By the acyl rearrangement of chloramphenicol (II) with hydrochloric acid,
O-dichloro-acetylaminodiol hydrochloride (III), m.p. 166-168° (decomp.), was obtained in 63% yield. The same rearrangement of (II) with methanesulfonic acid gave two kinds of
O-dichloro-acetylaminodiol methanesulfonate, one being the compound (IV), m.p. 151-152°, [α]
D19=-45° (MeOH), (yield, 55%) in which the acyl group had migrated to the hydroxyl in 1-position, while the other (V), m.p. 180-181°, [α]
D19=+11° (MeOH) (yield, 17%), a compound acylated in the 3-position. (III) was assumed to be the compound in which the rearrangement occured at the hydroxyl in 1-position from the specific rotation, [α]
D18=-48° (EtOH). The products obtained by the acyl rearrangement of
dl-
N-acetylaminodiol (VI) by the application of
d-camphor-β-sulfonic acid,
d-and
l-
O-acetylaminodiol
d-camphor-β-sulfonate (VII) (
d-, m.p. 140-141°;
l-, m.p. 172-173°), were resolved, alkalized to effect acyl rearrangement and optically active compound (VI) was obtained. The same resolution of
dl-chloramphenicol (II) gave
l-compound of
O-dichloroacetyl-aminodiol
d-camphor-β-sulfonate (
l-VIII), m.p. 178-179°, which was isolated, the same acyl rearrangement carried out and
l-compound of (II) was obtained. The mother liquor obtained after separation of (
l-VIII) was also alkalized for acyl rearrangement to yield a mixture of
dl-(II) and
d-(II) from which
d-(II) was obtained by recrystallization.
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