· (MW 149.40)
(formation of 2,2,2-trichloroethyl esters and amides;2 protection of phosphoryl groups in nucleotide synthesis5)
Physical Data: mp 17 °C; bp 150 °C; d 1.557 g cm-3.
Solubility: sol common organic solvents.
Form Supplied in: clear liquid, widely available.
Handling, Storage, and Precautions: poisonous liquid when absorbed by intravenous or intraperitoneal routes. Do not mix with strong alkali solutions.1
The 2,2,2-trichloroethyl moiety is a useful protecting group for acids since it is both formed and cleaved under very mild conditions (eq 1).2 Woodward exploited the facile removal of this group in his classic synthesis of cephalasporin C (eq 2).3
These acetals are most conveniently formed by exchange with dialkyl acetals. They are cleaved under conditions similar to the above esters (eq 3).4
In various instances the trichloroethyl group has been utilized in nucleotide chemistry for the protection of phosphoryl groups (eqs 4-6). In this seminal example the mononucleotide of thymidine-3´-O-acetate was formed.5a Selectively formed phosphotriesters have been converted to diesters under similarly mild conditions.5 See also 2,2,2-Trichloroethyl Phosphorodichloridate for related chemistry.
- 1. Sax, N. I.; Lewis, R. J. Dangerous Properties of Industrial Materials, 7th ed.; Van Nostrand Reinhold: New York, 1989; Vol 3, p 3328.
- 2. (a) Greene, T. W.; Wuts, P. G. M. Protective Groups in Organic Synthesis, 2nd ed.; Wiley: New York, 1991; p 240 and references cited therein. (b) Marinier, B.; Kim, Y. C.; Navarre, J.-M. CJC 1973, 51, 208. (c) Eckert, H.; Ugi, I. AG(E) 1976, 15, 681.
- 3. Woodward, R. B.; Huesler, K.; Gosteli, J.; Naegeli, P.; Oppolzer, W.; Ramage, R.; Ranganathan, S.; Vorbrüggen, H. JACS 1966, 88, 852.
- 4. (a) Greene, T. W.; Wuts, P. G. M. Ref. 2(a), p 183. (b) Isodor, J. L.; Carlson, R. M. JOC 1973, 38, 554.
- 5. (a) Eckstein, F. AG(E) 1965, 10, 876. (b) Werstiuk, E. S.; Neilson, T. CJC 1972, 50, 1283. (c) Owen, G. R.; Reese, C. B.; Ransom, C. J.; van Boom, J. H.; Hercheid, J. D. H. S 1974, 704. (d) van Boom, J. H.; Burgers, P. M. J.; van Deursen, P. H. TL 1976, 869. (e) Sawai, H.; Lesiak, K.; Imai, J.; Torrence, P. F. JMC 1985, 28, 1376.
Patrick D. Lowder
Rhône-Poulenc Agricultural Products, Research Triangle Park, NC, USA
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