76-78-8

Basic information

• Product Name: QUASSIN
• Synonyms: QUASSIN;11,16-trione,2,12-dimethoxy-picrasa-12-diene-1;(3aS,6aR,7aS,8S,11aS,11bS,11cS)-1,3a,4,5,6a,7,7a,8,11,11a,11b,11c-dodecahydro-2,10-dimethoxy-3,8,11a;Picrasa-2,12-diene-1,11,16-trione, 2,12-dimethoxy-;QUASSINPOWDER;(3As,6ar,7as,8S,11as,11bs,11cs)-1,3A,4,5,6A,7,7A,8,11,11A,11B,11C-dodecahydro-2,10-dimethoxy-3,8,11A,11C-tetramethyldibenzo(de,G)chromene-1,5,11-trione;2,12-Dimethoxypicrasa-2,12-diene-1,11,16-trione;Einecs 200-985-9
• CAS NO: 76-78-8
• Molecular Formula: C22H28O6
• Molecular Weight: 388.45
• EINECS: 200-985-9
• Mol File: 76-78-8.mol
• Article Data: 14

Chemical Properties

• Melting Point: 222°
• Boiling Point: 586.3 °C at 760 mmHg
• Flash Point: 255.4 °C
• Appearance: /
• Density: 1.23 g/cm³
• Vapor Pressure: 9.98E-14mmHg at 25°C
• Refractive Index: 1.552
• Storage Temp.: -20°C Freezer, Under inert atmosphere
• Solubility: Chloroform (Slightly), Methanol (Slightly)
• CAS DataBase Reference: QUASSIN(CAS DataBase Reference)
• NIST Chemistry Reference: QUASSIN(76-78-8)
• EPA Substance Registry System: QUASSIN(76-78-8)

Safety Data

• Hazardous Substances Data: 76-78-8(Hazardous Substances Data)

Usage

Uses

Quassin is a naturally occurring extract from quassia trees and is used in traditional chinese medicine for its antiulcerogenic properties. Quassin have also been used as an additive in soft drinks.

InChI:InChI=1/C22H28O6/c1-10-7-14(26-5)20(25)22(4)12(10)8-15-21(3)13(9-16(23)28-15)11(2)18(27-6)17(24)19(21)22/h7,10,12-13,15,19H,8-9H2,1-6H3/t10-,12+,13+,15-,19+,21-,22+/m1/s1

Synthetic route

2,12-Dimethoxy-2,12-picradiene-1,11,16-trione 16-(ethylene ketal) (139276-56-5) → quassin (76-78-8)

Conditions	Yield
With 2,3-dicyano-5,6-dichloro-p-benzoquinone In acetone at 25℃; for 0.75h;	82%

2,12-Dimethoxy-2,12-picradiene-1,11-dione 16-(trans-1,2-cyclohexanediyl ketal) → quassin (76-78-8)

Conditions	Yield
With 2,3-dicyano-5,6-dichloro-p-benzoquinone In acetone at 25℃; for 0.75h;	75%

diazomethane (186581-53-3, 908094-01-9) + 11-dihydro-12-norneoquassin → quassin (76-78-8)

Conditions	Yield
With chromium(VI) oxide 1.)acetone, room temp.; 2.)ether; Yield given. Multistep reaction;

2,12-Dimethoxy-1β-hydroxy-2,12-picradiene-11,16-dione (139276-59-8) → quassin (76-78-8)

Conditions	Yield
With oxalyl dichloride; dimethyl sulfoxide; triethylamine 1.) CH2Cl2, -78 deg C, 1 h, 2.) -78 to 25 deg C, 1 h; Yield given. Multistep reaction;

diazomethane (186581-53-3, 908094-01-9) + 2,3-didehydropicrasin B (26121-57-3) → quassin (76-78-8)

Conditions	Yield
	1.7 mg
In diethyl ether	1.7 mg

2,3-didehydropicrasin B (26121-57-3) → quassin (76-78-8)

Conditions	Yield
With sodium hydride; methyl iodide

β-Neoquassin (88980-56-7) → quassin (76-78-8)

Conditions	Yield
With silver carbonate In benzene Heating;

neoquassin → quassin (76-78-8)

Conditions	Yield
With sodium dichromate; water; acetic acid
With potassium dichromate; acetic acid

neoquassin (76-77-7, 76022-76-9, 88980-55-6, 88980-56-7) → quassin (76-78-8)

Conditions	Yield
With silver carbonate In benzene for 2.5h; Oxidation; Heating;	3.8 mg

2,12,16β-trimethoxypicrasa-2,12-diene-1,11-dione (89498-93-1) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: AcOH / H2O / 0.42 h / Heating 2: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 2 steps 1: CH3CO2H / H2O / Heating 2: Ag2CO3 on Celite / benzene / Heating View Scheme

(2S,3aS,5S,6aR,7aS,8R,11R,11aS,11bR,11cS)-3,8,11a,11c-Tetramethyl-hexadecahydro-6-oxa-benzo[de]anthracene-2,5,10,11-tetraol → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 8 steps 1.1: conc. HCl / 1 h / 0 °C 2.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 3.1: 7 mg / NaH / dimethylformamide / 1 h / -20 °C 4.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 4.2: MoOPH / tetrahydrofuran / -78 - 0 °C 5.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 6.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 7.1: AcOH / H2O / 0.42 h / Heating 8.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 8 steps 1: conc. HCl / 0 °C 2: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 3: NaH / dimethylformamide / -20 °C 4: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 5: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 6: NaH / dimethylformamide / -20 °C 7: CH3CO2H / H2O / Heating 8: Ag2CO3 on Celite / benzene / Heating View Scheme

(2S,3aS,5S,6aR,7aS,8R,11R,11aS,11bR,11cS)-5-Methoxy-3,8,11a,11c-tetramethyl-hexadecahydro-6-oxa-benzo[de]anthracene-2,10,11-triol → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 7 steps 1.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 2.1: 7 mg / NaH / dimethylformamide / 1 h / -20 °C 3.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 3.2: MoOPH / tetrahydrofuran / -78 - 0 °C 4.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 5.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 6.1: AcOH / H2O / 0.42 h / Heating 7.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 7 steps 1: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 2: NaH / dimethylformamide / -20 °C 3: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 4: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 5: NaH / dimethylformamide / -20 °C 6: CH3CO2H / H2O / Heating 7: Ag2CO3 on Celite / benzene / Heating View Scheme

1α,12α-dihydroxypicrasane-2,16-dione (204130-82-5) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 9 steps 1.1: DIBAL-H / tetrahydrofuran; hexane / 0.5 h / -78 °C 2.1: conc. HCl / 1 h / 0 °C 3.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 4.1: 7 mg / NaH / dimethylformamide / 1 h / -20 °C 5.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 5.2: MoOPH / tetrahydrofuran / -78 - 0 °C 6.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 7.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 8.1: AcOH / H2O / 0.42 h / Heating 9.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 9 steps 1: DIBAL-H / tetrahydrofuran / -78 °C 2: conc. HCl / 0 °C 3: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 4: NaH / dimethylformamide / -20 °C 5: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 6: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 7: NaH / dimethylformamide / -20 °C 8: CH3CO2H / H2O / Heating 9: Ag2CO3 on Celite / benzene / Heating View Scheme

2,16β-dimethoxypicras-2-ene-1,12-dione (204130-83-6) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 5 steps 1.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 1.2: MoOPH / tetrahydrofuran / -78 - 0 °C 2.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 3.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 4.1: AcOH / H2O / 0.42 h / Heating 5.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 5 steps 1: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 2: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 3: NaH / dimethylformamide / -20 °C 4: CH3CO2H / H2O / Heating 5: Ag2CO3 on Celite / benzene / Heating View Scheme

(3aS,5S,6aR,7aS,8S,11aS,11bS,11cS)-1-Hydroxy-5,10-dimethoxy-3,8,11a,11c-tetramethyl-3a,4,5,6a,7,7a,8,11a,11b,11c-decahydro-1H,3H-6-oxa-benzo[de]anthracene-2,11-dione → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 4 steps 1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 2: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 3: AcOH / H2O / 0.42 h / Heating 4: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 4 steps 1: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 2: NaH / dimethylformamide / -20 °C 3: CH3CO2H / H2O / Heating 4: Ag2CO3 on Celite / benzene / Heating View Scheme

1α-benzyloxy-12α,13α-epoxypicras-14-ene-2,16-dione (204130-81-4) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 10 steps 1.1: 92 percent / H2 / Pd/C / ethanol / 48 h / 20 °C 2.1: DIBAL-H / tetrahydrofuran; hexane / 0.5 h / -78 °C 3.1: conc. HCl / 1 h / 0 °C 4.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 5.1: 7 mg / NaH / dimethylformamide / 1 h / -20 °C 6.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 6.2: MoOPH / tetrahydrofuran / -78 - 0 °C 7.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 8.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 9.1: AcOH / H2O / 0.42 h / Heating 10.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme
Multi-step reaction with 10 steps 1: 92 percent / H2 / Pd/C / ethanol / Ambient temperature 2: DIBAL-H / tetrahydrofuran / -78 °C 3: conc. HCl / 0 °C 4: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 5: NaH / dimethylformamide / -20 °C 6: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 7: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 8: NaH / dimethylformamide / -20 °C 9: CH3CO2H / H2O / Heating 10: Ag2CO3 on Celite / benzene / Heating View Scheme

2-hydroxy-16β-methoxypicras-2-ene-1,12-dione → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 6 steps 1.1: 7 mg / NaH / dimethylformamide / 1 h / -20 °C 2.1: LDA / tetrahydrofuran / 0.5 h / -78 °C 2.2: MoOPH / tetrahydrofuran / -78 - 0 °C 3.1: DMSO; TFAA; Et3N / CH2Cl2 / -78 - 20 °C 4.1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 5.1: AcOH / H2O / 0.42 h / Heating 6.1: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme

(3aR,5S,6aR,7aS,8S,11aS,11bS,11cS)-2-Hydroxy-5,10-dimethoxy-3,8,11a,11c-tetramethyl-3a,4,5,6a,7,7a,8,11a,11b,11c-decahydro-6-oxa-benzo[de]anthracene-1,11-dione → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: 5.7 mg / NaH / dimethylformamide / 0.67 h / -20 °C 2: AcOH / H2O / 0.42 h / Heating 3: 3.8 mg / Ag2CO3 on Celite / benzene / 2.5 h / Heating View Scheme

(3aS,5S,6aR,7aS,8R,11aS,11bS,11cS)-5-Methoxy-3,8,11a,11c-tetramethyl-dodecahydro-6-oxa-benzo[de]anthracene-2,10,11-trione → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 6 steps 1: NaH / dimethylformamide / -20 °C 2: 1) LDA, 2) MoO5-pyridine complex / 1) THF, -78 deg C, 2) THF, -78 deg C to 0 deg C 3: 1) DMSO, TFAA, 2) Et3N / 1) CH2Cl2, -78 deg C, 2) CH2Cl2, -78 deg C to room temperature 4: NaH / dimethylformamide / -20 °C 5: CH3CO2H / H2O / Heating 6: Ag2CO3 on Celite / benzene / Heating View Scheme

(3aS,5S,6aR,7aS,8S,11aS,11bS,11cS)-5,10-Dimethoxy-3,8,11a,11c-tetramethyl-3a,4,5,6a,7,7a,8,11a,11b,11c-decahydro-3H-6-oxa-benzo[de]anthracene-1,2,11-trione → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: NaH / dimethylformamide / -20 °C 2: CH3CO2H / H2O / Heating 3: Ag2CO3 on Celite / benzene / Heating View Scheme

nigakilactone I (26121-56-2) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 2 steps 1: 5.8 mg / Jones reagent / 4 h / 0 °C 2: 1.7 mg View Scheme
Multi-step reaction with 2 steps 1: DMSO, FFAA, Et3N 2: NaH, MeI View Scheme

picrasinoside-A (83543-82-2) → quassin (76-78-8)

Conditions	Yield
Multi-step reaction with 3 steps 1: 9.5 mg / 3N sulfuric acid / methanol; butan-1-ol / 17 h / 90 °C 2: 5.8 mg / Jones reagent / 4 h / 0 °C 3: 1.7 mg View Scheme

quassin (76-78-8) → neoquassin (76-77-7, 76022-76-9, 88980-55-6, 88980-56-7)

Conditions	Yield
With sodium tetrahydroborate In ethanol for 3.5h; Ambient temperature;	99%
With sodium tetrahydroborate In ethanol for 2.5h; Ambient temperature;

quassin (76-78-8) → 2,3-didehydropicrasin B (26121-57-3)

Conditions	Yield
With hydrogenchloride In acetic acid at 115℃; for 2h;	69%

quassin (76-78-8) → 1α-hydroxy-2,12-methoxypicrasa-2,12-diene-11,16-dione (110128-47-7)

Conditions	Yield
With sodium hydroxide; sodium tetrahydroborate at 80℃; for 30h;	50%
With sodium hydroxide; sodium tetrahydroborate at 80℃; for 0.5h;	45 mg

quassin (76-78-8) → nigakilactone I (26121-56-2)

Conditions	Yield
With chloro-trimethyl-silane; sodium iodide In acetonitrile at 25℃; for 18h; Mechanism;	42%
With chloro-trimethyl-silane; sodium iodide In acetonitrile at 25℃; for 18h;	42%
Multi-step reaction with 4 steps 1: iodomethylsilane, sodium iodide / acetonitrile 2: iodomethylsilane, sodium iodide / acetonitrile 3: iodomethylsilane, sodium iodide / acetonitrile 4: chlorotrimethylsilane, sodium iodide / acetonitrile / 18 h / 25 °C View Scheme

quassin (76-78-8) → 2,12-dihydroxypicrasa-2,12-diene-1,11,16-trione (4281-38-3)

Conditions	Yield
With boron tribromide In dichloromethane -60 deg C, room temperature, 1.5 h;	41%
With boron tribromide In dichloromethane at -78℃; for 0.333333h;	41%

quassin (76-78-8) → 2-methoxy-2-deoxypicrasin B (123834-97-9)

Conditions	Yield
With (iodomethyl)silane; sodium iodide In acetonitrile	9%
With (iodomethyl)silane; sodium iodide In acetonitrile Yield given;

sodium acetate (127-09-3) + quassin (76-78-8) → Isoquassin (21293-20-9)

Conditions	Yield
beim Erhitzen erfolgt partielle Umwandlung;

quassin (76-78-8) → pseudoquassinolic acid

Conditions	Yield
With sodium hydroxide; water

quassin (76-78-8) → Isoquassin (21293-20-9)

Conditions	Yield
beim Erhitzen erfolgt partielle Umwandlung;

trans-1,2-bis[(trimethylsilyl)oxy]cyclohexane (13871-93-7, 39789-20-3, 39789-21-4, 125329-92-2) + quassin (76-78-8) → 2,12-Dimethoxy-2,12-picradiene-1,11-dione 16-(trans-1,2-cyclohexanediyl ketal)

Conditions	Yield
With trimethylsilyl trifluoromethanesulfonate In dichloromethane at 25℃; for 18h; Yield given;

quassin (76-78-8) → (3aR,6aR,7aS,8S,11aS,11bS,11cS)-9-Iodo-2,10-dimethoxy-3,8,11a,11c-tetramethyl-11-trimethylsilanyloxy-3a,4,6a,7,7a,8,9,11a,11b,11c-decahydro-6-oxa-benzo[de]anthracene-1,5-dione

Conditions	Yield
With (iodomethyl)silane; sodium iodide In acetonitrile

tetrachloromethane (56-23-5) + water (7732-18-5) + quassin (76-78-8) → pseudoquassinolic acid

hydrogenchloride (7647-01-0) + methanol (67-56-1) + quassin (76-78-8) → Isoquassin (21293-20-9)

Conditions	Yield
es erfolgt partielle Umwandlung;

hydrogenchloride (7647-01-0) + ethanol (64-17-5) + quassin (76-78-8) → Isoquassin (21293-20-9)

Conditions	Yield
es erfolgt partielle Umwandlung;

tetrachloromethane (56-23-5) + water (7732-18-5) + quassin (76-78-8) → carboxylic acid C22H30O7 of mp: 222 degree + carboxylic acid C22H30O7 of mp: 240 degree

ethanol (64-17-5) + water (7732-18-5) + quassin (76-78-8) + palladium/charcoal + KOH → dihydroquassin

Conditions	Yield
Hydrogenation;

ethanol (64-17-5) + quassin (76-78-8) + Raney nickel → neoquassin

Conditions	Yield
Hydrogenation;

hydrogenchloride (7647-01-0) + water (7732-18-5) + acetic acid (64-19-7) + quassin (76-78-8) → norquassin

hydrogenchloride (7647-01-0) + water (7732-18-5) + acetic acid (64-19-7) + quassin (76-78-8) → quassinol

Upstream product

• 88980-56-7 β-Neoquassin 
• 76-77-7 neoquassin 
• 23460-59-5 4-epinorquassin 
• 135441-00-8 (1aR,4S,4aS,5aR,8aS,8bR,9R,10aS,10bS,10cS)-1a,10b-Dihydroxy-4,8b,9,10c-tetramethyl-dodecahydro-1,6-dioxa-benzo[mno]aceanthrylene-2,7,10-trione 
• 135440-95-8 (2R,3S,3aR,6aS,7aR,8S,11aR,11bR,11cS)-2,10,11b-Trihydroxy-3,8,11a,11c-tetramethyl-2,3,3a,6a,7,7a,8,11a,11b,11c-decahydro-4H-6-oxa-benzo[de]anthracene-1,5,11-trione 
• 4281-38-3 4-epibisnorquassin 
• 77-78-1 dimethyl sulfate 
• 135440-96-9 (2R,3S,3aR,6aS,7aR,8S,11aR,11bR,11cS)-2,11b-Dihydroxy-10-methoxy-3,8,11a,11c-tetramethyl-2,3,3a,6a,7,7a,8,11a,11b,11c-decahydro-4H-6-oxa-benzo[de]anthracene-1,5,11-trione 
• 135440-97-0 (1aR,4R,4aS,5aR,8aS,8bR,9R,10aS,10bS,10cS)-1a,10b-Dihydroxy-2-methoxy-4,8b,9,10c-tetramethyl-1a,4a,5,5a,8a,8b,9,10a,10b,10c-decahydro-4H,8H-1,6-dioxa-benzo[mno]aceanthrylene-7,10-dione 
• 75924-43-5 ((1R,4aR,4bR,5S,8S,8aR,10aR)-5-Methoxy-2,4b,8,10a-tetramethyl-10-oxo-1,4,4a,4b,5,6,7,8,8a,9,10,10a-dodecahydro-phenanthren-1-yl)-acetic acid ethyl ester 
• 125590-26-3 1,2,3,4,4a,5,6,7,8,8a-decahydro-5β-hydroxy-8β,8aβ-methano-4aβ-methyl-2,2-ethylenedioxynaphthalene 
• 75935-29-4 (2α,9β,11β,16β)-2,11-dihydroxy-16-methoxypicrasane-1,12-dione 
• 75924-45-7 (9β,16β)-16-methoxypicrasane-1,12-dione 
• 75924-47-9 (1β,9β,12β,16β)-16-methoxypicrasane-1,12-diol 

Downstream Products

• 139092-14-1 (6aR,7aS,8S,11aS,11bS,11cR)-10-Methoxy-3,8,11a,11c-tetramethyl-6a,7a,8,11a,11b,11c-hexahydro-7H-6-oxa-benzo[de]anthracene-1,5,11-trione 
• 76-78-8 isoquassin 
• 76-78-8 (3aR,6aS,7aR,8R,11aR,11bS,11cR)-2,10-Dimethoxy-3,8,11a,11c-tetramethyl-3a,6a,7,7a,8,11a,11b,11c-octahydro-4H-6-oxa-benzo[de]anthracene-1,5,11-trione 
• 76-78-8 d,l-quassin 
• 21293-20-9 Isoquassin 
• 76-78-8 Alloquassin 
• 30315-04-9 (-)-picrasin B acetate 
• 30315-04-9 Acetic acid (3aR,6aR,7aS,8R,10S,11aS,11bS,11cS)-2-methoxy-3,8,11a,11c-tetramethyl-1,5,11-trioxo-1,3a,4,5,6a,7,7a,8,9,10,11,11a,11b,11c-tetradecahydro-6-oxa-benzo[de]anthracen-10-yl ester 
• 210623-98-6 Benzoic acid (3aR,6aR,7aS,8S,11aS,11bS,11cS)-2-methoxy-3,8,11a,11c-tetramethyl-1,5,11-trioxo-1,3a,4,5,6a,7,7a,8,11,11a,11b,11c-dodecahydro-6-oxa-benzo[de]anthracen-10-yl ester 
• 26121-57-3 2,3-didehydropicrasin B 
• 26121-56-2 nigakilactone I 
• 26121-56-2 (+)-picrasin B 
• 123834-97-9 2-methoxy-2-deoxypicrasin B 

Relevant articles and documents

Hydrolysis of 1,4,6-trioxaspiro[4.5]decanes to δ-lactones using 2,3- dichloro-5,6-dicyanobenzoquinone in aqueous acetone

A selective hydrolysis of 1,4,6-trioxaspiro[4.5]decane orthoesters by 2,3- dichloro-5,6-dicyanoquinone (DDQ) in aqueous acetone in the presence of other acid-sensitive ketals is suggested to involve the formation of a charge- transfer complex followed by hydrolysis. A hydride-transfer mechanism for this oxidation was excluded.

Total Synthesis of (+)-Quassin

A total synthesis of (+)-quassin from naturally occurring (S)-(+)-carvone is described. The total number of steps was 28, and the overall yield was about 2.6%. The synthetic strategy for the construction of the tetracyclic carbon framework was based on a C→ABC→ABCD ring annulation sequence, involving an aldol reaction, an intramolecular Diels - Alder reaction, and an intramolecular acylation as the key steps. Subsequent functionalization of ring A and ring C then afforded the target (+)-quassin.

ON EQUILIBRATION OF QUASSIN AND 4-EPIQUASSIN

Equilibration of quassin and 4-epiquassin is described.Various quassin derivatives are characterized and their relationship to quassin (I) is discussed.A regioselective deprotonation is achieved in quassin and 4-epiquassin (III) by the introduction of a diosphenolate grouping which makes a potentially acidic H-atom unavailable for attack by base.