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Reduction of cinnamic acid with water-sodium borohydride-Raney nickel; 3-phenylpropionic acid

SyntheticPage 521
DOI: 10.1039/SP521
Submitted Dec 09, 2011, published Jan 11, 2012
Ramesha Ramakrishna (ramesha63@hotmail.com)


			Reaction Scheme: <IMG src="/images/empty.gif">Reduction of <SPAN id=csm1338027211733 class=csm-chemical-name title="cinnamic acid" grpid="1">cinnamic acid</SPAN> with water-<SPAN id=csm1338027254051 class=csm-chemical-name title="sodium borohydride" grpid="3">sodium borohydride</SPAN>-<SPAN id=csm1338027315546 class="csm-chemical-name csm-not-validated" title="Raney nickel" grpid="6">Raney nickel</SPAN><IMG src="/images/empty.gif">

Chemicals Used

cinnamic acid
sodium borohydride
sodium hydroxide
Raney-Nickel

Procedure

In a 5 L four necked round bottom flask equipped with a mechanical stirrer, 250 mL dropping funnel, thermometer and inlet port open to the atmosphere on a water bath wascharged with 2250 mL of distilled water. Stirring was started and the following reagents added in the order indicated through a funnel: sodium hydroxide (81 g, 2.026 mol, 1.2 equiv), cinnamic acid (250 g, 1.689 mol, 1 equiv), slurry containing activated W-6 Raney nickel (25 g wet) in distilled water. This was stirred for 15 min. Sodium borohydride solution (17.89 g, 0.472 mol, 0.28 equiv, in 1% aqueous  NaOH solution 100 mL)  was added dropwise through dropping funnel over a period of 45 min. The reaction mixture was stirred for additional 30 min at 40-45 oC. TLC analysis revealed that reaction was complete. The reaction flask was removed from the water bath, and the mixture cooled to a room temperature. Then solution was filtered through a Buchner funnel fitted with 2 L. filtration flask under vacuum and the W-6 Raney nickel in the flask rinsed with distilled water (200 mL). The cooled filtrate and washings were poured slowly with mechanical stirring into ice cold concentrated hydrochloric acid (250 mL) in a open 5 L flask . The resulting white colored solid precipitate was collected by Buchner filtration under vacuum, washed with distilled water (250 mL) and air dried to give 245.4 g (96.9 %) of 3-phenyl propionic acid .

 

Author's Comments

Care should be taken while handling Raney Nickel-it should be kept wet.
Sodium borohydride can give rise to flamable hydrogen gas if it comes in contact with acidic reagents. Therefore it should be added to alkaline aqueous solution (1 g sodium hydroxide in 100 mL  water).  The whole reaction medium should be maintained at alkaline pH.

Data

13C,1H NMR data included

3-phenyl propionic acid, m.p 48-50 oC. A white color crystal is pure by IR, 1H NMR and 13C NMR.

IR (KBr) 3404, 3059, 2929, 1699 cm-1. 1H NMR (400 MHz, CDCl3) δ: 7.31-7.19 (m, 5H, ArH), 2.96 (t, 2H, J = 7.6 Hz, CH2), 2.68 (t, 2H, J = 7.8 Hz, CH2). 13C NMR (100 MHz, CDCl3) δ: 30.5, 35.5, 126.3, 128.2, 128.5, 140.1, 179.0. GC-MS (m/z): Calculated for (C9H10O2): 150, found: 150.


Lead Reference

Synthetic Communication. 2012, 42, 893-904. Slightly modified for large scale synthesis

Other References

None

Supplementary Information

Supporting Info (support-information Dec 2011.doc)

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Get structure file (.cdx, .sk2, .mol)

Keywords: alkenes, Raney-nickel, reduction, sodium borohydride, unsaturated carboxylic acids

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