Toward the Development of a Cephalosporin-Based Dual-Release Prodrug for Use in ADEPT
摘要:
In previous work we have shown that a cephalosporin structure bearing an S-aminosulfenimine at the 7-position behaved as a beta-lactamase-dependent dual-release prodrug. Scission of the beta-lactam ring of such a structure led to the rapid loss of the sulfur-attached side chain moiety via an intramolecular displacement, while the T-group was lost via the well-established elimination process at that position. In the present work we report on an evaluation of the scope and limitations of exploiting the S-aminosulfenimine functionality to generate a cephalosporin-based prodrug incorporating two biologically active components. Starting from 7-ACA, a viable synthetic cycle was put in place that avoided formation of the Delta(2) isomer throughout and that allowed incorporation of aminoglutethimide at the 3'-position and of a tosyl S-aminosulfenimine at the 7-position. The direct incorporation of a biologically active sulfonamide (ethoxzolamide) or a sulfamate (coumate) at this latter position was not achieved as a result of the difficulty of generating the corresponding sulfur diimides. An indirect route for the formation of an S-aminosulfenimine was put in place, as was a general method of alkylation (Mitsunobu reaction) of the tosyl S-ammosulfenimine following its incorporation.
Toward the Development of a Cephalosporin-Based Dual-Release Prodrug for Use in ADEPT
摘要:
In previous work we have shown that a cephalosporin structure bearing an S-aminosulfenimine at the 7-position behaved as a beta-lactamase-dependent dual-release prodrug. Scission of the beta-lactam ring of such a structure led to the rapid loss of the sulfur-attached side chain moiety via an intramolecular displacement, while the T-group was lost via the well-established elimination process at that position. In the present work we report on an evaluation of the scope and limitations of exploiting the S-aminosulfenimine functionality to generate a cephalosporin-based prodrug incorporating two biologically active components. Starting from 7-ACA, a viable synthetic cycle was put in place that avoided formation of the Delta(2) isomer throughout and that allowed incorporation of aminoglutethimide at the 3'-position and of a tosyl S-aminosulfenimine at the 7-position. The direct incorporation of a biologically active sulfonamide (ethoxzolamide) or a sulfamate (coumate) at this latter position was not achieved as a result of the difficulty of generating the corresponding sulfur diimides. An indirect route for the formation of an S-aminosulfenimine was put in place, as was a general method of alkylation (Mitsunobu reaction) of the tosyl S-ammosulfenimine following its incorporation.
Sulfonamides, such as N-[N-(2-chloro-5-(trifluoromethyl)phenyl]-N-[2,4-dinitro-6-(trifluoromethy l)phenyl]aminothio]-N,4-dimethylbenzenesulfonamide, are useful for control of arthropod pests of plants and animals and fungus disease of plants.
Non-staining vulcanized elastomeric composition and tires having sidewalls comprising said composition
申请人:THE GOODYEAR TIRE & RUBBER COMPANY
公开号:EP0240448A2
公开(公告)日:1987-10-07
A vulcanizable composition which comprises diene rubber, an EPDM that has been modified to crosslink with the diene rubber, and a polymeric antidegradant, while being substantially free of staining antidegradants. This composition has particular utility in the sidewalls of tires.
The present invention reveals a polymer alloy which is comprised of (a) at least one highly unsaturated rubbery polymer which is covulcanized with at least one N-chlorothio-sulfonamide modified EPDM rubber and (b) at least one thermoplastic resin. A blend of polypropylene with nitrile rubber which has been cocured with an N-chlorothio-sulfonamide modified EPDM rubber is a representative example of such a polymer alloy.
N-halothiosulfonamide modified rubber products and process for preparing the same
申请人:EXXON CHEMICAL PATENTS INC.
公开号:EP0430529A2
公开(公告)日:1991-06-05
N-halothiosulfonamide-modified rubber products are provided. The modified rubber products are prepared by reaction of a rubber, such as a butyl rubber or a halogenated butyl rubber, with a N-halothiosulfonamide in the absence or in the presence of a catalyst.
N-halothiosulfonamide-modified non-rubbery thermoplastic polyolefins are provided. The modified polyolefin products are prepared by reaction of a non-rubbery thermoplastic polyolefin polymer with an N-halothiosulfonamide in the absence or, preferably, in the presence of a catalyst. The preferred catalyst for use in the preparation of these products are salts of weak acids of specified metals.