Beecham Group Plc

Stephen T Carpenter

Derek R Buckle

A process for preparing a compound of formula (I) ##STR1## wherein X phenyl optionally substituted by one halogen, C.sub.1-4 alkyl or C.sub.1-4 alkoxy; or pyridyl; R.sup.1 is hydrogen or C.sub.1-6 alkyl; and n is an integer of from 1 to 6; which process comprises, cyclizing a compound of formula (II): ##STR2## wherein X, R.sup.1 and n are as defined in relation to formula (I); Y is an hydroxy or an acid activating group and R.sup.x is hydrogen or an N- protecting group and thereafter if desired carrying out one or more of the following steps: (i) removing any protecting group R.sup.x, (ii) preparing a salt of the compound of formula (I).

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Stephen T Carpenter