Chemistry of Cephalosporin Antibiotics. XIII. Ilesac-etoxycephalosporins. The Synthesis o f Cephalexin' and Soine Analogs
hCWt\lt I The cephalosporiii antibiotic-, member- of the 8NHR h t a m clas.: of antibioticq, are of interest becituqe of their marlied bactericidal activity itlid excellent C,H,CHCOSH-~' Pd-BaSO, stability t o t h r :tctiori of :icid and peiiicilliiiav.2 Recently. Spericei,. P f nl.,J of this 1:iboratory reported 0 of ;4cveraI j,heilylglycyl-T-nIninoccphnloCOLH deriv:itives. I n addition t o t h e nhoveInelit ioned features. the p:ireiit coiiipouid cephaloI. R = H 11, R = Boc characterized by :I broad -pectriiiii of d high potency :igaiiibt gram-negative NHR orgitiiiqm;4. Cephriloglyciri also TI well a b s o r b d At least two following oral administration to mice of these characteri-tics, the activity against gr:tmnegative orgai1i.m- arid the or:tl :horptivity, : t r ~ CO,H :tisociated with the phcnylglyciiic s i d c chain. I t vas of interest. thcrc~forc~. t o exaniirlci the cffect t h c phcnIIIa, R = Boc Va. R = H ylglycyl group niiglit have o i l thc bio1ogic:tl x t i v i t y of cephalosporin- derived from nuclei other t h i the ~ ~ ~ € ~I1 I , V l cvqhaloglyciii nucleus, T-:iniinocephalospor~~iiic2icitl. One riiicleuh that 11c' have chowii to -tudy i+ i-amiiioNH-BOC clesacetoxycephalosporaiiic acid (T-A\IX'Al) I BuOCOCl 7 ADCA There \wre several logical hynthetic routes t o t h c CHC02H Et z clesired clcrivntivcls, : t i i d TW li:~vc txamiried two R Yynthehes that :ire of gericwl applicability. Iri thti VH-BOC first method w c ~ c1e:~vccl tlir acetouyl giwnp froin cqhuloglyciii (I) hydrogeiiolytic~iily 0 1 . mor('
