Abstract: Process for preparing pyrrolidinone derivatives of (1) ##STR1## in which R is hydrogen, alkyl or acyl characterized in that a compound of (2) ##STR2## wherein R.sup.1 is hydrogen and R.sup.2 is benzyl or substituted benzyl, or R.sup.1 and R.sup.2 can together form a group ##STR3## where R.sup.4 and R.sup.5 are independently hydrogen, alkyl, phenyl or optionally substituted aryl or together are 1,4-butylene or 1,5-pentylene; R.sup.3 is hydrogen or straight or branched alkyl of 1 to 4 carbon atoms; and X is alkyl subjected to N-deprotection and the deprotected intermediate is cyclized intramolecularly.The deprotected intermediates can be isolated as acid-addition salts.

Abstract: A process for preparing compounds (1) ##STR1## where Y is NR.sup.1 R.sup.2 or OR, R.sup.1 and R.sup.2 are hydrogen or C.sub.1-3 alkyl, and R is C.sub.1-3 alkyl, which comprises protecting the hydroxy group of a compound (2) ##STR2## cyclizing the product under basic conditions and removing the protecting group.

Abstract: A process for preparing compounds (1) ##STR1## where Y is NR.sup.1 R.sup.2 or OR, R.sup.1 and R.sup.2 are hydrogen or C.sub.1-3 alkyl, and R is C.sub.1-3 alkyl, which comprises protecting the hydroxy group of a compound (2) ##STR2## cyclising the product under basic conditions and removing the protecting group.