An cffkht synthesis of a potentially useful phoa&fkity labeling magent, S-mphan, is described_ Starting firm 5-niuoindol~ we used a modified procedm of the original method of Cavallini and Ravennaz (Scheme 1) and obtained 5-nitrogramine in high yield. The substituted and unsubstituted gnunines have been anployed in the c-akylatial of acemmidom&nate and/or nim alluutetothe synthesis of txyptophan and its derivatives.~~ We chose the mctioa between ethyl nitmacetate and 5 nitmgmmim to prepare the desired ethyl I-nitrw2-(5-nitro-3-indolyl)pfopiona!e (2). since we expected that the two nitro groups could be reduced in a single step, rendering it mom efficient than alternate routes. Initial runs were caked out, thaefom. acmrding to the procedure of Lyttle and Weisblat fa the synthesis of 1-nitro-2-(3-indolyl)propionate.3~ The cnuk oil obtained in the reaction was dissolved in chlorof~ and extracted with 5% NaOH solution. The latter solution was acidifial and extracted with chlomfom. However, only a small amount of brown oily mat&al was retricval after removal of the solvent. 'I& workup plucahm was thus changu& along with sonx mamcatim of the ma&r l?acdon course. om final ~~~isquicesinrple:(l)heatingamixtlaeofS-~~aadethyl~inxyltnes at 92 'C for 15 h, (2) washing the resulting solution (after mixed with mcthylene chloride) with 2 N HCl ami watm and (3) nmoval of the solvents yielding the mysmUnc product (2) in 8646 yield.4 Reduction of 2 using the standard proccdunx of catalytic hydmgenation~ (10% H/C!. 40-M psi) reSulted only in a complex mixture. An alternafive reduction method employing Pd/C in cmjumticm with such hydrogen donors as formic acid a phosphorous acid6 appear4 promisiig fa our putpose. It was found,howcvcr,thatwhcn2wastrcatcdwith formicacidinthepresenccof1O%w/Catroom