Inhibitors of histone deacetylase

A compound of formula (I)

• 16
• or a therapeutically acceptable salt thereof, wherein
• n is 1 or 2;
• L1 is selected from the group consisting of alkenylene, alkylene, alkynylene, cycloalkylene, heteroalkylene, —(alkylene)—C(O)N(R5)—(alkylene)—, —(alkylene)—O—(alkylene)—;
• wherein each group is drawn with its left-hand end being the end which attaches to L2, and its right-hand end being the end which attaches to the carbon substituted with R1, R2, and R3;
• L2 is selected from the group consisting of a bond, C2 alkenylene, —O—, —S—, —SO2—, —OC(O)NR5—, —N(R6)C(O)—, —C(O)N(R6)—, —SO2N(R6)—,—N(R6)SO2—, —C═N—O—, —N(R6)C(O)N(R6)—, and —C(O)N(R6)N(R6)C(O)—;
• wherein each group is drawn with its left-hand end being the end which attaches to R4, and its right-hand end being the end which attaches to L1;
• R1 is selected from the group consisting of alkanoyl, alkoxycarbonyl, aminocarbonyl, carboxy, haloalkyl, and heterocycle, wherein the heterocycle is selected from the group consisting of oxazolyl, dihydrooxazolyl, oxadiazolyl, and tetraazolyl;
• R2 and R3 are hydroxy;
• or
• R2 and R3 together are oxo;
• R4 is selected from the group consisting of alkoxyalkyl, alkyl, aryl, arylalkyl, cycloalkyl, (cycloalkyl)alkyl, heterocycle, and (heterocycle)alkyl;
• and
• R5 and R6 are independently selected from the group consisting of hydrogen, alkyl, aryl, and arylalkyl;
• or
• R4 and R6, together with the nitrogen atom to which they are attached, form a heterocycle selected from the group consisting of morpholinyl, piperazinyl, piperidinyl, and thiomorpholinyl;
• wherein the morpholinyl, the piperazinyl, the piperidinyl, and the thiomorpholinyl can be optionally substituted with one, two, or three substituents independently selected from the group consisting of alkyl and spiroheterocycle.