N-Phenylacetyl derivative

Cephalosporin C, 7-ACA and related compounds converted to N-phenylacetyl derivatives by spraying dried chromatogram with pyridine in 50% acetone (v/v) until barely damp. Then, lightly spray with 2% (w/v) phenylacetyl chloride in acetone, and again with the pyridine solution until a spot of bromocresol green placed on the paper immediately turns blue (pH 5.0). Dry in air 3-5 min and bioautograph vs. Staphylococcus aureus (Oxford strain N.C.T.C. 6571)... 

Some use has the been made of the N-Grignard derivative of carbazole phenylacetyl (from the acid chloride), ethoxycarbonylcarbonyl, acetyl and 5-bromopent-4-enoyl, and various a-aminoacyl derivatives, (all... 

Cephalosporin C, which contains a dihydrothiazine-j8-lactam ring system, shows at least 10% of the activity of cephalosporin N against Staph, aureus and induces the formation of the enzyme penicillinase by Staph, aureus and Bacillus cereus. This may be attributed to the fact that the stereochemistry of a major part of the cephalosporin C nucleus is similar to that of 6-aminopenicillanic acid. The precise factors which determine the ability of a substance to act as an inducer of penicillinase are clearly different from those which make the substance a good substrate of the enzyme. The /9-lactam ring in cephalosporin C is insensitive to penicillinase. However, the affinity of a substance for a penicillinase varies with the source of the enzyme. Cephalosporin C acts as a competitive inhibitor of the action of penicillinase from Bacillus cereus, but not from Staph, aureus, on benzylpenicillin. In contrast, the V-phenylacetyl derivative of 7-aminocephalosporanic acid is a powerful inhibitor of the staphylococcal enzyme12... 

A 3D model of the fibrinogen-derived (very late antigen-4, VLA-4) inhibitor 4-[N -(2-methylphenyl)ureido]phenylacetyl-Leu-Asp-Val was derived from the X-ray structure of the related integrin-binding region of the vascular cell adhesion molecule-1 (VCAM-1). A 3D pharmacophore was generated with the program Catalyst, and a 3D search was performed in 8624 molecules from... 

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