Solution and Solid Phase Synthesis of Unusual a-Amino Acids From

302.1604, found 302.1593; Anai. calcd for Ci4&N06: C, 55.80; H, 7.69; N, 4.64.
Found: C, 56.0 1 ; H, 7.96; N, 4.86.
2A.10 l,l,l-Triacetony-l,l-dihydro-1,2-benziod0~01-3(îR)1one, 2A8.P
Potassium bromate (19 g, O. 11 mol) was added over a 0.5 hour period to a vigorously
stimng mixture of 2-iodobenzoic acid (21 -3 g, 0.08 mol) and 200 rnL of 0.73 M HtS04.
During addition the temperature of the reaction was kept below 5S°C but then warmed to
65°C and stirred for an additionai 3.5 h. The mixture was then cooled to 0°C and the
precipitate filtered off then washed with 700 mL of water and two 30 mL portions of cold
ethanol. The precipitate was dried under water aspirator then taken up in Ac20 (90 mL,
0.85 mol) and AcOH (75 rnL. 1.4 mol) under NZ. The vigorously stimng mixture was
slowly heated to 85°C over 1 h and the now clear solution stirred for 1.5 h at 85°C then
allowed to cool to ambient temperature under N2. The solution was tightly sealed,
wrapped in foi1 and allowed to slowly crystallized over 2 days. The crystals were
transferred under N2 through a male-male adapter into a Schlenk tube. The white crystals
were thoroughly washed with freshly distilled Et20 (10 x 50 mL) using positive Nz
pressure and vacuum to assist in the filtration. The crystals were dned under N2 then
transferred to dry amber vials and purged with N2.
mp 125-126.S°C; 'H NMR (CDCI>,250 MHz) 6 8.69 ( br dd, lH, A m, 8.33 (d, lH, J =
8.SHz, ArH), 8.29 (d, lH, J = 8.5Hz, ArH), 7.90 (br dd, 1H, ArH), 2.27 (s, 3H, CfiCO),
2.0 1 (s, 6H, 2 CH3CO).