The disclosed embodiments detail improved methods for the synthesis of diketopiperazines from amino acids. In particular improved methods for the cyclocondensation and purification of N-protected 3,6-(aminoalkyl)-2,5-diketopiperazines from N-protected amino acids. Disclosed embodiments describe methods for the synthesis of 3,6-bis-[N-protected aminoalkyl]-2,5-diketopiperazine comprising heating a mixture of an amino acid in the presence of a catalyst in an organic solvent. The catalyst is selected from the group comprising sulfuric acid, phosphoric acid, p-toluenesulfonic acid, 1-propylphosphonic acid cyclic anhydride, tributyl phosphate, phenyl phosphonic acid and phosphorous pentoxide among others. The solvent is selected from the group comprising: dimethylacetamide, N-methyl-2-pyrrolidone, diglyme, ethyl glyme, proglyme, ethyldiglyme, m-cresol, p-cresol, o-cresol, xylenes, ethylene glycol and phenol among others.

The disclosed embodiments detail improved methods for the synthesis of diketopiperazines from amino acids. In particular improved methods for the cyclocondensation and purification of N-protected 3,6-(aminoalkyl)-2,5-diketopiperazines from N-protected amino acids. Disclosed embodiments describe methods for the synthesis of 3,6-bis-[N-protected aminoalkyl]-2,5-diketopiperazine comprising heating a mixture of an amino acid in the presence of a catalyst in an organic solvent. The catalyst is selected from the group comprising sulfuric acid, phosphoric acid, p-toluenesulfonic acid, 1-propylphosphonic acid cyclic anhydride, tributyl phosphate, phenyl phosphonic acid and phosphorous pentoxide among others. The solvent is selected from the group comprising: dimethylacetamide, N-methyl-2-pyrrolidone, diglyme, ethyl glyme, proglyme, ethyldiglyme, m-cresol, p-cresol, o-cresol, xylenes, ethylene glycol and phenol among others.

Provided are compounds of Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2A, R.sup.2B, R.sup.3, R.sup.4, and R.sup.5 are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (I), or a pharmaceutically acceptable salt thereof.

Provided are compounds of Formula (I):

##STR00001##

or a pharmaceutically acceptable salt thereof, wherein R.sup.1, R.sup.2A, R.sup.2B, R.sup.3, R.sup.4, and R.sup.5 are as defined herein. Also provided is a pharmaceutically acceptable composition comprising a compound of Formula (I), or a pharmaceutically acceptable salt thereof. Also provided are methods of using a compound of Formula (I), or a pharmaceutically acceptable salt thereof.

Disclosed herein are p38α mitogen-activated protein kinase inhibitors, pharmaceutical compositions thereof, and therapeutic methods of using the p38α mitogen-activated protein kinase inhibitors.

Disclosed herein are p38α mitogen-activated protein kinase inhibitors, pharmaceutical compositions thereof, and therapeutic methods of using the p38α mitogen-activated protein kinase inhibitors.

Disclosed herein are diketopiperazine microparticles having a specific surface area of less than about 67 m.sup.2/g. The diketopiperazine microparticle can be fumaryl diketopiperazine and can comprise a drug such as insulin.

Disclosed herein are diketopiperazine microparticles having a specific surface area of less than about 67 m.sup.2/g. The diketopiperazine microparticle can be fumaryl diketopiperazine and can comprise a drug such as insulin.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.

Disclosed embodiments relate to improved methods for the synthesis of activated fumarate intermediates and their use in chemical synthesis. Disclosed embodiments describe the synthesis of activated fumarate esters including those derived from activating groups including: 4-nitrophenyl, diphenylphophoryl azide, pivaloyl chloride, chlorosulfonyl isocyanate, p-nitrophenol, MEF, trifluoroacetyl and chlorine, for example, ethyl fumaroyl chloride and the subsequent use of the activated ester in situ. Further embodiments describe the improved synthesis of substituted aminoalkyl-diketopiperazines from unisolated and unpurified intermediates allowing for improved yields and reactor throughput.