[FeLiXe]

hi

I'm supposed to make Phenyl-acetic-acid out of Benzoic-acid. So all I am actually doing is putting in CH2. I have no idea how I am supposed to that. some kind of rearrangement?

thanks for any help

[plu]

Using basic organic chemistry, you'll need a few steps for this:
1) LiAlH₄, ether
2) H₃O⁺
3) PBr₃, ether
4) Mg, ether
5) formaldehyde, ether
6) KMnO₄, H₃O⁺

[AWK]

See Arndt-Eistert synthesis

[HP]

Heres some of the common methods  of preparation phenylacetic acid: See especially refferences 3 and 4 for your case i think...

The standard method of preparation of phenylacetic acid is by the hydrolysis of benzyl cyanide with either alkali[1a] or acid.[2a] The acid hydrolysis runs by far the more smoothly and so was the only one studied. There are numerous other ways in which phenylacetic acid has been formed, but none of them is of practical importance for its preparation. These methods include the following: the action of water on phenyl ketene;[3a] the hydrolysis and subsequent oxidation of the product between benzaldehyde and hippuric acid;[1] the reduction of mandelic acid;[2] the reduction of benzoylformic acid with hydriodic acid and phosphorus;[3] the hydrolysis of benzyl glyoxalidone;[4] the fusion of atropic acid with potassium hydroxide;[5] the action of alcoholic potash upon chlorophenylacetylene;[6] the action of benzoyl peroxide upon phenylacetylene;[7] the alkaline hydrolysis of triphenylphloroglucinol;[8] the action of ammonium sulfide upon acetophenone;[9] the heating of phenylmalonic acid;[10] the hydrolysis of phenylacetoacetic ester;[11] the action of hydriodic acid upon mandelonitrile.[12]

[1a] Ann. 96, 247 (1855); Ber. 14, 1645 (1881); Compt. rend. 151, 236 (1910).

[2a] Ber. 19, 1950 (1886).

[3a] Ber. 44, 537 (1911).

[1] Ann. 370, 371 (1909)a

[2] Chem. (2) 1, 443 (1865); Ber. 14, 239 (1881).

[3] Ber. 10, 847 (1877)

[4] J. prakt. Chem. (2) 82, 52, 58 (1910).

[5] Ann. 148, 242 (1868).

[6] Ann. 308, 318 (1899).

[7] J. Russ. Phys. Chem. Soc. 42, 1387 (1910); Chem. Zentr. 1911 (I) 1279.

[8] Ann. 378, 263 (1911).

[9 Ber. 21, 534 (1888); J. prakt. Chem. (2) 81, 384 (1910).

[10] Ber. 27, (1894).

[11] Ber. 31, 3163 (1898)

[12] Inaugural Dissertation of A. Kohler (1909), Univ. of Bern.

Checked by O. KAMM and A. O. MATTHEWS.

[FeLiXe]

thanks everyone

I think I'll go for Arndt-Eistert. It's the rearrangement I've been looking for.

[HP]

Please be carefull working with diazomethane its explosive! Think about in situ method sinthesis it Best tesults in Wolff rearangement at the first step reaction is using Ag2O as catalyst + light.
Whish success

[FeLiXe]

well, actually it was just a question for a test

I'm sorry if I made it sound like I was actually synthesising it

[HP]

Aha i see..But you know this which can explode on paper much effectively could do it on real
Bu the way your phenylacetic acid is interesting for me because i am bulgarian chemist and proud for our national organic chemistry is well known Ivanov reagent(named on Acad. Dimitar Ivanov - eminent bulgarian chemist) and the corresponding very useful Ivanov aldol reaction with it. So:
Ph-CH2COOH + 2RMgBr--> PhCH=C(O:- +MgBr)2
This reagent readily react with aldehydes giving  ?-hydroxy acids, similar to the Aldol Addition.The stereoselectivity of the products can be explained with the Zimmerman-Traxler Model, which predicts a six-membered cyclic transition state leading to excellent stereoselectivity for anti-substituted products.

[bjrvangala]

hi
i have few questions for you.
 1.how to check purity of acetic acid.
 2)how to purify acetic acid in a large quantity.
 3.who to neutral ethyl acetate when it contains mandelic acid

[alphahydroxy]

Aha i see..But you know this which can explode on paper much effectively could do it on real

Yes, and diazomethane could literally explode if it came into contact with the rough surface of paper, or ground glass, or a scratch in your glassware which you overlooked...! Must always use fire polished glassware and rubber seals! Nasty!

[alphahydroxy]

hi
i have few questions for you.
 1.how to check purity of acetic acid.
 2)how to purify acetic acid in a large quantity.
 3.who to neutral ethyl acetate when it contains mandelic acid

1) nmr + GC

2) distillation (bp something like 112 celcius, off the top of my head)

3) not quite sure what you're asking here. If you just want to neutralise it, you could just add base, but I guess that's not what you wanted to know!