602 Letters in Organic Chemistry, 2012, Vol. 9, No. 8
Mohanazadeh et al.
production of side-products. Moreover, the isolation of the
products from the heterogeneous mixture is easy and not
time-consuming.
Product (Table 3, entry 13): 1H NMR 200 MHz,
CDCl3): ꢀ 0.82-0.87 (t, 3H), 1.23-1.29 (m, 12H), 3.23-3.27
(t, 2H).
Product (Table 3, entry 14): 1H NMR 200 MHz,
CDCl3): ꢀ 0.82-0.87 (t, 3H), 1.24-1.29 (m, 8H), 1.40-1.45
(md, 3H), 1.62-1.67 (t, 2H), 3.71-3.79 (m, 1H).
EXPERIMENTAL
Procedure for Preparation of Silica Bromide
Product (Table 3, entry 15): 1H NMR 200 MHz,
CDCl3): ꢀ 3.19-3.22 (t, 2H), 3.59-3.63 (t, 2H), 7.25-7.38 (m,
5H).
Product (Table 3, entry 16): 1H NMR 200 MHz,
CDCl3): ꢀ 0.9-0.95 (t, 3H), 1.41-1.55 (m, 4H), 3.35-3.42 (t,
2H).
Product (Table 3, entry 17): 1H NMR 200 MHz,
CDCl3): ꢀ 1.51-1.58 (m, 3H), 1.75-1.90 (m, 7H), 3.31-3.33
(t, 2H), 3.57-3.58 (t, 2H), 3.60-3.75 (m, 2H), 4.68 (dd, 1H).
To silica gel (40 g) and dry toluene (80 mL) in a round
bottomed flask equipped with a condenser and a drying tube,
was added phosphorus tribromide (75 g, 0.21 mol) and re-
fluxed for 18 h. After cooling, the product was filtered and
washed, first with dry 1,4-dioxane (2 x 20 mL) and then with
dichloromethane (2 x 20 mL). The yellowish product was
kept in dessicator. The amount of bromosilyl group (2.2
mmole of Br/ g silica) was determined by a standard method
[18, 20].
Product (Table 3, entry 18): 1H NMR 200 MHz,
CDCl3): ꢀ 3.43-3.68 (d, 2H), 4.61-4.67 (t, 1H), 7.43-7.47 (m,
5H).
A Typical Procedure for the Conversion of Benzyl Alco-
hol to Benzyl Bromide
To a round bottom flask contain a stirring mixture of sil-
ica bromide (1 g, 2.2 mmol Br/ g silica) in dry CH2Cl2 (10
mL) at room temperature, was added benzyl alcohol (0.108
g, 1 mmol). After 3 min, GC analysis showed the completion
of the reaction. The reaction mixture was filtered and the
solvent was evaporated under vacuum. Benzyl bromide was
obtained as a colorless liquid (0.167 g, 97%, bp 195-196.5
oC, lit.20 bp 196-198 oC).
CONFLICT OF INTEREST
The author(s) confirm that this article content has no con-
flicts of interest.
ACKNOWLEDGEMENTS
Declared none.
1H NMR data for selected compounds
Product (Table 3, entry 1): 1H NMR 200 MHz, CDCl3):
ꢀ 4.28-4.29 (s, 2H), 7.25-7.39 (m, 5H).
REFERENCES
[1]
[2]
[3]
[4]
Merrifield, R.B. Solid phase peptide synthesis. I. The synthesis of a
tetrapeptide. J. Am. Chem. Soc., 1963, 85, 2149-2154.
Letsinger R.L.; Mahade, Van V. Oligonucleotide synthesis on a
polymer support. J. Am. Chem. Soc., 1965, 87, 3526-3527.
Erickson B.W.; Merrifield, R.B. In The proteins; Neurath, H.; Hill,
R. L., eds.; Academic Press: New York, 1976, 2, 256-527.
Fridkin, M.; Patchornik,A,; Katchalski, E. Use of polymers as
chemical reagents. I. Preparation of peptides. J. Am. Chem. Soc.,
1966, 88, 3164-3165.
2H), 6.87-7.18 (m, 4H).
Product (Table 3, entry 3): 1H NMR 200 MHz, CDCl3):
ꢀ 2.17 (s, 3H), 4.26 (s, 2H), 7.32-7.39 (m, 4H).
Product (Table 3, entry 4): 1H NMR 200 MHz, CDCl3):
ꢀ 4.26 (s, 2H), 7.45-7.48 (m, 4H).
Product (Table 3, entry 5): 1H NMR 200 MHz, CDCl3):
ꢀ 4.28 (s, 2H), 7.34-8.05 (m, 4H).
Product (Table 3, entry 6): 1H NMR 200 MHz, CDCl3):
ꢀ 6.28 (s, 1H), 7.23-7.47 (m, 10H).
Product (Table 3, entry 7): 1H NMR 200 MHz, CDCl3):
ꢀ 3.19-3.22 (t, 2H), 3.59-3.63 (t, 2H), 7.25-7.38 (m, 5H).
Product (Table 3, entry 8): 1H NMR 200 MHz, CDCl3):
ꢀ 2.09-2.10 (d, 3H), 5.24-5.28 (q, 1H), 7.29-7.50 (m, 5H).
Product (Table 3, entry 9): 1H NMR 200 MHz, CDCl3):
ꢀ 3.55-3.58 (t, 2H), 4.09-4.11 (t, 2H), 6.94-7.02 (m, 5H).
Product (Table 3, entry 10): 1H NMR 200 MHz,
CDCl3): ꢀ 3.71-3.77 (d, 2H), 6.55-6.57 (d, 1H), 7.16-7.19 (tt,
1H), 7.32-7.74 (m, 5H).
Product (Table 3, entry 11): 1H NMR 200 MHz,
CDCl3): ꢀ 3.70-3.72 (d, 2H), 4.99-5.02 (m, 1H), 7.01-7.06
(m, 1H).
Product (Table 3, entry 12): 1H NMR 200 MHz,
CDCl3): 1.40-1.58 (m, 4H), 1.80-1.89 (m, 6H), 4.05-4.09 (m,
1H).
[5]
(a) Camps, F.; Castells, J.; Font, J.; Vela, F.; Organic syntheses
with functionalized polymers: II. Wittig reaction with polystyryl-p-
diphenylphosphoranes. Tetrahedron Lett., 1971, 12, 1715-1716. (b)
Frechet, J.M.J.; Haque, K.E.; Polymeric reagents. Preparation of
resins containing polyvinylperbenzoic acid units. Macromolecules,
1975, 8, 130-134.
[7]
(a) Fridkin, M.; Patchornik, A.; Katchalski, A. A Synthesis of
cyclic peptides utilizing high molecular weight carriers. J. Am.
Chem. Soc., 1965, 87, 4646-4648.
[8]
Jayalekshmy, P.; Mazur, P.; Pseudodilution, S. The solid-phase
immobilization of benzyne. J. Am. Chem. Soc., 1976, 89, 6710-
6711.
[9]
Harrison, I.T.; Harrison, S. Synthesis of a stable complex of a
macrocycle and a threaded chain. J. Am. Chem. Soc., 1967, 89,
5723-5724.
[10]
Kraus, M.K.; Patchornik, A. Directed mixed ester condensation of
two acids bound to a common polymer backbone. J. Am. Chem.
Soc., 1971, 93, 7325-7327.
[11]
[12]
Kawama, M.; Emoto, S. Asymmetric synthesis on an insoluble
polymer support. Tetrahedron Lett.,1972, 13, 4855-4858.
Letsinger, R.L.; Kornet M.J.; Mahadevan, V.; Jerina, D.M.
Reactions on polymer supports. J. Am. Chem. Soc., 1964, 86, 5163-
5165.
[13]
(a) Crosby, G.A.; Weinshenker, N.M.; Uh, H.S. Polymeric rea-
gents. III. Synthesis of an insoluble polymeric thioanisole and its
utilization for the oxidation of alcohols. J. Am. Chem. Soc., 1975,
7, 2232-2235.