you cannot perform the coupling in aqueous solution.....starting from the acid, dissolve it in amonia soultion in aprotic organic solvent such as THF or Dioxane (commercially available http://www.acros.com/portal/alias__rainbow/lang__en/tabID__132/DesktopDefault.aspx) and treat it with 1.1 eq edc and 1.2 hobt.....to enanche the solubility sonicate or heat...

Good luck

From GLENMARK PHARMACEUTICALS S.A.

Patent: WO2006/90244 A1, 2006 ;

Location in patent: Page/Page column 27-28

Step 1: 1-Adamantanecarboxamide: To a stirred and cooled (-10 °C) solution of adamantane-1 -carboxylic acid (5.0 g, 27.74 mmol) and triethylamine (3.61 g, 33.27 mmol) in THF (80 ml) was added ethyl chloroformate (3.65 g, 36.06 mmol) to result in a white precipitate. The mixture was stirred at the same temperature for 30 min and 30 percent NH4OH (20 ml) was added. The reaction mixture was gradually warmed to room temperature and further stirred for 30 min. THF was evaporated under reduced pressure and the solid precipitated was filtered and washed with cold water to afford the desired product as a white solid (4.8 g, 97 percent); IR (KBr) 3515, 3422, 2899, 2853, 1634, 1596 cm-1; 1H NMR (300 MHz, DMSO-d6) δ 1.64-1.69 (m, 6H), 1.73-1.74 (m, 6H), 1.94 (brs, 3H), 6.68 (brs, 1H), 6.94 (brs, 1H).

I've attached the patent for your perusal.

you can do an HATU coupling with the acid and ammonium chloride. Did this many times.

Thank you so much for all of you. All your answer are so helpful.

 Convert 1-adamantane carboxamide from 1-adamantane carboxylic acid into ester then hear with NH3 solution to get solid amide    Or Take  1-adamantyl carbonyl chloride and heat with ammonia solution & remove ecxess of ammonia to get amide derivative.

The following reference might help, Convert 1-adamantane carboxamide from 1-adamantane carboxylic acid into ester followed by in presence of sodium methoxide and formamide as solvent & reagent.

a) Synth. commun., 20 , 1203 (1990)