77982-91-3Relevant articles and documents
New route to 3-(substituted) methyl 1-oxa- and (1-thia)cephems from 3-exomethylene intermediates via sulfenyl chloride adducts
Aoki,Konoike,Itani,et al.
, p. 2515 - 2526 (2007/10/02)
Addition of methane- and benzenesulfenyl chlorides to 3-exomethylene-1-oxacephams 10 and 14 gave 3β-sulfenyl-3α-chloromethyl adducts 11 and 15. Nucleophilic substitution of the adducts proceeded facilely to afford compounds 18-23, which were converted into Δ3-dervatives 26 and 27 by oxidative elimination. This new route, as illustrated by the sequence 6 → 7 → 8 → 3, has an essential advantage in using the saturated intermediated 7 and 8 with a stabler β-lactam ring which is compatible in nucleophilic substitution, alkaline ester hydrolysis and further manipulations. These synthetic features are well demonstrated by successful synthesis of 1-oxacefamandol 35 and 7β-(2-thienylacetyl-amino)-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-ceph em-4-carboxylic acid (45).
SYNTHESIS OF 1-OXA ANALOGUES OF NATURALLY OCCURRING CEPHALOSPORINS AND CEPHAMYCINS
Sendo, Yuji,Konoike, Toshiro,Murakami, Masayuki,Yoshioka, Mitsuru
, p. 599 - 603 (2007/10/02)
The title compounds 15a-c and 16a-c were synthesized from a 3-exomethylene-1-oxacepham compound 4.Its chlorohydroxylation provided a key intermediate 5e in synthesis of the 3'-oxygen-functionalized 1-oxacephems.