O-Xylene → Ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylate

HRID 1503477Notes

Reaction equation

HRID 1503477 reaction equation
[N:1]1O[C:3]([O-])=[C:4]2[CH2:8][CH2:7][CH2:6][N+:5]=12.[C:10]([O:14][CH2:15][CH3:16])(=[O:13])C#C.[C:17]1(C)C(C)=CC=CC=1>>[N:1]1[N:5]2[CH2:6][CH2:7][CH2:8][C:4]2=[C:3]([C:10]([O:14][CH2:15][CH3:16])=[O:13])[CH:17]=1

Participants

4

Reactant 3

HCID 7237O-XyleneHCID 12182Ethyl propiolateHCID 150890374H,5H,6H-7lambda5-pyrrolo[1,2-c][1,2,3]oxadiazol-7-ylium-3-olate

Product 1

HCID 12841167Ethyl 5,6-dihydro-4H-pyrrolo[1,2-b]pyrazole-3-carboxylate

Conditions

Temperature
125 °C

Procedure

A mixture of 5,6-dihydro-4H-pyrrolo[1,2-c]oxadiazol-7-ium-3-olate (355.4 mg, 2.82 mmol) and ethyl propiolate (0.87 mL, 8.46 mmol) in xylene (10 mL) in a round-bottom flask equipped with a condenser was heated to 125° C. overnight. The reaction mixture was concentrated in vacuo, adsorbed onto silica and purified by column chromatography (0-100% EtOAc in Heptane) to afford the title compound as a yellow oil (161 mg, 32%, more polar regioisomer). 1H NMR (400 MHz, CDCl3) δ 7.90 (s, 1H), 4.27 (q, J=7.1 Hz, 2H), 4.16 (t, J=7.3 Hz, 2H), 3.09 (t, J=7.4 Hz, 2H), 2.70-2.60 (m, 2H), 1.33 (t, J=7.1 Hz, 3H). LC-MS (ESI): m/z=181.1 (M+H)+.

Workup

  1. customequipped with a condenser
  2. concentrationThe reaction mixture was concentrated in vacuo
  3. custompurified by column chromatography (0-100% EtOAc in Heptane)

Sources & evidence

ORD record
ord-9fc9a21b46b24054b06e74d24b7936a4
Source dataset
uspto-grants-2015_12
Patent number
US09212186B2

Reaction notes

Loading…