Ethyl carbamate-derived sulfones

Table 3 Bi(OTf)3-catalyzed allylation of ethyl carbamate-derived sulfones 3 with allyltri-methylsilane...

Additional semipermeable membrane—forming polymers are selected from the group consisting of acetaldehyde dimethyl cellulose acetate, cellulose acetate ethyl carbamate, cellulose dimethylamino acetate, semipermeable polyamides, semipermeable polyurethanes, or semipermeable sulfonated polystyrenes. Semipermeable cross-linked selectively permeable polymers formed by coprecipitation of a polyanion and a polycation also can be used for this purpose.22 23 Other polymer materials such as lightly cross-linked polystyrene derivatives, semipermeable cross-linked poly(sodium styrene sulfonate), and semipermeable poly (vinylbenzyltrimethyl ammonium chloride) may be considered.24,25... 

Ethyl carbamate (urethan), another monofunctional alkylating agent, when administered intraperitoneally (100 mg/kg) will not have any noticeable effect on meiotic chromosomes. If the same dose is given to F2 male Armenian hamsters derived from grandsires treated with ethyl methane-sulfonate, totally different results are obtained—1 to 7 days after treatment there are no chromosome anomalies on day 8 the number of bivalents is reduced from 11 to ten and nine. In 80% of the spermatocytes ten bivalents can be encountered, and in about 10% of the spermatocytes nine bivalents are encountered. The reduction in the number of bivalents was due to associations of two and/or three bivalents. 

Optimization of the previously reported Mannich-type reaction of trimethyl (pent-2-en-3-yloxy)silane with the sulfone Is derived from phenyl acetaldehyde (Table 5, entry 11) led to the corresponding (3-amino ketone in a good yield with moderate diastereoselectivity (2 mol% Bi(0Tf)3-4H20, yield = 84%, 24v/24v syn/anti = 72 28) (Scheme 8). Reduction of the major diastereoisomer 24v with lithium tri-ferf-butoxyaluminohydride afforded 25 as the only one diastereoisomer. Further cyclization of the latter with NaH afforded 4-benzyl-6-ethyl-5-methyl-l,3-oxazinan-2-one 26. The relative configuration of the six-membered carbamate was established as cis-cis by NMR analysis. 

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