MD-Phenylacetonitrile -> MDP2P (+ NMR/TLC data)

[Rhodium]

Il Farmaco Volume 57, Issue 10 , 24 September 2002, Pages 853-859
DOI:

10.1016/S0014-827X(02)01276-4

Synthesis of 1,3-benzodioxole-5-acetic acid methyl ester

1,3-Benzodioxole-5-acetonitrile (1) (2 g, 12.4 mmol) was dissolved in a freshly prepared solution of MeOH/MeCOCl (1/1, v/v, 60 ml) and the reaction mixture was stirred at 0°C for 8 h. The solvent was removed under vacuum and the residue was treated with water (60 ml) and extracted with ethyl ether (2×80 ml). The pooled organic extracts were dried (Na₂SO₄) and the solvent was evaporated at reduced pressure to yield 1,3-benzodioxole-5-acetic acid methyl ester (2.3 g, 95%) as an oil.

Synthesis of 1-(1,3-benzodioxol-5-yl)-2-propanone (MDP2P)

To a stirred solution of 1,3-Benzodioxole-5-acetonitrile (1) (4 g, 24.8 mmol) and methyl magnesium bromide (3.0 M solution in THF, 9.5 ml, 28.5 mmol), in THF (80 ml) was added CuBr (64 mg, 0.43 mmol), and the mixture was refluxed under nitrogen for 30 min. After cooling to 0–5°C, 5 ml of H₂O was cautiously added, followed by 30 ml of 15% H₂SO₄. After stirring for 14 h, 60 ml of ether was added, the phases were separated, and the aqueous layer was extracted twice more with 50 ml portions of ether. The combined organic phase was dried (Na₂SO₄) and the solvent removed under reduced pressure to afford 1-(1,3-benzodioxol-5-yl)-2-propanone  (MDP2P) (yield 30%, 1.32 g) as a light brown oil.

R_f (cyclohexane/EtOAc, 60/40) 0.56 
¹H NMR: 2.14 (s, 3H, CH₃), 3.59 (s, 2H, CH₂), 5.93 (s, 2H, OCH₂O), 6.61–6.77 (m, 3H, Ar).

[bones]

hmm.. not really great yield.. but its nice to see methods that dont rely on distillation ...i saw that on scifinder...but i coiuld never get it.. so thankx rhodium...\.... but to be honest i dont think this method is going to have wide application... seems like some of those reagents may be difficult to come by ...