An Improved Protocol for the Preparation of 3-Pyridyl- and Some Arylboronic Acids
Process
Research Department, Merck Research Laboratories, P.O. Box 2000,
Rahway, New Jersey 07065 wenjie_li@merck.com; dorian_nelson@merck.com
J. Org. Chem., 2002, 67 (15), pp 5394–5397
DOI: 10.1021/jo025792p
Publication Date (Web): June 13, 2002
Copyright © 2002 American Chemical Society
Abstract
3-Pyridylboronic
acid was prepared in high yield and bulk quantity from 3-bromopyridine
via a protocol of lithium−halogen exchange and “in situ quench”. This
technique was further studied and evaluated on other aryl halides in the
preparation of arylboronic acids.
paper
4 ............... tris(3-pyridyl)boroxin
Tris(3-pyridyl)boroxin:
Pyridine, 3,3',3"-(2,4,6-boroxintriyl)tris-; (160688-99-3)
compd4= The checkers obtained trispyridylboroxin in various hydration levels (0.85 - 1.0 H2O). A satisfactory melting point for this solid could not be obtained. 1H NMR pdf (400 MHz, CD3OD): δ 7.66 (br s, 1H), 8.38 (d, J=6.6, 1H), 8.51 (dd, J=1.2, 4.4, 1H), 8.61 (br s, 1 H). 1H NMR spectra were complicated in other solvents such as CDCl3 and DMSO-d6. Anal Calcd. for C15H12B3O3N3 · 1.0H2O: C, 54.15; H, 4.24; N, 12.63. Found: C, 53.95; H, 3.91; N, 12.35. Yield based on this formula is 85%. The submitters report obtaining the product in 91% yield.
7 ....................3-PYRIDIN-3-YLQUINOLINE
3-Pyridin-3-ylquinoline:
Quinoline, 3-(3-pyridinyl)-; (96546-80-4)
compd7= The following characterization data was obtained: mp: 122-125°C; IR (KBr pellet): cm−1 3044, 1568, 1495, 1410, 1338, 1298, 1187, 1126, 1059, 1022, 952, 932, 816, 784, 758, 709, 909, 808, 786, 752, 709, 61; 1H NMR pdf (500 MHz, CDCl3): δ 7.45 (ddd, J=0.9, 4.9, 7.9, 1H), 7.60 (dt, J=0.9, 7.9, 1H), 7.75 (ddd, J=1.2, 6.8, 8.3, 1H), 7.90 (dd, J=0.9, 8.1, 1H), 8.00 (dt, J=2.2, 7.8, 1H), 8.15 (d, J=8.4, 1H), 8.32 (d, J=2.3, 1H), 8.68 (dd, J=1.5, 4.9, 1H), 8.97 (d, J=2.1, 1H), 9.15 (d, J=2.1, 1H); 13C NMR (126 MHz, CDCl3) δ 123.8, 127.3, 127.8, 128.0, 129.3, 129.9, 130.6, 133.57, 133.63, 134.6, 147.7, 148.5, 149.27, 149.29; MS (EI, 70 eV): 207 (16), 206 (M+, 100), 205 (40); HRMS (EI) m/z 206.0847, calcd for C14H10N2 206.0944. Anal. Calcd for C14H10N2: C, 81.53; H, 4.89; N, 13.58. Found: C, 81.43; H, 4.86; N, 13.40.
5.........3-pyridylboronic acid pinacol ester
3-(4,4,5,5-Tetramethyl-[1,3,2]dioxaborolan-2-yl)pyridine.
Pyridine, 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-; (329214-79-1)
compd5= obtained the product in 74-82% yield in different runs. The product exhibits the following physical properties: mp 102-105°C; IR (KBr pellet) cm−1 2994, 2968, 2932, 1609, 1572, 1476, 1410, 1361, 1209, 1154, 1063, 1017, 953, 926, 859, 833, 800, 759, 705; 1H NMR pdf (500 MHz, CDCl3): δ 1.33 (s, 12H), 7.25 (ddd, J=1.1, 4.9, 7.5, 1H), 8.03 (dt, J=1.8, 7.5, 1H), 8.64 (dd, J=1.9, 4.9, 1H), 8.93 (d, J=1.1, 1H); 13C NMR (126 MHz, CDCl3) δ 24.8, 84.1, 123.0, 142.2, 152.0, 155.5; MS (EI, 70 eV): 205 (M+, 46), 204 (15), 191 (12), 190 (100), 189 (25), 162 (10), 148 (44), 147 (14), 120 (18), 119 (11), 106 (100), 105 (35), 85 (15), 59 (17), 58 (19); HRMS (EI) m/z 205.1280, calcd for C11H16NO2B 205.1274. Anal. Calcd for : C11H16BO2N: C, 64.43; H, 7.86; N, 6.83. Found: C, 64.23; H, 7.99; N, 6.88.
EILAT, ISRAEL
At פארק תמנע.
שבת שלום !!!
— at King City Eilat.
/////////
No comments:
Post a Comment