6. Experimental section
6.3. Synthesis of S-(2-cyanoethyl)-S-(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-
tetramethylammonium salt
S
(CH2)4 CO2C2H5
CO2C2H5
NHCOCH3
NC
-2TMA+
C20H49B12N3O5S 572.6
TMA+ S
2-C11H39B12N3S 374.6
CN
Cl NHCOCH3
CO2C2H5
CO2C2H5
C13H22ClNO5
307.45 5
S-(2-cyanoethyl)-thio-undecahydro-closo-dodecaborate(2-) bis-tetrametylammonium salt 5 (0.39 g, 1.04 mmol) was suspended in 15 ml of acetonitrile at room temperature. A solution of 0.48 g (1.56 mmol) 4-bromobutylacetamidodiethylmalonate was added. The reaction mixture was refluxed during 24 hours. HPLC control showed signals of starting compounds.
Yield: reaction failed.
6.4. Synthesis of S-(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-thio-undecahydro-closo-dodecaborate(2-) bis-tetramethylammonium salt (7)
S
(CH2)4 CO2C2H5 CO2C2H5 NHCOCH3
NC
-2TMA+
C20H38B12N4O5S 575.6
TMA+
N(CH3)4OH
S
(CH2)4 CO2C2H5 CO2C2H5 NHCOCH3
2-C21H46B12N4O5S 595.6
6 7
Tetramethylammonium salt 6 0.5 g (0.87 mmol) was dissolved in 50 ml of hot acetone.
Tetramethylammonium hydroxide as a 25% solution in methanol was added in equimolar amounts. The resulting compound 7 precipitated, was filtered off, and recrystallized from hot water:methanol 1:1.
Yield: 78% (0.4 g) Mp 163-165°C HPLC 8.75 min
1H-NMR (CD3CN, ppm): 7.10 (1H, s, -NH-), 4.16 (4H, q, -C(-COOCH2CH3)2(NHCOMe)), 3.09 (24H, s, N+(CH3)4), 2.32 (2H, t, -S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 2.10 (2H, t, -S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 2.08 (3H, s, -NHCOCH3), 1.50 (4H, m, -S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 1.20 (6H, q, -C(-COOCH2CH3)2), 2.30-(-0.70) (broad, B12H11).
IR (KBr, cm-1): 3431(m) (-NH-), 3234(w) (-NH-), 3028(w), 2481(s) (B-H), 1738(s) (C=Oester), 1638(m) (C=Oamide), 1489(w), 1291(w),1218(w), 1186(w),951(w), 843(w), 720(w), 669(w), 618(w), 525(w).
MS: (pos. ESI, CH3CN) 74.0 (cat+, 100%), 667* (A2-+3cat+, z=+1, 60%), (neg. ESI, CH3CN) 141.0* (B12H11-, z=-1, 10%), 185.6* ((A2- -COOC2H5)/2, z=-2, 25%), 162.6* ((A2- -(COOC2H5)(OC2H5))/2, z=-2, 100%), 222.6* (A2-/2, z=-2, 100%).
13C-NMR (CD3CN, ppm): 169.98 (-COOC2H5), 169.20 (-NHCOCH3), 67.56 (-S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 63.07 (-OCH2CH3), 56.30 (N+(CH3)4), 33.39-22.92
(-S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2, -S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2,
-NHCOCH3, -S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2,
-S-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 14.41 (-COOCH2CH3).
11B-NMR (CD3CN, ppm): -15.04 (broad, 12B)
6.5. Synthesis of
S-(5-amino-5-carboxypentyl)-thio-undecahydro-closo-dodecaborate(2-) bis-tetraphenylphosphonium salt (9)2TMA+ S
(CH2)4 CO2C2H5
CO2C2H5 NHCOCH3
2-C21H46B12N4O5S 595.6
1)NaOH, HCl 2)Ph4PBr
S
(CH2)4 COOH NH2
2Ph4P+
2-C54H63B12NO2P2S 980.6
7 9
Bis-tetramethylammonium salt 7 (2.25 g, 3.8 mmol) was suspended in 50 ml of 6M NaOH.
During heating the salt dissolved. Hydrolysis was carried out for 3 days (HPLC control). The cold reaction mixture was neutralized with 6M HCl to pH 7. Ph4PBr 3.1 g (7.6 mmol) in 50 ml of water was added. The precipitate was filtrated off and washed with water. Recrystallization from methanol gave 1.8 g of compound 9.
Yield: 47%
Mp 73-75°C HPLC 3.98 min
1H-NMR (CD3CN, ppm): 7.84-7.68 (40H, m, ((C6H5)4P+)2), 3.01 (1H, t, -S-CH2CH2CH2CH2CH(COOH)(NH2)), 2.21 (2H, t, -S-CH2CH2CH2CH2CH(COOH)(NH2)), 1.65-1.32 (6H, m, -S-CH2CH2CH2CH2CH(COOH)(NH2)), 2.30-(-0.70) (broad, B12H11).
IR (KBr, cm-1): 3430(m), 3060-2849(w) (-NH3+), 2479(s) (B-H), 1636(m) (br, NH3+, COO-), 1585(m) (CHarom), 1437(s) (Ph4P+), 1317(w), 1189(w) (CCN), 1108(s) (Ph4P+), 1044(w), 996(w), 836(w), 757(w), 722(s) (Ph4P+), 689(m), 529(s) (Ph4P+).
MS: (pos. ESI, CH3CN) 339.0 (cat+, 100%), (neg. ESI, CH3CN) 141.0* (B12H11-, z=-1, 40%), 642.3* (A2-+cat+, z=-1, 100%), 561* (A2-+cat+-81, z=-1, 30%).
13C-NMR (CD3OD, ppm): 174.80 (-COOH), 136.86-118.69 ((C6H4)4P+), 56.28 (-S-CH2CH2CH2CH2CH(COOH)(NH2)), 33.31 (-S-CH2CH2CH2CH2CH(COOH)(NH2)), 32.25 (-S-CH2CH2CH2CH2CH(COOH)(NH2), 32.02 (-S-CH2CH2CH2CH2CH(COOH)(NH2), 25.56 (-S-CH2CH2CH2CH2CH(COOH)(NH2).
11B-NMR (CD3CN, ppm): -7.18 (1B, B1), -16.31 (11B, B2-12).
6.6. Synthesis of
S-(2-cyanoethyl)-S-(2-oxopropyl)-sulfonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt (10)
S
2-2TMA+
S
-Cl O CH3
CN NC O
CH3
TMA+
C11H39B12N3S 374.6
C3H5ClO 92.5
C10H32B12N2OS 357.6
5 10
Bis-tetrametylammonium salt 5 (2.55 g, 6.79 mmol) was dissolved in 70 ml of dry acetonitrile at room temperature. Chloroacetone (0.94 g, 10.2 mmol) was added. The reaction mixture was refluxed during 12 hours (HPLC control). After cooling, acetonitrile was evaporated under reduced pressure. The resulting green oil was crystallized from diethylether. Recrystallization from acetonitrile gave 2.31 g of white crystals of compound 10.
Yield: 93%
Mp 105-107°C HPLC 4.58 min
1H-NMR (CD3CN, ppm): 4.32 (2H, d, -S-CH2COCH3), 3.44 (12H, s, N+(CH3)4), 2.35-3.10 (4H, m, -S-CH2CH2CN), 2.35 (3H, s, -S-CH2COCH3), 2.10-(-0.90) (broad, B12H11).
IR (KBr, cm-1): 3429(m), 3020(w), 2966(w), 2921(w), 2504(s) (B-H), 2249(w) (C≡N), 1723(m) (C=Oketon), 1486(s), 1414(w), 1360(w), 1287(w), 1155(w), 1045(m), 949(s), 822(w), 720(w), 558(w).
MS: (pos. ESI, CH3CN) 74.0 (cat+, 100%), 432* (A-+2cat+, z=+1, 20%), (neg. ESI, CH3CN) 141.0* (B12H11-, z=-1, 10%), 284.2* (A-, z=-1, 100%).
13C-NMR (CD3CN, ppm): 173.67 (-COCH3), 118.98 (-C≡N), 55.25 (N+(CH3)4), 53.37 (-S-CH2 -COCH3), 37.67 (-S-CH2CH2CN), 29.78 (-S-CH2-COCH3), 16.14 (-S-CH2CH2CN).
11B-NMR (CD3CN, ppm): -9.50 (1B, B1), -12.73, -14.43 (11B, B2-12).
6.7. Synthesis of S-(2-oxopropyl)-thio-undecahydro-closo-dodecaborate(2-) bis-tetramethylammonium salt (11)
S
2-2TMA+ S
-NC O O
CH3
TMA+
N(CH3)4OH
CH3
C10H32B12N2OS 357.6
C11H29B12N2OS 366.6
10 11
Tetramethylammonium salt 10 (2.3 g, 6.43 mmol) was dissolved in 180 ml of hot acetone.
Tetramethylammonium hydroxide as a 25% solution in methanol was added in equimolar amounts. The resulting compound 11 precipitated, was filtered off, and washed with diethylether.
Yield: 72% (1.75 g) Mp 238-240°C HPLC 4.94 min
1H-NMR (CD3CN, ppm): 3.01 (24H, s, N+(CH3)4), 2.23 (3H, s, -S-CH2COCH3), 2.08 (2H, s, -S-CH2COCH3), 2.30-(-0.30) (broad, B12H11).
IR (KBr, cm-1): 3438(m), 3026(w), 2484(s) (B-H), 1702(m) (C=Oketon), 1487(m), 1353(w), 1287(w), 1235(w), 1050(w), 949(m), 844(w), 722(w), 667(w).
MS: (pos. ESI, CH3CN) 74.2 (cat+, 100%), 452.6* (A2-+3cat+, z=+1, 20%); (neg. ESI, CH3CN) 87.1* (B12H11SH2-/2, z=-2, 10%), 115.0* (A2-/2, z=-2, 100%), 141.0* (B12H11-, z=-1, 20%).
13C-NMR (CD3CN, ppm): 208.88 (-COCH3), 55.70 (N+(CH3)4), 44.1 (-S-CH2-COCH3), 27.67 (-S-CH2-COCH3).
11B-NMR (CD3CN, ppm): -0.66 (1B, B1), -9.88, -12.17 (11B, B2-6).
6.8. Synthesis of
5-(methylene-thio-undecahydro-closo-dodecaboratyl)-5-methylhydantoin (2-) bis-tetramethylammonium salt (12) (way 1)
S
2-2TMA+ O
CH3 NaCN (NH4)CO3
S N
H O NH
O
2-2TMA+
C11H29B12N2OS 366.6
C13H42B12N4O2S 447.6
11 12
A mixture of compound 11 (2.13 g, 5.6 mmol), 50% aqueous ethanol (45 ml), sodium cyanide (0.54 g, 10.12 mmol) and ammonium carbonate (2.85 g, 29.8 mmol) were placed in an autoclave and kept at 60°C for 4 hour. The mixture was acidified with 6M HCl, and filtered through a pad of activated carbon. Solvents were removed by evaporation at room temperature, and the solid material of 12 which remained was recrystallized from water.
Yield: 57% (1.75 g) Mp >250°C
HPLC 5.52 min
1H-NMR (CD3CN, ppm): 8.19 (1H, s, -CONHCOhydant), 6.11 (1H, s, -CNHCOhydant), 3.09 (24H, s, N+(CH3)4), 2.75 (2H, m, -S-CH2-Cq-), 1.32 (3H, s, -Cq-CH3), 2.00-(-0.80) (broad, B12H11).
IR (KBr, cm-1): 3362(m), 3181(m) (-NH-), 3030(w) (-NH-), 2925(w), 2488(s) (B-H), 1773(m) (COhydant), 1718(s) (COhydant), 1630(w), 1487(s), 1416(m), 1285(w), 1168(w), 1050(m), 949(m), 840(w), 733(w), 718(w), 646(w), 588(w).
MS: (pos. ESI, CH3CN) 74.1 (cat+, 100%), (neg. ESI, CH3CN), 87.1* (B12H11SH2-/2, z=-2, 10%), 141.0* (B12H11-, z=-1, 5%), 150.1* (A2-/2, z=-2, 100%), 374.2* (A2-+cat+, z=-1, 70%).
13C-NMR (D2O, ppm): 180.83 (C=Ohydant), 158.68 (C=Ohydant), 65.19 (-Cq-), 55.70 ((N+(CH3)4), 39.75 (-S-CH2-Cq-), 22.42 (CH3-Cq-).
11B-NMR (CD3CN, ppm): -0.66 (1B, B1), -9.88, -12.17 (11B, B2-12).
6.9. Synthesis of
5-(methylene-thio-undecahydro-closo-dodecaboratyl)-5-methylhydantoin (2-) bis-tetramethylammonium salt (12) (way 2)
S
-NC O
CH3
TMA+
C10H32B12N2OS 357.6
NaCN (NH4)CO3
S N
H O NH
O
2-2TMA+
C13H42B12N4O2S 447.6
10 12
A mixture of compound 10 (0.3 g, 0.84 mmol), 50% aqueous ethanol (5 ml), sodium cyanide (0.08 g, 1.68 mmol) and ammonium carbonate (0.43 g, 4.48 mmol) were placed in an autoclave and kept at 60°C for 4 hour. The mixture was acidified with 6M HCl, and filtered through a pad of activated carbon. Solvents were removed by evaporation at room temperature, and the solid material of 12 which remained was recrystallized from water.
Yield: 30% (0.11 g)
6.10. Synthesis of
S-(2-amino-2-carboxypropyl)-thio-undecahydro-closo-dodecaborate(2-) bis-tetraphenylphosphonium salt (13)S
2-2Ph4P+ NH2
CH3 S
H3C NH O NH
O
2-2TMA+
1)NaOH, HCl COOH
2)Ph4PBr
C13H42B12N4O2S 447.6
C52H59B12NO2P2S 952.6
12 13
Compound 12 (1.7 g, 3.87 mmol) was suspended in 30 ml of 6M NaOH. During heating the salt dissolved. Hydrolysis was carried out for 24 hours (HPLC control). After cooling 6M HCl was added until pH 7. Ph4PBr (3.25 g, 7.74 mmol) in 50 ml of water was added. The precipitate was filtrated off and washed with water. Recrystallization from methanol gave 1.8 g of compound 13.
Yield: 49%
Mp 132-134°C HPLC 3.97 min
1H-NMR (CD3CN, ppm): 7.84-7.68 (40H, m, ((C6H5)4P+)2), 2.85 (2H, m, -S-CH2-C-), 1.38 (-C-CH3), 2.5-(-0.2) (broad, B12H11).
IR (KBr, cm-1): 3430(m), 3055(w) (NH3+), 2488(s) (B-H), 1613 (br, NH3+, COO-), 1483(w), 1437(m) (Ph4P+), 1109(s) (Ph4P+), 995(w), 756(w), 722(m) (Ph4P+), 690(m), 529(s) (Ph4P+).
MS: (pos. ESI, CH3CN) 339.0 (cat+, 100%), (neg. ESI, CH3CN) 87.1* (B12H11SH2-/2, z=-2, 80%), 141.0* (B12H11-, z=-1, 20%), 614.0* (A2-+cat+, z=-1, 100%), 630.1* (A2-+cat+-H++OH-, z=-1, 40%), 646.1* (A2-+cat+-2H++2OH-, z=-1, 15%), 662.1* (A2-+cat+-3H++3OH-, z=-1, 10%), 678.1* (A2-+cat+-4H++4OH-, z=-1, 5%), 694.1* (A2-+cat+-5H++5OH-, z=-1, 2%).
13C-NMR (CD3CN, ppm): 173.81 (-COOH), 135.91-119.23 ((C6H4)4P+), 62.60 (-Cq-), 41.26 (-S-CH2-C(COOH)(NH2)(CH3)), 22.63 ((-S-CH2-C(COOH)(NH2)(CH3)).
11B-NMR (CD3CN, ppm): -0.66 (1B, B1), -9.88, -12.17 (11B, B2-12).
6.11. Synthesis of
S-(2-amino-2-carboxypropyl)-thio-undecahydro-closo-dodecaborate(2-) bis-cesium salt (13a)S
2-2Ph4P+ NH2
CH3 COOH
C52H59B12NO2P2S 952.6
S
2-2Cs+ NH2
CH3 COOH
C4Cs2H19B12NO2S 540.6 CsF
13 13a
1.8 g (1.9 mmol) of 13 was dissolved in 10 ml of methanol. CsF 0.6 g (4.1 mmol) was dissolved in 3 ml of methanol and added to stirring solution of 13. Precipitated compound was filtered off and washed with 5 ml of methanol. Recrystallization from water gave 0.9 g of 13a.
Yield: 91.8%
MS: (pos. ESI, H2O) 133.0 (cat+, 100%), (neg. ESI, H2O) 87.1* (B12H11SH2-/2, z=-2, 100%), 141.0* (B12H11-, z=-1, 30%), 408.6* (A2-+cat+, z=-1, 20%).
6.12. Synthesis of O-(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-oxy-undecahydro-closo-dodecaborate(2-) bis-cesium salt (14)
O
(CH2)4 CO2C2H5
CO2C2H5 NHCOCH3
2-2TBA+
C13 Cs2H33B12N1O6
694.4
2Cs+ OH
2-C32H84B12N2O 641,6
Br NHCOCH3
CO2C2H5 CO2C2H5
C13H22BrNO5
352
1) K2CO3 2) CsF
4 14
1.24 g (3.5 mmol) of 4-brombutylacetamidodiethylmalonate and 1.77 g (12.8 mmol) of K2CO3
were added to solution of 2.06 g (3.2 mmol) of hydroxy-undecahydro-closo-dodecaborate(2-) bis-tetrabutylammonium salt 4 in 50 ml of acetone. Reaction mixture was reflux during 3 days, then cooled to room temperature and filtered off. The compound 14 was isolated as cesium salt by addition 0.97 g (6.4 mmol) of CsF in methanol to the filtrate followed by the recrystallization of the precipitate from water.
Yield: 53% (1.17 g) Mp >250°C
HPLC 3.19 min
1H-NMR (D2O, ppm): 4.14 (4H, q, -C(-COOCH2CH3)2), 3.36 (2H, t,
-O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 2.05 (2H, m,
-O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 1.95 (3H, s, NHCOCH3), 1.41 (4H, m, -O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 1.15 (6H, t, -C(-COOCH2CH3)2), 2.4-(-0.6) (broad, B12H11).
IR (KBr, cm-1): 3567(m), 3431(m) (NH), 2983(w), 2492(s) (B-H), 1734(m) (C=Oester), 1653(m) (C=Oamide), 1373(w), 1203(w), 1170(w), 1155(w), 1094(w), 1033(m), 908(w), 720(w), 668(w).
MS: (pos. ESI, H2O) 132.7 (cat+, 100%), 827.8* (A2-+3cat+, z=+1, 60%), (neg. ESI, H2O) 79.2*
(B12H11OH2-/2, z=-2, 10%), 141.0* (B12H11-, z=-1, 20%), 214.8* (A2-/2, z=-2, 25%), 562.6* (A 2-+cat+, z=-1, 100%).
13C-NMR (D2O, ppm): 173.81 (-COOC2H5), 169.82 (-NHCOCH3), 69.00 (-O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 64.17 (-OCH2CH3), 33.21-19.98 (-O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2, -O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2,
-NHCOCH3, -O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2,
-O-CH2CH2CH2CH2C(NHCOMe)(COOEt)2), 13.53 (-COOCH2CH3).
11B-NMR (CD3CN, ppm): -0.78 (1B, B1), -9.29 (5B, B2-6), -10.32 (5B, B7-11), -12.40 (1B, B12).
6.13. Synthesis of
O-(5-amino-5-carboxypentyl)-oxy-undecahydro-closo-dodecaborate(2-) bis-tetraphenylphosphonium salt (16)O
(CH2)4 CO2C2H5 CO2C2H5
NHCOCH3
2-C13CsH33B12NO6
561.5
1)NaOH 2)HCl Ph4PBr
O
(CH2)4 COOH
NH2 2Ph4P+
2-2Cs+
C54H63B12NO3P2
964.6
14 16
Bis-cesium salt 14 (0.53 g, 0.9 mmol) was suspended in 10 ml of 6M NaOH. During heating the salt dissolved. Hydrolysis was carried out for 2 days (HPLC control). The cold reaction mixture was neutralized with 6M HCl. Ph4PBr 0.79 g (1.8 mmol) in 20 ml of water was added. The precipitate was filtrated off and washed with water. Recrystallization from methanol gave 0.46 g of compound 16.
Yield: 53%
Mp 230-232°C HPLC 3.52 min
1H-NMR (DMSO, ppm): 7.91-7.66 (40H, m, ((C6H5)4P+)2), 3.30 (1H, t, -O-CH2CH2CH2CH2CH(COOH)(NH2), 3.00 (2H, m, -O-CH2CH2CH2CH2CH(COOH)(NH2)), 1.78-1.30 (6H, m, -O-CH2CH2CH2CH2CH(COOH)(NH2)), 2.3-(-0.7) (broad, B12H11).
IR (KBr, cm-1): 3434(s), 3055-2849(w) (-NH3+), 2467(s) (B-H), 1634 (w, br, NH3+, COO-), 1585 (w) (CHarom), 1484(m) (Ph4P+), 1336(w),1108(m) (Ph4P+), 1047(w), 1021(w), 996(w), 899(w), 756(w), 722(m) (Ph4P+), 689(m), 668(w), 527(m) (Ph4P+).
MS: (pos. ESI, CH3CN) 339.0 (cat+, 100%), (neg. ESI, CH3CN) 79.3* (B12H11OH2-/2, z=-2, 60%), 141.0* (B12H11-, z=-1, 50%), 626.8* (A2-+cat+, z=-1, 100%).
13C-NMR (CD3CN, ppm): 136.86-118.69 ((C6H4)4P+), see paragraph 6.1.
11B-NMR (DMSO, ppm): -5.77 (1B, B1), -14.92 (5B, B2-6), -16.93 (5B, B7-11), -18.91 (1B, B12).
6.14. Synthesis of
O-(5-amino-5-carboxypentyl)-oxy-undecahydro-closo-dodecaborate(2-) bis-cesium salt (16a)O
(CH2)4 COOH
NH2 2Ph4P+
2-C54H63B12NO3P2 964.6
O
(CH2)4 COOH NH2
2-C6Cs2H23B12NO3 552.6
CsF 2Cs+
16 16a
0.46 g (0.5 mmol) of 16 was dissolved in 5 ml of methanol. CsF 0.16 g (1.03 mmol) was dissolved in 3 ml of methanol and added to the stirred solution of 16. The precipitate was filtered off and washed with 5 ml of methanol. Recrystallization from water gave 0.25 g of 16a.
Yield: 92.5%
MS: (pos. ESI, H2O) 133.0 (cat+, 100%), 556.9* (A2-+2cat++H+, z=+1, 5%), 686.0* (A2-+3cat+, z=+1, 5%), (neg. ESI, H2O) 87.1* (B12H11SH2-/2, z=-2, 100%), 141.0* (B12H11-, z=-1, 30%), 408.6* (A2-+cat+, z=-1, 20%).
6.15. Synthesis of O-(2-oxopropyl)-oxy-undecahydro-closo-dodecaborate(2-) bis-cesium salt (15)
O
2-2Cs+ OH
2- O
2TBA+ CH3
Cl
O CH3
C32H84B12N2O 641.6
C3ClH5O 92.45
C3H16B12Cs2O2 479.4 1) K2CO3
2) CsF
4 15
Chloroacetone 0.25 g (2.7 mmol) and 0.7 g (5 mmol) of K2CO3 were added to solution of 0.8 g (1.25 mmol) of hydroxy-undecahydro-closo-dodecaborate(2-) bis-tetrabutylammonium salt 4 in 30 ml of acetone. The reaction mixture was reflux during 3 days, then cooled to room temperature and filtered. The compound 15 was isolated as cesium salt by addition 0.38 g (2.5 mmol) of CsF in methanol to the filtrate followed by recrystallization of the precipitate from water.
Yield: 68.4% (0.41 g) Mp >250°C
HPLC 4.23 min
1H-NMR (D2O, ppm): 4.30 (2H, s, -O-CH2COCH3), 2.13 (3H, s, -O-CH2COCH3), 2.3-(-0.4) (broad, B12H11).
IR (KBr, cm-1): 3564(w), 3436(m), 2480(s) (B-H), 1731(m) (C=Oketon), 1411(w), 1385(w), 1352(w), 1199(w), 1153(m), 1019(m), 897(w), 723(w), 685(w), 612(w).
MS: (pos. ESI, H2O) 132.9 (cat+, 100%), (neg. ESI, H2O) 79.3* (B12H11OH2-/2, z=-2, 10%), 107.2* (A2-/2, z=-2, 100%), 141.0* (B12H11-, z=-1, 10%), 347.2* (A2-+Cs+, z=-1, 10%).
13C-NMR (D2O, ppm): 173.56 (-COCH3), 75.41 (-O-CH2-COCH3), 25.68 (-O-CH2-COCH3).
11B-NMR (D2O, ppm): 6.58 (1B, B1), -17.24 (10B, B2-7), -21.79 (1B, B12).
6.16. Synthesis of 5-(methylene-oxy-undecahydro-closo-dodecaboratyl)-5-methylhydantoin (2-) bis-cesium salt (17)
O
2-2Cs+ O
CH3 NaCN (NH4)CO3
O H3C
NH O NH
O
2-2Cs+
C3H16B12Cs2O2 479.4
C5H11B12Cs2N2O3 549.4
15 17
A mixture of comp 15 (2.03 g, 4.2 mmol), 50% aqueous ethanol (45 ml), sodium cyanide (0.41 g, 8.37 mmol) and ammonium carbonate (2.1 g, 21.8 mmol) was placed in an autoclave and kept at 60°C for 4 hour. The mixture was acidified with 6M HCl, and filtered through a pad of activated carbon. Solvents were removed by evaporation at room temperature, and the solid material 17 which remained was recrystallized from water.
Yield: 64% (1.14 g) Mp >250°C
HPLC 3.96 min
1H-NMR (D2O, ppm): 3.63 (2H, m, -O-CH2C), 1.19 (3H, s, CCH3), 2.6-(-0.4) (broad, B12H11).
IR (KBr, cm-1): 3383(w), 3144(m) (-NH-), 3074(w), 2492(s) (B-H), 1765(m) (COhydant), 1723(s) (COhydant), 1630(w), 1407(s), 1315(w), 1260(w), 1168(m), 1075(w), 1021(w), 907(w), 726(w), 592(w).
MS: (pos. ESI, H2O) 133.0 (cat+, 100%), 682.1* (A2-+3cat+, z=+1, 5%), (neg. ESI, H2O) 79.3*
(B12H11OH2-/2, z=-2, 15%), 141.0* (B12H11-, z=-1, 20%), 142.3* (A2-/2, z=-2, 100%), 416.2*
(A2-+cat+, z=-1, 10%).
13C-NMR (D2O, ppm): 180.77 (NH-CO-NH), 158.99 (C-CO-NH), 72.46 (-Cq-), 66.03 (-O-CH2 -), 18.58 (CH3-Cq-).
11B-NMR (DMSO, ppm): 6.69 (1B, B1), -16.83 (5B, B2-6), -17.86 (5B, B7-11), -22.49 (1B, B12).
6.17. Synthesis of O-(2-amino-2-carboxypropyl)-oxy-undecahydro-closo-dodecaborate(2-) bis-tetraphenylphosphonium salt (18)
O
2-2Ph4P+ NH2
CH3 O
H3C NH O NH
O
2-2Cs+
1) 6M NaOH COOH
2) Ph4PBr
C5H18B12Cs2N2O3
549.4
C52H59B12NO3P2
936.6
17 18
Bis-cesium salt 17 (1.1 g, 2.0 mmol) was suspended in 20 ml of 6M NaOH. During heating the salt dissolved. Hydrolysis was carried out for 24 hours (HPLC control). After cooling, 6M HCl was added to pH=7. Ph4PBr (1.68 g, 4.0 mmol) in 30 ml of water was added. The precipitate was filtrated off and washed with water. Recrystallization from methanol gave 1.2 g of compound 18.
Yield: 64%
Mp >250°C HPLC 3.88 min
1H-NMR (DMSO, ppm): 7.98-7.66 (40H, m, ((C6H5)4P+)2), 3.72-3.30 (2H, m, -O-CH2-C-), 1.14 (1H, s, -C-CH3), 2.30-(-0.50) (broad, B12H11).
IR (KBr, cm-1): 3421(m), 3060(w) (NH3+), 2472(s) (B-H), 1618(m) (br, NH3+, COO-), 1585(m), 1483(m), 1436 (Ph4P+), 1145(m), 1108(s) (Ph4P+), 1049(w), 1017(w), 996(w), 759(w), 722(m) (Ph4P+), 689(m), 527(s) (Ph4P+).
MS: (pos. ESI, CH3CN) 339.0 (cat+, 100%), (neg. ESI, CH3CN) 79.0* (B12H11OH2-/2, z=-2, 10%), 141.0* (B12H11-, z=-1, 3%), 497.6* (B12H11OH2-+cat+, z=-1, 5%), 553.6* (A2-+cat+ -COOH, z=-1, 30%), 598.7* (A2-+cat+, z=-1, 100%).
13C-NMR (CD3CN, ppm): 136.86-118.69 ((C6H4)4P+), see paragraph 6.1.
11B-NMR (DMSO, ppm): 6.96 (1B, B1), -16.57 (5B, B2-6), -17.92 (5B, B7-11), -22.61 (1B, B12).
6.18. Synthesis of N,N-bis(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-ammonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt (20) and N-(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-ammonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt (22)
NH
(CH2)4 CO2C2H5
CO2C2H5 NHCOCH3
(CH2)4
-C30H68B12N4O10 773.6
TMA+ NH3
-C4H26B12N2
231.6
Br NHCOCH3
CO2C2H5
CO2C2H5
C13H22BrNO5
352 TMA+
C2H5O2C C2H5O2C
NHCOCH3
H2N
(CH2)4 CO2C2H5
CO2C2H5
NHCOCH3
-C17H47B12N3O5 502.6
TMA+ KOH
3
20
22
Ammonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt 3 (0.3 g, 1.3 mmol) was dissolved in 20 ml of acetonitrile. 0.15 g (2.6 mmol) of KOH was added. After 30 minutes a solution of 0.45 g (1.3 mmol) 4-bromobutylacetamidodiethylmalonate in 5 ml of acetonitrile was added. Reaction was carried out at room temperature. After 24 hours HPLC showed 2 signals.
Acetonitrile was removed in vacuum and solid material was analyzed.
HPLC 4.36; 6.42 min
MS: mixture (pos. ESI, CH3CN) 73.9 (cat+, 100%), (neg. ESI, CH3CN) 141.0* (B12H11-, z=-1, 20%), 158* (B12H11NH3-, z=-1, 15%), 357.3* (A-mono-CO2C2H5, z=-1, 15%), 429.3* (A-mono, z=-1, 100%), 556* (A-di-(CO2C2H5), z=-1, 10%), 628.4* (A-di-CO2C2H5, z=-1, 15%), 700.4* (A-di, z=-1, 50%).
6.19. Synthesis of N,N-bis(5-bis(ethoxycarbonyl)-5-acetamidopentyl)-(N-methyl)-ammonio-undecahydro-closo-dodecaborate(-)
tetramethylammonium salt (21) and N-(5-bis(ethoxycarbonyl)-5- acetamidopentyl)-(N-methyl)-ammonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt (23)
NCH3
(CH2)4 CO2C2H5
CO2C2H5 NHCOCH3
(CH2)4
-TMA+ NHCH3
-Br NHCOCH3
CO2C2H5
CO2C2H5
TMA+
C2H5O2C C2H5O2C
NHCOCH3
H3CHN
(CH2)4 CO2C2H5
CO2C2H5 NHCOCH3
-TMA+ KOH
C13H22BrNO5
352
C31H70B12N4O10 787.6
C18H49B12N3O5
516.6 C5H28B12N2
245.6 19
21
23
(N-methyl)-ammonio-undecahydro-closo-dodecaborate(-) tetramethylammonium salt 19 (3.76 g, 15.3 mmol) was dissolved in 30 ml of acetonitrile. 1.7 g (30.6 mmol) of KOH was added. After 30 minutes a solution of 6.46 g (1.8 mmol) 4-bromobutylacetamidodiethylmalonate in 15 ml of acetonitrile was added. Reaction was carried out at room temperature. After 12 hours HPLC showed a lot of signals. Acetonitrile was removed in vacuum and solid material was analyzed.
MS: mixture, not pure (pos. ESI, CH3CN) 74.3 (cat+, 100%), (neg. ESI, CH3CN) 141.0* (B12H11
-, z=-1-, 50%)-, 173.3* (B12H11NH2CH3-, z=-1, 80%), 443.5* (A-mono, z=-1, 100%), 556* (A-di, z=-1, 10%).