Oxo(1,3,4-thiadiazol-2-ylamino)acetic acid → 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(2-(1,3,4-thiadiazol-2-ylamino)-2-oxoacetamido)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoic acid

Participants

Reaction Steps

The title compound was prepared in 21% yield from methyl 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-amino-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoate following the same procedure as described for the preparation of 4-((1R,3aS,5aR,5bR,7aR,11aS,11bR,13aR,13bR)-3a-(3-(dimethylamino)propanamido)-5a,5b,8,8,11a-pentamethyl-1-(prop-1-en-2-yl)-2,3,3a,4,5,5a,5b,6,7,7a,8,11,11a,11b,12,13,13a,13b-octadecahydro-1H-cyclopenta[a]chrysen-9-yl)benzoic acid, except 2-(1,3,4-thiadiazol-2-ylamino)-2-oxoacetic acid was used instead of 3-(dimethylamino)propionic acid hydrochloride in Step 1. LCMS: m/e 683.6 (M−H)−, 1.77 min (method 9). 1H NMR (500 MHz, 2:1 MeOD:CDCl3) δ=9.13 (s, 1H), 7.92 (d, J=8.5 Hz, 2H), 7.45 (s, 1H), 7.21 (d, J=8.2 Hz, 2H), 5.37-5.24 (m, 1H), 4.81-4.78 (m, 1H), 4.67 (s, 1H), 2.67-2.56 (m, 2H), 2.55-2.47 (m, 1H), 2.15 (dd, J=6.4, 17.1 Hz, 1H), 1.99-1.90 (m, 1H), 1.82 (dd, J=10.5, 16.3 Hz, 3H), 1.74 (s, 3H), 1.71 (br. s., 1H), 1.59-1.44 (m, 9H), 1.44-1.39 (m, 1H), 1.30-1.24 (m, 1H), 1.22-1.14 (m, 2H), 1.10 (s, 3H), 1.07 (s, 3H), 1.03 (s, 3H), 0.95 (s, 3H), 0.94 (s, 3H).

Provenance & Evidence