Patent GB-878233-A (GB)
Title: Improvements in or relating to penicillins
Inventor: DOYLE FRANK PETER
IPC: C07D499/60
Filed: 1959-01-22
Abstract: Relates to penicillins of the general formula <FORM:0878233/IV (b)/1> wherein R1 and R2 are the same or different and are each a halogen atom or an alkyl, alkenyl, aryl, aralkyl, cycloalkyl or heterocyclic group which groups may be substituted, or R1 and R2 together with the carbon atom to which they are attached form an aromatic, cycloaliphatic or heterocyclic ring system, and R3 is any one of the groups defined under R1 and R2, or the group OR4 or SR4 where R4 is an alkyl, alkenyl, aryl, aralkyl or cycloalkyl group, and non-toxic salts thereof.  The Specification mentions a large number of penicillins of the above formula of which the following are typical examples: triphenylmethyl, triethyl methyl, tri-n-propyl methyl, a -phenoxy isopropyl, mono-p-hydroxytriphenylmethyl, a ,a -di-n-propylbenzyl, a ,a -diphenylethyl, a -methoxydiphenylmethyl, a -ethylthiodiphenylmethyl, a -phenylthioisopropyl, a ,a -diphenyl-2-thienyl methyl, 1 - phenylcyclopentyl, 9-p-methoxyphenyl-9-fluorenyl and trichlormethyl penicillin.  The penicillins may be prepared by reacting 6-aminopenicillanic acid or a fermentation liquor containing 6-aminopenicillanic acid obtained by growing a penicillin-producing mould in a nutrient medium, with or without subsequent partial purification, with an acid chloride, bromide, anhydride or mixed anhydride derived from a tri-substituted acetic acid of the general formula  <FORM:0878233/IV (b)/2> Acid chlorides for use in the above reaction may be prepared by treating the corresponding acids with thionyl chloride with or without the presence of pyridine as catalyst, acid chlorides referred to being mono-p-hydroxytriphenyl acetyl, mono - p - methylthiotriphenylacetyl, mono-p-methylsulphonyltriphenylacetyl, a  - (4-methyl-1-naphthyl) diphenyl acetyl, tri-(p-methoxyphenyl) acetyl, a ,a  - diphenylvaleryl, a ,a  - diphenylhexoyl, a ,a  - diphenylisovaleryl, a ,a  - dicyclohexylphenylacetyl, a  - methoxydiphenylacetyl, a -ethoxydiphenylacetyl, a -isopropoxydiphenylacetyl, a -butoxydiphenylacetyl, a -ethylthiodiphenylacetyl, a -n-propylthiodiphenylacetyl, a -n-butylthiodiphenylacetyl, a -isopropylthiodiphenylacetyl, a  - sec.butylthiodiphenylacetyl, a -benzylthiodiphenylacetyl, a -phenylthiodiphenylacetyl, a -p-tolylthiodiphenylacetyl, a -ethyl-a -phenylthiobutyryl, a -propyl-a -phenylthiovaleryl and a  - 2 - thionyldiphenylacetyl chloride.  Tri-(p-methoxyphenyl) acetic acid may be prepared by condensing anisilic acid with anisole in the presence of sulphuric and acetic acids.  a ,a -diphenyl hexoic acid may be obtained by alkylating diphenylacetonitrile with butyl bromide in the presence of sodamide and hydrolysing the resulting a ,a -diphenyl hexonitrile with alcoholic potassium hydroxide.  a -n-propylthiodiphenylacetic acid may be prepared by condensing benzylic acid with n-propyl mercaptan.  The isopropyl compound may be obtained similarly from isopropyl mercaptan.  a -ethyl-a -phenylthiobutyric acid may be obtained by the action of thiophenol on ethyl a -bromo-a -ethyl butyrate in the presence of aqueous alcoholic sodium hydroxide.  a -propyl-a -phenylthiovaleric acid may be obtained by the action of thiophenol on ethyl a -bromo-a -propyl valerate in the presence of aqueous alcoholic sodium hydroxide.ALSO:A pharmaceutical composition comprises a pharmaceutical carrier and a penicillin of the general formula <FORM:0878233/VI/1> where R1 and R2 are the same or different and are each a halogen atom or an alkyl, alkenyl, aryl, aralkyl, cycloalkyl or heterocyclic group which groups may be substituted, or R1 and R2 together with the carbon atom to which they are attached form an aromatic, cycloaliphatic or heterocyclic ring system, and R3 is any one of the groups defined under R1 and R2, or the group OR4 or SR4 where R4 is an alkyl, alkenyl, aryl, aralkyl or cycloalkyl group, or a non-toxic salt thereof (see Group IV (b)).