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11 Kusumoto S, and Fukase K. inventors; Jpn. Kokai Tokkyo Koho JP
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12 Kusumoto S, and Fukase K. inventors; Jpn. Kokai Tokkyo Koho JP
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In the past a number of other cleavage
protocols have been developed and examined in orthogonal protecting
group strategies:
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13i Kariyone K, and Yazawa T. inventors; Japan.
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16 Analogous preparation to the oxidation
of Wang resin is described by: Yan B.
Sun Q.
Wareing JR.
Jewell CF.
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Frechet JM.
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18 All resins prepared have been characterized
by IR spectro-
scopy and by elemental analysis before and
after immobili-zation [resin 1:
nitrogen analysis (route A), bromine and nitrogen analysis (route
B); resin 2: chlorine and nitrogen analysis] as
well as Fmoc-calibration for resin 1.
The structures of all non-polymeric
compounds have been characterized by NMR, IR and elemental analysis
or HRMS. The synthesis of compound 12 was
carried out as follows:
19a PPh3 (6
equiv), CCl4 (3 equiv), -20 °C,
25 min to 0 °C, 16 h, CH2Cl2,
92%;
19b
n-BuLi
(1.6 M solution in hexane, 2 equiv), -78 °C,
5 h, THF, 71%;
19c
n-BuLi
(1.6 M solution in hexane, 1.1 equiv), -78 °C
to r.t., 19.5 h, THF, 74%;
19d DIBALH (1 M in Toluol,
2 equiv), -78 °C to r.t., 16 h, quant.
Compound 12: 1H NMR (200 MHz,
CDCl3): δ [ppm] = 7.43-7.29
(m, 7 H, C-Harom.), 6.92-6.87 (m, 2
H, C-Harom.), 5.04 (s, 2 H, O-CH2),
4.46 (s, 2 H, CH2-OH), 1.78 (br s, 1 H, CH2-OH). 13C
NMR (50.3 MHz, CDCl3): δ [ppm] = 158.97
(O-Carom.), 136.56 (CH2-Carom.),
133.22, 128.66, 128.14, 127.50, 114.89 (Carom.), 86.00
(CºC), 85.64 (CºC), 70.05 (CH2-OBn),
51.73 (CH2-OH); one quaternary signal of the
aromatic region is overlapped by the adjacent tertiary signal. Elemental
analysis: C16H14O2 (238.27 g/mol)
calcd: C, 80.65; H, 5.92. Found: C, 80.58; H, 6.05. MS (FD): m/z = 238.5 (100.00),
239.5 (16.15), 240.6 (1.60).
20 Although the solution-phase reaction
conditions were not directly applicable to the solid support, the
combined procedures proved to be advantageous during characterization
of the resins by IR-spectroscopy: Grice P.
Leuch AG.
Ley SV.
Massi A.
Mynett DM.
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2000,
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491
21
Chan KS.
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22
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23a
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Crisp GT.
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For example:
24a
Thorand S.
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24b
Glase SA.
Akunne HC.
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25 The in situ deprotection protocol
of Y. Fukase, K. Fukase, S. Kusumoto,
[10]
when
applied to propargyloxycarbonyl-protected phenylalanine methylester
on 1.5 mmol scale, resulted in a product mixture and unsatisfactory
product purity.
26
Nicholas KM.
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