and r 1 each represents a hydrogen atom an alkyl or arylsulfonyl group preferably having up to 20 carbon atoms and more preferably a phenylsulfonyl group or a substituted phenylsulfonyl group having a total hammett 39 s substituent constant of 0 5 or more or an acyl group preferably having up to 20 carbon atoms and more preferably a benzoyl group a substituted benzoyl group having a total hammett 39 s substituent constant of 0 5 or more or a substituted or unsubstituted straight or branched chain or cyclic aliphatic acyl group the substituent including for example a halogen atom an ether group a sulfonamido group a carbonamido group a hydroxyl group a carboxyl group a sulfonic acid group etc the most preferred among these groups as represented by r 0 or r 1 is a hydrogen atom specific but non limiting examples of the compounds represented by the formula i are shown below str4 in the above described formula ii the blocking group represented by c a is conventionally known and includes for example blocking groups such as an acyl group a sulfonyl group etc as described in japanese patent publication no 9968 73 japanese patent application opi nos 8828 77 and 82834 82 and u s pat no 3 311 476 and japanese patent publication no 44805 72 corresponding to u s pat no 3 615 617 blocking groups capable of releasing a development restrainer upon the so called reverse michael reaction as described in japanese patent publication nos 17369 80 9696 80 and 34927 80 corresponding to u s pat nos 3 888 677 3.