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ChemicalBook CAS DataBase List (S)-4-Ethyl-4-hydroxy-7,8-dihydro-1h-pyrano[3,4-f]indolizine-3,6,10(4h)-trione
110351-94-5

(S)-4-Ethyl-4-hydroxy-7,8-dihydro-1h-pyrano[3,4-f]indolizine-3,6,10(4h)-trione synthesis

14synthesis methods
Synthesis of (S)-4-Ethyl-4-hydroxy-7,8-dihydro-1h-pyrano[3,4-f]indolizine-3,6,10(4h)-trione: Compound (Formula 4) 4.3 g (100 mmol), 200 ml of dichloromethane, 200 ml of 2M sulfuric acid, stirred at room temperature for 2 h, separated the organic layer, washed with saturated brine, dried, recovered dichloromethane to dryness, and recrystallized from isopropanol to obtain S-tricyclic lactone (Formula 1) 1.5 g, mp 172-174°C, [α]D15+115.6° (C=0.5, chloroform), yield 57%.
Synthesis of (S)-4-Ethyl-4-hydroxy-7,8-dihydro-1h-pyrano[3,4-f]indolizine-3,6,10(4h)-trione
-

Yield:110351-94-5 93%

Reaction Conditions:

with trifluoroacetic acid at 20; for 6 h;

Steps:

30.7 Step (7):(5 ′S) -1,5-dioxo- (5′-ethyl-5′-hydroxy-2′H, 5′H, 6′H-6-oxopyran)-[3 ′, 4 ′, f] -Δ6 (8) -tetrahydroindolizine(Intermediate M) Preparation

The intermediate M14 (1.0 g, 3.26 mmol) was dissolved in trifluoroacetic acid (30 ml),The reaction was stirred at room temperature for 6 hours, and was concentrated by rotary evaporation to obtain a dark brown oily liquid.Purification by silica gel column chromatography (dichloromethane: ethyl acetate = 4: 1) gave 0.88 g of a pale yellow solid with a yield of 93%.

References:

CN110590796,2019,A Location in patent:Paragraph 0223-0227; 0250-0253

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