Organosilicon Chemistry

Oxidative addition of halosilanes to zero-valent platinum complexes

“…Difference NOE spectra of 4 [e.g., 20% NOE, H-5' and H-l"; 6.1%, N-CH3 (8 2.42) and H-6' (8 3.92)] supported the 1,4perhydrodiazepine structure, amino sugar substitution at C-5', and the uracil-1' linkage.…”

“…The linkage of 3-acyloxy-12-methyltridecanoate was deduced by an upfield shift of H-3'" (5 4.4) in 6 compared with 1 (8 5.4). Ester linkage of 3-methylglutaric acid to /3-hydroxyl of the fatty acid was indicated by a downfield shift (1 ppm) of the fatty acid /3-proton as compared with the unsubstituted hydroxy acids.18 The sulfate ester was located at C-2" by comparing amino sugar assignments in 'H and 13C NMR19 of 4 with those of 1, 5, and (12) White, K. D.; Sphon, J. A.; Hall, S. Anal.…”

The structure of liposidomycin B, an inhibitor of bacterial peptidoglycan synthesis

“…NMR spectra were measured by using JEOL GX 400, GSX 400, GSX 270 instruments; 1, NMR CDjOD(TMS): uracil moiety, 7.82 (1 H, d, J = 8 Hz), 5.76 (1 H, d, J = 8 Hz); 3-methylglutaryl moiety, 1.0 (3 H, d, J = 6.4 Hz), 2.37 (1 H, m), 2-2.4 (4 H, m); 3-hydroxy-12-methyltridecanoyl moiety, 0.88 (6 H, d, J = 6.8 Hz), 1.51 (1 H, m), 1.3 (12 H, m), 1.6 (1 H, m), 5.2 (1 H, m), 2.61 (1 H, dd, J = 8.5 Hz, J = 15.7 Hz), 2.69 (1 H, dd, J = 4.4 Hz, J = 15.7 Hz), 1', 5.64 (1 H, d, J = 1.5 Hz), 2', 4.14 (1 H, overlapping), 5', 4.42 (1 H, brd, J = 10.7 Hz), 6', 3.79 (1 H, d, J = 10.7 Hz), 1", 5.45 (1 H, s), 2", 4.67 (1 H, d, J = 4.8 Hz), 3", 4.30, (1 H, overlapping), 4", 4.16 (1 H, overlapping), 5", 3.43 (1 H, dd, J = 2.7 Hz, 7=12 Hz), 3.24 (1 H, dd, 7 = 3.7 Hz, 7=12 Hz), 3"', 5.45 (1 H, m). 1, ,3C NMR CD3OD(TMS): COOR, CON (176.7, 173.8, 172.9, 172.6, 171.1 each s), 4 (166.5, s), 2 (152, s), 6 (142.5, d), 1" (110.2, s), 5 1240 cm"1, 820 cm"1) and by the characteristic expulsion of S03 (loss of 79.9517 mass units) from the MH+ ion.12 Negative ion MS/MS measurements13 on 1 demonstrated the sulfate to be bound to a C5 unit identified as outlined below to be an amino pentose (m/z 228, amino sugar sulfate anion). The amino pentose structure is based on (i) loss of 131.0531 mass units (C5H9N03) from the MH+-S03 ion from 1; (ii) elemental composition of the structural unit C5HuN07S calculated as the difference between 1 and the sum of isolated hydrolysis products, having a total of three rings or double bonds and four exchangeable hydrogen atoms;5 (iii) NMR [CHr5", 3.43 (1 H, dd, J = 1 Hz, J = 15 Hz), 3.24 (1 H, dd, J = 4.4 Hz, 7=15 Hz)] and 13C NMR [C-l", 110] which characterize the amino sugar as having a furanose ring;14 (iv) detailed analysis of the NMR spectra of hydrolysis product 4 (below).…”

“…The linkage of 3-acyloxy-12-methyltridecanoate was deduced by an upfield shift of H-3'" ( 4.4) in 6 compared with 1 ( 5.4). Ester linkage of 3-methylglutaric acid to /3-hydroxyl of the fatty acid was indicated by a downfield shift (1 ppm) of the fatty acid /3-proton as compared with the unsubstituted hydroxy acids.18 The sulfate ester was located at C-2" by comparing amino sugar assignments in 'H and 13C NMR19 of 4 with those of 1, 5, and (12) White, K. D.; Sphon, J. A.; Hall, S. Ana!.…”

“…(14) Breitmaier, E.; Haas, G.; Voelter, W. In Atlas of Carbon-13 NMR Data\ Heyden: London, 1979; Vol. (16) JEOL, GSX 400, D20, 320 scans, 1: 3.7 ms, 2: 60 ms. C-l" of 4 ( 109.2); 5 (S 107); 6 ( 108); 1 ( 110.2). C-3" of 4 ( 69.9); 5 ( 69.2); 6 ( 69.2); 1 ( 70.1).…”