[lab.star]

I find a problem in esterifying the (OH) of hydroxy aliphatic dicarboxylic acid with another acid. Is there a suitable solution for this? To avoid formation of inner lactone, is protection of the two carboxylic groups by initial esterification considered to be the only solution?

[Doc Oc]

I'm having some trouble understanding what you're asking.  It sounds like you have a linear dicarboxylic acid and you are trying to esterify one or both of the acids, but avoid the intramolecular lactonization, is that correct?  If so you have a very challenging transformation, particularly if you can form a 5 or 6 membered ring lactone.

[lab.star]

I'm having some trouble understanding what you're asking.  It sounds like you have a linear dicarboxylic acid and you are trying to esterify one or both of the acids, but avoid the intramolecular lactonization, is that correct?  If so you have a very challenging transformation, particularly if you can form a 5 or 6 membered ring lactone.

What I want to do is to esterify a hydroxy group in a compound (this compound contains two carboxylic groups beside its hydroxy group, as it is a hydroxy acid).

[g-bones]

it sounds like you want to add some kind of acyl group onto the alcohol to transform it into an ester.  if so, it seems like treatment with acetyl chloride should do the trick.  the alcohol should be more nucleophilic than the acids, and even if you place an acyl group onto the acids to make the mixed anhydride, it would probably be so labile it would fall apart upon aqueous workup to release your acid again. 

[animanga008]

I don't get what you are asking...You want to add an acid to a carboxylic acid? What?

If you want to change a carboxylic acid to an ester, could you try using EDC with HOBT and the thing you want to add? Or DCC wile activating the other thing with NBS?

[discodermolide]

I'm having some trouble understanding what you're asking.  It sounds like you have a linear dicarboxylic acid and you are trying to esterify one or both of the acids, but avoid the intramolecular lactonization, is that correct?  If so you have a very challenging transformation, particularly if you can form a 5 or 6 membered ring lactone.

What I want to do is to esterify a hydroxy group in a compound (this compound contains two carboxylic groups beside its hydroxy group, as it is a hydroxy acid).

You could try a para-methoxybenzyl group, react p-methoxybenzyl alcohol with trichloroacetonitrile with catalytic NaH. Isolate the trichloroimidate then react it with the hydroxy acid using pPTSA or PyOTsA as a catalyst. Look in the literature for the etherifiaction of Roche ester etc. If the acidic groups esterify remove them by very mild hydrogenation, the ether should stay put.

[MissPhosgene]

Just did a similar transformation. Acetyl chloride or the corresponding imid. work superbly.