Phosphorus oxychloride → 1-Methyl-3,4-dihydropyrrolo[1,2-a]pyrazine

HRID 1448947Notes

Reaction equation

HRID 1448947 reaction equation
[N:1]1([CH2:6][CH2:7][NH:8][C:9](=O)[CH3:10])[CH:5]=[CH:4][CH:3]=[CH:2]1.P(Cl)(Cl)(Cl)=O>>[CH3:10][C:9]1[C:2]2[N:1]([CH:5]=[CH:4][CH:3]=2)[CH2:6][CH2:7][N:8]=1

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 2767072HCID 2767072, compound

Product 1

HCID 5842861-Methyl-3,4-dihydropyrrolo[1,2-a]pyrazineYield 95%

Procedure

The solid N-[2-(1H-pyrrol-1-yl)ethyl]acetamide (8 g, described in Example 1) is added cautiously in small portions into phosphorus oxychloride (45 ml) upon stirring. The mixture is refluxed for 60 min and evaporated under reduced pressure (1 mm Hg). The residue is partitioned between 10% sodium hydroxide and diethyl ether, and the organic phase is separated and evaporated. The residue is filtered through a column of neutral alumina packed in chloroform and the eluates are evaporated to obtain 6.7 g of the title compound which solidified: mp 25°-27° C. and nmr(CDCl3) δ 2.28(s), 3.84(s), 6.12(t), 6.36(d) and 6.64.

Workup

  1. temperatureThe mixture is refluxed for 60 min
  2. customevaporated under reduced pressure (1 mm Hg)
  3. customThe residue is partitioned between 10% sodium hydroxide and diethyl ether
  4. customthe organic phase is separated
  5. customevaporated
  6. filtrationThe residue is filtered through a column of neutral alumina
  7. customthe eluates are evaporated

Sources & evidence

ORD record
ord-e39a5102a2f14d0c89681a64745abe10
Source dataset
uspto-grants-1980_02
Patent number
US04188389

Reaction notes

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