Potassium Hydroxide → HCID 53850664, compound

Participants

Reaction Steps

The operation is carried out in a fashion similar to that described in Example 77, but starting from 0.76 g of methyl (2R,4R)-3-{3-{2-[4-tert-butoxycarbonyl-2-(2-methoxyphenyl)-3-thiazolidinyl]-2-oxoethyl}ureido}phenylacetate in 6 cm3 of a water/methanol (30/70 by volume) mixture and 0.09 g of potassium hydroxide. The crude product (0.45 g) is dissolved in 7.5 cm3 of a 0.1N aqueous sodium hydroxide solution. The solution thus obtained is washed with 2 times 10 cm3 of diethyl ether, brought to a pH of 2 by addition of a 1N aqueous sulphuric acid solution, then extracted with 2 times 20 cm3 of ethyl acetate. The organic phases are combined, dried over magnesium sulphate and concentrated to dryness under reduced pressure at 40° C. After vigorous stirring in diisopropyl ether, 0.25 g of (2R,4R)-3-{3-{2-[4-tert-butoxycarbonyl-2-(2-methoxyphenyl)-3-thiazolidinyl]-2-oxoethyl}ureido}phenylacetic acid is thus obtained in the form of an amorphous product ([α]D20 =+6.4°±1.0° (C=0.466%; CHCl3), [proton NMR (200 MHz, DMSO D6 plus several drops of CD3COOD, δ in ppm, J in Hz), 2 rotamers at room temperature, peak coalescence at 120° C., characteristic chemical shifts at 120° C.: 1.55 (s, 9H, --C(CH3)3); 3.22 and 3.45 (2dd, J=12.5 and 7, 2H, S--CH2 --); 3.51 (s, 2H, ArCH2COO--); 3.65 (bd, 1H of N--COCH2 --N); 3.93 (s, 3H, --OCH3); 4.05 (d, J=17.5, 1H, the other H of N--COCH2 --N); 4.91 (t, J=7, 1H, N--CH--COO); 6.5 (s, 1H, S--CH--N); 6.85 (bd, J=8, 1H, in position 4 on CO--NM--Ph); 6.9 to 7.4 (m, 6H, aromatic); 7.9 (bd, J=8, 1H, in position 6 on S--CH--Ph--)], [infrared spectrum (KBr), characteristic bands in cm-1 : 3390, 2975, 2930, 2840, 2700 to 2250 (broad band), 1735, 1645, 1610, 1600, 1595, 1560, 1495, 1370, 1245, 1155, 1025, 760, 705].

Provenance & Evidence