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. 2009 Feb 5;82(1):89–94. doi: 10.1016/j.antiviral.2009.01.003

Table 1.

Chemical structure and physico-chemical properties of the test compounds.a.

Compound R Yield (%) HPLCbRT TLCcRf Formula Molecular weight
Calculated Measured MALDI-TOFd (M+Na)+
Aglycones
1 Me 90 14.68 (A) 0.62 C53H52N8O17Cl2 1143 1165
2 H 65 14.60 (B) 0.26 C60H51N7O19 1173 1196



Squaric acid amide esters
4 Me graphic file with name fx1.gif 83 13.60 (A) 0.73 C58H54N8O20Cl2 1254 1275
5 H 60 36.51 (D) 0.36 C65H53N7O22 1284 1306



Asymmetric squaric diamides
graphic file with name fx2.gif
Compound R R1 Yield (%) HPLCbRT TLCcRf Formula Molecular weight
Calculated Measured MALDI-TOFd (M+Na)+
7a Me —(CH2)5–CH2OH 38 12.99 (B) 0.13 C63H65N9O20Cl2 1139 1160
8a H 72 13.06 (B) 0.42 C70H64N8O22 1369 1392



7b Me —(CH2)5–COOH 34 13.02 (B) 0.12 C63H63N9O21Cl2 1353 1374
8b H 38 13.03 (B) 0.24 C70H62N8O23 1383 1405



8b1 H —(Gly)3–COOH 62 10.90 (A) 0.68 C70H60N10O25 1441 1464



7c Me graphic file with name fx3.gif 68 13.28 (C) 0.29 C65H61N9O21Cl2 1375 (3) 1396
8c H 87 ND (B) 0.43 C72H60N2O23 1405 1428



8d H graphic file with name fx4.gif 73 16.68 (B) 0.59 C75H65N9O21 1428 1450



7e Me graphic file with name fx5.gif 63 18.24 (B) 0.44 C70H63N9O19Cl2 1405 1426
8e H 68 18.47 (B) 0.53 C77H62N8O21 1435 1457



7f Me graphic file with name fx6.gif 58 16.70 (B) 0.28 C67H59N9O19Cl2 1365 1386
8f H 54 16.75 (B) 0.73 C74H58N8O21 1395 1417



7g Me graphic file with name fx7.gif 20 21.16 (C) 0.60 C75H65N9O19Cl2 1467 (65) 1488
8g H 42 21.21 (C) 0.56 C82H64N8O21 1496 1519



8h H graphic file with name fx8.gif 62 19.31 (B) 0.75 C78H60N8O21 1445 1467



8i H graphic file with name fx9.gif 75 10.07 (B) 0.34 C70H62N8O26 1431 1454



8j H graphic file with name fx10.gif 69 10.05 (B) 0.35 C70H62N8O26 1431 1454
a

After conversion of the aglycons aglycovancomycin (1) and aglycoristocetin (2) into their squaric acid amide esters (4 and 5, respectively), these were converted to the asymmetric squaric diamides (7a–g, derived from aglycovancomycin, and 8a–j, derived from aglycoristocetin).

b

HPLC conditions: instrument: Waters 600 with UV230nm detection; column: Lichrospher RP-8 (4 mm × 250 mm; 10 μm); injection volume: 20 μl (corresponding to 2 μg compound); solvents: (A) CF3COOH–H2O (pH 2.6) and (B) acetonitrile–H2O; gradient elution from 10 to 90% B; ND: not done.

c

TLC conditions: silicagel 60F25; solvent systems: (A) nBuOH–Pyr–AcOH–H2O (15:10:3:12); (B) toluene–MeOH–AcOH (1:1:0.01); (C) nBuOH–AcOH–H2O (4:2:2); (D) toluene–MeOH–AcOH (1:1:0.05).

d

MALDI-TOF MS: instrument: Brucker BIFLEX III. The analytes at a concentration of 5 mg per ml in acetontrile–H2O–0.1% HCOOH (50:50:0.1) were prepared with 2,5-dihydroxybenzoic acid (DHB) matrix (20 mg/ml in DMSO).