Avermectin → Ivermectin B1a

HRID 1648803

Reaktionsgleichung

Reaktionsgleichung von HRID 1648803
[CH3:1][CH2:2][CH:3]([C@H:5]1[O:10][C@:9]2([O:15][C@@H:14]3[CH2:16][CH:17]=[C:18]([CH3:61])[C@@H:19]([O:40][C@@H:41]4[O:46][C@@H:45]([CH3:47])[C@H:44]([O:48][C@@H:49]5[O:54][C@@H:53]([CH3:55])[C@H:52]([OH:56])[C@@H:51]([O:57][CH3:58])[CH2:50]5)[C@@H:43]([O:59][CH3:60])[CH2:42]4)[C@@H:20]([CH3:39])[CH:21]=[CH:22][CH:23]=[C:24]4[CH2:25][O:26][C@@H:27]5[C@H:32]([OH:33])[C:31]([CH3:34])=[CH:30][C@@H:29]([C:35]([O:37][C@@H:12]([CH2:13]3)[CH2:11]2)=[O:36])[C@:28]45[OH:38])[CH:8]=[CH:7][C@@H:6]1[CH3:62])[CH3:4]>C1(C)C=CC=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.[Cl-].[Rh]>[CH3:1][CH2:2][C@@H:3]([C@H:5]1[O:10][C@:9]2([O:15][C@@H:14]3[CH2:16][CH:17]=[C:18]([CH3:61])[C@@H:19]([O:40][C@@H:41]4[O:46][C@@H:45]([CH3:47])[C@H:44]([O:48][C@@H:49]5[O:54][C@@H:53]([CH3:55])[C@H:52]([OH:56])[C@@H:51]([O:57][CH3:58])[CH2:50]5)[C@@H:43]([O:59][CH3:60])[CH2:42]4)[C@@H:20]([CH3:39])[CH:21]=[CH:22][CH:23]=[C:24]4[CH2:25][O:26][C@@H:27]5[C@H:32]([OH:33])[C:31]([CH3:34])=[CH:30][C@@H:29]([C:35]([O:37][C@@H:12]([CH2:13]3)[CH2:11]2)=[O:36])[C@:28]45[OH:38])[CH2:8][CH2:7][C@@H:6]1[CH3:62])[CH3:4]

Komponenten

4

Edukt 1

HCID 6858006Avermectin

Produkt 1

HCID 6321424Ivermectin B1aAusbeute 98 %

Reagenzien, Katalysatoren, Lösungsmittel 2

HCID 84599Chlorotris(triphenylphosphine)rhodium(I)KatalysatorHCID 1140TolueneLösungsmittel

Reaktionsbedingungen

Temperatur
40 °C

Versuchsvorschrift

39 g of Avermectin Bla is dissolved in 1540 ml of toluene and introduced into a 4 liter stirred autoclave. To this is added 3.9 g of tris(triphenylphosphine)rhodium (I) chloride (Wilkinson's catalyst). A hydrogenation pressure of 40 psi and a temperature of 40° C. is maintained with stirring for 41/2 hours. At the end of this period liquid chromatographic analysis indicates 98% yield of dihydro avermectin Bla with 1.5% of tetrahydro avermectin Bla. The toluene is removed by evaporation in vacuo and the dark red gum is dissolved in ethanol at a rate of 4 ml of ethanol per gram of product. Formamide at a rate of 10 ml per gram of product is added and the solution heated on the steam bath to 40°-50° while adding water at a rate of 2 ml per gram of product. After crystallization commences the heat is removed and the solution allowed to cool slowly with stirring overnight. The solid is filtered off and washed with a mixture 3 parts water and 1 part ethanol and dried in vacuo overnight. The solids are dissolved in 150 ml of ethanol and warmed to 35°-40° C. on the steam bath. Water, 150 ml is added slowly with stirring. When solution is complete at 35° C. the heat is removed and the solution allowed to cool slowly overnight. The crystals are removed by filtration and washed with aqueous ethanol and dried in vacuo overnight affording 32.55 g of 22,23-dihydro avermectin Bla with a m.p. of 155°-157° C.

Aufarbeitung

  1. additionintroduced into a 4 liter
  2. stirringwith stirring for 41/2 hours

Quellen und Nachweise

ORD-Eintrag
ord-af9f858e3dd44360ab64bcd4e539c9f0
Quelldatensatz
uspto-grants-1983_11
Patentnummer
US04413118

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