2-Acetylbutyrolactone

2-Acetylbutyrolactone (ABL) is a derivative of γ-butyrolactone that is used as a precursor in organic synthesis, and it is used to identify primary amines through chemical fluorescence.

Preparation
2-Acetylbutyrolactone can be prepared by a condensation reaction between an ester of acetic acid (such as ethyl acetate) with butyrolactone in an alkaline solution.

2-Acetylbutyrolactone can also be prepared by reacting ethylene oxide with ethyl acetoacetate in alkaline conditions.

Spectrofluorimetry
2-Acetylbutyrolactone itself is only slightly fluorescent, but its derivatives show high UV fluorescence. The carbonyl group readily reacts with amines to form Schiff bases. It is for this reason that 2-acetylbutyrolactone is frequently used to confirm the creation of amines during organic synthesis. 2-Acetylbutyrolactone can also undergo a Japp‐Klingemann reaction to form fluorescent molecules with arylamines.

Drug precursor
Uses of 2-Acetylbutyrolactone also includes synthesis of:
 * 1) Risperidone
 * 2) Ritanserin
 * 3) Paliperidone
 * 4) Ocaperidone
 * 5) Seganserin
 * 6) Setoperone
 * 7) Metrenperone
 * 8) Pirenperone
 * 9) Novoldiamine (1-Diethylamino-4-aminopentane) [140-80-7]
 * 10) Clomethiazole
 * 11) Barmastine
 * 12) R 59-022 [93076-89-2]
 * 13) ID-4708 [42048-72-6].
 * 14) Santalene
 * 15) α-methylene-γ-butyrolactones.