Reaktion #1833298

Reaktionsgleichung

bendamustine hydrochloride

docosyl alcohol

dicyclohexyl carbodiimide

→

desired product

Ausbeute 43.3%

4-{5-[Bis-(chloroethyl)-amino]-1-methyl-1H-benzimidazol-2-yl}butyric acid docosyl ester

Ausbeute 43.3%

Lösungsmittel

dichloromethane

Reaktionsbedingungen

Aufarbeitung

1. 1
   SonstigeSolids were removed by vacuum filtration
2. 2
   Waschenthe wetcake was washed with 50 mL
3. 3
   SonstigeTwo alternate purification procedures
4. 4
   WaschenThe filtrate was washed with DI water (2×150 mL)
5. 5
   Trocknendried over sodium sulfate
6. 6
   Filtrationfiltered
7. 7
   Einengenconcentrated to dryness in vacuo
8. 8
   SonstigeThe resultant waxy residue was chromatographed on 80 g of silica gel 60, 230-400 mesh
9. 9
   Wascheneluting with a gradient
10. 10
    Sonstige0.5% methanol/MDC and finally 1% methanol/MDC collecting 100-150 mL fractions
11. 11
    workup.ADDITIONFractions containing the desired product
12. 12
    Einengenconcentrated to dryness in vacuo
13. 13
    SonstigeThe residue was again triturated with 20 mL of MDC
14. 14
    Sonstigethe undesired solids removed by filtration
15. 15
    EinengenThe filtrate was concentrated in vacuo

Vorschrift

A 250 mL three necked round bottom flask equipped with a stir bar, thermocouple and nitrogen in/outlet was charged with 5.0 g (12.7 mmol) of bendamustine hydrochloride, 4.2 g (12.9 mmol, 1.01 eq) of docosyl alcohol, 2.7 g (12.9 mmol, 1.01 eq) of dicyclohexyl carbodiimide (DCC), 50 mL of dichloromethane (MDC) and 0.16 g (1.27 mmol, 0.1 eq) of N,N-dimethylamino pyridine (DMAP). The reaction mixture was stirred at room temperature overnight at which time an HPLC analysis indicated the reaction was complete. Solids were removed by vacuum filtration and the wetcake was washed with 50 mL. Two alternate purification procedures were developed. The filtrate was washed with DI water (2×150 mL), dried over sodium sulfate, filtered and concentrated to dryness in vacuo. The resultant waxy residue was chromatographed on 80 g of silica gel 60, 230-400 mesh eluting with a gradient beginning with 100% MDC, then 0.5% methanol/MDC and finally 1% methanol/MDC collecting 100-150 mL fractions. Fractions containing the desired product were combined and concentrated to dryness in vacuo. The residue was again triturated with 20 mL of MDC and the undesired solids removed by filtration. The filtrate was concentrated in vacuo to yield 3.65 g (5.5 mmol, 43.1%) of the desired product as a waxy white solid with a purity of 95.7A %. 1H NMR (400 MHz, CDCl3) δ 7.17 (d, J=8.72 Hz, 1H), 7.08 (d, J=2.28 Hz, 1H), 6.78 (dd, J=2.36, 8.72 Hz, 1H), 4.05 (t, J=6.76 Hz, 2H), 3.72 (m, 4H), 3.70 (s, 3H), 3.63 (m, 4H), 2.91 (t, J=7.44 Hz, 2H), 2.49 (t, J=7.08 Hz, 2H), 2.18 (m, 2H), 1.60 (m, 2H), 1.32 (m, 38H), 0.88 (t, J=6.64 Hz, 3H).

Quelle