| 摘要 |
<p>1,141,293. Cephemoic acids; substituted diazomethane. GLAXO LABORATORIES Ltd. 10 Dec., 1965 [23 Dec., 1964], No. 52288/64. Headings C2A and C2C. [Also in Division A5] Cephemoic acids of formula where R<SP>1</SP> is a carboxylic acyl and R<SP>2</SP> is carboxylic acyl which may be the same or different from R<SP>1</SP>, are prepared from the corresponding 3-hydroxymethyl analogue by (a) aralkylating the 4-carboxy group, (b) acylating the 3- hydroxymethyl group, and (c) removing the aralkyl group from the 4-carbaralkoxy group. Aralkylation (a) is by means of an aryldiazoalkane e.g. aryldiazomethane or an aryl chloride or bromide with an alkali metal salt of the 3-hydroxymethyl analogue. Acylation (b) is with an acid chloride, acid anhydride or mixed acid anhydride in the presence of an organic base. Removal of the protecting group (c) is by acid hydrolysis or hydrogenolysis e.g. hydrogenation in the presence of a palladium catalyst. The invention also relates to (A) esters of 3-hydroxymethyl derivatives of cephemoic acid of formula where R<SP>1</SP> is carboxylic acyl and R<SP>3</SP> is aralkyl; and (B) cephemoic acids of formula wherein R<SP>2</SP> is carboxylic acyl other than acetyl and R<SP>4</SP> is benzyl, and non-toxic salts thereof. Typical compounds are 3-phenylacetoxymethyl - 7 - phenylacetamido - ceph - 3 - emoic - acid, 3 - (4 - methylbenzoyloxymethyl) - 7 - phenylacetamido - ceph - 3 - emoic acid and 3-propionoxymethyl-7-phenylacetamidoceph-3-emoic acid. The compounds have antibacterial activity and are used medicinally (see Division A5). Bis-(4-methoxy phenyl) diazomethane is prepared by treating bis-(4-methoxy) benzophenone hydrazone with KOH and mercuric oxide in ether and methanol containing a little water.</p> |
