Processes for production of intermediates for 2-alkyl cephem compounds

A process for preparing a compound of formula (II) or a salt thereof,

• wherein,
• R5A is lower alkyl;
• Y is halogen;
• L is lower alkylene or lower alkenylene;
• P1 is acyl, phthalimide, optionally substituted aralkanoyl, optionally substituted aralkyl, optionally substituted arylimino, optionally substituted lower alkylimino, or tri-lower alkylsilyl;
• and
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups,
• which comprises:
• reduction of a compound of formula (XVI)′ or a salt thereof,
• wherein,
• R5 is hydrogen or lower alkyl;
• and
• the wavy line means that the bond is in cis or trans configuration, or a mixture thereof,
• provided that -L-Y is not —CH2—O—C(═O)—CH3;
• and
• the other symbols are as defined above,
• to give the compound of the formula (II) or a salt thereof.

A process for preparing a compound of formula (III) or a salt thereof,

• wherein,
• R5A is lower alkyl;
• Y is halogen;
• L is lower alkylene or lower alkenylene;
• P1 is acyl, phthalimide, optionally substituted aralkanoyl, optionally substituted aralkyl, optionally substituted arylimino, optionally substituted lower alkylimino, or tri-lower alkylsilyl;
• and
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups,
• which comprises:
• reduction of a compound of formula (II) or a salt thereof,
• wherein each symbol is as defined above,
• to give the compound of the formula (III) or a salt thereof.

A compound of formula (II) or a salt thereof,

• wherein
• R5A is lower alkyl;
• Y is halogen;
• L is lower alkylene or lower alkenylene;
• P1 is acyl, phthalimide, optionally substituted aralkanoyl, optionally substituted aralkyl, optionally substituted arylimino, optionally substituted lower alkylimino, or tri-lower alkylsilyl;
• and
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups.

A compound of the formula (III) or a salt thereof,

• wherein
• R5A is lower alkyl;
• Y is halogen;
• L is lower alkylene or lower alkenylene;
• P1 is acyl, phthalimide, optionally substituted aralkanoyl, optionally substituted aralkyl, optionally substituted arylimino, optionally substituted lower alkylimino, or tri-lower alkylsilyl;
• and
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups.

A compound of the formula (VII) or a salt thereof,

• wherein
• R5A is lower alkyl;
• Y is halogen;
• L is lower alkylene or lower alkenylene;
• and
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups.

A compound of the formula (XVI) or a salt thereof,

• wherein
• L is lower alkylene or lower alkenylene;
• Y is halogen;
• R5 is hydrogen;
• P1 is acyl, phthalimide, optionally substituted aralkanoyl, optionally substituted aralkyl, optionally substituted arylimino, optionally substituted lower alkylimino, or tri-lower alkylsilyl;
• P2 is lower alkyl, alkylcarbonyloxymethyl in which the alkyl group is lower alkyl, optionally substituted aralkyl, or silyl groups;
• and
• the wavy line means that the bond is in cis or trans configuration, or a mixture thereof.