2,2,2-Trichloroethyl carbamates

Zn, THF-H2O, pH 4.2, 25°, 4 h. The authors suggest that selective cleavage should be possible by this method since at pH 4.2, 25°, 2,2,2-trichlo-roethyl esters are cleaved in 10 min, 2,2,2-trichloroethyl carbamates are cleaved in 30 min, and the 2,2,2-trichloroethyl carbonate of estrone, formed in 87% yield from estrone and the acid chloride, is cleaved in 4 h (97% yield). 

Trichloroethyl Carbamate (Troc-NR2) R2NCO2CH2CCI3 Formation/Cleavage ... 

Methyl Carbamate 5. 9-Fluorenylmethyl Carbamate 8. 2,2,2-Trichloroethyl Carbamate 11. 2-Trimethylsilylethyl Carbamate 16. 1,1-Dimethylpropynyl Carbamate 20. 1-Methyl-1-phenylethyI Carbamate 22. 1-Methyl-l-(4-biphenylyl)ethyl Carbamate 24. 1,1 -Dimethy 1-2-haloethyl Carbamate 26. l,l-Dimethyl-2-cyanoethyl Carbamate 28. r-Butyl Carbamate... 

The first reported synthesis of cyprodime utilized as starting material the highly potent opioid agonist 4,14/J-dimethoxy-iV-methylmorphinan-6-one (24) which is available from oxymorphone in six steps [72]. A-Demethyla-tion was achieved with the 2,2,2-trichloroethyl carbamate to give (25) which was cleaved reductively with activated zinc and ammonium chloride to afford /V-normorphinan (26). Alkylation with cyclopropylmethyl chloride provided cyprodime (23). 

Trichloroethyl Carbamate (Troc-NRz) Cl3CCH20C(0)NR2) (Chart 8) Formation... 

FIGURE 9.10 Derivatization of TMA and DMA. DMA and TMA were derivatized to form A,A-dimethyl-p-toluene sulfonamide and Af,A-dimethyl-2,2,2-trichloroethyl carbamate. These were isolated using gas chromatography and fragmented using electron impact ionization. 

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