تفاعل #6329

معادلة التفاعل

Acetic anhydride

N-[(9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide

sodium bicarbonate

→

title compound

N-[(7-acetyl-9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide

المذيبات

methane sulfonic acid

methylene chloride

ظروف التفاعل

المعالجة

1. 1
   درجة الحرارةto warm to 20°-25° during this time
2. 2
   workup.ADDITIONAt the end of this time, a small amount of ice is added
3. 3
   workup.ADDITIONis added slowly
4. 4
   أخرىThe solvent layers are separated
5. 5
   استخلاصthe aqueous layer is extracted with additional methylene chloride (7×1 ml)
6. 6
   تجفيفThe combined organic layers are dried over magnesium sulfate
7. 7
   تركيزconcentrated
8. 8
   أخرىto provide an oil
9. 9
   أخرىThis oil is purified on a silica preparative plate (1000μ)

الإجراء التجريبي

Acetic anhydride (91 μl) is added to a mixture of (±) (1S,9aS/1R,9aR) N-[(9,9a-dihydro-3-oxo-1H,3H-oxazolo[3,4-a]indol-1-yl)methyl]acetamide (X diastereomer B, EXAMPLE 11, 74 mg) in methane sulfonic acid (1 ml) at 0° over 1 minute. The mixture is stirred for 20.5 hours and allowed to warm to 20°-25° during this time. At the end of this time, a small amount of ice is added and the mixture is diluted with methylene chloride. To this mixture of sodium bicarbonate (2.4 g) is added slowly. The solvent layers are separated and the aqueous layer is extracted with additional methylene chloride (7×1 ml). The combined organic layers are dried over magnesium sulfate and concentrated to provide an oil. This oil is purified on a silica preparative plate (1000μ) by developing it in methanol/methylene chloride (5/95, 3×) which provides the title compound, NMR (CDCl3, 300 MHz) 7.88, 7.84, 7.43, 6.40, 4.62, 4.57, 3.75, 3.36, 3.13, 2.58 and 2.08 δ; CMR (CDCl3, 75.47 MHz) 23.15, 26.62, 34.24, 41.02, 61.84, 83.26, 114.37, 125.53, 129.86, 132.98, 134.2, 144.1, 154.7, 170.6 and 196.5 δ; IR (CHCl3) 3660, 3440, 2980, 2920, 1760, 1670, 1600, 1480, 1420, 1350, 1260, 1120, 1050, 980 and 700 cm-1 ; MS (m/e) 288, 244, 229, 216, 201, 185, 170, 160, 144, 130, 118, 85, 73 and 43, exact mass calcd for C15H16 --N2O4 (288.1110), found 288.1105.

المصدر