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Organic Synteses vol 70 - Meyers A.I.

Meyers A.I. , Boecman R.K. Organic Synteses vol 70 - John Wiley & Sons, 1992. - 163 p.
ISBN 0-471-57743
Download (direct link): organicsynthesesvol701992.pdf
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11. Commercially available anhydrous ether (obtained from Fisher Scientific Company) was used directly from a freshly opened can.
12. The product exhibits the following properties: mp (~ 4°C/min) 133-135°C
(darkens), 173°C (dec) (rapid); [a]D -15.8° (DMF, c 2.2); IR (Fluorolube mull) cm-1: 3040, 1833, 1547; 1H NMR (360 MHz, d7 DMF) S: 2.3 (s, 3 H, ArCth), 4.66 (m, 1 H, CHHO), 4.74 (m, 1 H, CHHO), 5.54 (dd, 1 H, J = 4.6, 6.5, CH), 7.15 (d, 2 H, J = 8, m-ArH), 7.64-7.7 (d, 2 H, J = 8, o-ArH); FAB MS (glycerol) m/z 260 (MH®). Anal. Calcd for C10H13NO5S: C, 46.32; H, 5.05; N, 5.40; S, 12.37. Found: C, 46.44; H, 5.14; N, 5.24;
S, 12.41.
Waste Disposal Information
All toxic materials were disposed of in accordance with "Prudent Practices for Disposal of Chemicals from Laboratories"; National Academy Press; Washington, DC, 1983.
3. Discussion
Recent work has shown that a large variety of carbon, nitrogen, oxygen, sulfur, and halogen nucleophiles attack chiral N-protected serine p-lactones at the p-carbon to give optically pure N-protected a-amino acids.2 4 However in certain cases (e.g., P-azidoalanine5) these products are unstable to most common deprotection conditions. The procedure given here describes the preparation of (S)-3-amino-2-oxetanone p-toluenesulfonic acid salt, a compound which reacts with a variety of nucleophiles to afford unprotected, optically pure a-amino acids directly (Scheme 1).6 This salt has a long shelf life (many months) at room temperature provided that it is stored dry. It reacts rapidly with water (t 1/2 ~ 2.5 hr in unbuffered water; 11/2 ~ 10 min in 50 mM potassium phosphate at pH 6.8). However, good nucleophiles such as thiols afford high yields of sulfur-containing amino acids in water if the pH is kept at 5.0-5.5.6 Since both enantiomers of serine are relatively inexpensive, and L-serine is readily available in isotopically labeled form, this approach should prove useful for syntheses of sensitive D-amino acids as well as for preparation of the labeled L-isomers.
1. Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada, T6G 2G2.
2. (a) Arnold, L. D.; Kalantar, T. H.; Vederas, J. C. J. Am. Chem. Soc. 1985, 107, 7105; (b) Arnold, L. D.; Drover, J. C. G.; Vederas, J. C. J. Am. Chem. Soc. 1987, 109, 4649.
3. Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2923.
4. See accompanying preparation of N“-(benzyloxycarbonyl)-p-(pyrazol-1-yl)-L-alanine. Pansare, S. V.; Huyer, G.; Arnold, L. D.; Vederas, J. C. Org. Synth. 1991, 70, 1.
5. Owais, W. M.; Rosichan, J. L.; Ronald, R. C.; Kleinhofs, A.; Ni!an, R. A. Mutat. Res. 1983, 118, 229.
6. Arnold, L. D.; May, R. G.; Vederas, J. C. J. Am. Chem. Soc. 1988, 110, 2237.
Scheme 1
V=.N NH2
Chemical Abstracts Nomenclature (Collective Index Number); (Registry Number)
N-tert-Butoxycarbonyl-L-serine p-lactone: Carbamic acid, (2-oxo-3-oxetanyl)-,
1,1-dimethylethyl ester, (S)- (11); (98541-64-1)
(S)-3-Amino-2-oxetanone p-toluenesulfoante: 2-Oxetanone, 3-amino-, (S)-,
4-methylbenzenesulfonate (12); (112839-95-9)
Triphenylphosphine: Phosphine, triphenyl- (8,9); (603-35-0)
Diethyl azodicarboxylate: Formic acid, azodi-, diethyl ester (8); Diazenedicarboxylic acid, diethyl ester (9); (1972-28-7)
N-tert-Butoxycarbonyl-L-serine: Serine, N-carboxy-, N-tert-butyl ester, L- (8); L-Serine, N[(1,1-dimethylethoxy)carbonyl]- (9); (3262-72-4) p-Toluenesulfonic acid monohydrate (8); Benzenesulfonic acid, 4-methyl-, monohydrate (9); (6192-52-5)
Trifluoroacetic acid: Acetic acid, trifluoro- (8,9); (76-05-1)
3-OXAZOLIDINECARBOXYLATE: A USEFUL SERINAL DERIVATIVE (3-Oxazolidinecarboxylic acid, 4-formyl-2,2-dimethyl-,
1,1-dimethyl ester, (S)- or (R)-)
A HO^Y'002'4 1 ■ Boc20 ^ HQ-^\^C02Me
NH2 2.CH3I NHBoc
о ил'лчУС°2Ме DMP ,*,C02Me
B. HO ^ cat. TsOH О I
c- °v T P'BAL r о T
'Boc '78 C 'Boc
Submitted by Philip Garner and Jung Min Park.1 Checked by Mayumi Takasu and Hisashi Yamamoto.
1. Procedure
A. N-[(1,1 -Dimethylethoxy)carbonyl]-L-serine methyl ester. A solution of di-tert-butyl dicarbonate [(Вос)гО] (78.4 g, 0.36 mol, Note 1) in dioxane (280 mL, Note 2) is added to an ice-cold, magnetically stirred solution of L-serine (31.7 g, 0.30 mol, Note 3) in 1 N sodium hydroxide (620 mL) by means of an addition funnel. The two-phase mixture is stirred at 5°C for 30 min, then allowed to warm to room temperature over 3.5 hr at which time TLC analysis shows the reaction to be complete (Note 4). The mixture is concentrated to half its original volume by rotary evaporation at 35°C, cooled in an
ice-water bath, acidified to pH 2-3 by the slow addition of 1 N potassium bisulfate (620 mL), and then extracted with ethyl acetate (3 x 1000 mL). The combined extracts are dried over magnesium sulfate, filtered and concentrated to give N-Boc-L-serine (63.0
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