Acetic Acid → (S)-2-ethynyl-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol

HRID 1199193

반응식

HRID 1199193 반응식
C(O[C@@:5]([CH3:21])([C:19]#[CH:20])[CH2:6][CH2:7][C:8]1[C:9](=[O:18])[C:10]([CH3:17])=[C:11]([CH3:16])[C:12](=[O:15])[C:13]=1[CH3:14])(=O)C.C(O)(=O)C>C(Cl)Cl.[Zn]>[C:19]([C@:5]1([CH3:21])[CH2:6][CH2:7][C:8]2[C:13]([CH3:14])=[C:12]([OH:15])[C:11]([CH3:16])=[C:10]([CH3:17])[C:9]=2[O:18]1)#[CH:20]

참가 물질

5

반응물 2

HCID 176Acetic AcidHCID 14478578(R)-2-[3-(acetyloxy) 3-methyl-4-pentynyl]-3,5,6-trimethyl-2,5-cyclohexadiene-1,4-dione

생성물 1

HCID 9859440(S)-2-ethynyl-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol수율 25%

시약·촉매·용매 2

HCID 23994Zinc촉매HCID 6344Dichloromethane용매

반응 조건

온도
4 °C

실험 절차

A solution of 285 mg (0.99 mmol) of (R)-2-[3-(acetyloxy) 3-methyl-4-pentynyl]-3,5,6-trimethyl-2,5-cyclohexadiene-1,4-dione in 4 mL of CH2Cl2 was stirred with 250 mg of Zn dust, and 250 mg of glacial acetic acid. The reaction mixture was stirred at 4° C. under argon for 50 min. then filtered. It was worked up with CH2Cl2 as described above. The crude hydroquinone acetate was taken into 6 mL of CH2Cl2 and treated with 20 mg of AgClO4 ·H2O as described above to give 124 mg of crude product after workup, and purification by flash chromatography. Crystallization of this material from toluene-hexane (1:1) at -15° C. gave 57 mg of (S)-2-ethynyl-3,4-dihydro-2,5,7,8-tetramethyl-2H-1-benzopyran-6-ol: [α]D25 +20.20°, (c 1.3, CHCl3).

후처리

  1. filtrationthen filtered
  2. additiontreated with 20 mg of AgClO4 ·H2O
  3. customto give 124 mg of crude product
  4. customafter workup, and purification by flash chromatography
  5. customCrystallization of this material from toluene-hexane (1:1) at -15° C.

출처 및 근거

ORD 기록
ord-f2d5e3af4e014a908249a6be66c0cf40
출처 데이터셋
uspto-grants-1990_02
특허 번호
US04898953

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