hydroxyl, optionally substituted C1-C8 alkyl, C3-C8 cycloalkyl, C2-C8 alkenyl, C2-C8 alkynyl, 4-12-membered heterocyclyl, 6-10-membered aryl or 5-10-membered heteroaryl;
• R2 is selected from cyano, —C═ONR6R7, —C═ONR6NR7R8, —C═ONHOR6, —S(O)mR8, —S(O)m—NHR8 or —C═OOR6;
• L is selected from amino, —NR6C═O—, —NR6C═ONR10—, —C═ONR10—, —C═ONR6O—, —C═ONR6NR10—, —NR6S(O)m—, —S(O)mNR6—, —NR6S(O)mNR7—, —S(O)m—, —C═O— or —C═OO—;
• or L is absent;
• R3 is selected from H, optionally substituted C1-C8 alkyl, C3-C8 cycloalkyl or —C═OR6;
• R4 and R5 are each independently selected from H, deuterium, halogen, cyano, nitro, optionally substituted C1-C8 alkyl, C3-C8 cycloalkyl, 6-10-membered aryl or 5-10-membered heteroaryl;
• R6, R7 and R10 are each independently selected from H, optionally substituted C1-C8 alkyl or C3-C8 cycloalkyl;
• or, R10 taken with N and R1 to which it is attached can form an optionally substituted 4-12-membered heterocyclyl;
• wherein the substituent groups in the ring A and R1 are each independently selected from one or more of halogen, hydroxyl, cyano, amino, sulfydryl, nitro, C1-C8 alkyl, C1-C8 alkoxy, C3-C8 cycloalkyl, 4-12-membered heterocyclyl, 6-10-membered aryl, 5-10-membered heteroaryl, —(CH2)nC═OOR8, —OC═OR8, —C═OR8, —C═ONR8R9, —NHC═OR8, —NR8R9, —OC═ONR8R9, —NHC═ONR8R9, —S(O)mR8, —S(O)m—NHR8, —NHC═OOR8 or —NHS(O)mR8;
• m is selected from 1 or 2;
• n is selected from 1, 2, 3, 4 or 5;
• R8 and R9 are each independently selected from H, optionally substituted C1-C8 alkyl or C3-C8 cycloalkyl;
• and
• the substituent groups in the R3, R4, R5, R6, R7, R8, R9 and R10 are each independently selected from one or more of deuterium, halogen, hydroxyl, cyano, amino, sulfydryl, nitro, C1-C8 alkyl, C1-C8 alkoxy or C3-C8 cycloalkyl.